The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), in an update to its mammal detections, reported 11 more positive H5N1 avian influenza tests in mammals, and Colorado wildlife officials reported three more detections in three different mammal species.
In the APHIS update, officials report detections in eight states, mostly in the West but some in the Midwest.
Oregon reported the virus in two skunks and a raccoon. Wyoming, Wisconsin, and South Dakota reported detections in red foxes. California and Washington reported the virus in bobcats. Meanwhile, Montana reported H5N1 in a grizzly bear.
Also, Nebraska reported H5N1 in an Amur tiger and a mountain lion from Scotts Bluff County, which may be linked to an outbreak at a zoo where an earlier grizzly bear death was reported. Four deaths of zoo cats were reported in December, one of them with a confirmed infection and others with suspected H5N1 illnesses, according to a local media report.
The updates raise the number of H5N1 detections in US mammals to 121.
Variety of species affected in Colorado
In related developments, Colorado Parks and Wildlife (CPW) yesterday reported three more detections in wildlife. They include a black bear from Huerfano County that was sick in October, a skunk from Weld County that tested positive in November, and a mountain lion from Gunnison County that was recently confirmed as positive.
CPW said all three animals showed signs of illness before death or upon necropsy. Neurologic symptoms included seizures or circling, weakness, and lack of responsiveness to humans. Signs of organ damage include encephalitis, hepatitis, and pneumonia.
Other similar suspected mammalian cases have been detected in the state, with confirmatory testing pending.
"Other similar suspected mammalian cases have been detected in the state, with confirmatory testing pending," CPW said. The agency added that the number of mammal cases is low, despite the growing variety of infected species.
Health officials are concerned about the growing number of reports in mammals, given that the circulating H5N1 strain has characteristics that make it more recognizable to mammal airway cells.