Biotechnology Forums - Diseases and Diagnostics

How accurate tridot test kit are?

Fri, 29 Oct 2021 10:50:01 +0000

How reliable is the TRI-DOT HIV test? Is there a case where a person is infected but the TRI-DOT showed a negative result? Recently I have gotten to know through my diagnostic lab colleague about this. he is currently using HIV Test Kit provided by a company J Mitra. According to him, the results are good & accurate. just want to suggest.

Triple-negative breast cancer

Fri, 26 Jan 2018 20:31:23 +0000

Cell-free DNA as prognostic factor of metastasic TNBC? Liquid biopsy must be the future.

I FAINTED during the BLOOD DRAW today! Ever happened to you?

Tue, 24 Oct 2017 08:45:51 +0000

Today, my company conducted an initiative for employee health welfare, wherein a thorough physical and biochemical examination of each employee would be done.

There were a series of non-invasive tests conducted (parameters noted) for each employee (height, weight, body fat, visceral fat, BMI etc). I was more or less within 'normal' range, except for the blood pressure which was 103/72. And, when it came to blood tests, I fainted (literally blacked out) as soon as they pricked me for drawing blood. I didn't remember anything thereafter, until I woke up to the scene of whole staff surrounding me (I was made to lie down on the floor with my feet elevated). After waking up, I was back to normal (feeling little drained off energy though).

Upon some research I found out that it is Neurally Mediated Syncope (also referred to as vasovagal syncope or a vasovagal response) wherein one's blood pressure drops abruptly, and brain doesn't receive required amount of oxygen to stay active. Triggers are often anxiety/ emotional distress,or even a sight of blood during the blood draw (for me I wasn't looking at the blood being drawn; anxiety/ stress is something one can't be conclusive about).

I hope there is nothing serious associated with it. Anyone experienced similar episode?

SLEEP: Do you sleep enough? How much sleep do I need?

Sat, 30 Sep 2017 16:05:07 +0000

As per New York Academy of Sciences and CDC, modern world is suffering from the Sleep Deprivation epidemic. Everyone has a bare minimum requirement of sleep cycle to keep him/ her healthy. Here is a 2 min video that sheds light on the same.

Share it with everyone who you think badly needs some sleep in his / her life. Sleep well!!

DNA Surgery on Embryos to eliminate Diseases

Thu, 28 Sep 2017 19:49:31 +0000

Following is the Abstract of this research that involves the precise base editing (also called Chemical Surgery of DNA) in Human Embryos for curing Thalassemia.

Titled: Correction of β-thalassemia mutant by base editor in human embryos

Abstract: β-Thalassemia is a global health issue, caused by mutations in the HBB gene. Among these mutations, HBB −28 (A>G) mutations is one of the three most common mutations in China and Southeast Asia patients with β-thalassemia. Correcting this mutation in human embryos may prevent the disease being passed onto future generations and cure anemia. Here we report the first study using base editor (BE) system to correct disease mutant in human embryos. Firstly, we produced a 293T cell line with an exogenous HBB −28 (A>G) mutant fragment for gRNAs and targeting efficiency evaluation. Then we collected primary skin fibroblast cells from a β-thalassemia patient with HBB −28 (A>G) homozygous mutation. Data showed that base editor could precisely correct HBB −28 (A>G) mutation in the patient’s primary cells. To model homozygous mutation disease embryos, we constructed nuclear transfer embryos by fusing the lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes. Notably, the gene correction efficiency was over 23.0% in these embryos by base editor. Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%. In addition, we found that base editor variants, with narrowed deamination window, could promote G-to-A conversion at HBB −28 site precisely in human embryos. Collectively, this study demonstrated the feasibility of curing genetic disease in human somatic cells and embryos by base editor system.

Read the entire research at Journal of Protein & Cell

Dengue Antibodies Act as Vaccine Against Zika

Tue, 26 Sep 2017 14:20:35 +0000

Researchers from Imperial College London and Washington University in St Louis conducted an important experiment to test the impact of Antibodies taken from the patients infected with Dengue virus, on early stage Zika patients (in this case, a mouse model).

And, interestingly those antibodies not only prevented infection in Zika-infected mice, but also protected the fetus of female mice from the infection. This discovery can be path-breaking if replicated in humans as well; as it can lead to emergence of a single vaccine for both the viral diseases.

The research and the findings make sense as both Zika and Dengue are caused by the viruses belonging to Flaviviridae family (and in fact are transmitted by the same species of mosquito as well!). The entire study has been published in Nature Immunology in Aug 2017 under the title:

Human antibodies to the dengue virus E-dimer epitope have therapeutic activity against Zika virus infection

Following is the abstract taken from the publication (Nature Immunology):

Quote:The Zika virus (ZIKV) epidemic has resulted in congenital abnormalities in fetuses and neonates. Although some cross-reactive dengue virus (DENV)-specific antibodies can enhance ZIKV infection in mice, those recognizing the DENV E-dimer epitope (EDE) can neutralize ZIKV infection in cell culture. We evaluated the therapeutic activity of human monoclonal antibodies to DENV EDE for their ability to control ZIKV infection in the brains, testes, placentas, and fetuses of mice. A single dose of the EDE1-B10 antibody given 3 d after ZIKV infection protected against lethality, reduced ZIKV levels in brains and testes, and preserved sperm counts. In pregnant mice, wild-type or engineered LALA variants of EDE1-B10, which cannot engage Fcg receptors, diminished ZIKV burden in maternal and fetal tissues, and protected against fetal demise. Because neutralizing antibodies to EDE have therapeutic potential against ZIKV, in addition to their established inhibitory effects against DENV, it may be possible to develop therapies that control disease caused by both viruses.

Refer the journal for full details:

http://www.nature.com/ni/journal/vaop/nc....3849.html

Heart Arrhythmia: Symptoms, Causes, Treatment and Prevention

Mon, 13 Mar 2017 04:54:03 +0000

What is Arrhythmia?
Meaning of heart arrhythmia is there in its nomenclature itself - heart beats that tend to miss the regular rhythm or in simpler terms, irregular heartbeats are classified as arrhythmic (also called dysrhythmia).

Arrhythmia is different from 'abnormal heart rate (which normally is 50-100 beats per minute). Arrhythmias can occur with a normal heart rate, as well as with heart rates that are slow (called bradyarrhythmias) or rapid (called tachyarrhythmias).

In the United States alone, more than 850,000 people are hospitalized for an arrhythmia each year (source: medicinenet).

What causes Arrhythmia?

Following are the common causes of Arrhythmia:

Some less serious causes:

*Electrolyte imbalances in blood
*During recovery from a heart surgery
*It can sometimes occur in perfectly healthy hearts as well

Some serious causes:

*Coronary artery disease (plaque depositions etc)
*Changes in heart muscles or cardiomyopathy

What are the symptoms of Arrhythmia?
Following are the common symptoms of Arrhythmia:

*Palpitations
*Pounding
*Shortness of breath
*Dizziness
*Fatigue

Diagnosis of Arrhythmia:
Arrhythmia diagnosis is easy to perform using the state of art yet simplistic and cost effective instruments. Following are various diagnostic measures:

a) ECG
b) Holter Monitoring
c) Stress Test
d) Electrophysiology study (EPS)
e) Echo Test
f) Head-up tilt table test
g) Event monitoring

Treatment of Arrhythmia:
Treatment of Arrhythmia is administered based on type and severity of Arrhythmia. It is often a combination of prescribed drugs and life style changes (or surgical intervention in severe causes).

Following two categories of drugs are often prescribed:

∆ Antiarrhythmic drugs:
Such drugs come under the category of beta-blockers and help in controlling the heart rate

∆ Anticoagulant or antiplatelet therapy:
These drugs are aimed at reducing the risk of clot formation (and hence a stroke). Warfarin, Aspirin and Pradaxa are the common prescriptions in this category.

Lifestyle changes that are must for an Arrhythmic person:

1. Limited alcohol intake
2. Quitting smoking
3. Limited caffeine intake
4. No intake of stimulating substances (cough syrups and medicine for cold are also stimulating substances!)

A News that triggered the need for this thread:
LaMarcus Aldridge, an American professional basketball player, playing for San Antonio Spurs of NBA, had to go for a leave of indefinite period after experiencing heart Arrhythmia. This has been on news all around and has suddenly lead to a surge of queries about Arrhythmia. He is currently undergoing tests to ascertain the severity of the event. Best of health wished his way.

Ebola Vaccine with 100% Protection

Mon, 26 Dec 2016 07:36:10 +0000

Prologue:
'In a study published (on Thursday, 22nd December 2016) , an experimental (rVSV-vectored) vaccine against the Ebola virus has been found to be 100% effective! This study and its results have emerged as a great sigh of relief not only for Africa (this disease created havoc in 2014 by causing death of over 11,000 people!) but also......'

If you find it interesting and worth sharing, please do spread the news in your social network.

In a study published in 'The Lancet' (on Thursday, 22nd December 2016) , an experimental (rVSV-vectored) vaccine against the Ebola virus has been found to be 100% effective!

This study and its results have emerged as a great sigh of relief not only for Africa (this disease created havoc in 2014 by causing death of over 11,000 people!), but also for the entire world where the Ebola Virus has been spreading ceaselessly. As quoted by Dr. KeÏta Sakoba, director of Guinea's 'National Agency for Health Security'.

Quote:Ebola left a devastating legacy in our country. We are proud that we have been able to contribute to developing a vaccine that will prevent other nations from enduring what we endured”

About this 'Ebola Vaccine'

rVSV-ZEBOV, the vaccine used in the study, is a recombinant, replication competent vesicular stomatitis virus-based candidate vaccine expressing a surface glycoprotein of Zaire Ebolavirus.

