LIFE CYCLE OF INFLUENZA A

What is Relenza?

Relenza (zanamivir) is an antiviral medication. It blocks the actions of viruses in your body.

Relenza is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Relenza may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Zanamivir will not treat the common cold.

Relenza should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

What is Tamiflu?

Tamiflu (oseltamivir) is an antiviral medication that blocks the actions of influenza virus types A and B in your body.

The making of a Russian blockbuster drug

Antiviral and anti-inflammatory activity of arbidol hydrochloride in influenza A (H1N1) virus infection

Thirty-one years ago, W. Neal Burnette published a paper that described a technique called Western blotting. The paper initially was rejected by the journal Analytical Biochemistry, but it went viral among molecular biologists as a preprint. Eventually the journal agreed to publish the paper, which now has been cited more than 6,000 times.

The term “blotting” refers to the transfer of biological samples from a gel to a membrane and their subsequent detection on the surface of the membrane. Western blotting (also called immunoblotting because an antibody is used to specifically detect its antigen) was introduced by Towbin, et al. in 1979 and is now a routine technique for protein analysis. The specificity of the antibody-antigen interaction enables a target protein to be identified in the midst of a complex protein mixture. Western blotting can produce qualitative and semiquantitative data about that protein.

ELISA (enzyme-linked immunosorbent assay) is a plate-based assay technique designed for detecting and quantifying substances such as peptides, proteins, antibodies and hormones. Other names, such as enzyme immunoassay (EIA), are also used to describe the same technology. In an ELISA, an antigen must be immobilized to a solid surface and then complexed with an antibody that is linked to an enzyme. Detection is accomplished by assessing the conjugated enzyme activity via incubation with a substrate to produce a measureable product. The most crucial element of the detection strategy is a highly specific antibody-antigen interaction.

Seasonal Influenza Vaccination amongst Medical Students: A Social Network Analysis Based on a Cross-Sectional Study

When to have vaccinations

Targeting popular people is the best way to vaccinate against flu

infections and Networks

This project is funded by the Colt Foundation.

Influenza is an acute, contagious respiratory infection. Influenza causes considerable mortality and morbidity each year and can be a primary, underlying or contributing factor to cause of death. In hospital, influenza poses a risk to both medical staff and patients; it is one of the leading causes of respiratory infection and can be fatal in the elderly. Vaccination remains the most effective method of influenza prevention and control.

Principles of Epidemiology in Public Health Practice, Third Edition
An Introduction to Applied Epidemiology and Biostatistics

Fomites are inanimate objects that when contaminated with infectious agents can transfer disease to a new host. Normally, when we think of a fomite, we usually conjure obvious ones…a scalpel,  a phone, a pencil. But sometimes it is the most obvious objects that are at fault, but still overlooked. For example,   a small study published in 2009 indicated that not only were 15% of all stethoscopes tested contaminated with MRSA, but also that the MRSA on the stethoscopes had survived there for upwards of 60 days!

Also, most hospitals do not allow artifical fingernails or nail enhancement on health care workers because the false nails (fomites) consistently have higher bacterial loads than natural nails. Also, there have been a number of studies (example) where doctor’s neckties were found to be commonly contaminated with bacteria. Not all that shocking when you think about  how often men wash their ties?

But most recently, a new  study published in the American Journal of Infection Control, 60-65% of scrubs and lab coats of health care workers tested in the report were contaminated with potentially dangerous bacteria.  The pockets, sleeves, and abdominal areas were tested. Additionally, 21 of nurse’s samples and 6 from the doctor’s samples taken were drug resistant.  Eight of the samples were identified as MRSA (methicillin resistant Staph aureus ).

This is not exactly news, as there are several previous articles detailing how  bacteria can survive on various cloth and plastic surfaces, as well as on lab coatsin general.

Hospitals  and doctors are struggling to get it right, though. Just announced in 2010, the  DocFroc:

lab coats and scrubs that are embedded with Tri-Active, an FDA approved silver-based antimicrobial compound that can kill resistant micro-organisms such as MRSA, ECOLI and Salmonella.

It appears that the most important factor in prevention of disease is to simply better identify what has been transferring disease in the first place.

 

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Fomites Shown to Spread Influenza

A trio of researchers evaluated the role of fomites (coveralls, boots, gloves) as indirect means of influenza transmission between pig populations.

Immune System: Diseases, Disorders & Function

Influenza A: Understanding the Viral Life Cycle

Abstract

Influenza A virus belongs to the family of Orthomyxoviridae. It is an enveloped virus with a negative sense RNA segmented genome that encodes for 11 viral genes. This virus has evolved a number of mechanisms that enable it to invade host cells and subvert the host cell machinery for its own purpose, that is, for the sole production of more virus. Two of the mechanisms that the virus uses are “cap-snatching” and preventing the host cell from expressing its own genes. This mini-review provides a brief overview as to how the virus is able to invade host cells, replicate itself, and exit the host cell.

Keywords: Influenza A, virus, cap-snatching, host shut off, sialic acid, hemagglutinin, HA, NA, PB1, PB2, PA, M2, M1, NP, PB1-F2, NEP, NS1, NS2

PLOS

Influenza virus structure

Influenza viruses are roughly spherical, although somewhat pleomorphic, particles, ranging from 80 to 120 nm in diameter. 1, 7 

ANIMATION

This science animation was developed for Zirus, a biopharmaceutical company that was working on the development of a new class of antivirals.

– See more at: http://www.xvivo.net/animation/influenza-a/#sthash.Fa3atH6y.dpuf

Hemagglutinin

Influenza virus binds to cells and infects them using hemagglutinin

Influenza hemagglutinin. The portion spanning the membrane is not included in the structure and is shown schematically.

Download high quality TIFF image

Influenza virus is a dangerous enemy. Normally, the immune system fights off infections, eradicating the viruses and causing a few days of miserable flu symptoms. Yearly flu vaccines prime our immune system, making it ready to fight the most common strains of influenza virus. But once every couple of decades, a new strain of influenza appears that is far more pathogenic, allowing it to spread rapidly. This happened at the end of World War I, and the resultant pandemic killed over 20 million people, more than twice the number of people that were killed in the war.

Influenza Neuraminidase

Neuraminidase is an important target for influenza drugs

Ectodomain of neuraminidase (top), with Relenza (center) and Tamiflu (bottom), and three zinc fingers from Klf5 (bottom).

Download high quality TIFF image

Influenza virus is continually changing and every decade or so, a dangerous new strain appears and poses a threat to public health. In 2009, there was an outbreak of a new strain of H1N1 flu, more commonly known as swine flu. The H1N1 designation refers to the two molecules that cover the surface of the virus: hemagglutinin and neuraminidase. Together, these two molecules control the infectivity of the virus. Hemagglutinin plays the starring role as the virus approaches a cell, binding to polysaccharide chains on the cell surface and then injecting the viral genome into the cell. Neuraminidase, on the other hand, plays its major role after the virus leaves an infected cell. It ensures that the virus doesn’t get stuck on the cell surface by clipping off the ends of these polysaccharide chains.
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