None of the samples taken from migratory waterfowl, live-bird markets, poultry farms, and backyard flocks in Connecticut has yet tested positive for the deadly strain of bird flu virus being reported in Asia and Europe, according to UConn scientists.
It’s only a matter of time however, they warn, until the potentially deadly virus arrives in New England. The avian flu virus, H5N1, is highly lethal, and while it doesn’t spread easily to people, human beings have virtually no immunity.
“It’s important to recognize that the potential is there,” says Mazhar Khan, a professor of pathobiology who specializes in bird pathology. “Most of the scientists involved with this say it’s coming. And from what I saw when I was in China a couple of months ago, I have to agree.”
Khan works in the Connecticut Veterinary Medical Lab on campus, which
monitors the health status of domestic
birds and wildlife species in the northeast region. He spent two months this summer in China helping train Chinese scientists
in avian diagnostic pathology.
The pathobiology department’s Diagnostic Testing Services Laboratory, the only animal disease testing site in New England accredited by the U.S. Department of Agriculture, works closely with the region’s state departments of public health and environmental protection, veterinarians, and the livestock and other animals industries to provide bacteriology, parasitology, serology, and virology testing.
The laboratory is geared to respond to current and emerging disease problems and is provides diagnostic services for official control programs in, for example, Lyme disease, West Nile virus encephalitis, and chronic wasting disease of deer.
“We are the first line of defense in the Northeast,” says Herbert Van Kruiningen, professor of
veterinary pathobiology and department head.
“We see birds
in our labs every day ranging from pheasants, quail, and Canada
geese to ducks, ostrich, and emus. They are our sentinel flocks. If
avian influenza emerges here we’re going to find it. It won’t stay under- ground for more than 48 hours.”
With the deadly strain of avian influenza killing millions of wild birds and chickens in Asia and Europe, and scientists warning this could be the first phase of a potential worldwide human influenza pandemic, Van Kruiningen and his staff are expanding their surveillance of migrating waterfowl and domestic flocks as potential carriers of the bird flu.
Avian influenza is spread from bird to bird through exposure to respiratory excretions and feces. Unlike in Asia, the vast majority of commercial poultry in the U.S. is kept in sealed chicken houses, making contact with wild birds extremely difficult.
Khan and his students routinely test birds from farms or backyard flocks throughout Connecticut and New England, hoping for early detection. Of the approximately 2,500 samples screened to determine the presence of any known subtype of avian influenza virus, none has indicated the deadly H5N1 virus or any other highly pathogenic strain of avian influenza.
| Stephanie White-Hunt, a postdoctoral fellow in pathobiology, screens chickens for avian flu.
|Photo by Melissa Arbo
With his doctoral students, Khan is working to develop a rapid-response field diagnostic test that commercial organizations can use to detect avian influenza. Early detection improves the odds of containing or eradicating the virus before it can spread, he says.
Khan’s teams also regularly inspect New England’s three remaining live-bird markets in Boston, Providence, and Bridgeport. But, he notes, “there needs to be more systematic coverage.
“Historically, surveillance has not been a high priority,” Khan adds. “There has never been an urgency until now.”
Should the deadly H5N1 flu strain arrive in the United States, it’s not known whether it would mutate in a way that would allow human-to-human transmission, says Antonio Garmendia, a virologist in UConn’s veterinary science department. Garmendia is trying to understand the evolution and prevalence of all avian influenza viruses in wild birds.
He notes that while there is no evidence of regular human-to-human transmission of the virus, scientists are concerned that H5N1 could mutate to a strain that people have never experienced before, leading to a pandemic that could kill millions of people around the world. The virus is continually evolving, and the number of countries where birds are infected and come into contact with humans continues to increase, he says.
“Everybody knows birds are where these viruses come from, but no one knows how they get from birds to humans,” Garmendia says. “We want to identify what genetic changes are important when a normally low-pathogen becomes a high- pathogen strain.”
The 1918 influenza virus that caused one of history’s most deadly epidemics was identified in October as a bird flu that jumped directly to humans. An estimated 50 million people died, and almost half of those who died were healthy young adults.
According to the National Institutes of Health, the virus now circulating in Asia has acquired five of the 10 gene sequence changes responsible for the human-to-human transmission that occurred in 1918.