In this study, the effect of rVSV-ZEBOV in preventing Ebola virus disease in contacts and contacts of contacts of recently confirmed cases in Guinea, west Africa was tested.

Following is the brief of their story:

In 2015, this experimental vaccine was administered to residents of Guinea 'who were in contact with patients who had recently confirmed cases of Ebola'.

Few months post these early trials, the WHO identified the preliminary results of the trials as an “extremely promising development.”

The trial involving > 11000 people, was later led by WHO in conjunction with Guinea’s Ministry of Health.

Total 5,837 people were administered the rVSV-ZEBOV vaccine, and none recorded any case of Ebola post 10 days or longer.

Vaccine side effects in some subjects were observed, but were limited to headaches, fatigue and muscle pain. Two subjects had serious reactions, one who having an allergic reaction.

Ring strategy of this study for 100% Effective Ebola Vaccine

Ebola is not new to the world (first discovered in 1976). Being limited to isolated African communities for almost 3 decades, its outbreaks were always manageable, and hence wasn't considered a major threat.

But, in 2014, a major outbreak took place, wherein Ebola virus reached cities and started spreading like wildfire (catching the entire global health community off guard and clueless about this sudden and huge outbreak). From Africa, it started spreading to other continents/countries/states/cities and countrysides. This called for a concerted effort.

Categorized as a highly contagious virus, Ebola can spread once patients are symptomatic. So, the relatives of the patients are at great risk of exposure while they try to take care of their loved ones. With an aim to combat this, researchers designed the vaccine administration approach in such a way that the Ebola Vaccine should be doled out to "clusters” or “rings” — groups of people who had been in contact with an Ebola patient (same strategy that was used to eradicate smallpox).

The logic behind this approach, as explained by John-Arne Rottingen of the Norwegian Institute of Public Health to CNN is quite legit:

Quote:“The premise is that by vaccinating all people who have come into contact with an infected person, you create a protective ‘ring’ and stop the virus from spreading further”

After this huge reported success, the Ebola vaccine production has been fast tracked by US and European regulatory agencies.

Merck, Sharp & Dohme manufactured the vaccine for the trial and are producing for further actions as well.

As per the promise of Merck: 300,000 doses of the vaccine will be available in case of a new Ebola flareup. Merck will be submitting the Ebola vaccine for licensing by the close of 2017.

Following is the entire research paper published in "The Lancet":

Science and Biotechnology has yet again proved its worth to life and living forms.

All there is to know about Middle-East Respiratory Syndrome (MERS)

Sun, 27 Dec 2015 15:22:32 +0000

What is Middle East Respiratory Syndrome?

(Source: australiafirstparty.net)

The Middle East respiratory syndrome (MERS), or what is known as camel flu, is a respiratory infection caused by MERS-coronavirus (MERS-CoV). MERS was first reported in 2012. There are around 1641 confirmed cases of MERS in about 20 countries as updated in December 2015. The existence of this virus was first reported by Dr. Ali Mohamed Zaki an Egyptian virologist, in the year 2012. A previously unknown coronavirus was isolated by Dr. Zaki from a man’s lungs. This was later identified as MERS-CoV. The symptoms are not fatal unless the infected person has a weakened state of immunity due to other health problems. The symptoms include fever, cough, diarrhea, and shortness of breath.

In the very same year, the similar symptoms were observed in a 49-year-old male in Qatar. Most of the MERS cases which were observed were confined to Arabian Peninsula. There were, however, two cases reported in California. Two healthcare providers who treated people in Saudi Arabia were infected with the virus. This outbreak led to the rapid research and monitoring on the symptoms and the deaths associated with this virus. The first two cases had similarities in the genetic sequences.

MERS-CoV is a beta coronavirus which is derived from bats. Serum isolated from camels have the antibodies for MERS-CoV. However, the source of the infection has not been identified in camels. It is also believed that the camels transfer the virus to humans, but, the exact mechanism is unknown. Human-human transmission is on close contact. The mortality rate is 40%.

Symptoms of MERS

(Source: Wikipedia)
The appearance of the symptoms is after an incubation period of 5 days. Fever, cough, and shortness of breath are the most common symptoms. Myalgia is one of the symptoms observed in a small fraction of people. Apart from these symptoms, gastrointestinal symptoms like vomiting, diarrhea, and abdominal pain are also seen in a small fraction of people. Three-quarters of the total number of people infected need medical attention and support of ventilators to survive. Though the symptoms appear non-fatal, MERS can be asymptomatic and lead to severe pneumonia which in turns causes Acute Respiratory Distress Syndrome (ARDS). It can also further complicate by causing kidney failure, disseminated intravascular coagulation (DIC), and pericarditis.

More about MERS-CoV

(Source: sciencenews)
MERS-CoV belongs to the beta group of coronavirus. Though it was referred to as SARS-like virus until 2013, it has now been identified to be distinct from SARS coronavirus.

In humans, the adherence of the virus is to the nonciliated bronchial epithelial cells. The virus is equipped to evade the immune system and they hinder the production of the interferon (IFN) production in these cells. The reason this is unique is because most respiratory disease causing viruses have a strong tropism for ciliated cells. Dipeptidyl peptidase 4 (DPP4) or CD26 is the receptor for the virus. This receptor is highly conserved and only expressed in human bronchial epithelium and the kidneys.

Transmission between human-human is very low unless the person infected is in constant contact with healthy individuals. It has also been observed that only 20% of the epithelial cells are infected with the virus on a whole. This indicates that the number of virions which have to be inhaled to cause the disease will not likely transfer from human-human through normal contact. However, Dr. Anthony S. Fauci of the National Institutes of Health in Bethesda, Maryland, has raised a cause for concern. The infection though does not transmit from human-human, its mutation to a more transmissible strain can pose a major health hazard. Healthcare providers are exposed the most to this virus. The major outbreak in South Korea with 125 confirmed cases of MERS has CDC on high alert. Egyptian tomb bats are the natural reservoirs of this virus. The virus has undergone evolution over a long period of time. The viral strains in bats are similar to the ones isolated from humans. Nevertheless, recent reports have identified camels to be the natural reservoirs of the virus. The presence of protein-specific antibodies against MERS-CoV spike proteins are in evidence of this. Countries in the Arabian Peninsula are known to drink large amounts of camel milk and camel meat as well. This is one of the main reasons for the transmission of the virus.

Diagnosis of MERS

The diagnosis of the disease is based on the symptoms displayed by an individual. The probable cases of MERS show the following symptoms: acute pneumonia, flu-like symptoms, fever, and cough, a history of travel to other countries, contact with an infected person or consumption of camel products.

X-ray of the lungs reveals bilateral patchy infiltrates which is consistent with viral pneumonitis and ARDS. Interstitial infiltrates are also seen.

Low lymphocyte count is characteristic of this disease. PCR is performed by taking samples from the lower respiratory tract. Sputum sample or tracheal aspirate is also taken for examination. RT-PCR is also performed for the rapid identification of the infection. The PCR targets the amplification of sequence upstream the E gene. RdRp, which is present in all coronaviruses is targeted by sequencing amplicons.

Though immunofluorescence assays have been developed, the antibodies cross-react within the genus and thus make it difficult to detect the infection. A protein microarray specific to the infection has been developed. There was no cross-reactivity observed. However, the assay is tedious which is why WHO came up with the conclusion that all the positive serological test results in the absence of PCR and other sequencing techniques are to be taken as probable cases of MERS.

Prevention of MERS

For any infection, the transmission matters the most. Once the transmission is prevented, the infection is automatically controlled.

1. Camel milk should be thoroughly pasteurized before consumption and camel meat too should be cooked well prior to consumption.

2. People handling camels should wash their hands clean after coming in contact with them. The same way, unwell camels should be given proper medical attention and should be kept away from the healthy ones to prevent the spread of the infection.

3. Protective gear should be worn by healthcare providers while treating infected individuals.

4. Handling body fluids with care is advised.

5. Wearing long gowns which are impermeable and non-sterile is mandatory.

6. Only a limited number of people should be allowed to care for the patient.

7. The patient is advised to limit activity to a bare minimum to avoid contamination of surfaces at home or hospital.

Treatment of MERS

Interferon activity is hindered by the virus. To counter this, treatment procedure involves administration of exogenous interferons which minimize the viral replication process. There is no specific antiviral treatment. The treatment is mostly symptomatic and in severe cases, the patients are provided care to keep the vital organs functioning.

Zika Fever: What is it?

Tue, 22 Dec 2015 07:48:30 +0000

Everyone around is so worried about mosquito bites leading to malaria or dengue fever. Not even roaches draw that kind of attention these days. Like the scare of malaria and dengue isn’t enough, there is another fever emerging which is slowly making room for itself amongst us. Ever heard of Zika virus? It causes a disease called, “zika fever” or “zika disease” in humans. This disease was first discovered in 1952 when a caged rhesus monkey in the zika forest near the East African Virus Research Institute in Uganda, was seen to develop a fever. They could isolate the transmissible agent which was found to be zika virus. It was originally thought to be confined to parts of Asia and Africa. It was rediscovered in 2007 in a patient in Yap, Federated States of Micronesia. Aedes aegypti mosquito is the known vector of this virus. The virus can be transferred between human-human through sexual contact and also through blood transfusion. Detection of zika virus RNA in amniotic fluid suggests that it can be transferred vertically and that it can cross the placental barrier and can also affect the fetus. The Pan American Health Organization (PAHO) has confirmed its presence in parts of Panama and Venezuela in December 2015.

