New Compound Fights Seasonal And Bird Flu Viruses

Scientists from Hong Kong and Canada have identified a chemical compound that can halt the replication of both the H5N1 bird flu virus and the seasonal human flu virus.

The scientists discovered that the chemical "nucleozin" fought off both viruses in mice as well as in cell cultures.

Identifying new flu drugs is critical as flu viruses mutate and are skillful at evading the limited number of antiviral drugs currently available.

"We have now brand-new weapons to combat influenza virus resistant to … (antiviral drugs like) oseltamivir and zanamivir," Reuters quoted microbiologist Richard Yao at the University of Hong Kong, the study’s leader, as saying.

Zanamivir is the generic name for Relenza, a flu drug made by GlaxoSmithKline and Biota Inc., while oseltamivir is the generic name for Tamiflu, made by Roche AG and Gilead Sciences Inc.

Indeed, nearly all of the seasonal H1N1 viruses circulating in the U.S. during the 2008-2009 flu season were resistant to Tamiflu, according to a report about the study published in the journal Nature Biotechnology.

An older class of drugs known as Adamantanes was also ineffective against seasonal H3N2 flu viruses in the U.S. during that period.

Nucleozin targeted a flu virus protein known as nucleoprotein, which is responsible for virus replication, said Yao in an interview with Reuters.

The scientists chose nucleozin from a chemical library with more than 50,000 compounds, he said. 

It was the same library used by experts to study the SARS virus.

"Nucleozin is highly potent in cell culture and also in mice infected with the highly pathogenic influenza virus H5N1 … (it can) stop the virus from replicating," Yao said.

The compound was effective against H1N1, H3N2, and H5N1 viruses and scientists can now seek out nucleoprotein to combat flu, he added.

"Scientists could now use nucleoprotein as a target to develop antiviral therapeutics for the treatment of influenza infection.”
 
The seasonal H1N1, a cousin of the newer H1N1 swine flu virus, has been in circulation for some time.  SARS emerged in southern China in 2003, killing some 800 people throughout the world.

Although H5N1 is mainly a disease in birds, it was first discovered in people in 1997.   The virus has a mortality rate of 60 percent when it infects humans. 

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On the Net:

• University of Hong Kong
• Nature Biotechnology Abstract