There’s been a lot of concern about the recent identification of H5N1 avian flu in cattle in the US, along with a single human infection in a person working with infected cattle. Some of the concern is warranted, but some is overblown.  We need to balance awareness versus paranoia, and try to better understand the problem and reduce the risk, while avoiding excessive, ineffective or harmful responses. That sweet spot is hard to define early on with emerging diseases. We should liberally apply the precautionary principle, but also ensure we keep re-assessing the risks based on emerging evidence.

Here are some initial thoughts on what we can all do regarding the current situation at this stage:

Cattle farmers

  • Be on the lookout for sick animals. Based on what we’ve seen do far, flu will likely cause mild signs in cattle such as decreased appetite and decreased milk production.
  • Call your veterinarian as soon as possible if you suspect a problem in your herd (good advice at any time!), and allow testing of suspect cases (good to know what’s going on, whether it’s influenza or not).
  • Although it’s tough, try as much as possible to keep wild birds out of barns. Also try to discourage migrating waterfowl in particular from entering cattle housing areas or taking up residence in fields.
  • If you’re sick, stay away from cattle. We don’t want human and animal influenza viruses mixing, and putting an infected person in a barn with potentially infected cattle increases this risk. Farmers are notorious for “sucking it up” and working as long as they’re not fully dead, but we need to encourage a culture shift that limits contact of sick people with animals. If that’s not possible (which is often the case), farm personnel that might have the flu should minimize contact with animals as much as possible, and wear a mask to reduce the risk of spread.
  • If there’s flu activity in wild birds in the area, it’s not unreasonable to wear a mask around cattle, but I realize that’s unlikely to happen.
  • Consider adjusting grazing practices to reduce exposure of cattle to infected birds or their feces, especially if there is flu activity in wild birds in the area, and particularly if dead birds are found in the pasture.
  • If your cattle might have flu, definitely wear a mask and eye protection around and sick animals, and limit close contact. Also, think about high risk items and surfaces that may get contaminated by sick cattle, and take additional measures as appropriate (e.g. increasing routine disinfection, reducing direct contact, wearing appropriate PPE when contact is required). Contamination with respiratory secretions from sick animals were the main initial concern, but recent information suggests that milk could be more important for potential cow-to-cow transmission during milking (e.g. shared milking equipment). Contact with milk and milking equipment might pose a risk for people too, meaning we should take extra precautions with contact with the udder, milk and any in-contact surfaces. I’d also take care around cattle feces until we better understand if cattle can also shed the virus that way (but there are lots of other reasons to avoid contact with cattle feces besides flu too).
  • Keep cattle away from any other species that might carry or acquire an influenza virus, which basically means keep cattle away from all other mammals and birds, but with a particular focus on avoiding higher-risk flu species (i.e. domestic poultry and pigs).
  • If you develop flu-like illness, make sure your physician knows you have contact with cattle. If your cattle are sick at the same time, absolutely make sure your veterinarian, physician and public health know so the situation can be properly investigated.


  • As for farmers, consider flu in cattle and on beef and dairy farms, and be on the lookout for it.
  • Communicate with farmers, infectious disease specialists, labs and government agencies if you have concerns about flu in a particular herd.
  • Use standard infection control practices to minimize the risk of farm-to-farm spread of flu (and other pathogens). That route of transmission is pretty unlikely for flu, but there is potential for veterinarians to track flu between farms, which can’t be ignored.
  • As for farmers, if you might have the flu, stay away from animals (at least birds and mammals) as much as possible. Yes, that’s tough since that means not working, but we don’t want co-infections of people or animals with different flu viruses.
  • Consider wearing a mask around cattle. I realize that’s not likely to happen routinely, but definitely wear a mask and eye protection if you suspect flu might be present in cattle you’re seeing. Take particular care around handling the udder and with milk sampling.
  • If you develop flu-like illness, do the same as mentioned above for farmers.


  • Support testing for influenza A in cattle. We don’t know what we don’t know. We need a fairly wide net of testing to understand this issue. That costs money, and it’s hard to expect farmers to cover all the costs of this kind of testing, especially when there’s limited direct benefit to them (because so far flu only causes mild disease in cattle, and there’s no specific treatment).
  • Don’t make it hard to get testing done. Sometimes, we run into barriers when we want to test for emerging diseases. Don’t make veterinarians jump through permission processes to limit testing. We need more information, not push back against getting more information.
  • Support farmers who have suspected or confirmed cases of influenza in cattle. We need to see a balance of measures that are adequately restrictive to contain flu, but not so extreme that they drive the situation underground. If the response is over-the-top, there will be a strong disincentive for anyone to test for flu, and that just makes the situation worse.


  • Relax.
  • Don’t drink raw milk (for lots of reasons).
  • Avoid fearmongering Twitter threads.
  • Relax.

Public farm events/petting zoos

  • I really have no idea what to say here. Petting zoos or other similar animal exhibit events can result in large numbers of random people have contact with cattle, with limited hygiene, no health screening  and no contact tracing. There’s a risk, but it’s too early to say how much of a risk. We need to see how the situation evolves.
  • Fortunately, these kinds of events are most common in the summer and early fall, so we have a bit of time. At the moment, if there’s flu activity in wild birds in the area, it’s reasonable to say that we shouldn’t allow random access to cattle, pigs and other flu-susceptible species.
  • If visitor contact is allowed, make sure cattle are assessed daily to confirm none look sick, try to keep sick people away, try to maximize ventilation in animal areas, and facilitate (and encourage) hand hygiene.

As with any emerging disease, guidance will change. People don’t like that, but it’s actually a good sign – it means we’re learning and responding. We shouldn’t be so arrogant to think that what we recommend now will ultimately be the optimal approach. Hopefully we’re pretty close, and we can make good recommendations based on what we know now, but I’d be disappointed if we don’t change them at least a bit (because that would more likely mean we didn’t adapt than we knew it all from the start).