Symptoms of zika fever

Not everyone who is infected with zika virus develops the disease. According to CDC, 1 in 5 people develops zika fever. The incubation period of the disease is between 3 to 12 days. During this period, people show the following symptoms- fever, rashes, headaches, conjunctivitis/red eyes, muscle pain, and vomiting. The disease is mild and there are no reports of hospitalization or death. The illness starts to lose its hold within 4-7 days. The rashes are called maculopapular rashes. They start at the face and then proceed to form all over the body. This disease is not seen to cause any further complications. However, infection with zika virus during pregnancy has raised red flags. Certain autoimmune, neurological and neurodevelopmental conditions like microcephaly and Guillain-Barre syndrome in newborns who are infected with ZIKV has been noticed. In 2015, Zika virus has been isolated from a newborn in Ceara, Brazil. This child was born with microcephaly. Following this, there were about 739 cases of infants being born with congenital neurological disorders. As of December 1, 2015, the ministry of Brazil has confirmed the virus to be responsible for microcephaly in infants. 1,248 cases with 7 fatalities were reported in 14 States of the country.

Virology

Above is an image of the structure of the Flaviviridae virus (Source: lookfordiagnosis).

The zika virus belongs to the family Flaviviridae like its counterparts causing dengue, yellow fever, West Nile and Japanese encephalitis. The virus is icosahedral in symmetry which is due to the arrangement of the surface proteins. It has a positive sense single-stranded RNA genome that is 10794 kb in length and unsegmented. There are two flanking coding regions that are cleaved into capsid, the precursor of the membrane (prM), envelope (E) and seven non-structural proteins (NS). It has a nucleocapsid and is enveloped by a host-derived lipid bilayer consisting of the E and M proteins.

The virus enters the host cell by attaching itself to the host cell receptors. This is brought about by the envelope proteins of the virus which induce endocytosis in the virion. Upon the fusion of the virus membrane with the endosomal membrane of the host, the ssRNA is released into the host cell. The ssRNA gets translated to a polyprotein and then differentiates into structural and non-structural proteins. The viral factors responsible for the replication of the viral genome carry forward their task and these factors along with the endoplasmic reticulum of the host form dsRNA. The genome is then assembled in the ER of the host cell and then to the Golgi complex. From here, they exit into the intracellular space and continue to infect other host cells.

Diagnosis

1. PCR is performed to detect the presence of the viral DNA.

2. ZIKV antibodies (IgM) are detected in the serum. Though the ZIKV antibodies are detectable after 3-5 days of infection, cross-reactivity with dengue, West Nile, and Japanese encephalitis is commonly seen. However, the cross-reactivity was seen in people who were previously exposed to viruses belonging to Flaviviridae. Patients infected with ZIKV for the first time did not show such cross-reactivity. CDC has developed an ELISA to detect the ZIKV IgM.

3. Urine samples are analyzed for the virus as the RNA is present in the urine up to 10 days of infection.

4. Differential clinical diagnosis is advised as there can be chances of co-infection with dengue or chikungunya and malaria which are also transmitted through mosquito bites.

Treatment

Since the disease is self-limiting and mild, there is no vaccine or specific treatment which has been developed. Patients are suggested to rest and keep themselves hydrated. Medications are usually prescribed against the symptoms like fever, vomiting, headaches and muscle pains. Antihistamines are prescribed for pruritic rashes. Also, the healthcare provider should be cautious while administering drugs as certain drugs like non-steroid anti-inflammatory agents and acetylsalicylic acid can cause side effects like hemorrhages in the patients infected with a Flaviviridae group of viruses.

Prevention

Above is an image of the health advisory issued by the Ministry of Health, Brazil in the efforts to convey the steps to prevent the disease (Source: Guardian).

Since the disease is transmitted through a vector, the preventive measures usually focus on not giving a chance to the vector to transmit the virus to the host.

1. Keeping the surroundings clean by reducing the breeding ground for mosquitoes helps majorly in the prevention of this disease.

2. Protecting oneself from a mosquito bite is of importance to prevent the infection.

3. Wearing long sleeved clothes, during the highest hours of mosquito activity.

4. Travelers are advised to find out the diseases which are endemic to the place and go about protecting themselves accordingly.

5. A person infected with zika virus is advised to follow safe sex practices or to avoid sexual contact until the healthcare provider gives clearance.

Zika virus is slowly emerging as a pathogen. Since the virus causes mild infection in humans, it hasn’t been studied for its potential to be a disease causing agent.

Swine Flu: Knowing it Inside Out.

Fri, 18 Dec 2015 08:21:06 +0000

Swine influenza commonly known as Swine Flu is an infection caused by the swine influenza viruses. These viruses cause pig influenza and their transmission from pigs to humans is uncommon. The immune system is perfectly capable of producing antibodies to fight the virus and thus does not lead to an infection. Zoonotic infection is common amongst people who are regularly in contact with the pigs.

It was in the mid-20th century that the subtypes of the swine flu virus were identified. Upon its identification, studies showed that the subtypes caused zoonotic infections in humans. These strains were not known to pass from human to human. Such incidences were of rare occurrence. It was in 2009 that H1N1 virus responsible for H1N1 infection or commonly known as swine flu was discovered. H1N1 is also known as swine flu as the symptoms are very close to those that are observed in pig influenza.

Signs and symptoms of swine flu

Below is an illustration of the symptoms seen in swine flu (Source: thefitindian).

In humans, zoonotic infections are common. The symptoms of the H1N1 swine flu are much like any other influenza infections. The incubation period is 1-4 days and the infection can show symptoms up to 2 weeks after the infection unless it is severe. The symptoms include fever; a cough, sore throat, watery eyes, body aches, shortness of breath, headache, weight loss, chills, sneezing, runny nose, coughing, dizziness, abdominal pain, lack of appetite and fatigue.

The outbreak in 2009 led to the identification of diarrhea and vomiting as the other symptoms of swine flu. The transfer of the H1N1virus is not zoonotic, but it is the aerosols from the infected people that brings about the transmission of this disease. The symptoms are not limited to swine flu, hence, differential diagnosis combined with laboratory tests are essential for the identification of this infection. Though swine flu on its own is not fatal, death can occur due to respiratory failure. Pneumonia, high fever, dehydration, electrolyte imbalance and kidney failure also can cause fatality in both children and adults.

It is more of a risk in pregnant women as they undergo hormonal changes, physical changes, and the immune system also changes in accordance to the developing fetus and an infection with H1N1 at this stage can cause complications. Hence, they are advised to take vaccine shots.

Virology

The structure of the virus is illustrated in the image below (Source: medicaljournalonline)

The virus causing swine flu in humans has been identified to be a strain influenza A virus which is designated as H1N1. This influenza virion is roughly spherical. It is enveloped in an outer lipid membrane. This lipid membrane is taken from the host cells which the virus replicates. The lipid layer has “spikes” of proteins embedded in it. These spikes are glycoproteins - haemagglutinin and neuraminidase, which is why they are designated as H1N1, H1N2, etc. based on the type of H and N antigens expressed. Haemagglutinin is responsible for the clumping of blood cells and this binds the virus to the infected cells. Neuraminidase is a glycoside hydrolase enzyme which helps in the movement of virus particles across the infected cells and also aids in the budding of the virus from the host cell. The worrisome part is the ability of the virus to mutate during transmission from human to human.

The influenza viruses have segmented genome, i.e. the viral RNA code is not a complete strand but is fragmented into eight parts. All the eight parts are present in the virus. Avian or human influenza virus can infect a pig’s host cell at the same time as the swine flu virus. This can cause a mixing of the genes and thus can bring about the replicating human RNA viral genomes to be embedded in the swine flu virus. Thus, transfer of the human virus through pigs is possible. This creates room for more subtypes of the virus to come up due to the various combinations of the human and swine RNA fragments being present in the virus. This overall is known as antigenic shift. The characteristics of the virus would be that of a swine flu virus, but it can infect a human due to the human RNA fragments in the genome. Such small changes do not drastically affect us unless the changes accumulate and produce enough minor changes to alter the entire makeup of the virus.

Below is the illustration of antigenic shift and antigenic drift (Source: medicinenet).

The reason pigs are considered to be the intermediate host is because they can host swine, avian and human flu types in their cells. This is because pigs feed on the feces shed by birds. If the birds in question carry the avian flu virus, this virus can enter the pig’s host cells and the fragments of avian flu RNA can be picked up by the swine flu virus. This way, the avian flu virus enters the mammalian population.

Diagnosis of swine flu

The first thing to be considered while diagnosing for swine flu is the contact of the person in question with someone tested positive for swine flu infection. A nasopharyngeal swab is done to identify whether it is an influenza A or B virus. If the test is positive for influenza B virus, it is likely to be not swine flu. If tested positive for influenza A virus, it is taken as a confirmation of conventional flu or swine flu. Pathological tests on the tissue sample of the specimen lead to the identification of the virus type.

The definitive identification involves identifying the surface antigens present in the virus. The diagnosis is done using rt-PCR and certain influenza diagnostic tests. Centre for Disease Control (CDC) also advises antiviral susceptibility testing by pyrosequencing. A rapid influenza diagnostic test is performed for the identification of an infection by influenza A virus. This is a test based on the detection of influenza viral nucleoprotein antigen. Serological tests are also performed where the sera of the patients infected for a week and more than 2 weeks are taken for research purposes. Not all labs are authorized for serological testing. The FDA approved assay is the CDC rt-PCR Swine Flu Assay.

