Although the current avian influenza outbreak began more than two years ago, detections have been made in recent weeks in cattle, cats and large commercial poultry flocks across the country and in Michigan.
Kimberly Dodd is the director of the Michigan State University Veterinary Diagnostic Laboratory, or MSU VDL, in the College of Veterinary Medicine. Dodd is an expert in laboratory diagnostics and outbreak response for emerging infectious diseases.
The MSU VDL has worked closely with state and federal agencies to respond to the ongoing highly pathogenic avian influenza, or HPAI, outbreak since it began in February 2022. The lab has performed more than 12,500 HPAI tests, which include surveillance for wild birds, disease investigations and surveillance in domestic poultry, and testing of wild and domestic mammals.
Dodd answers questions about what the public should know about avian influenza and the role of her lab, which functions as the only laboratory in Michigan approved by the United States Department of Agriculture to test for HPAI in any species.
What is avian influenza?
As the name suggests, avian influenza or “bird flu” is caused by influenza A viruses and circulates in wild bird populations without causing serious disease. Domestic birds that interact with wild birds or areas frequented by migratory birds are at risk of exposure and infection.
Since the outbreak in 2022, nearly 86 million domestic birds have been affected. HPAI has been detected in more than 1,100 commercial and backyard flocks. Right now, we are dealing with an outbreak of highly pathogenic avian influenza — virus strains are classified as either highly pathogenic avian influenza, or HPAI, or low pathogenic avian influenza, or LPAI, based on how severely they affect domestic poultry species.
How is the avian influenza circulating now different from previous strains or outbreaks?
The HPAI strain currently circulating is unique because it has severely affected wild birds. Waterfowl, which do not usually become ill, have exhibited signs of illness and died. We have also seen significant illness and deaths in raptors like bald eagles, hawks and owls; scavengers such as crows; and even songbirds. Early on, large numbers of birds died from the virus. Now, although we are still finding the virus in wild bird populations, mortality has decreased.
The current strain has also been found in several mammals, including big cats, bears, coyotes, fishers, foxes, martens, opossums, otters, raccoons, seals, skunks and squirrels. Infection is believed to be through consumption of or close contact with sick or dead birds.
Has the virus been found in cows?
Most recently, and perhaps most surprisingly, the virus has been found in dairy cattle in several states, including here in Michigan. The disease in cattle has been associated with herd-level decreases in milk production, and most animals recover within two weeks. So far, analysis of the virus found in cattle indicates the virus is the same strain that has been affecting wild birds, domestic poultry, some wild mammals, and, in rare cases, domestic cats.
Why is finding avian influenza in livestock significant?
Although we have seen infections in mammals that feed on or have close contact with infected birds, finding the virus in cattle and goats is new. Scientists and animal health experts across the country are currently working to understand the mechanism of transmission from birds to livestock and subsequent transmission within herds.
Should people be worried about catching avian influenza?
According to the U.S. Centers for Disease Control and Prevention, the current risk to the public remains low. To date, there is no evidence of changes to the virus that would make it more likely to cause disease in people.
As a precaution, avoid contact with wild birds. Do not handle sick or dead wild or domestic birds, their feces or any surface potentially contaminated with their saliva, feces or other bodily fluid without wearing personal protective equipment.
Is our milk supply safe?
According to the Food and Drug Administration, the commercial milk supply remains safe due to both federal animal health requirements and pasteurization. Pasteurization has continuously been proven to inactivate bacteria and viruses, like influenza, in milk.
What should producers or veterinarians do if they have concerns about cattle or other animals?
Producers or animal owners who notice any signs of illness in their animals should contact their veterinarian. Veterinarians can access information about cattle sample collection, handling and submission on the MSU VDL website and contact the MSU VDL at 517-353-1683 with any questions about testing, sample collection or submission.
Anyone who suspects the presence of HPAI in domestic animals should contact the Michigan Department of Agriculture and Rural Development immediately at 800-292-3939 (daytime) or 517-373-0440 (after hours).
