A MARTÍNEZ, HOST:
Concerns about bird flu and its potential to infect humans are increasing. After a summer lull, bird flu is back, infecting animals on farms across the country. It's infecting poultry flocks and is also showing up in cow's milk, and that means concerns about the virus and its potential to infect humans are also increasing. Here's NPR's Will Stone.
WILL STONE, BYLINE: It's been a rough stretch for Minnesota turkeys. They've become casualties of the virus as wild birds have migrated south and spread it to poultry farms.
KAREN MARTIN: Certainly, it has really picked up.
STONE: That's Karen Martin, an epidemiologist with the Minnesota Department of Health.
MARTIN: Since mid-September, we've had 23 outbreaks identified.
STONE: Other states in the middle of the country, like the Dakotas and Indiana, are also dealing with a resurgence. Martin says, right now, her state is monitoring about 35 people who were exposed in case they develop symptoms.
MARTIN: I say Minnesota is doing quite well. There's always a possibility that something can go unnoticed or slip through our fingers, but we have very strong surveillance.
STONE: On the surface, the situation might look reassuring compared to last year, when hundreds of dairy herds were infected and dozens and dozens of people caught the virus. There hasn't been a human case detected since early this year. But Seema Lakdawala, an influenza researcher at Emory, says, just wait.
SEEMA LAKDAWALA: Absolutely. We're going to see human infections, just like we did a year ago. Nothing has changed substantially to suggest otherwise.
STONE: What Lakdawala has found on dairy farms is sobering. She says cattle, even ones that don't look sick, are expelling tons of virus in their milk. It ends up in the milking parlor, on the equipment, in manure lagoons.
LAKDAWALA: There is so much virus just in the environment around these cows that they are bombarded. And so of course they're going to become infected.
STONE: And even though it's hard for humans to catch the virus, all of this presents a very real threat for workers.
LAKDAWALA: We found virus in the air in dairy parlors. It's infectious.
STONE: Nationally, it's not clear how much testing is still happening. Keith Poulsen, who runs the Wisconsin Veterinary Diagnostic Laboratory, says, in some states west of the Mississippi, bird flu is now a fixture in the dairy cattle population. Cattle are constantly moving from farm to farm. And he says critical data from the federal government on how the virus may be changing has slowed to a trickle.
KEITH POULSEN: Now, with the government shutdown, it just kind of pours gas on a smoldering fire. It makes us vulnerable. It's a national security issue.
STONE: In a statement, a spokesperson for the Department of Health and Human Services said the CDC Influenza Division was not affected by cutbacks and that response to urgent public health threats can continue during a shutdown. A year ago, Wendy Puryear, a virologist at Tufts University, felt like she had a pretty good handle on the situation. She's part of a network of influenza researchers. They were in constant contact with their counterparts at federal agencies, mapping out what to study and monitor.
WENDY PURYEAR: A lot of that infrastructure has been completely closed down or significantly hampered.
STONE: And she says much of the research that would give us a better picture of how often people are being infected, perhaps without symptoms, was halted because the Trump administration cut funding.
PURYEAR: I think there are a lot more cases going on that we're not catching.
STONE: That's been an issue all along. Gaining the trust of farmers and their workers, who are often undocumented, has been tough. Bethany Boggess Alcauter is with the National Center for Farmworker Health. She recently surveyed workers in affected states about bird flu.
BETHANY BOGGESS ALCAUTER: We were interviewing people over the phone 'cause they didn't want to leave their house. I think it's definitely more intense than it was, and there already was a lot of reluctance to get tested.
STONE: She expects it will only get harder as the Trump administration continues its immigration enforcement. Meanwhile, their survey found about 20% of workers in affected states had symptoms while animals on their farms were sick, and many of those people said they were never tested for the virus.
Will Stone, NPR News. Transcript provided by NPR, Copyright NPR.
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