Michigan farmworker is second US case of bird flu likely transmitted from cow to human

A Michigan dairy farmworker is the second person in the U.S. to contract avian influenza from a cow, state health officials said Wednesday.

The worker, a man, developed conjunctivitis, which is an eye infection commonly known as pinkeye, as his only symptom and has fully recovered, Dr. Natasha Bagdasarian, the state's chief medical officer, told the Free Press.

The man worked on a farm with cattle infected with the highly pathogenic H5N1 influenza strain that's spreading across the U.S. in poultry and dairy cows. He had direct contact with sick cattle, she said. The Texas dairy farmworker who had the first known U.S. case of cow-to-human transmission, which was identified April 1, also worked closely with infected cattle.

Citing privacy concerns, no details were released Wednesday about specifically which farm employed the Michigan worker or in which county the infection occurred. The Michigan Department of Agriculture and Rural Development reported Monday that avian influenza outbreaks have been identified in 18 dairy cow herds in the following Michigan counties: Clinton, Gratiot, Ionia, Allegan, Ingham, Isabella, Montcalm, Barry and Ottawa.

It's more cow herd outbreaks than in any other state, according to the Center for Infectious Disease Research and Policy at the University of Minnesota. Since the outbreak began in February 2022, H5N1 avian influenza also has been detected in domestic birds from 23 Michigan counties: Bay, Branch, Cass, Eaton, Genesee, Gratiot, Ingham, Ionia, Kalamazoo, Lapeer, Livingston, Macomb, Menominee, Montmorency, Muskegon, Newaygo, Oakland, Ottawa, Saginaw, Sanilac, Tuscola, Washtenaw and Wexford.

'The system worked'

A surveillance program set up by the Michigan Department of Health and Human Services and MDARD led to the detection of the state's first human case, Bagdasarian said.

"We set up a robust public health symptom monitoring system to detect cases and that's exactly what the system did," she said. That includes an automated text messaging system that allows farmworkers to complete surveys about symptoms that might be indicative of an H5N1 infection and could signal a need for testing.

"Our local health departments have relationships with the farms in their jurisdictions and are working with them in whatever way works best for them in that particular situation. ... There's symptom monitoring using text messages, automated text messages, where folks can just reply, 'yes,' if they're having any of the symptoms mentioned."

It's unclear, Bagdasarian said, whether this infected farmworker used the text messaging system or some other method to alert local public health leaders about his symptoms.

"The lesson learned from this is that these are the things that public health needs to do ... to track the emergence of new diseases, monitor changes in disease epidemiology," she said. "The system worked.

"It is unsurprising, given what we know about H5 influenza, to find one sporadic case in a human because we know that H5 influenza does cause sporadic cases in humans when there is close exposure to impacted animals."

No need to panic

Though a Michigan man has contracted avian influenza, Bagdasarian said the average Michigander shouldn't panic.

"The risk to the general public remains low," she said. "And that's for a few reasons: No. 1, we have not seen evidence of sustained human-to-human transmission. ... For this to become a bigger risk to the general public, we would be looking for sustained human-to-human transmission and we have not seen that."

Farmworkers, especially those working with infected animals, however, have a higher level of risk.

"We have recommendations regarding personal protective equipment. We have made personal protective equipment available and we'll continue to encourage people to use it," Bagdasarian said.

Additionally, she said, symptom monitoring will continue and if workers do get infected with the virus, antiviral drugs will be recommended for treatment and for postexposure prophylaxis.

"We have seasonal influenza vaccines so that we can make sure that people are not co-infected with multiple strains of influenza, so we'll continue to use those. We'll continue to use all the tools that we have at our disposal," Bagdasarian said.

Symptomatic eyes

What's unique about the Michigan man with avian influenza is that his nasal swab sample tested negative for the virus, but a sample from the worker's eye, which was sent to the U.S. Centers for Disease Control and Prevention for additional testing, came back positive, said Dr. Nirav Shah, principal deputy director of the CDC, during a Wednesday afternoon news conference.

"We received the samples yesterday (Tuesday), tested them throughout the day," Shah said, and results were reported Tuesday night to Michigan health officials.

