The detection, found through routine milk testing, brings the number of states with infected dairy herds to 21 and follows Washington's first cases in October.
The USDA’s Animal and Plant Health Inspection Service (APHIS) has confirmed highly pathogenic avian influenza (HPAI) H5N1 in a dairy herd in Indiana, marking the state's first reported case of the virus in cattle.1
On November 2, the APHIS National Veterinary Services Laboratories (NVSL) confirmed HPAI H5N1 genotype B3.13 in the herd using PCR testing. The Indiana herd was identified through routine testing under the National Milk Testing Strategy rather than pre-movement surveillance.1 APHIS is working with the Indiana State Board of Animal Health on additional on-farm investigations, diagnostic testing, and epidemiological data collection to better understand the detection and prevent further spread, according to the release.
Dairy cattle in 21 states have now been infected since the outbreak began in March 2024, and APHIS has seen cases in previously unaffected states this year.
The Indiana case comes less than a month after Washington confirmed its first HPAI cases in dairy cattle. On October 8, APHIS announced that NVSL had identified HPAI H5 clade 2.3.4.4b in 2 Washington herds, with genetic sequencing still in progress at the time.2 Infections had been reported in 19 states when the Washington cases were announced.2
Unlike the Indiana herd, the Washington herds were tested after cattle showed signs consistent with avian influenza. Both had repeatedly tested negative through routine National Milk Testing Strategy surveillance beforehand.
According to APHIS, the Indiana detection does not change the USDA's HPAI eradication strategy. The agency continues to recommend enhanced biosecurity measures for all dairy farms and urges producers to immediately report livestock with clinical signs, as well as any unusual sick or dead wildlife, to their state veterinarian.1
APHIS biosecurity recommendations for dairy operations include limiting farm access and keeping a visitor log, disinfecting vehicles and equipment, wearing dedicated boots and coveralls around the herd, keeping wild birds, pets, and rodents away from cattle, and isolating new, returning, or sick animals.2 USDA financial assistance is also available to help producers cover biosecurity planning and HPAI-related costs such as influenza A testing, veterinary care, personal protective equipment (PPE), and milk disposal and losses. Producers can enroll through their Area Veterinarian in Charge or state animal health official.2
APHIS stated that the detection does not pose a risk to consumer health or affect the safety of the commercial milk supply. The US Food and Drug Administration is confident that pasteurization inactivates HPAI virus, and milk from affected animals is being diverted or destroyed so it does not enter the human food supply.1
The CDC considers the risk to the general public low. However, people with job-related or recreational exposure to infected birds or mammals are at higher risk of infection and should follow CDC precautions. CDC's interim worker-safety guidance identifies poultry and dairy workers as the most likely to be exposed and also lists veterinarians and veterinary staff among those who may be at risk. For the highest-exposure tasks, such as contact with potentially infected animals or their raw milk, CDC recommends engineering and administrative controls alongside high-exposure PPE.2
References