Treatment for swine flu

Vaccines are available in the form of nasal sprays, injections and intradermal shots which prevent the onset of this infection. However, it is to be noted that the nasal spray has the live attenuated virus. People with weak immune system are advised against taking nasal spray based vaccine as it can lead to complications.

Apart from vaccines, antiviral agents like zanamivir and oseltamivir are also available in the market. They are known to reduce the symptoms of the flu. Nevertheless, the resistance of the virus to these drugs has already been seen. Thus, people with more than 48 hours of infection are not given these drugs. In non-responsive patients, IV delivery of the drug is possible provided the healthcare provider has given a clearance to do so.

Prevention of swine flu

Below is an illustration of the preventive measures which are to be followed (Source: funonthenet)

Vaccine shots are the best way to prevent the spread of the disease. washing hands after coming in contact with an infected person, covering mouth while sneezing or coughing and limiting contact with people and household articles if infected are the best ways to ensure that the infection does not spread further.

Ebola Infection and its Treatment

Tue, 15 Dec 2015 14:27:44 +0000

Ebola infection and treatment

Ebola Virus Disease

Ebola is a disease which causes viral hemorrhagic fever in humans and in primates. This disease is currently known as Ebola Virus Disease (EVD). The virus belongs to a group of viruses called the ebolaviruses. This virus was first discovered in 1976 during the outbreak in Sudan and ever since its discovery, the recent outbreak in March 2014 in West Africa is known to be the most complex outbreak. EVD is mostly severe and is often fatal in humans. The virus appears to be normal flora in fruit bat which acts as the natural carrier of this disease. Bushmeat is the meat of the fruit bats which are hunted for food in places like Ghana and other parts of Africa. This serves as a means to transmit the disease.

Transmission of EVD

The disease spreads through contact with body fluids of the infected human or animal. Airborne spread of the disease between humans or primates and both humans and primates has not been documented in the laboratory setup as well as in the natural environment. Body fluids not only refer to blood but also to mucus, sweat, saliva, vomit and semen. A person recovering from EVD can carry the virus for weeks or months in the semen as well as in breast milk. The virus can survive in semen for 3 months, during which the transmission can occur through sexual intercourse. This can be one of the means of transfer between humans. Containers used to hold the body fluids of the patients, the syringes and the needles also work as the transmission agents for the disease. The portals of entry for this virus are the nose, mouth, open wounds, cuts, and abrasions. It can survive for a few hours in dried state on the containers which were in contact with the body fluid. Though people who recover from the disease do not pose a threat in terms of transmission, the dead bodies of infected people are to be handled very carefully. Modern procedures like embalming and burials can transfer EVD. The health care professionals are at a higher risk of contracting EVD. Transmission through food other than bushmeat, water, and air has not been observed.

Symptoms of the Infection

The image below illustrates the various symptoms since the onset of the infection (Source: youcaring)

Onset of the infection
The time between the exposure to the virus and the development of symptoms or the incubation period is between 2 to 21 days and usually between 4 to 10 days, respectively. Symptoms usually involve an onset of a flu-like stage which is mainly characterized by tiredness, fever, weakness, decreased appetite, muscular pain, joint pain, headache, and sore throat. The body temperature during fever is usually higher than 101 °F or 38.3 °C. This is often followed by vomiting, diarrhea, and abdominal pain. Next, shortness of breath and chest pain may occur, along with swelling, headaches and confusion. In about 50% of the cases, the skin may develop a flat red area covered with bumps also known as maculopapular rash, 5 to 7 days after symptoms begin.

Bleeding during the infection
Internal and external bleeding is seen in some people. This typically begins five to seven days after the first symptoms. The clotting factors decrease in the infected people which eventually leads to a decrease in the blood clotting time. Bleeding from mucous membranes or from sites of needle punctures has been reported in half of the cases. This may cause vomiting blood, coughing up of blood, or blood in the stool. Bleeding into the skin may create petechiae, purpura, ecchymoses or hematomas (especially around needle injection sites). Bleeding into the whites of the eyes may also occur. Heavy bleeding is uncommon; if it occurs, it is usually located within the gastrointestinal tract.

Recovery and death
Within 7 to 14 days of the appearance of initial symptoms, recovery may be seen. In people with severe fluid loss, there is a significant drop in the blood pressure which eventually leads to death. The occurrence of death is seen between 6 to 16 days of the appearance of the first symptoms. In general, bleeding doesn’t result in a good outcome as the patient might even end up being in the coma during the last stages of the disease. The people infected for a longer duration usually show signs of weakness, tiredness, and vision-related problems, decreased appetite, muscle and joint pains, liver inflammation and also decreased hearing. On exposure to Ebola virus, antibodies are developed by the immune system which can last for up to 10 years in the system. But, their effect in providing immunity on a second exposure to the disease is unclear.

Virology

Ebola virus (EBOV) which was previously known as Zaire ebolavirus is one of the five viruses in the genus Ebolavirus. EBOV has a single-stranded RNA in the genome. Ebolavirus genomes contain seven genes including 3'-UTR-NP-VP35-VP40-GP-VP30-VP24-L-5'-UTR. The genomes of all the ebolaviruses have variations in their sequences and the locations of the gene overlap also vary. The virions are 80 nm in width and up to 14,000 nm in length. They are filamentous in nature and have the shape of a shepherd's crook, of a "U" or of a "6,” They can also be either coiled, toroid or branched.
The image below is of the Ebola Virus under an electron microscope (Source: Wikipedia).

The virions attach to the cellular surface by identifying specific receptors such as C-type lectins, DC-SIGN, or integrins. This is then followed by the fusion of the viral envelope with cellular membranes. The virions which are now inside the cells travel to acidic endosomes and lysosomes where the viral envelope glycoprotein GP is cleaved. This enables the virus to bind to the cell proteins to help it in the fusion with the internal cellular membranes and thus, the viral nucleocapsid is released. GP1, 2 is the structural glycoprotein which is responsible for the virus’ ability to bind to and infect targeted cells. The nucleocapsid is partially uncoated by the viral RNA polymerase which then transcribes it into positive mRNAs and thus the structural and non- structural proteins are coded. The concentration of the nucleoprotein in the host determines when L switches from gene transcription to genome replication. Replication results in the production of full-length, positive-strand antigenomes that are, in turn, transcribed into genome copies of negative-strand virus progeny. The newly synthesized parts of the virus then assemble inside the cell. The virions then separate from the cell after being enveloped in the cell membrane. The mature virions remain within the cell to repeat the cycle. The genetics of the Ebola virus are difficult to study because of EBOV's virulent characteristics.

This below is an illustration of the structure of Ebola virus (source: ukaye.wordpress.com).

Pathophysiology of the infection

Below is an illustration of the activity of the virus and the spread of the infection in the host (Source: Lancet)

EBOV replicates very efficiently in a wide range of cells like monocytes, macrophages, dendritic cells, hepatic cells, fibroblasts and adrenal gland cells. A state of sepsis is induced due to the inflammatory response and chemical signals triggered by the viral replication. Following infection with the virus, the virus-infected host cells carry the virus to the lymph nodes where the virus replicates itself to further the infection to the next stage. The lymphatic system and bloodstream are infected in this process and thus, carrying the virus to all parts of the body. Macrophages are the first cells infected with the virus, and this infection results in programmed cell death. Lymphocytes are also targeted by EBOV which lowers their count due to programmed cell death. Other types of white blood cells, such as lymphocytes, also undergo programmed cell death leading to an abnormally low concentration of lymphocytes in the blood and thus the immune system is weakened. The lower count of lymphocytes is a factor that is observed while diagnosing for EVD.

Endothelial cells are infected within the first 3 days of exposure and their breakdown which leads to blood vessel injury can be caused by the EBOV glycoproteins. Liver damage and improper clotting are observed due to the lack of the specific integrins which are responsible for cell adhesion to the intercellular structure. The affected people experience shock, and swelling is also seen due to the blood loss. There is an increase in the activation of the extrinsic pathway of the coagulation cascade which attributes to the dysfunctional bleeding and clotting as there is excessive tissue factor that is produced by macrophages and monocytes.
After infection, a small soluble glycoprotein (sGP or GP) is synthesized. The protein synthesis in the infected cells of the immune system is overwhelmed by the EBOV replication. A trimeric complex is formed between the GP and the endothelial cells. The signaling of neutrophils in intercepted by a dimeric protein formed by the sGP which aids the virus in evading the immune response as the activation of the neutrophils in nipped in the early stages. The presence of viral particles and the cell damage resulting from viruses budding out of the cell causes the release of chemical signals (such as TNF-α, IL-6, and IL-8), which are molecular signals for fever and inflammation.

Diagnosis of the disease

Laboratory diagnosis includes:-
1. A low platelet count and an initial decrease in the white blood cells, specifically lymphocytes is observed.
2. Elevated levels of liver enzymes like alanine aminotransferase (ALT) and aspartate aminotransferase (AST) is observed.
3. There are certain abnormalities in the clotting of the blood like prolonged prothrombin time, partial thromboplastin time and bleeding time.
4.Though the virus can be observed under an electron microscope, this method cannot be used for diagnosis as the differentiation of various filoviruses is not possible.
5. Detection of specific RNA or proteins post isolation of the virus and the detection of antibodies in the blood is performed as a part of the specific diagnosis. The positive results in any of the above diagnostic methods are taken as a confirmation to being infected with the virus.
6. Isolation of the virus by cell culture, detection of the viral RNA by polymerase chain reaction (PCR) and the detection of proteins by enzyme-linked immunosorbent assay (ELISA) are used as diagnostic tools during the early stages of the infection.
7. Later detection is done by identifying antibodies in the blood of the infected people and in the blood of those who recover from the infection.
8. Detection of IgM and IgG during the onset of the infection, i.e., between 2 days and 6 to 18 days respectively.
9. Real-time PCR and ELISA are the two diagnostic tools which are considered to be the most effective in giving quick results.

