Bird-flu outbreak wanes along with bird migration, but could resurge; virus is infecting foxes, bobcats, other mammals

Photo from U.S. Department of Agriculture/Flickr/Creative Commons

"A bird-flu outbreak in the U.S. that led to the deaths of more than 40 million chickens and turkeys and contributed to a spike in egg and meat prices appears to be waning, but experts caution the virus hasn’t disappeared and worry another surge could take hold this fall," The Associated Press reports.

The lingering threat was illustrated this month by a culling of more than 2 million birds "after infections were discovered at two large farms in Colorado," Josh Funk reports. "The number of birds culled to limit its spread dropped from a peak of almost 21 million in March to less than 800,000 in May."

In Iowa, the nation's top egg producer, which has lost the most birds (13.4 million), "No cases have been reported in the state since May 4, likely because migrating wild birds, which are blamed for spreading the virus, have moved out of Iowa," AP reports. "Agriculture Secretary Mike Naig said the virus still poses a risk because more cases are being reported, but that 'It really does feel like we’re on the tail end of it for this year.'"

But "Richard Coker, a spokesman for the Animal and Plant Health Inspection Service of the U.S. Department of Agriculture, told AP, “We are not ready to say the outbreak is winding down. We remain vigilant and encourage producers to continue to practice strong biosecurity.” AP reports, "The summer heat should help kill off the disease, but experts worry that the latest version of the virus may be hardy enough to survive the season, leading to a new outbreak when wild birds migrate later in the year."

The outbreak remains smaller than one in 2015, when 50 million turkeys and chickens were killed, making it "the most expensive animal health disaster in U.S. history," AP notes. "The government spent nearly $1 billion then to deal with infected birds, clean up barns and compensate farmers. The USDA has so far approved $793 million to cover costs this year," but that won't cover lost income, National Turkey Federation spokeswoman Beth Breeding told AP.

Wisconsin red fox kit, recovering (Dane County Humane Society)

Meanwhile, Emily Anthes of The New York Times reports that the virus is infecting wild mammals: "At least seven U.S. states have detected the virus in red fox kits, to which the pathogen appeared to be particularly lethal. Two bobcats in Wisconsin, a coyote pup in Michigan and skunks in Canada have also tested positive for the virus, as have foxes, otters, a lynx, a polecat and a badger in Europe. (Two human cases, one in the United States and one in Britain, have been reported as well, both of which were in people who had close contact with birds.) There is no evidence that mammals play a significant role in spreading the virus, and the risk to humans remains low, experts said."