#17,959
Yesterday another unusual spillover of HPAI H5N1 to mammals was announced (see Lisa Schnirring's report on CIDRAP), this time involving baby goats on a farm in Minnesota which had recently experienced an avian flu outbreak in poultry.
Yesterday's statement from the Minnesota Board of Animal Health (BOAH) only focuses on one positive test result, although the WOAH WAHIS announcement below cites 10 recent goat kid deaths and 5 positive test results (see below) from this farm:This is the first detection of clade 2.3.4.4b H5N1 in a ruminant in the United States, although cattle have previously been successfully infected in the laboratory with older clades (see EID Journal Experimental Infection of Cattle with HPAI H5N1).
EPIDEMIOLOGICAL COMMENTS
USDA’s National Veterinary Services Laboratories confirmed highly pathogenic avian influenza (HPAI) in neonatal goat kids that demonstrated neurologic signs from a Minnesota backyard premises recently affected with HPAI. The goats on the premises shared the same pasture and sole water source with infected ducks and chickens. The goats began to kid only days after the birds were depopulated.
Of 10 goat kids that have died, ranging from 5 days to 9 days of age, five goat kids between 7 and 9 days of age have tested positive on brain and other tissues for H5N1 clade 2.3.4.4b virus. Whole genome sequence data available to date from the chickens, ducks, and the first goat kid tested share high identity, and are Eurasian/North American reassortant genotype B3.6 (GenoFlu https://github.com/USDA-VS/GenoFLU)
Next, the BOAH statement, after which I'll return with a bit more.
Stevens County goat tests positive for same influenza virus affecting poultry
A Stevens County goat kid (juvenile goat) residing on a farm with a Highly Pathogenic Avian Influenza (HPAI) positive poultry flock tested positive for the same virus. This is the first U.S. detection of HPAI in a domestic ruminant (cattle, sheep, goats, and their relatives). All poultry on the property were already quarantined from the February HPAI detection. Following the confirmation of HPAI in the goat, the Board quarantined all other species on the premises. The Board is working with the U.S. Department of Agriculture (USDA) to investigate the transmission of the virus in this case.
“This finding is significant because, while the spring migration is definitely a higher risk transmission period for poultry, it highlights the possibility of the virus infecting other animals on farms with multiple species,” said State Veterinarian, Dr. Brian Hoefs. “Thankfully, research to-date has shown mammals appear to be dead-end hosts, which means they’re unlikely to spread HPAI further.”
Earlier this month the owner notified the Board of unusual deaths of newly kidded goats on the property where a backyard poultry flock was depopulated due to HPAI in February. The goats and poultry had access to the same space, including a shared water source. One of the goat carcasses was taken to the University of Minnesota Veterinary Diagnostic Laboratory (VDL), where it tested positive for influenza A. The National Veterinary Services Laboratories (NVSL) later confirmed H5N1 HPAI, which is the same virus circulating in the national outbreak that began in 2022. Samples from the adult goats were negative for HPAI and all appear healthy; no more sick goat kids have been reported since March 11.
HPAI has been previously diagnosed in other mammalian species such as skunks, dogs and cats. Animals with weakened or immature immune systems, like the goat kids in this case, are at higher risk of contracting disease. There has been limited experimental data on HPAI infection in ruminants, and there are no prior reports of natural HPAI infection in goats. The USDA has tracked more than 200 detections of HPAI in mammals across the country since the start of the 2022 HPAI outbreak.
The Minnesota Department of Health (MDH) provided recommendations for personal protective equipment and is monitoring the health of those in direct contact with the infected goats. Anyone who develops respiratory or gastrointestinal symptoms after exposure to the goats may be voluntarily tested for avian influenza and other respiratory pathogens. The risk to the public is extremely low, and any risk of infection is limited to people in direct contact with infected animals. To date, no people in the United States have become ill following contact with mammals infected with this virus.
Biosecurity is the first line of defense for anyone to protect their animals from disease and includes simple measures like cleaning equipment and housing regularly, separating livestock from wild animals, and calling your veterinarian when animals appear sick. To learn more important steps to protect your animals from HPAI and other diseases, visit the Board’s biosecurity webpage. For more information on the Board’s work to combat the spread of HPAI in Minnesota, please visit our response webpage.
Admittedly, swine, mink, foxes, and other farmed fur animals (see below) are viewed as far bigger risks for contracting and spreading avian flu.
Eurosurveillance: HPAI H5N1 on Multiple Fur Farms in the South and Central Ostrobothnia Regions of Finland, July 2023
Netherlands: Zoonoses Experts Council (DB-Z) Risk Assessment & Warning of Swine As `Mixing Vessels' For Avian Flu)
But yesterday's report reminds us that even after more than 2 decades of research and surveillance, HPAI H5N1 still has the ability to surprise us.
