The California Department of Fish and Wildlife (CDFW) says “Bird Flu” killed two cougars and a bobcat, but the agency does not think the disease poses a major threat to the state’s population of large felines.
Bird Flu “Avian influenza” is a serious threat to birds and now it appears to be one more threat facing the state’s beleaguered mountain lion population. Inbreeding, habitat fragmentation, mange and traffic are among the threats California cougars face. Although it killed two cougars, CDFW thinks avian influenza is a far less serious threat.
What is bird flu? According to the Centers for Disease Control and Prevention (CDC):
“Avian influenza or bird flu refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses naturally spread among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Bird flu viruses do not normally infect humans. However, sporadic human infections with bird flu viruses have occurred. “
According to PubMed the disease was first identified in Italy more than 100 years ago. That it can jump to humans was discovered in the 1990’s. So far, about 117 cases of human infection have been comprehensively identified. Of these cases, from four Asian countries, 60 have died. Thus, the disease can be very serious for humans. Recent outbreaks have been responsible for the death or euthanization of an estimated 150 million domestic birds. There is some concern that a mutated form of Avian flu could result in a pandemic.
According to the CDFW:
“The Eurasian lineage of avian influenza is primarily a disease impacting birds but is occasionally being detected in wild mammals. We don’t expect this to have a population-level impact for California’s mountain lions or other mammalian carnivores, but it is a disease we will continue to monitor,” said Dr. Jaime Rudd, a pesticide and disease investigations specialist in CDFW’s Wildlife Health Lab.
“The main route of disease transmission for carnivores seems to be through ingestion of infected birds – typically waterfowl such as geese. Biologists following the movements of these mountain lions noted that they had preyed upon wild Canada geese in the past,” Rudd said.
The mountain lions a mother and daughter, died of encephalitis (inflammation of the brain). .They died last December and this January. They died near Mono Lake in Mono County. Both were collared as part of a wildlife study and thus were quickly located and necropsied. Necropsy is an autopsy performed on an animal. A bobcat also died in Butte County. CDFW says Avian flu has been detected in 45 of California’s 58 counties.
The CDFW went on to say:
“Notwithstanding the mountain lion and bobcat detections, infection of wild mammals with avian influenza viruses appears to be relatively rare. Elsewhere in the U.S. and Canada, periodic detections of HPAI H5N1 have been made in mammalian carnivores including foxes, bobcats, raccoons, skunks and bears. Detections in mountain lions have occurred in five other states. The virus has also been detected in a small number of marine mammals.
The strain of HPAI H5N1 currently circulating in the U.S. and Canada has caused illness and death in a higher diversity of wild bird species than during previous avian influenza outbreaks, affecting raptors and avian scavengers such as turkey vultures and ravens. Mammalian and avian predators and scavengers may be exposed to avian influenza viruses when feeding on infected birds.”
The state’s mountain lion population is believed to be robust and relatively stable. But a comprehensive estimate of the current numbers has not been completed. Most of California is considered “prime” mountain lion habitat. An estimated 5,000 of the cats make the state their home.