Treatment

Providing the right care in terms of oral rehydration solutions and intravenous fluids to infected people to prevent the massive fluid loss is one way to counter the symptoms and improve the survival. There is as yet no proven treatment available for EVD. However, potential treatments include blood products, immune therapies, and drug therapies. No licensed vaccines are available yet, but two potential vaccines are undergoing human safety testing.

Preventive measures

Risk reduction should focus on several factors like:-

1. Reducing the risk of wildlife-to-human transmission- animals should be handled appropriately and the meat should be thoroughly cooked prior to consumption.

2. Reducing the risk of human-to-human transmission- people should be made aware of how to handle the body fluids of the infected patients. Gloves should be worn at all times while handling patients and hand washing should be frequent after visiting patients in the hospital or at home.

3. Reducing the risk of possible sexual transmission- the people recovering from Ebola are often advised to abstain from sex of all types for at least 3 months since the onset of symptoms. if abstinence is not possible, protection during sex is the only way to prevent sexual transmission. Washing hands and intimate areas are also of importance to prevent the spread of Ebola.

4. Outbreak containment measures- the virus is active in the corpses which make it mandatory to follow safe burial practices to avoid the spread of the disease. the people who have come in contact with the dead are monitored for the initial symptoms to prevent the spread if they are infected.

5. Health-care workers should always take standard precautions like wearing protective equipment and also follow safe injection and safe burial practices.

6. Extra care should be taken if the patient is diagnosed positive for Ebola. The handling of the body fluids, clothing and bedding should be thorough. Wearing a protective mask, gloves and body cover while around such cases is always advised.
7. Laboratory workers are also at risk. Samples taken from humans and animals for investigation of Ebola infection should be handled by trained staff and processed in suitably equipped laboratories.

DIAGNOSIS AND TREATMENT OF HEART ATTACK

Wed, 21 Oct 2015 17:22:54 +0000

Acute myocardial infarction is a company dedicated to the group of acute coronary syndromes. They are characterized by the sudden appearance of a box suffering ischemic (lack of irrigation) to a portion of the heart muscle caused by acute and total of one of the coronary arteries that feed obstruction.
Myocardial infarction is the leading cause of death for men and women worldwide.
Many cardiac risk factors are modifiable, so many heart attacks can be prevented if he maintained a lifestyle healthier.
What are the symptoms?
The stroke is recognized by the sudden appearance of the characteristic symptoms: severe pain in the chest, in the chest area (where the tie), general ill feeling, dizziness, nausea and sweating. The pain may spread to the left arm, jaw, shoulder, back or neck.
It should be noted that about half of heart attacks occur without warning symptoms, ie, that the attack is the first manifestation of ischemic heart disease.
Sometimes, however, a few months before having the heart attack patient has chest discomfort, feeling unwell, fatigue, increased irritability, etc., or even sometimes upset stomach, they do confuse the symptoms of stroke with those from other organs.
What is your prognosis?
Most patients with acute myocardial infarction and recover quickly enough to play a normal life. The few that do not get too may undergo percutaneous revascularization or be seized, so very acceptable recoveries are achieved.
The only difference between the patient who has had a myocardial respect of which it has not had is that it should be much stricter with regard to the abandonment of snuff, the practice of regular exercise, proper diet (including restriction of fats animal origin and maintenance of the correct weight) and control of blood pressure levels, cholesterol and blood sugar.
Usually you have to take medicine after infarction. Although recovery of the infarct is successful, the person who suffered should prevent the occurrence of other cardiovascular complications (another heart attack, stroke, aneurysms, etc), which is slightly more likely than other people without heart attack because of its factors particular risk.
Who can get it?
Much of heart attacks occur in people who have known risk factors.
These are, apart from some familial predisposition and age, smoking, hypertension, diabetes and changes in blood fats (cholesterol).
Do you have or suspect suffering acute myocardial infarction?
Anyone with a precordial pain accompanied by malaise, should go as quickly as possible to an Emergency Department. It is best to notify the Homecare Service Urgent appropriate
The reason is that the main risk of acute myocardial infarction is the outpatient phase (ie, before entering the hospital) mortality in this phase exceeds 40%. Once admitted to the hospital, if done well in advance (before the four hours ideally), modern treatments (angioplasty, thrombolysis) permit a satisfactory recovery of stroke and complications they are relatively rare.
What treatments does the doctor has to do?
Some treatments are initiated immediately if a heart attack is suspected, even before the diagnosis is confirmed. Among them they are:
• Oxygen.
• Aspirin to prevent further blood clots.
• Nitroglycerin to decrease the workload of the heart and improve blood flow through the coronary arteries.
For treatment of a heart attack can use several different types of drugs. Among these they are:
• Thrombolytic: Used to dissolve clots that are blocking the coronary arteries.
• Beta-blockers: They reduce the work the heart has to perform and serve to prevent further heart attacks.
• Angiotensin-converting enzyme inhibitors: lower blood pressure and decrease strain on the heart has to do.
• Anticoagulants They make the blood less thick and prevent the formation of clots in the arteries.
• Antiplatelet agents: prevent platelets stick to one another and form unwanted clots.
Non-pharmacological treatment
• Balloon Angioplasty: it can be used to open coronary arteries that are blocked by a clot.
• Coronary Bypass: a section of a vein or artery from another part of the body is taken and is sewn to the coronary artery above and below the narrowed or blocked area.
After a heart attack care HOW?
- If you smoke, quitting is absolutely essential
This is the first step to take because smokers have a high coronary disease presenting irrigation. The goal is the complete abandonment of snuff. It is therefore essential that the patient is informed about the harm caused by snuff and benefits to be gained if you leave your addiction. The risk of stroke is proportional to the number of cigarettes smoked per day and the number of years of smoking. The use of filters and low-nicotine cigarettes has not proven risk reduction. Patients with heart disease who quit smoking live longer than those who continue to smoke.
Unfortunately, leaving the snuff is not easy. Many patients require assistance that can be offered in a specialized smoking consultation. Also avoid secondhand smoke.
- Watch your weight and cholesterol level

We must reduce consumption of foods high in cholesterol and saturated fat: egg yolks, whole milk and dairy products, lean meats, seafood, meats and offal. We recommend the use of vegetables, legumes, fruits, lean meats, poultry, fish, skim milk, margarine and vegetable oils such as olive, sunflower or corn. If you are hypertensive, you need to make a salt-free diet and, if you have diabetes, follow the recommendations for treatment, diet and exercise endocrinologist directed.
- Sport benefits your heart

Doing exercise is advised because it can bring a number of benefits but always under the supervision of your cardiologist. Cycling, swimming or walking outdoors are the most recommended exercises avoiding overexertion and extreme temperatures.
- Take your work with tranquility
Your cardiologist will tell if his physical ability allows him to return to his regular job. Under normal circumstances, you can return to work but trying not obsessed with work.
- Gradually Resume sexual activity
Patients have a great fear that during intercourse may seem a new stroke. Should wait a reasonable time before starting to gradually return to normal sexual activity. If there are no medical contraindications can be resumed this activity after the second week, starting step by step without obsessing.
- Quiet driving
It is best not to drive during the first weeks by the stress, but once this period can start to drive but as long as does not involve an emotional overload and distances are small.
- Control your emotions, learn to relax.
It would be desirable to reduce stress and learn to relax practicing some relaxation techniques or self-control. In general it should not be obsessed with time and work.
How to prevent it?

Being a disease that has no previous symptoms, it is very important to try to detect it before it manifests clinically, ie, carry out what is called "primary prevention".

To do this it is advisable, from 30 years conducting clinical and / or cardiac monitoring periodically. There he made professional studies such as echocardiography, and resting electrocardiogram and / or force. Out also it can lead a stress test, which the patient's overall risk cover. Then, according to the results, it will move forward or not with more complex studies.

In this preventive stage, doctors focus on identifying whether the patient is within the parameters we call risky, then emphasize the dietary recommendation hygienic measures.

These are:

If you smoke quit.

Do aerobic activity 3 times a week, regardless of age. Examples: running, walking, swimming or cycling. Go to the gym to lift weights not the same function.

Have a healthy diet, increasing the intake of fibers found in fruits and vegetables, and consumption of unsaturated fatty acids found in fish and olive oil.

REMEMBER YOU AND YOUR FAMILY ARE IMPORTANT FOR THAT TAKE CARE OF YOUR HEART
And as a final recommendation remember: The first is YOUR heart.

Abdominal Aortic Anuerysm - the silent killer

Tue, 20 Oct 2015 11:57:36 +0000

Abdominal Aortic Aneurysm (AAA) - the silent killer

AAAs are the 9th and 14th leading causes of death in men over 65 years in Canada and the United States respectively leading to an increasing public health burden in developed countries. Persons with AAAs rarely presents with symptoms until rupture and when they do the mortality rate is 60-80%.

Death resulting from a ruptured AAA accounts for approximately 1% of all deaths in the Western world.

An aneurysm is defined as a focal dilatation of a blood vessel 1.5 to 2 times the diameter of the native vessel.

There are different forms of aneurysms including:
·        Saccular–a localised dilatation of the wall of the vessel forming a sac.
·         Fusiform – an outpouching of the entire circumference of the vessel.
·        Pseudoaneurysm or false – occur when the outpouching wall is not made up of the actual vascular wall such as a haematoma. This normally occurs after penetrating trauma or at an anastomotic site.

