The current strain of H5N1 highly pathogenic avian influenza (HPAI) circulating in the United States emerged in U.S. poultry in February 2022. HPAI has affected domestic birds, wild birds, and several species of mammals including big cats, bears, coyotes, foxes, opossums, otters, seals, skunks, and squirrels. In Michigan, H5N1 HPAI infections have been confirmed in wild mammals such as red fox, opossum, raccoons, and coyotes since the outbreak began in 2022. Infection can cause illness, severe disease, and even death especially in young wild animals.

Most recently, infections of dairy cattle have been confirmed in herds in several states including here in Michigan. On and around affected dairies, sick and dead wild mammals and domestic cats have been widely reported, presumably linked to exposure to infected raw milk which often contains high levels of virus. As part of the effort to track the virus, the United States Department of Agriculture (USDA) is covering the testing costs of sick and dead cats and wildlife near H5N1 positive premises, as well as cats with neurologic signs testing negative for rabies.

According to the U.S. Centers for Disease Control and Prevention (CDC), detections of H5N1 HPAI infections in cats have been reported during outbreaks in the early 2000’s in Thailand and Germany, and Poland and South Korea in 2023. The source of previous HPAI infection in cats is unclear in many cases.

Because finding HPAI in dairy cattle is unusual and there is still much to be learned, animal health experts are also learning about the increased risk to cats through infections in cattle. According to the USDA, cats appear to be highly susceptible to the currently circulating strain of H5N1 HPAI. Increased vigilance is needed to both protect cats from infection and to better understand virus transmission between animal species.

According to the World Organization for Animal Health, "cats are not significant epidemiological vectors of avian influenza to humans or other animals."

• Limit contact between pets and wild birds as well as ill livestock and environments that could be contaminated with the virus.
• Consider changing clothing and shoes after interacting with animals or birds with unknown health status, and before interacting with personal pets.
• Wash your hands thoroughly after touching or interacting with animals outside your household.
• Avoid contact with sick or dead wildlife.
• Contact your veterinarian immediately if your pet has decreased energy and appetite progressing to neurologic signs (lack of coordination, inability to stand, tremors, seizures). Respiratory signs (nasal discharge, coughing, sneezing) may or may not be present.

For more information, please see the Michigan Department of Agriculture and Rural Development's FAQ about HPAI in feral and domestic cats.

• Follow CDC recommendations for veterinarians evaluating and handling cats potentially infected with H5N1 HPAI.
• Use your clinic’s isolation and patient handling protocols for suspected infectious and/or zoonotic disease cases.
• Contact the Michigan Department of Agriculture and Rural Development at 800-292-3939 to discuss possible testing options and to facilitate a diagnostic plan.
• Complete the MSU VDL HPAI Other Mammal Submission Form and contact the MSU Veterinary Diagnostic Laboratory at 517-353-1683 with any questions about sample collection, handling, or submission.

H5N1 highly pathogenic avian influenza is a reportable disease in any animal species in Michigan. Anyone who suspects the presence of HPAI or any other reportable disease in domestic animals in Michigan should contact the Michigan Department of Agriculture and Rural Development immediately at 800-292-3939 (daytime) or 517-373-0440 (after-hours).

Page last updated: July 8, 2024

Page published: May 24, 2024