Avian Influenza (H5N1) Update – May 8, 2024

Infectious Diseases Staying Safe

Avian Influenza (H5N1) Update

This update is accurate as of May 8, 2024.

Q: What’s the latest in the H5N1 outbreak?

A: We are beginning to get more information about how this virus spreads and what the public health community could be doing to improve its response.

The current outbreak of avian influenza (H5N1) has many people worried. Most public health agencies continue to maintain that, at present, the virus does not pose an immediate threat to most people. That said, we have to be extremely vigilant about watching how this virus spreads, and we have to attempt to be one step ahead of it at all times. Easier said than done. The USDA still asserts that the outbreak has been found in 36 herds across 9 states, although it is widely recognized that the spread is likely much larger than that due to low volume of cows being tested.

Scientists think the virus may be spreading from contaminated surfaces and objects, just like people can get influenza viruses by touching contaminated surfaces and then touching their mouths, noses, or eyes. The dairy farmer in Texas who is the only known human case in this outbreak and presented with conjunctivitis probably got it from the air in the milking parlor that went straight in his eye (since he had no eye protection) or it was on his hand or gloves and he touched his eye. A new preprint from May 3 found that tissue from mammary glands in cows contains abundant receptors to which H5N1 can attach but far fewer in the brain or respiratory tract. Some scientists are nervous that cows, like pigs, could serve as “mixing vessels” to create a new form of the virus that could spread from person to person. Many scientists, however, also think this is unlikely since cows have not traditionally been that susceptible to human flu viruses. They are still worried about seeing human-to-human transmission from the virus jumping around to different hosts (cow to human, cow to cat, etc.).

Some people are pointing out various ways we can make our infectious disease outbreak response more robust. Some feel there’s not enough surveillance of flu activity in wildlife in general, and that we should have better infrastructure for this. Others think wastewater surveillance, which most of us know about from COVID, should be used to detect outbreaks in their earliest stages. This is a relatively cheap method of surveillance. It has some problems, though, including that it can’t tell human and animal waste apart, but there are some scientists who are already working on getting around this. This might help us pick up on early human-to-human spread. At the moment, cow herds have to be tested when they move across state lines, but some scientists are calling for intrastate testing too, including live identification and tracking of more animals.

What should you be doing now to stay safe? (Hint: these tips are pretty similar to what they were last week):

** Avoid consuming raw dairy products! Absolutely do not do this. You shouldn’t do this anyway because it’s an easy way to potentially get very sick but especially not now.

** Keep up with updates on this topic (as much as is reasonable for you). We aim to provide one every week, so stay tuned.

** Do not handle sick or dead animals – keep your distance at all times.

We hope this is a helpful update. We’ll be back with another one next week.

Stay safe and stay well,
Those Nerdy Girls

Further reading:

CDC update on HPAI

NYT urges caution around raw milk

FDA updates on HPAI

NYT coverage of extent of H5N1 in milk

Overall spread of H5N1 among animals, including before this outbreak

About spread from mammals to human

NEJM article on dairy farmer who was infected

On the need for wastewater surveillance

How bird flu virus fragments got into milk

On the need to track animals better

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