Figure 1: Diagram showing the different types of aneurysms

Epidemiology of AAA

The prevalence of AAA is estimated at 2-5% in men over 60 years. The incidence is approximately 30-60% per 1000 population and there is strong evidence that the prevalence has increased over the past few decades. It is found in 1 in 5 patients with Peripheral Arterial Disease (PAD).

AAAs are more common in men than women with a ratio of 4:1 and it is commonly diagnosed in the 6th or 7th decade of life.

The normal diameter of the infrarenal aorta is about 2cm. 80% of aneurysm occur infrarenally with 70% involving the iliac arteries and 20% associated with the peripheries.

Pathophysiology of Aneurysm formation

Large and medium arteries consist of three distinct layers – intima, media and adventitia.
Intima - the innermost layer. This consists of a layer of flat endothelial cells supported on a thin underlying matrix of collagen and elastic fibres.

Media – middle layer. This layer consists of varying amounts of collagen, smooth muscles and elastic fibres. The innermost portion of the media gets its nutrients from circulating blood while the outer portion is nourished by the vasa vasorum. The vasa vasorum are small vessels that penetrate the outer walls of the media and it’s these vessels that are affected by the atherosclerotic process decreasing the strength of the wall.

Adventitia – outermost layer which contains a high elastic and collagen content.
The intima and the media are separated by an internal elastic membrane and an external elastic membrane separates the media from the adventitia.

Figure 2: Different components of a blood vessel

Aneurysms form as a result of degeneration and weakening of the compartments of the arterial wall. Rupture will occur if the intraluminal pressure exceeds the tensile strength of the wall. Although the pathogenesis is complex, atherosclerosis is an important factor in the formation of aneurysms.

It is thought that the mechanisms in aneurysm formation is multifactorial -
1. Atherosclerotic damage to elastin and collagen – atherosclerosis is thought to increase the pressure load and reduce the ability of the vessel to bear load thus forming an aneurysm. Weakening of the arterial walls is due the changes in the blood vessels caused by atherosclerosis degeneration. The focal accumulation of lipids and fibrous and calcium deposits in the intima and media leads to the destruction of elastin and probably secondary failure of collagen.

It is suggested that atherosclerotic plaques may weaken the aortic wall either directly or through reduction in the amount of nutrient reaching the media via diffusion from the lumen. The vasa vasorum can also become obliterated which may result in necrosis of the media and additional weakening of the vessel.

Additionally, inflammatory mediators produced in response to the atherosclerotic process can weaken and destroy the media.

2. Genetic abnormality in collagen – there is no single genetic defect however there is a familial clustering of HLA subtype suggesting a genetic role.

3. Biomechanical wall stress – elastin levels and the elastin-collagen ratio decrease progressively distal down the aorta. Reduced elastin is related with dilatation and collagen degradation predisposes to rupture.

4. Increased proteolytic enzyme activity – degradation of the smooth muscle cells in the media and macrophages increase the production of matrix metalloproteinases (MMPs) in the extracellular matrix. The leads to stimulation of the proteolytic enzymes in the aortic wall and destruction of the matrix proteins. there are increased expressions of collegenases MMP-1 and -13 and elastases MMP-2,-9 and -12 in AAAs.

Figure 3: Diagram showing aneurysm formation infrarenally

In addition certain haemodynamic principles may assist in the formation of aneurysm such as the reflective pressure waves at the iliac bifurcation. When arterial flow reaches a bifurcation,as aortic flow into iliacs, some of the flow is reflected against the arterial wall just proximal to the bifurcation. When the ratio of the cross sectional area of the outflow arteries to the inflow artery is approx 1.0, the reflective wave pressure is minimum. With increasing age, this ratio decreases and the pressure of the reflective wave increases. This can result in dilatation of the vessel at this point.

Aetiology of AAA

1.       Atherosclerotic degeneration
2.       Congenital – Tuner Syndrome, Menke Syndrome, idiopathic
3.       Infection – Salmonella, Streptococcus, Staphylococcus, Syphilis
4.       Arteritis
5.       Mechanical – trauma, anastomotic
6.       Inflammatory
7.       Connective tissue abnormalities – Marfan’s Syndrome, Ehlers-Danlos Syndrome

Risk factors

It was found that the risk factors for the development of AAA and atherosclerosis are overlapping. The table shows the risk factors of aneurysm formation.

Table 1: Risk factors of Aneurysm Formation

Clinical Presentation

Most AAAs are silent until they rupture. An AAA can present in any one of the following ways:
1. Asymptomatic – 30% of AAAs are found incidentally in patients during routine physical examinations for other presenting complaints. During investigations such as abdominal X-rays, abdominal or Kidneys, Ureters and Bladder (KUB) ultrasounds or abdominal CT scans, AAAs are found. All patients with an incidental finding of an AAA should be referred to the vascular team for further investigations.

2.  Symptomatic – 20% of persons with AAAs present with pain in central abdomen, lumbar back, loin or groin areas. This pain is due to the stretching of the retroperitoneal fascia. AAAs can also cause a pulsatile beating in the abdomen, with a double impulse on respiration.

Thrombus formation within the sac can be a source of emboli to the lower limbs leading to reduced peripheral pulses and thrash feet.

3. Rupture – a ruptured AAA can present with severe abdominal pain, pulsatile abdominal mass and even shock from hypotension. An AAA can rupture into the retroperitoneum, the peritoneal cavity or surrounding structures. Rupture most commonly occurs in the inferior vena cava leading to an aortocaval fistula.

Investigations and Diagnostic Studies

Based on clinical examinations and whether or not there are any presenting symptoms of the patient, the aim of the investigations is to confirm the diagnosis of an AAA. A number of radiological investigations can be performed with the gold standard being a dynamic contrast enhanced CT scan.

1. Radiographs - approximately two thirds of AAAs are calcified and can be exhibited on plain abdominal radiographs. An egg shell appearance representing the outline of the AAA circumference would be seen.

Figure 4: Abdominal X-ray showing the calcified edges of an AAA

2.  Ultrasound – the best method to calculate the size of the AAA and to confirm the diagnosis would be with an abdominal ultrasound scan. Ultrasounds can also be used for follow up of patients with asymptomatic AAAs.

3. Dynamic contrast enhanced CT scans - this is the investigation of choice. Abdominal CT scans will provide information on the size and the extent of the aneurysm. In addition information about the actual location of the aneurysm is determined with a CT scan, whether there is renal or iliac involvement and other surrounding structures as well as other possible intra-abdominal pathology.

Figure 5: Image of a Contrast Enhanced Abdominal CT Scan showing AAA

4. Aortography - can be used to help determine if there are other occlusive diseases if there is lower limb involvement.

In addition to radiological investigations, routine haematological investigations can be performed for supportive purposes. They can also be used to establish baseline data and in cases for preparation of emergency surgeries.

An AAA that persists over a number of years will cause turbulence of the blood flow stimulating platelets and the coagulation system. Thus with an AAA the haematological studies should highlight increased fibrinogen and a reduced platelet count.

Management of AAA

In considering the management of an AAA, the size of the aneurysm plays a major factor. In a number of trials that have performed is was found that surveillance of AAA of 4.0 cm to 5.5.cm was safe in compliant patients and that early surgery did not result in any long term survival advantage.
What influences the decision to select patients for surgery?
The decision to select patients for AAA repair is influenced by the following:
1. Aneurysm rupture risk – the diameter of an AAA is the best predictor of rupture risk.5 Rupture risk increases proportionally with increasing diameters from 5cm to 6cm. AAAs <5cm have a very low rupture risk and most vascular surgeons tend to use this size as the cut off for an indication for surgery.

Table 2: Estimated annual rupture risks with increasing diameter

2. Expansion rate - the rate of growth of an aneurysm is an important determinant in the choice of surgery. A small AAA that expands 0.5cm or more over a six month period is considered high risk for rupture and will need elective surgery.

3. Life expectancy and operative risk – age and other existing comorbid conditions must be considered when deciding on elective surgery. In general the 5-year survival rate following AAA repair is reduced compared to age and sex matched population data averaging 60% to 65% as compared with 75% to 80% anticpated. Higher 5-year survival rates are associated with younger ages, no comorbidities, a serum creatinine value <1.5, no or minimal angina and no significant COPD.

4.  Patient preference – active patient participation is required at all stages of the management process regardless of the diameter of the aneurysm. Compliant patients tend to have better outcomes and they are willing to show up for follow up clinics, agree to smoking cessation and medication compliance. In addition the patient ultimately agrees for elective surgery and must be cognizant of the situation.

Screening

Selective screening can be costly to the average patient and sometimes it might be worth performing a cost benefit analysis. Abdominal ultrasounds is the most appropriate form of investigation to be used for screening purposes. Screening is recommended in:
·         Men aged 65 -75 years who have a history of smoking should be screened at least once. There is little benefit in repeat screening with negative results.
·         Family history of aneurysms
·         Known extremity aneurysms
·         Persons aged 55-80 years and have existing peripheral vascular disease

Figure 6: Flowchart showing Treatment Options

Medical Management

Medical therapy may be helpful in patients with small to medium sized aneurysms that have not been chosen for elective surgery. It is recommended that patients be put on beta blocker therapy as it not only controls HTN or angina but also have shown to reduce the rate of expansion of AAA.

It has also been shown that patients who were receiving antibiotic therapy have a reduced rate of mean annual expansion compared to those receiving placebo therapy.

