Michigan leading US on monitoring and studying bird flu outbreak

As questions swirl about the spread of bird flu among livestock and people, one US state – Michigan – has taken the lead on monitoring and studying the outbreak.

Other states have seemed wary of tracking cases among animals and people, but Michigan has taken a proactive approach, with daily text messages and phone calls to check on farm workers who work with cows that have tested positive for H5N1. They also have offered free tests if symptoms develop.

Officials weren’t surprised when a third person tested positive for the highly pathogenic avian influenza, and they weren’t surprised that it happened in Michigan. Nearly two-thirds of the people being monitored for H5N1 symptoms are in Michigan, Nirav Shah, principal deputy director of the US Centers for Disease Control and Prevention (CDC), said recently.

As of 22 May, 35 out of 40 tests among people had been conducted in Michigan. That means only five other bird flu tests took place in other states, including Texas, the only other state to report a case among humans in this outbreak.

Michigan is the state with the highest concentration of influenza A in its wastewater, according to WastewaterScan. H5N1 belongs to the influenza A family, and relatively high levels of flu A indicate possible outbreaks of H5N1 – most likely among animals.

But that’s not the only reason Michigan keeps coming up in news about bird flu.

“I don’t think we’re the only state that has cases. I think we’re the only state that is detecting our cases,” other than Texas, said Dr Natasha Bagdasarian, chief medical executive for the state of Michigan. “It gives me hope that the system is working here.”

It’s not just testing and monitoring. Michigan also invited epidemiologists from the US Department of Agriculture (USDA) to study transmission of the virus. The authors of a recent USDA report thanked Michigan dairy producers for their openness and transparency. “This report could not have been completed without them,” the researchers wrote.

Michigan officials announced new biosecurity rules for farms following the first detection of bird flu in cows, and soon began promoting seasonal flu vaccines among dairy and poultry workers to prevent the possibility of flu variants mixing together and causing more serious illness.

Michigan also announced additional funding for flu-affected farms, beyond the federal assistance available. Up to 20 farms affected by H5N1 may receive as much as $28,000 for participating in studies and working with health officials.

“Michigan has been doing a lot of work to really understand what’s going on with H5N1,” said Marisa Eisenberg, associate professor of epidemiology and co-director of the Michigan Public Health Integrated Center for Outbreak Analytics and Modeling at the University of Michigan.

“Some of what we’re seeing is just that when you look for something, that’s how you find it.”

It’s important for state and local officials to work closely with agricultural industries – covering cows, chickens, pigs and other potentially affected animals – to understand how transmission is happening and how to stop it, experts said.

“It’s to everyone’s benefit to try and be as proactive as you can,” Eisenberg said. “Because if you put your head in the sand, ostrich-style, then it will continue to spread and continue to cause a wider range of problems – from a public health perspective, from a milk-production and economic perspective.”

In Michigan, that approach has involved checking in regularly with farm workers for symptoms, and working closely with officials from state and local agriculture and health departments.

“We’re seeing how human health and animal health are inextricably linked and making sure that we are approaching these things together,” Bagdasarian said.

Farm owners and workers who are in contact with sick cows receive daily text messages or phone calls to check for even mild or unusual symptoms.

Those who report any symptoms are tested for H5N1 and, in the cases of two people who tested positive, offered antivirals.

That program, Eisenberg said, “has been really helpful in terms of finding the two cases that we’ve seen so far, and also encouraging testing from farms and from dairies in particular”.

One Michigan worker who tested positive developed conjunctivitis, or pinkeye, after milk from a sick cow splashed into the person’s eyes.

The other worker developed more typical flu symptoms, including a cough, congestion, a sore throat and watery eyes, after working in close quarters with a sick cow.

The risk of bird flu to most people is still low, but anyone in close contact with potentially sick animals should take precautions, officials say.

“It really highlights how helpful personal protective equipment can be for individuals who are having prolonged exposure to sick animals,” Bagdasarian said.

But such protective equipment can be difficult to wear while working on a farm, amid conditions like summer heat and splashing from water and milk.

“One of the big concerns has been visibility,” Bagdasarian said. “When you’re working with a large animal and there’s risk for injury, anything that blocks your vision can also be difficult to use.”

Officials in Michigan are being careful not to disclose details that might identify affected farms or individuals while also announcing new cases.

“Michigan as a state has been pretty good at navigating the concerns around privacy and not wanting to identify farms specifically, but also wanting to share data in a transparent way,” Eisenberg said.

Throughout this bird flu outbreak, officials have emphasized the importance of trust.

“One of the things we learned in Covid is that you need to have established relationships before there is any sort of public health emergency,” Bagdasarian said.

“We have a lot of health clinics and outreach staff who work directly with farm workers, and the local health departments know the farms in their jurisdictions.”

If an H5N1 vaccine becomes available for people, it could fall prey to some of the same politicization and misinformation around vaccines that accelerated during the pandemic, she said – including lower uptake of the seasonal flu vaccine.

“We are still working to re-establish that public trust,” Bagdasarian said.

The bird flu outbreak is “concerning, but we can’t yet say whether it’s going to really become a major problem that the public at large needs to worry about”, Eisenberg said.

“It’s enough of a concern that we should certainly be doing everything we can to make sure that it doesn’t turn into a bigger problem.”