Bird flu: A Thing of the Past?

By Nick Gubitosi

This past Friday (February 26, 2010) a group of scientists led by a virologist from the University of Wisconsin published a study about a new antiviral, which was found to be highly effective against the pathogenic H5N1 avian influenza virus.  What stands out about this new antiviral, known as CS-8958, is that it has been proven to be effective against Tamiflu resistant strains of H5N1. This makes it a promising candidate for the future treatment and prevention of the bird flu.

Antiviral drugs are used in the treatment of viral infections by inhibiting the development of disease causing pathogens, and are a vital component in the countermeasure against human influenza viruses.  Recently many new strains have been emerging, which show resistance to Tamiflu, an antiviral that slows the spread of the influenza virus within the body.  These resistant strains pose a threat and make the development of new antivirals a pressing issue.

Professor Yoshihiro Kawaoka from the University of Wisconsin and his team of scientists tested a drug created from a novel neuraminidase inhibitor on mice in order to see its effectiveness against H5N1 strains of influenza.  Neuraminidase inhibitors are a class of antiviral drugs that specifically target the influenza virus by blocking one of its proteins, therefore preventing its replication within the body.

They began their tests by giving a single dose of the CS-8958 antiviral drug nasally to mice, two hours after infection with the H5N1 influenza virus.  The results showed that the survival rates were higher in the mice given this new drug when compared to mice given a standard five day treatment with Tamiflu.  In another experiment, CS-8958 was found to be effective against highly pathogenic and Tamiflu resistant strains of H5N1, while it was also shown to protect mice against lethal H5N1 infection when it was administered seven days before infection with the virus.

With the information gained from this study, future treatment and prevention of H5N1 with this CS-8958 antiviral could be the most effective treatment to date due to its ability to eliminate newly emerging drug resistant strains in only one dose.  While future studies still need to be conducted to make sure that these results are the same when tested on humans, the potential of this new antiviral is promising and could possibly put an end to the fear of the bird flu pandemic.

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Flu to the rescue!

By Shelly Hwang

February 17, 2010

It’s flu season, and with the H1N1 virus being the spotlight of current news and the CDC pushing for nation-wide flu vaccination, people have become terrified of the influenza virus. However, a recent study done by researchers at the Yale University School of Medicine (published in the February 18 issue of Cell Host and Microbe) revealed that the stress response caused by the flu actually protects against death by secondary infection by using mice with bacterial infections.

Influenza can damage the lungs but usually does not kill. However, secondary infections such as pneumonia can occur after infection with the influenza virus and are much more deadly. Each year, more than 200,000 U.S. residents are hospitalized for flu-related complications, and about 36,000 Americans die on average per year from complications of the flu (CDC Statistics).

While previous studies on the flu have shown repressing of the immune system, such studies have only studied a single pathogen and focused on local effects of influenza at the site of infection. In reality, organisms are exposed to multiple infectious agents at a time and the effect of influenza on the whole immune system has not been studied.

This study, led by Dr. Rusian Medzhitov from the Department of Immunology, used a mouse model to examine the effects of the lung infection caused by influenza on the immune response to bacterial infection. Surprisingly, the researchers found that the influenza lung infection led to increased production of glucocorticoids (GC), which are produced in response to stress and known to play a key role in regulating inflammation. They found that virus-induced GC production is essential to controlling inflammation, as shown by the death of mice lacking GC’s that were infected by multiple pathogens.

So the next time you find yourself miserable and overwhelmed with the unpleasant flu FACTS symptoms (Fever, Aches, Chills, Tiredness, Sudden symptoms), remember to thank the virus for protecting you from fatal secondary infections.

Press Release

Department of Immunobiology at Yale