Surgical Management
Open repair of AAA is carried out through a long midline incision. Control of the aorta is achieved by occluding the aorta and iliac vessels. Aortic clamping should be infrarenal to prevent renal ischaemia during the procedure and thus, it may not be possible to repair juxtarenal aneurysms. The aneurysm is repaired by placing a synthetic graft (such as Dacron) in the lumen of the aneurysm. This may either be a tube graft, which is anastamosed to the infrarenal aorta proximally and the supra-iliac aorta inferiorly, or a bifurcated graft which replaces aneurysmal common iliac arteries as well as the aorta.

Endovascular aneurysm repair (EVAR) has emerged as the definitive treatment for AAAs it offers fewer complications, reduced blood less, reduced intensive care and hospital stay and faster recovery. EVAR is less invasive compared to the conventional open repair. However there can be complications during an EVAR procedure which may require switching to an open repair.
EVAR has the advantage of small incisions, avoids a laparotomy and does not require aortic cross clamping. It is carried out under direct radiological guidance by passing the graft through small groin incisions and expanding it in the aneurysm. One of the disadvantages of the technique is that the patients receive a relatively high dose of nephrotoxic contrast, which can cause postoperative renal dysfunction. In the medium term, blood can leak around the graft to fill the aneurysm sac (termed endoleak) requiring further operative intervention. These patients require frequent and prolonged clinical and radiological follow-up to monitor for endoleaks.

References

1. Aggarwal S. et al. (2011) Abdominal aortic aneurysm: A comprehensive review. ExpClin Cardiology 16(1):11-15 Available at http:///www.www.ncbi.nlm.nih.gov

2. Singh K. et al (2001) Prevalence of and risk factors for Abdominal Aortic Aneurysm in a population-based study. American Journal of Epidemiology Vol 154,3:236-244. Available at http://www.aje.oxfordjournals.org

3. Blanchard J. et al (2000) Risk factors for Abdominal Aortic Aneurysm: Results of a Case-Control study. American Journal of Epidemiology Vol 151,6:575-583. Available at http://www.aje.oxfordjournals.org

4. Fillinger MF et al. (2002) In vivo analysis of mechanical wall stress and abdominal aortic aneurysm rupture risk. Journal of Vascular Surgery Vol 36,3:589-597. Available at http://www.ncbi.nlm.nih.gov

5. Brewster DC et al. (2003) Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery. Journal of Vascular Surgery 5:1106-1117. Available at http:///www.www.ncbi.nlm.nih.gov

6. Ouriel K et al. (1992) An evaluation of new methods of expressing aortic aneurysm size: Relationship to rupture. J Vasc Surg. 15:12–8. Available at http://www.pubmed.com

7. Silverberg E, Boring CC, Squires TS. (1990)Cancer statistics 1990. CA Cancer J Clin. 40:9–26. Available at http://www.pubmed.com

8. McPhee JT, Hill JS and Eslami MH. (2007)The impact of gender on presentation, therapy, and mortality of abdominal aortic aneurysm in the United States, 2001–2004. J Vasc Surg. 45:891–9. Available at http://www.pubmed.com

9. Singh K et al. (2001)Prevalence of and risk factors for abdominal aortic aneurysms in a population-based study: The Tromso Study. Am J Epidemiol. 154:236–44. Available at http://www.pubmed.com

The Future of Viral Diagnostics: One Test For Every Human And Animal-Borne Virus

Sat, 17 Oct 2015 05:39:14 +0000

The Future of Viral Diagnostics:

One Test For Every Human and Animal-borne Virus

The Ebola Virus

INTRODUCTION:

A September 2015 study published in the American medical journal Genome Research examines a revolutionary new diagnostic method known as “Enhanced Virome Sequencing Using Targeted Sequence Capture,” or ViroCap.

Developed jointly by the McDonnell Genome Institute and the Department of Pediatrics at Washington University School Of Medicine, the test claims to detect nearly all viruses which affect both humans and animals, and with far greater accuracy than standard diagnostic techniques.

This unique synthesis of scope and precision is expected to yield a wide range of health-care benefits for all people, from identifying lethal viruses, treating common infections, perhaps even the discovery of new, previously unknown diseases.

THE STANDARD MODEL: METAGENOMIC SHOTGUN SEQUENCING

Before looking at ViroCap an investigation of the prevailing technique is required. This way, the reader can better judge how the two systems compare.

The current model used in analyzing viruses is known as Metagenomic Shotgun Sequencing (or MSS), so called because the DNA sequence is “randomly sheared into small pieces” like a shotgun blast (California State University). It can be described thus:

Quote: "a relatively unbiased, culture-independent method in which nucleic acid extracted from a sample is sequenced [and] classified based on similarity to reference genomes. This approach allows comprehensive study of the viral component...."

— Genome Research (September 22, 2015)

MSS: Metagenomic Shotgun Sequencing

Or to put it in simpler terms, the benefits of MSS include:

Providing vital genetic information
Ability to classify data into groups
Culture-independence (samples do not have to be grown in a lab and can be taken directly from a patient/environment)

MSS is “particularly useful to studies of the human microbiome, or in layman’s terms, all of the bacteria/viruses/fungi that live in our bodies,” explains MassGenomics.org, an American medical blog dedicated to in-depth analysis of the latest research papers.

However, MSS also has its drawbacks.

According to Dan Koboldt, head of the Human Genetics Analysis Group at Washington University's Genome Institute, “Most efforts to chart the human microbiome have focused on bacteria [which have] relatively stable genomes....Viruses, in contrast, are somewhat under-studied. Part of that is due to the small size and highly variable nature of viral genomes.”

The Human Microbiome

Although MSS is well-adapted for studying the human microbiome, the quote above reveals most of these inquiries have focused on bacterial genomes due to their relative simplicity. Viruses, however, are far more complex and volatile, and therefore less suited to the MSS model.

Another significant flaw of MSS and various diagnostic techniques is their lack of precision. Identifying the countless viruses which infect humans can prove difficult, often requiring several unnecessary tests before a correct diagnosis is found. “That’s because current tests aren’t sensitive enough to detect low levels of viral bugs,” say researchers at Washington University, or they're “limited to detecting only those viruses suspected of being responsible for a patient’s illness.”

Despite its advantages, the statement above shows MSS as less than ideal when it comes to pinpointing viruses. Either the test is not keen enough to find more elusive strains, or multiple attempts are required before determining the correct illness.

This makes the present system of diagnosing viruses a process of elimination. But sometimes patients do not have any time to spare; while their doctors scramble to learn the cause of their sickness the patient may already be dying.

The recent Ebola outbreak is vivid proof of that reality.

According to a September 2015 report from the World Health Organization, the Ebola virus has left over 11,300 dead. If, however, the lethal virus had been correctly diagnosed back in December 2013, that may have prevented it from spreading beyond Guinean borders into neighboring regions and eventually to faraway nations such as Italy, Spain, the United Kingdom and America.

HEALTH-CARE WORKERS TAKING PRECAUTIONS AGAINST EBOLA

All of these facts and statements demonstrate just how flawed our present day system can be for identifying viruses.

Now let's compare it to the ViroCap test.

VIROCAP: WHAT IS IT AND HOW DOES IT WORK?

ViroCap is an alternate method used to enrich the genome sequence of a virus. To develop the test, researchers targeted unique stretches of DNA and RNA from every known group of viruses that infect both humans and animals, according to researchers at Washington University.

The creators of ViroCap describe their new technology as:

Quote: “a comprehensive viral targeted sequence capture panel that could be used to 1) assess all viruses known to infect vertebrate cells and 2) detect divergent viruses. To this end, we created ViroCap, a targeted sequence capture panel that enhances the detection of a
comprehensive set of viruses with vertebrate hosts.”
— Genome Research (September 22, 2015)

In short, ViroCap differs from MSS in that it specifically targets a certain group of viral genes. Unlike a shotgun blast, ViroCap is more akin to a sniper rifle. However, the data it yields is both detailed and comprehensive.

Additionally, the new test is far more ambitious in scope than MSS: its goal is to analyze all viruses that infect vertebrate cells and even variant strains.

Now as to the question of evidence....

CLINICAL STUDIES

To prove ViroCap's superiority researchers performed two human clinical studies, comparing MSS against ViroCap's targeted sequence capture to see which was better at detecting DNA and RNA viruses.

(Note: the virus samples used in both experiments had already been tested positive by the virology lab at St. Louis Children's Hospital)

Process

In each study the same data was sequenced: first, without targeted sequence capture (pre-capture), and then by targeted sequence capture using ViroCap (post-capture).

Experiment 1:

A total of 14 viruses were present in the clinical samples.

Results:

10 viruses were found using MSS pre-capture method
14 viruses were found using ViroCap's targeted sequence capture
Median percent increase of viral reads was 674 (range >13 to 9335)
Median breadth of coverage increased from 2.1% (range 0 to 89.8%) to 83.2% (range 0.8 to 100%)

Researchers describe their findings thus:

Quote:
“Targeted sequence capture resulted in dramatic improvements in all sequence coverage metrics...including number and percent viral reads, breadth and depth of coverage...."
— Genome Research (Sept 22, 2015)

Primary results have so far established ViroCap as a leader in accuracy, having identified 100% or 4 more viruses than MSS with its targeted sequence capture approach.

Experiment 2:

A total of 18 viruses were present in the clinical samples.

Results:

11 viruses were found using MSS pre-capture method
18 viruses were found using ViroCap's targeted sequence capture
Median percent increase of viral reads was 296 (range >56 to 2,722)
Median breadth of coverage increased from 2.0% (range 0 to 99.9%) to 75.6% (range 13.5 to 100%)

Once more ViroCap was the superior of MSS. In Experiment 2, researchers “again found that targeted sequence capture resulted in dramatic improvements in sequencing parameters.”

