UN issues warning over mutant strain of H5N1, combination with H1N1

Sep 08, 2011
By dvm360.com staff
Rome — A major resurgence of the H5N1 Highly Pathogenic Avian Influenza through a mutant strain of the virus is spreading through Asia and global leaders are warning against a possible marriage between the highly lethal bird flu strain and the highly infectious H1N1.

Replikin Counts of the two virus strains are rising simultaneously—an occurrence that has not been seen before, warns the United Nations Food and Agriculture Organization (FAO). The viruses are at their highest levels in 50 years and clinical outbreak of both increase the risk that the two may come into contact with each other more frequently, facilitating the transfer of genomic material to form a hybrid.

Replikin Counts were identified in 2000 and have been helpful in predicting prior outbreaks, according to FAO. Increases in H1N1 Replikin Counts in 2008 predicted the 2009 H1N1 pandemic a year in advance, just like H5N1 Replikin Count increases in 2006 predicted lethal outbreaks in 2007. Outbreaks predicted a year ago for each strain are now occurring, says FAO.

The H5N1 virus has infected 565 people since it first appeared in 2003, killing 331 of them, according to the World Health Organization. The latest death occurred earlier this month in Cambodia, which has registered eight cases of human infection this year—all of them fatal. It was eliminated from most of the 63 countries infected at its peak in 2006, but remained endemic in six nations. Outbreaks have risen steadily since then, with almost 800 cases recorded in the last year.

The greatest cause for concern is in Asia, where Vietnam has been invaded by the new virus strain, known as H5N1 – The nation’s veterinary services are on high alert and reportedly considering a targeted vaccination campaign this fall, according to FAO. Although virus circulation in Vietnam poses direct threats to its neighbors, like Cambodia, Thailand and Malaysia, wild bird migration and poultry production increase global risks, says FAO.

"Wild birds may introduce the virus, but peoples' actions in poultry production and marketing spread it," says FAO Chief Veterinary Officer Juan Lubroth. Alarmingly, Lubroth says the new virus strain is apparently able to sidestep defenses provided by existing vaccines.

"The general departure from the progressive decline observed in 2004-2008 could mean that there will be a flare-up of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard," Lubroth says. "This is no time for complacency. No one can let their guard down with H5N1."

As for H1N1, cases dropped following the 2009 pandemic, but are now being reported in the Americas by the Pan American Health Organization, with at least six deaths in 56 cases.

The National Institutes of Health is working on a new vaccine in preparation to meet the threatened combination of H5N1 and H1N1, according to FAO. The vaccine was successful in its first trial and is undergoing further testing.