Heading south, around 6.5 million birds crossed Florida on Sunday night. That number will continue to climb as fall migration hits full swing—already an estimated 94 million birds have made the journey.
For Dr. Benjamin Anderson, assistant professor in the Department of Environmental and Global Health, migration means watching for an uptick in H5N1 cases, commonly called bird flu.
“We had a little bit of a lull in H5N1 detections over the last two months, but that does align with migratory bird patterns,” Anderson said in an interview.
The virus has historically spread through wild birds, and Anderson began tracking the rise in infections across the United States in recent years, anticipating seasonal incursions moving forward.
Since then, H5N1 has started impacting dairy farms and continued to affect commercial poultry flocks. The dairy cases started in Texas and have been detected in 14 states.
Florida hasn’t had dairy cases but has several active poultry outbreaks.
Anderson and UF Health officials monitor the cases and prepare plans for outbreaks. He said the most recent development happened this month with a confirmed human case of bird flu in Missouri.
While this marks the 14th person to get the virus since April 2024, this is the first case where the person didn’t work on poultry or dairy farms where the infection occurred. The Center for Disease Control (CDC) reports the exposure of the Missouri case remains undetermined.
“Once it gets to people, then we’re starting to be more reactionary,” Anderson said. “So, we want to try to catch it earlier on in the reservoirs that we can do more about. And that’s why the monitoring and the surveillance is so important.”
He said the Missouri case has lots of question marks and might mean epidemiologists need to start looking at other exposure pathways.
Anderson said it’s important for Floridians to know the resources available, especially on the reporting side.
Dead wildlife should be reported to the Florida Fish and Wildlife Commission to check for disease. Agricultural cases run through the Department of Agriculture and Consumer Safety.
He said homes with backyard flocks should take care to monitor for unusual deaths. These birds could be infected by wild birds passing through or even cats. An outbreak in cats was reported in Colorado.
Anderson said testing has shown pasteurized milk to be safe from carrying the virus from infected dairy cows, but unpasteurized milk remains a question of concern. He recommends boiling raw milk before consuming or giving it to other animals.
He said monitoring the cases, especially looking at the genetic sequence of the virus in different cases, allows health professionals to see how the virus is changing and could continue to adapt. H5N1, he said, has already shown its ability to change and evolve.
The CDC lists the immediate risk to the general public as low, with dairy and poultry workers most exposed.
Anderson noted that as cases get closer to humans—moving from waterfowl to livestock to companion animals—the exposure chances are greater and the need for monitoring increases.