The virus has caused the deaths of tens of millions of domestic chickens, geese, ducks and turkeys in the U.S., contributing to the rise in egg prices.<\/p><\/blockquote>\n
Over the past three years, more cases of H5N1 in wild mammals have been reported in Washington than in any other Western state except Colorado and New Mexico. Before H5N1 was identified in the two Olympic Peninsula cougars, sick animals had typically lived near wild bird populations infected with the virus. The 15 harbor seals that died in 2023, for example, frequented the same beach as a flock of infected Caspian terns. \u201cThe assumption was they were scavenging carcasses or even catching and eating sick birds,\u201d said Katherine Haman, a WDFW veterinarian.<\/p>\n
But the two cougars weren\u2019t living near any known outbreaks in wild birds or other prey species, according to the agency. Their deaths illustrate how little we know about how the disease spreads in wildlife, and how far it may have already reached.<\/p>\n
UNLIKE THE COUGAR in the cow pasture, Clallam County\u2019s second victim showed no obvious signs of disease. He had been fitted with a GPS collar as part of Panthera\u2019s Olympic Cougar Project, and Elbroch said that he looked to be \u201cin perfect health.\u201d Later analysis of movement data, though, revealed the cougar had started to behave differently, traveling shorter distances than previously.<\/p>\n
Virus-carrying prey can also appear healthy. \u201cWe don\u2019t really know which animals are carrying and which ones have been exposed and recovering,\u201d Elbroch said.<\/p>\n
While there were no documented H5N1 outbreaks in the area, the cougars may have eaten infected birds along the Pacific Flyway, a major north-south migration route that runs along the West Coast from Alaska to Mexico. Or they may have consumed a mammal \u2014 a raccoon, river otter, seal or sea lion \u2014 that had eaten an infected bird. Regardless of the cause, the two deaths in the same general area during the same short timespan suggest that bird flu is circulating undetected in the apex predators\u2019 prey. \u201cThat just really highlights, to me, that this virus may be more widespread on our landscape than we know or think it is,\u201d said Haman.<\/p>\n
Although 70 H5N1 cases have been confirmed in humans \u2014 mostly poultry and dairy farmworkers \u2014 in the U.S., public health officials say the virus still poses a low health risk: It has not yet spread between people, and its symptoms are usually mild. But the further it spreads among other mammals, the more opportunities it will have to mutate into a form easily contracted by humans. If the virus acquires the ability to be more readily transmitted between mammals or between humans, Haman said, \u201cwe have a potential brewing pandemic.\u201d<\/p>\n
In December, the wildlife agency announced that the state was seeing an uptick in cases in both wild birds and mammals. So far this winter, it\u2019s been detected in a long-tailed weasel, raccoon, harbor seal and bobcat.<\/p>\n
If H5N1 continues to proliferate among wild birds and mammals, isolated or small populations \u2014 including threatened and endangered species, such as ferrets and California condors \u2014 will be particularly vulnerable. \u201cFlu is \u2026 rarely considered a wildlife conservation issue,\u201d said Justin Brown, a wildlife veterinarian and professor at Pennsylvania State University. \u201cBut with this virus, now that it causes disease in (other) wildlife, there are some conservation concerns.\u201d<\/p>\n FULLY UNDERSTANDING any wildlife disease isn\u2019t easy, due to the lack of monitoring and surveillance. \u201cThere\u2019s just so much about this virus and the epidemiology and disease ecology of it that we don\u2019t understand, especially in wild mammals right now,\u201d Haman said. State wildlife agencies, which are chronically short of funding, primarily rely on the public to report sick and dead wildlife, meaning the numbers could be far greater than recorded.<\/p>\n Regular monitoring and sampling would help researchers better understand H5N1 and its spread. \u201cWe could get ahead of avian flu right now with the right resources,\u201d Elbroch said. After cases among dairy cows and farmworkers rose in California last fall, Gov. Gavin Newsom declared a state of emergency to free up resources for monitoring; as of February, it\u2019s the only state to do so. Though the federal government laid out a $1 billion plan to curb bird flu in domestic poultry in late February, the Trump administration is considering cutting funding for the development of a bird flu vaccine for people.<\/p>\n If the virus acquires the ability to be more readily transmitted between mammals or between humans. \u201cWe have a potential brewing pandemic.\u201d<\/p><\/blockquote>\n Brown, who is partnering with Washington wildlife officials to continue studying the disease, plans to test blood samples collected from living wild animals for H5N1 antibodies, an indication of recovery from infection. \u201cI think that this is a disease that will be here for the foreseeable future,\u201d Brown said. \u201cThe challenge then is: How do we tweak our research, our surveillance and our management to now deal with this new normal?\u201d<\/p>\n This article<\/a> by Kylie Mohr was first published by High Country News on 1 April 2025. Lead Image: A cougar infected with the H5N1 strain of avian influenza crosses a field in Clallam County, Washington, last fall. It was later euthanized. Courtesy of Mark Elbroch\/Panthera.<\/i><\/p>\n Wildlife continues to face threats, which include hunting, poaching, illegal trade in animal products, habitat loss as well as a rapidly changing climate.<\/p>\n Become a Wildlife Champion today by supporting our conservation partners<\/a> with a monthly donation as little as $1.<\/p>\n![\"Source:](\"https:\/\/i0.wp.com\/www.hcn.org\/wp-content\/uploads\/2025\/03\/bird-flu-57-04_2.jpg?resize=768%2C444&quality=100&ssl=1\" "\\"\\"")
What you can do<\/h2>\n