November 6, 2024

 

USDA strengthens H5N1 monitoring and biosecurity measures for dairy cattle and livestock

The US Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) announced plans to enhance testing and monitoring for the H5N1 avian influenza virus.

 

Building on previous measures, USDA will partner with state veterinarians to implement a tiered testing strategy, focusing on milk sample collection to improve tracking of H5N1 presence. This effort aims to inform both biosecurity and containment measures, as well as state-led initiatives to mitigate risks for farm workers exposed to infected animals.

 

Since the initial detection of H5N1 in dairy cattle in March 2024, USDA, alongside state and federal partners, has taken steps to understand and eliminate the virus in dairy herds. A Federal Order issued in May 2024 now mandates cattle testing before interstate movement, helping to restrict H5N1's spread. Over the last 30 days, the number of states with known H5N1 cases in dairy herds has dropped from 14 to two. USDA, however, sees further actions as necessary to proactively support biosecurity measures, which are critical for states and farmers to contain and eliminate infections in livestock.

 

USDA has prior experience with bulk milk testing approaches, notably in eradicating brucellosis from dairy herds. Following H5N1's detection in two counties, Colorado implemented state-wide bulk milk testing, which has since revealed no further evidence of the virus in herds. USDA plans to work with interested states and regions to expand bulk milk testing in the coming weeks.

 

Collaborating closely with state and private veterinary groups, USDA's initial efforts will involve bulk milk sampling at the regional level, with further testing at the farm level if necessary. The agency intends to work alongside state and private veterinarians to finalise implementation details and will provide guidance documents soon.

 

Emphasising biosecurity as the most effective defence against H5N1, USDA encourages farms across the country to maintain strong biosecurity practices, regardless of local virus presence. Data from the past seven months reveals that H5N1 can spread through farm equipment, people, or materials moving between farms, including poultry and dairy facilities. USDA's April 2024 Federal Order mandating cattle testing before interstate movement has helped limit the spread of H5N1 to 14 states. Additionally, USDA encourages herd owners to utilise available producer support programs, which provide funding for biosecurity, personal protective equipment for employees, and veterinary care.

 

In support of longer-term control, USDA is facilitating the development of H5N1 vaccines for dairy cattle and other species. Currently, two vaccine candidates for dairy cows are undergoing field trials.

 

USDA's response follows a science-based approach informed by ongoing research and monitoring of H5N1. Today's announcement marks a key step forward in this response strategy.

 

On the same day, USDA and the Oregon Department of Agriculture confirmed the first detection of H5N1 in swine on a non-commercial farm in Oregon. More details on this detection are available.

 

USDA scientists, in coordination with the Centres for Disease Control and Prevention (CDC), report no recent viral changes that would increase human transmission risk. While cases continue among those in direct contact with infected animals, CDC considers the public risk to remain low.

 

-      Farms.com