KANSAS CITY (Dow Jones)--Idaho and U.S. veterinary officials may never find the source of an infection that is killing wild mallard ducks in a small area of southeastern Idaho, although they probably will find the cause, said Mark Drew, wildlife veterinarian for the state Wildlife Health Laboratory, Thursday.
Since mallards are highly migratory birds, the source of the infection could be a field of moldy grain or something similar that is days away in terms of flight time for the birds, Drew said.
He stressed that there is no evidence that the Asian form of the H5N1 virus is anywhere in North America, downplaying the likelihood that the birds are dying from the highly pathogenic virus. The U.S. Department of Agriculture and the U.S. Fish and Wildlife Service have studied 20,000 birds in the Pacific Flyway in the last three months trying to find the H5N1 virus, and none has been found, Drew said.
There are several possibilities for the deaths of 1,000 to 1,500 birds so far, he said, but the top three are a fungal pneumonia, a bacterial pneumonia or “some sort of toxin.“
Idaho Department of Fish and Game regional supervisor Dave Parrish put the total of dead birds at “up to 2,500 by now.“
Drew said it was easier for him to draw a conclusion that the birds had been attracted to a field or a pile of moldy grain than to think they had injested a chemical. He said the presence of lesions in and around the lungs and the absence of problems in the digestive tract would lead him down this path for his initial investigations.
Samples have been sent to other laboratories, and initial results could be back by the end of the week, Drew said.
USDA spokeswoman Karen Eggert said the USDA is not yet involved in the investigation, although the department is “closely monitoring the situation.“ The USDA has biologists in that area to assist if needed, she said.
“We’re just monitoring the situation right now, and should it be a foreign animal disease or something we need to be involved with, we’re prepared to do that,“ Eggert said. “If there’s anything suspect, samples will be sent to NVSL (the National Veterinary Services Laboratory in Ames, Iowa).“
The USDA would get involved if local avian influenza tests produced a “presumptive positive“ result or if there were indications of avian influenza, Eggert said.
The USDA’s Web site says the NVSL serves as a national reference laboratory, providing other diagnostic laboratories with animal disease information and technical guidance. The NVSL also performs laboratory testing for the Veterinary Services unit of the USDA’s Animal and Plant Health Inspection Services.
Source: Lester Aldrich Dow Jones Newswires 913-322-5179 lester.aldrich@dowjones.com