Long story short — H5N1 continues to dominate the news headlines. Multiple federal agencies are conducting disease surveillance and responding to the situation. For epidemiologists —
“The world will expect you to be a fortune-teller… Those in epidemiology have a window into the future most people don’t have.” ~ Dr. Bill Foege
As an epidemiologist, I am (along with many others in public health) seeing how what is happening today could be the genesis of the next pandemic.
While information is coming at us like a tidal wave, there is NO need for concern.
What do we know about H5N1?
The H and N are the names of two proteins on the surface of the virus — hemagglutinin (H) and neuraminidase (N). The H5N1 virus is NOT new. In 1996, it was first identified in domestic waterfowl in Southern China. A year later (1997) H5N1 was diagnosed in a child in Hong Kong. The kid had contact with sick chickens before he got sick. He died of viral pneumonia.
Over the past 28 years, H5N1 has spread to wild animals such as foxes, bears, bald eagles, and seals; domestic animals such as cats and dogs; farm animals, such as goats, pigs, and mink, and zoo animals such as tigers and leopards.
What’s new?
In March (just 2 months ago), H5N1 was discovered in dairy cows. To date, there are 42 herds in nine states where there are known H5N1 infections in dairy cows.
Note — these are the known infected herds. We are finding asymptomatic cows — cows that are not sick (no signs of disease), but are testing positive for disease.
What’s being done?
CDC, USDA, and FDA are coordinating a response to the current outbreak in dairy cows (and other mammals) and working to prevent the further spread of disease.
On dairy farms, the USDA is assisting in increasing the number of tested cows and restricting the interstate movement of lactating herds (in other words, the USDA is limiting the movement of dairy cows from one state to another to prevent the further spread of H5N1 to additional herds). The USDA is also providing personal protective equipment (PPE) to farmers.
If you are working with cows or wild birds, wearing PPE is a necessity.
FDA is monitoring the commercial milk supply, which is SAFE.
The FDA announced on Friday —
“All final egg inoculation tests associated with this retail sampling study have been completed and were also found to be negative for viable HPAI H5N1 virus. These confirmatory test results mark the completion of our laboratory research efforts related to these 297 retail dairy samples.”
The CDC is working to develop an H5N1 vaccine. Additionally, the CDC is monitoring wastewater data for any evidence of unusual levels of influenza and is working to develop and validate an influenza wastewater metric. It is important to note — wastewater testing doesn't distinguish between various types, it can offer signals of "unusual levels" of the virus. Just this afternoon, a preprint (not peer-reviewed) paper by researchers at Baylor was shared online documenting that H5N1 has been detected in 9 of 10 cities in Texas where wastewater surveillance is being conducted.
Wastewater may be the best indicator of disease we have. Tomorrow CDC is set to unveil a new wastewater dashboard tracking influenza viruses, including H5N1.
What should you be doing/not doing?
At this point, there is not much to do.
Do NOT drink raw milk.
Stay home and away from others when sick. Work to break the chain of transmission by not passing your disease to others (regardless of whether it’s influenza, COVID, strep throat, or something else).
Plan to get a flu vaccine in the fall. While the annual/fall flu vaccine will NOT prevent you from getting sick from H5N1, it will reduce the risk of you getting sick with a season influenza (which can be prevented with the annual flu shot) and co-infected with H5N1.
We want to minimize opportunities for H5N1 to mix with human influenza viruses. We do NOT want H5N1 to pick up genes from human influenza virus that would allow it to spread easily from person to person.
That is the nightmare situation, which leads me to…
What’s keeping me up at night?
H5N1 is spreading from cow to cow.
We know that it is spreading asymptomatically. We also suspect that H5N1 is spreading undetected and (possibly) asymptomatically in humans, who have close contact with cows.
We know that cows can spread the disease to humans. Thankfully, we do NOT have evidence of human to human transmission of H5N1.
H5N1 is spreading without detection & it is getting harder to track — this is concerning.
And H5N1 is spreading in mammals, specifically mammals that humans have a lot of close contact with — this is concerning; there is an increased opportunity for humans to be infected by these mammals.
Helen Branswell (one of my favorite health writers) notes —
“It is not knowable whether H5N1 will ever acquire the capacity to easily infect people and spread person-to-person — in other words, trigger a pandemic. But ongoing transmission in a mammalian species gives the virus a chance to adapt to hosts that are far closer, genetically, to humans than are ducks or chickens. No one who has watched this virus thinks letting H5 get seeded into cow populations is a good idea.”
I am NOT worried about the cows getting sick.
I am NOT worried about the commercial milk supply.
I am worried that H5N1 will find a forever home in cows. Once this happens the possibility that H5N1 will mix with a human influenza virus and become more contagious increases.
The nightmare situation is that H5N1 evolves so it can spread person to person.
The nightmare situation is that H5N1 becomes highly virulent and kills the majority of people who get it.
The nightmare situation is that we ignore the warning signs that we are starting to see right now.
The nightmare situation is that public health continues to be underfunded.
The nightmare situation is that the majority of the public decides not to get a flu shot in the fall.
The nightmare situation is that we do not invest in preventive measures such as testing, quarantine, isolation, vaccination, and education.
That is what keeps me up at night.
That and the upcoming county fair season.
What is more concerning than occupational exposure to H5N1? Exposing the general public to cows without any protection at county fairs across the country in the coming months.
That is definitely keeping me up at night.
More about county fairs and disease prevention in the coming months. Stay tuned…
Questions? Concerns? Things you’ve read that need to be explained? Please ask…
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Epi(demiology) Matters is written by Dr. Becky Dawson, PhD MPH — an epidemiologist, teacher, mom, wife, and dedicated yogi. She is a tenured professor at Allegheny College, Research Director at a community hospital, and an exclusive contributor (all things health & medicine) at Erie News Now (NBC/CBS). Her goal is to create healthy communities for all. She writes Epi Matters — first & foremost because epidemiology does matter (to all of us) and she hopes that each post will help to educate and empower readers to be healthy and create healthy communities.
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I find it fascinating that now cows may be viral mixing vessels like pigs and ducks. Wastewater data is a bit disconcerting.