The evidence is strong: combining data from both experiments, we discover ViroCap identified a total of 32 viruses compared to MSS's 21, an increase of 52%.

ADDITIONAL EXPERIMENT DATA

ViroCap can generate complete/nearly complete genome sequences directly from clinical samples without first culturing the virus
ViroCap can identify RHINOVIRUSES by type
ViroCap can distinguish between HERPESVIRUS 6B and 6A, ADENOVIRUS types A and C, and POLYOMAVIRUSES JC and BK
MSS identified INFLUENZA A pre-capture, but ViroCap classified it specifically as type H3N2 post-capture
ViroCap also sequenced ENTEROVIRUS D68 genome directly from clinical samples

RHINOVIRUS

Once again the facts reinforce ViroCap's targeted sequence capture over the conventional MSS model. Not only can it fully map the genome sequences of a virus, but it does so with remarkable precision.

The significance of this last point cannot be overstated:

Quote:
“...while standard testing identified a virus as influenza A, which causes seasonal flu, [ViroCap] indicated that the virus was a particularly harsh subtype called H3N2. Last flu season, H3N2 contributed to some 36,000 deaths in the United States.”

—Washington University (September 29, 2015)

In the case above, standard MSS testing detected the influenza A virus but failed to pinpoint the H3N2 strain.

The result?

36,000 deaths last year in the United States alone; 28,800 in England (DailyMail.uk), and over 600 in Canada (Public Health Agency of Canada).

Media outlets publicized the large death-toll with headlines like “Flu Season Declared An Epidemic Due To Mutating H3N2 Virus, Ineffective Vaccines (International Business Times).”

H3N2 Strain of Influenza A

But as the experiments revealed, ViroCap was able to precisely identify the virus subtype, “And in some patients – particularly young children, older adults...knowing that the H3N2 strain is present may alter treatment (Washington University).”

ViroCap's ability to collect detailed genetic data may have helped identify the H3N2 strain of Influenza last year, giving doctors vital knowledge of how to fight the virus and lower the immense death-count.

VIROCAP—POTENTIAL MEDICAL BENEFITS

Because ViroCap is such a new medical development studies on its real-world use have yet to be published. According to Washington University it may take several years before the test is clinically available.

So, using my own reasoned arguments backed by proven facts, the following is a list of probable (though still theoretical) future benefits ViroCap may bring.

LOWER COST OF HEALTH-CARE

ViroCap's advantage lies in its precision and ability to detect the most elusive viruses, and for this reason I believe it will lower medical bills. “While PCR tests can screen for up to about 20 similar viruses at one time, it seems that ViroCap could theoretically test for virtually any virus,” reports MedicalNewsToday.com.

Fewer tests mean lower prices. For example, diagnosing Ebola costs roughly $1000 (Mirror Daily) but according to Genome Research, “ViroCap achieves better viral coverage while requiring...fewer total sequence reads. This increased efficiency has the potential to lower sequencing costs.”

Therefore, it is logical to assume that one of ViroCap's potential benefits would be reduced health-care payments from less testing.

IMPROVED LIFE EXPECTANCY

Researchers at Washington University state: “current tests...are limited to detecting only those viruses suspected of being responsible for a patient’s illness.”

Compare that to ViroCap:

Quote:
“With this test, you don’t have to know what you’re looking for...It casts a broad net and can efficiently detect viruses that are present at very low levels...especially useful in situations where a diagnosis remains elusive after standard testing...”

—Washington University (September 29, 2015)

Doctors will no longer be limited to specific tests which they believe may help them identify a patient's illness, or move from one diagnostic tool to another in the hunt for obscure viruses, but can use a single, far more efficient means of finding the correct diagnosis.

And because it “casts a broad net,” ViroCap can reveal diseases no one was searching for but were nonetheless present. Simply put: the new test can save lives by detecting the nearly undetectable, or identify future health risks through early diagnosis.

BETTER PATIENT CARE

Instead of enduring multiple tests which may cause pain or distress (especially among children, the elderly and mentally impaired) ViroCap would cut down the number of procedures to just one, making hospital care less invasive for patients.

Less testing also reduces risk of infection. The World Health Organization states that every year “hundreds of millions of patients are affected by health care associated infections around the world.”

As for their impact:

Quote:
“health care-associated infections create additional suffering and come at a high cost for patients and their families...prolong hospital stays, create long-term disability, increase resistance to antimicrobials, represent a massive additional financial burden for health systems...and cause unnecessary deaths.”

— World Health Organization (May 5, 2011)

Among several leading causes of infection WHO cites “prolonged and inappropriate use of invasive devices.”

The key word is devices—meaning more than one.

HOSPITAL RELATED INFECTIONS ARE EVER-PRESENT

Of course, not all medical equipment is used for diagnostic purposes, but many still are. And if greater frequency of testing increases the chances of infection, ViroCap's single diagnostic capabilities would reduce the odds of contagion, thereby saving lives and money.

BETTER VETERINARY CARE + SAFER HUMAN-ANIMAL INTERACTIONS

For a vast majority of readers ViroCap's most obvious benefit would be improvements to human health, but it's also a blessing for pet owners and animal lovers. As stated previously, “researchers targeted unique stretches of DNA and RNA from every known group of viruses that infect both humans and animals.”

ViroCap has the power to identify all animal-borne viruses, which means owners can ensure their beloved pets receive the best care from veterinarians. Early detection can lead to early treatment, so our pets can live longer and healthier lives.

VIROCAP MAY HELP PETS LIVE LONGER THROUGH ACCURATE DETECTION OF VIRUSES

Furthermore, endangered species will have a better chance of surviving with this new technology. Zoos and animal sanctuaries often have breeding programs for at-risk creatures, and being able to identify and treat viruses quickly (such as the canine distemper virus which killed four rare Bengal tigers last year—theguardian.com) can prolong their lives, increase populations, and eventually free them from the constant threat of extinction.

VIROCAP HAS THE POTENTIAL TO SAVE ENDANGERED SPECIES THROUGH EARLY AND ACCURATE VIRUS DETECTION

Lions, tigers, polar bears and leopards, these rare and majestic creatures may have a brighter future thanks to ViroCap.

Lastly, safer human-animal interaction can be achieved through ViroCap's keen ability to detect viruses. According to livescience.com, “About 60 percent of all human diseases and 75 percent of all emerging infectious diseases are zoonotic,” meaning they're passed from animals to humans.

Incredibly, over half the illnesses which affect people actually originate in the animal kingdom. And we're already familiar with some of them: Ebola, bird flu, West Nile, Hantavirus.

In most cases infection is spread to humans via livestock (livescience.com), but with ViroCap's ability to detect every known animal virus, there is a strong possibility of lowering the chances for transmission.

Therefore interactions with nature become less of a risk to our health.

HOW VIRUSES ARE PASSED FROM ANIMALS TO HUMANS (ZOONOTICS)

CONCLUSION

Although ViroCap is still years away from becoming clinically available it holds great potential. Its unique capacity for scanning a wide range of diseases coupled with its knife-like precision make it a vital tool in the identification and treatment of viruses.

Both humans and animals have a lot to gain from its success: lower health-care bills, increased efficiency and diagnostic speed, and quicker treatment, all of which promise longer, healthier lives.

The fact that the inventors of ViroCap are making their technology “publicly available to scientists and clinicians worldwide, for the benefit of patients and research” (Washington University) serves to help all nations, peoples and animals.

The following is a link to entire study published in Genome Research: http://genome.cshlp.org/content/early/20...9.115.long

LIST OF SOURCES (In Alphabetical Order):

Brazier, Yvette. (2015). “A single test could detect almost any virus.” Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/300259.php

Bryner, Jeanna. (2012). “13 Animal-to-Human Diseases Kill 2.2 Million People Each Year.” livescience.com http://www.livescience.com/21426-global-...spots.html

Glum, Julia. (2014) “2014-2015 Flu Season Declared An Epidemic Due To Mutating H3N2 Virus, Ineffective Vaccines.” International Business Times. Retrieved from http://www.ibtimes.com/2014-2015-flu-sea...es-1770728

Koboldt, Dan. (2015). “How to Catch a Virus: Targeted Capture for Viral Sequencing.” Mass Genomics. http://massgenomics.org/2015/10/targeted...ncing.html

Moore, Robert. (2015). “MAJOR MEDICAL BREAKTHROUGH: NEW VIRUS TEST KIT MIGHT DETECT ALL VIRUSES.” Mirror Daily. Retrieved from http://www.mirrordaily.com/breakthrough-...ses/24469/

Rogers, Amy. (2008). “Shotgun Sequencing.” California State University. Retrieved from http://www.csus.edu/indiv/r/rogersa/Bio1...hotgun.pdf

Todd N. Wylie, Kristine M. Wylie, Brandi N. Herter, and Gregory A. Storch. (2015). “Enhanced Virome Sequencing Using Targeted Sequence Capture.” Genome Research. Retrieved from http://genome.cshlp.org/content/early/20...9.115.long

(2015) “Influenza surveillance.” Public Health Agency of Canada. Retrieved from http://www.phac-aspc.gc.ca/influenza/ass...g.php#fig2

(2014). “Dog virus threatens India's dwindling tiger population.” The Guardian. Retrieved from http://www.theguardian.com/world/2014/ja...dia-tigers

(2011) “Health care-associated infections FACT SHEET.” World Health Organization. Retrieved from http://www.who.int/gpsc/country_work/gps...eet_en.pdf

(2015) “New test detects all viruses that infect people, animals.” Washington University In St. Louis. https://news.wustl.edu/news/Pages/28833.aspx