The H5N1 subtype of the bird flu virus has caused millions of deaths of birds (domestic and wild) in various parts of the world since its original detection in China in 1996. This version of the also known as bird flu or avian influenza, in addition, It has been detected in the last two years in 42 species of mammals in ten countries, including Spain, where cases were detected in mink farms in Galicia.
Last September, a health emergency was activated in the Galapagos Islands due to the death of birds infected by this virus and in October the first cases of birds infected with this flu were confirmed in the Antarctic zone and various experts warned of the danger for the populations of penguins.
On the other side of the planet, the Department of Environmental Conservation in Alaska (United States) has now confirmed the world's first known case of the death of a polar bear infected by the H5N1 avian flu virus. The animal's carcass was located last October near the town of Utqiagvik, in the North Slope region of Alaska (United States).
The information has not been released until now because "the discovery of the virus in the animal's body tissue has been a process that has required sampling and study by the North Slope County Department of Wildlife Management and other agencies," said Veterinary Doctor Bob Gerlach, from the Global Center for Health Security, at the University of Nebraska College of Medicine.
"This is the first polar bear case reported anywhere," Gerlach said. As such, it was reported to the World Organization for Animal Health and has drawn attention in other Arctic nations that have polar bears, he said.
Wildlife and animal health experts are studying the possible origin of the infection in the dead polar bear. Experts highlight, on the other hand, that this is also the first animal included in the Endangered Species Act in Alaska that has been a victim of bird flu. The extent of this epizootic may affect polar bears, which depend on sea ice that is decreasing due to climate change, and which were listed as a threatened species in the United States in 2008.
While polar bears typically eat seals they hunt on sea ice, it seems likely that this bear was scavenging dead birds and ingesting the influenza virus that way, Gerlach said. According to the Department of Environmental Conservation, numerous birds of various species on the northern slope have died from this avian influenza. From what is known so far, it would be necessary for the bear to directly eat an infected bird to contract the disease, as explained by Professor Gerlach in statements published by Juneau Empire.
"If a bird dies from H5N1, especially if the body is kept in a cold environment, the virus can be preserved alive for a time," said this expert. The death of the polar bear would in this case be a worrying sign of the persistence and extension of this strain of highly pathogenic avian influenza, identified for the first time in North America two years ago, animal health authorities in Alaska have indicated.
“What we are observing now is a scenario that we had not known until now, that is why there is no manual for action and the maximum possible precautions must be taken,” said Andy Ramey, wildlife geneticist at the United States Geological Survey and expert. in avian influenza.
