Bird Flu in Milk: US Testing Gap Raises Alarm in Top Dairy States

The United States faces a concerning gap in its surveillance efforts against avian influenza as three major milk-producing states remain outside a voluntary federal testing program, despite the emergence of a new variant in dairy cattle. This situation raises concerns among public health experts who emphasize the critical need for nationwide testing to effectively identify and contain the spread of the virus.

A Troubling Gap in Surveillance

The U.S. Department of Agriculture (USDA) initiated a voluntary milk-testing program in December 2023, following the detection of avian influenza in cattle in March of that year. While the risk to humans remains relatively low, experts argue that comprehensive testing is essential to prevent undetected cases from contributing to the virus's spread among animals and potentially to humans.

The Importance of Nationwide Testing

"It is incredibly difficult to control a disease of national importance unless we have a robust surveillance system in place," said Dr. K. Fred Gingrich II, executive director of the American Association of Bovine Practitioners. "If we were testing every dairy, I don’t think you’d have any cases slipping through the cracks."

However, Texas, Wisconsin, and Idaho—three of the top five milk-producing states—are not participating in the voluntary federal testing program. Although efforts are underway to encourage their participation, it remains unclear when they will join or how long it might take.

State Resistance and the Case for Surveillance

Texas, which experienced the first known case of bird flu in cattle, as well as a recent case in dairy cattle in December 2023, has opposed surveillance milk testing. State Agriculture Commissioner Sid Miller asserts that there are currently no active cases of avian influenza in commercial cattle or poultry, deeming surveillance testing unnecessary. He emphasizes the need for bovine vaccine development as a priority.

Despite this stance, a separate state agency, the Animal Health Commission, is collaborating with federal officials to develop a surveillance testing program for avian influenza. Notably, the USDA recently announced the discovery of a new strain in cattle through its federal milk-testing program in Nevada.

National Efforts and Progress

The USDA's National Milk Testing Strategy has gained momentum with nearly 40 states participating, representing about three-quarters of the country's milk production. The agency aims to enroll all 48 continental states.

Experts highlight the significance of early detection through testing, as avian influenza can often be identified days before dairy cows exhibit symptoms. This allows farmers to implement containment measures, quarantine affected animals, and test potentially exposed individuals.

"The more lead time we have in identifying where the virus is — that allows us to bolster the protection for the workers as well," said Dr. Kay Russo, a Colorado veterinarian who played a role in identifying the first confirmed case of avian influenza in cattle last year. "If we’re flying blind in a particular state, where we don’t know what the status is, we really can’t say for certain what the risk is."

Colorado, for instance, has implemented weekly milk testing on all farms since outbreaks in dairy cattle last year, significantly contributing to disease containment. This proactive approach has proven effective in identifying cases before animals display symptoms, providing valuable insights into the virus's presence and distribution.

The Need for Continued Vigilance

Despite progress in national surveillance efforts, the continued exclusion of major milk-producing states from the voluntary testing program poses a significant challenge. It underscores the urgent need for increased collaboration and coordinated action to ensure comprehensive monitoring and control of avian influenza, safeguarding both animal and human health.