"The fact that the nasal specimen here tested negative while the conjunctival specimen tested positive underscores two things: One is, in a sense, it's reassuring. It reduces the likelihood — it does not eliminate — but it reduces the likelihood of a respiratory route of transmission," Shah said. "The other thing is that it underscores the importance of PPE, barrier protection, in particular for the eyes because now this being the second case where conjunctivitis was a feature, if not the chief feature of illness.

"In the Texas example ... that individual tested positive for both their nasal and conjunctival swab."

The CDC recommends people who work on dairy farms and poultry farms and in slaughterhouses use personal protective equipment such as N95 particulate respirator masks, fluid-resistant coveralls, safety goggles or face shields, waterproof aprons, gloves, headcovers and rubber boots when working around farm animals.

However, the agency said it's unclear exactly how transmission between infected cattle and humans is occurring and why the two known human cases have involved eye infections.

"It may be from contamination of the eye(s), potentially with a splash of contaminated fluid, or touching the eye(s) with something contaminated with A(H5N1) virus, such as a hand. High levels of A(H5N1) virus have been found in unpasteurized milk from H5N1-infected cows," the CDC said in a statement released Wednesday.

"Given the high levels of A(H5N1) virus in raw milk from infected cows, and the extent of the spread of this virus in dairy cows, similar additional human cases could be identified. Sporadic human infections with no ongoing spread will not change the CDC risk assessment for the U.S. general public."

Help for farms

Help is available to any Michigan farm in need of PPE for workers, said Chelsea Wuth, a spokesperson for MDHHS.

"If any farm is in need of more PPE, MDHHS and MDARD are coordinating a one-time provision to meet this need and protect workers," Wuth said. "Farms can reach out to MDARD to request a one-time provision of PPE. MDARD will relay these requests to MDHHS which will determine local, regional, state or federal resources to fill requests.

"Local health departments remain in conversations with farms and may supply PPE as well depending on local needs. MDHHS and local health departments will support the farms and MDARD to help address these concerns."

Dawn O’Connell, assistant secretary for preparedness and response at the Administration for Strategic Preparedness and Response, said Wednesday that the Strategic National Stockpile also can provide such items as goggles and N95 respirators and gloves to states that request them.

In addition, O'Connell said, the antiviral drug Tamiflu will be made available from the federal stockpile if needed. And ASPR "started the fill-and-finish process for approximately 1.8 million doses of vaccine that is well matched to the currently circulating strain of H5N1 through the National Pre-pandemic Influenza Vaccine Stockpile Program," she said.

Eric Deeble, acting senior adviser for the U.S. Department of Agriculture, said the federal government also is offering financial assistance for farmers with dairy herds that have been infected with avian influenza and will be expanding the program to include funding even to farms where cattle have yet to be infected so they can shore up their biosecurity efforts, including the veterinary costs for testing animals and the shipping costs for those lab tests.

Avian influenza has torn through Michigan's bird population for two years, forcing commercial farmers and people with backyard coops to kill roughly 6.8 million infected chickens and turkeys, pheasants, quail, ducks, geese and guinea fowl across the state — all with the hope of slowing the spread of the highly pathogenic H5N1 virus.

Culling infected flocks hasn't been enough to curtail the assault from the virus, so earlier this month MDARD Director Dr. Tim Boring declared an "extraordinary emergency" in the state, requiring farms to implement biosecurity practices and create emergency preparedness plans.

“Since the first detection of influenza A (H5N1) in dairy cattle on March 29, Michigan has prioritized both the animal and human health aspects of this disease outbreak. Today’s news underscores the continued importance of limiting nonessential farm visits, including farm tours and field trips, as well as the use of personal protective equipment when working with livestock,” Boring said in a statement issued Wednesday.

The first human case of bird flu in the U.S. was reported in 2022 in a person in Colorado who had been exposed to infected poultry. The person's only symptom was fatigue.

Contact Kristen Shamus: kshamus@freepress.com. Subscribe to the Free Press.

This article originally appeared on Detroit Free Press: Michigan farmworker is 2nd US cow to human bird flu case