Bird Flu Detected in 2 California Mountain Lions

Rescued chickens gather in an aviary at Farm Sanctuary’s Southern California Sanctuary in Acton, Calif., on Oct. 5, 2022. A wave of the highly pathogenic H5N1 avian flu had entered Southern California, raising concerns for wild birds and poultry farms in the region. Mario Tama/Getty Images

The Eurasian strain of the highly pathogenic avian influenza (HPAI H5N1) has been detected in two mountain lions in California in recent months, wildlife health experts confirmed this week.

In a March 28 news release, the California Department of Fish and Wildlife (CDFW) said that while additional disease testing is currently being conducted to rule out the possibility of co-infections, avian influenza is suspected to be the cause of death for both mountain lions.

The remains of the mountain lions, a mother and daughter, were collected in Mono County on Dec. 23, 2022, and Jan. 14, 2023, and samples were submitted to the California Animal Health and Food Safety Laboratory in Davis for preliminary testing, officials said.

Last week, the U.S. Department of Agriculture’s National Veterinary Services Laboratories confirmed the detection of HPAI H5N1 after finding inflammation in the brains of the animals and lesions in the lungs causing pulmonary edema, both of which were associated with the virus.

Avian influenza, or bird flu, is a highly contagious viral disease mainly affecting birds. However, it has been discovered in other animals, such as pigs and dogs in China, Indonesia, and Vietnam, as well as domestic cats in Germany, according to the Centers for Disease Control and Prevention (CDC).

It spreads easily among birds through nasal and eye secretions, as well as manure, and it can prove deadly in domestic poultry.

Bird Flu Cases Across the Globe

The latest findings make the mountain lions the second wild mammal species known to have contracted avian influenza in California since the virus was reported in wild birds in July 2022.

In January, the virus was detected in a bobcat found in Butte County. Before that, avian influenza was first detected in wild birds in the state in July 2022.

To date, various strains of the virus have been found in 47 states, according to the CDC, and have affected more than 58 million farmed birds.

It was also detected in one individual in Colorado in April last year. According to health officials, the individual had direct exposure to poultry and was involved in the culling (depopulating) of poultry with bird flu. The patient, identified in media reports as a male, reported fatigue for a few days and was placed in isolation while he recovered.

Multiple other cases among humans have been detected in Canada, the United Kingdom, Ecuador, Chile, and China. A case of H5N1 infection in an 11-year-old girl in Cambodia led to her death last month.

The girl, from the rural southeastern province of Prey Veng, became ill on Feb. 16 and was hospitalized in the capital, Phnom Penh. She suffered throat pain and died shortly afterward, the health ministry said.

Risk to Humans Remains Low

Despite the cases discovered worldwide, the CDC considers the transmission risk of avian influenza to people to be low but recommends taking basic protective measures, such as avoiding direct contact with wild birds or touching surfaces that may be contaminated with saliva, mucous, or feces from wild or domestic birds.

The health agency also recommends people who work with birds wear protective equipment like gloves or an N95 respirator.

“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.

Rudd noted that detections of the virus in mountain lions have occurred in five other states and had also been detected in a small number of marine mammals.

“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 latest detection comes as the ongoing bird flu outbreak has sent the global price of eggs skyrocketing, worsened further by rising inflation, and cost farmers raising chicken and turkeys more than $1 billion, according to industry experts.