November 2, 2005

Scientists Track Avian Flu

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Is avian influenza the next pandemic? Are humans susceptible to the novel H5N1 strain, and if so is it contagious and capable of spreading nationwide?

These are serious questions and concerns that Cornell researchers are working hard to answer.

Alfonso Torres, director of the Animal Health Diagnostic Center and associate dean for veterinary public policy at the New York State College of Veterinary Medicine, and Susan Trock, a veterinary extension epidemiologist at the Veterinary Diagnostic Laboratory are a few of the Cornell researchers involved in investigating and analyzing any outbreak of the virus.

“The fear is that if the virus changes or recombines with a regular human flu, the virus may acquire the ability to be effectively transmitted from human to human, then it could become the big pandemic that everyone is very concerned about,” said Torres in an interview with The Cornell Chronicle.

Avian influenza, which has been responsible for thousands of avian fatalities in Southeast Asia, Turkey, Romania, Greece and Russia, is causing concern, because human infections have been reported. Approximately 120 individuals have been hospitalized and 60 have died from the virus in Asia. While the numbers are low, considering that farmers and bird handlers have been exposed to the virus many times, scientists worry that the virus that is normally non-transferable to humans could mutate and become virulent to humans.

Avian influenza, specifically the H5N1 strain, has been detected most recently in chickens, ducks and other waterfowl. These birds contract the virus from coming in contact with other bird’s waste, nasal secretions and saliva.

“Although avian influenza viruses, which are shed through a bird’s feces, won’t replicate in the environment, they can stay alive for several months, just waiting to be picked up by some live bird,” Trock told The Cornell Chronicle.

However, while it can spread so easily throughout bird populations and hence humans populations because of constant contact with birds, not a single case of the H5N1 virus has been found in a human in New York State.

“We have only found bird-strains of the flu that only affects birds – not humans,” said Jessica Chittenden, spokesperson for the New York State Department of Agriculture and Markets. “It’s important to realize that we have been surveying the avian flu in New York State for a long time.” This record is credited to the intricate system that tests birds along the way from their first sale to their slaughter.

“There are many stopgaps in the system,” Chittenden said. “Farmers must sell birds to licensed wholesalers to ensure that all the birds go through a licensed middleman. We also require testing for avian flu at the bird’s origin, even if it’s out-of-state, to ensure that the original supply isn’t contaminated.”

While these precautions are effective, the main cause and source of the virus spreading occurs in bird markets that either sell live birds or slaughter them in unsanitary conditions.

“Live bird markets, like ones located in the five boroughs of New York City, are places where people can purchase and have birds slaughtered on site,” Chittenden said. “In these conditions it is much more probable for the virus to get spread and infect other birds.”

Locations and practices such as these have led to laws being introduced to govern the purchase and exchange of birds. One such rule is that the birds cannot be sold alive, according to Chittenden.

With these precautionary regulations in place combined with rigorous testing of the bird locations and farms, it is very unlikely to have a large spread of the virus infect birds in New York, let alone people.

“We require quarterly testing of the bird facilities, but most sites usually get tested six to eight times a year,” Chittenden said.

These techniques, combined with efforts of scientists studying birds and the H5N1 strain could stop a potentially deadly pandemic.

Archived article by Carl Menzel
Sun Staff Writer