Gaps in Bird Flu Surveillance Pose Pandemic Risk, Experts Warn

Experts Urge Swift Action Amid Growing Concerns Over H5N1 Spread

Scientists monitoring the spread of bird flu are increasingly worried that insufficient surveillance could leave the world vulnerable to a new pandemic. Interviews with over a dozen leading disease experts by Reuters reveal that gaps in tracking the H5N1 avian flu subtype, which has been spreading among migratory birds since 2020, may hinder timely intervention.

The recent spread of the virus to 129 dairy herds across 12 U.S. states marks a significant shift, potentially bringing the virus closer to human transmission. Infections have also been found in various mammals, including alpacas and house cats.

“It almost seems like a pandemic unfolding in slow motion,” said Scott Hensley, a microbiology professor at the University of Pennsylvania. “Right now, the threat is pretty low … but that could change in a heartbeat.”

Early detection of the virus jumping to humans would enable global health officials to launch vaccine development, extensive testing, and containment measures. However, current federal surveillance in the U.S. is limited, focusing only on testing herds before interstate movement. State testing efforts vary, and there is scant testing of people exposed to infected cattle.

“You need to know which are the positive farms, how many of the cows are positive, how well the virus spreads, how long do these cows remain infectious, the exact transmission route,” said Ron Fouchier, a flu virologist at the Erasmus Medical Center in Rotterdam.

Dr. Jeanne Marrazzo, director of the U.S. National Institute of Allergy and Infectious Diseases, criticized the U.S. Centers for Disease Control and Prevention’s (CDC) human flu surveillance network as “really a passive reporting, passive presentation mechanism.” While the U.S. Department of Agriculture (USDA) is more proactive in testing cows, it does not disclose affected farms.

Experts caution that differing approaches between animal and human health agencies could slow response times. “If you were designing the system from scratch, you would have one agency,” said Gigi Gronvall, a biosecurity expert at the Johns Hopkins Center for Health Security. “This is not the only example where we have environmental or animal problems that cause human problems.”

The USDA stated that it is working “around the clock” with the CDC and other partners in a comprehensive response, emphasizing that America’s food supply remains safe and that sick cows generally recover. The CDC reassured that it has been preparing for the emergence of a novel influenza virus for nearly two decades.

Some pandemics, like COVID-19, arrive with little warning. In contrast, the last flu pandemic in 2009, caused by H1N1, spread among animals for years before infecting humans. More surveillance could have better prepared health authorities, according to Hensley.

Since late March, three people in the U.S. have tested positive for H5N1 after contact with cows, experiencing mild symptoms. Other cases have been reported in Mexico, India, China, and Australia, caused by different strains. The World Health Organization (WHO) maintains that H5N1’s risk to humans is low due to the lack of evidence for human-to-human transmission. Existing H5N1 vaccines and antiviral medications like Tamiflu are available if needed.

The Coalition for Epidemic Preparedness Innovations (CEPI) is preparing for potential human spread by creating a library of prototype vaccines for pathogens with pandemic potential. CEPI aims to enable large-scale production and distribution of vaccines within 100 days of an outbreak.

Some countries are already taking preemptive measures. The U.S. and Europe are securing doses of pre-pandemic flu vaccines for high-risk groups. Finland plans to offer preemptive bird flu vaccinations as early as next week, making it the first country to do so. Vaccinations will target workers exposed to animals, including those at fur and poultry farms, lab technicians, and veterinarians.

Meanwhile, the USDA will begin compensating dairy farmers for milk supply losses due to bird flu-infected cows. The agency has recorded infections in 132 dairy herds across 12 states since March. The compensation will cover 90% of lost milk production per cow, with applications opening on July 1.

Federal officials underscore that the risk to the public remains low, though the virus’s spread among cattle heightens the risk of human infection. Ensuring robust surveillance and swift response measures is critical to preventing a potential pandemic.

(This article is developed based on the information available from Reuters.