H5N1 avian flu found in skunk deaths from Vancouver area

Pair of skunks

Greg Schechter / Flickr cc

Animal health officials in British Columbia, Canada, yesterday reported that an investigation into skunks found dead in residential areas of two cities at the end of February have revealed H5N1 avian influenza.

In a statement, the British Columbia provincial government said that eight skunks were found dead in Vancouver and Richmond, about 9 miles to the south, and that they were taken to the BC Animal Health Centre due to concerns that they may have been deliberately poisoned.

Tests on samples from the dead skunks found that they were infected with the same H5N1 avian flu virus that has been killing wild birds and poultry in BC since April 2022. Officials said the skunks were probably scavenging infected wild birds.

Global health officials are tracking more frequent reports of H5N1 detections in mammals. Though the risk to humans is considered low, scientists are seeing more mutations that could influence virulence and replication in mammals.

Officials said there were a few earlier reports of infected mammals in the province, including two skunks and one fox, but those animals were found in rural areas. They said though the virus in skunks poses a low risk to humans, there are risks to people who come into close contact with sick or dead animals. It urged people who find dead skunks to leave the animals where they are and contact the BC Animal Health Centre.

Infected US mammals often had neuro involvement

A study of 67 wild animals in the United States that tested positive for clade H5N1 in 2022 found that many primarily showed neurologic signs. The group described their findings in a preprint study that appeared on Mar 12 on bioRxiv.

Species included red foxes, skunks, racoons, bobcats, possums, a coyote, a fisher, and a gray fox. Ten animals were found dead, and 56 were found alive, including 13 that were euthanized in the field. For one raccoon, the mechanism of death—natural or euthanasia—wasn't recorded. Of those collected alive, 12 later died.

The most common observed symptoms were neurologic, including seizures, ataxia, tremors, and lack of fear of people.

The most common lesions were necrotizing meningoencephalitis, interstitial pneumonia, and myocardial necrosis. However, the team saw species variation in lesion distribution. They concluded that multiple wild species in North America are susceptible to the circulating H5N1 virus, likely due to ingestion of infected wild birds, and that veterinarians should consider H5N1 infection in the differential diagnosis of wild animals with neurologic disease.

More H5N1 US and Chilean poultry

In other avian flu developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today reported one more outbreak, which involves a commercial farm housing 6,000 birds in Pennsylvania's Lancaster County.

Elsewhere, Chile reported its first outbreak at a commercial farm, according to a report from Reuters that cited the country's agriculture ministry.

An update on avian influenza yesterday from the Pan American Health Organization (PAHO) said the virus has been reported in 16 countries in the region, including 8 with outbreaks on poultry farms. Four have reported the virus in mammals: Canada, the United States, Chile, and Peru.

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