COVID-19 derailed our plans for some backyard chicken work (e.g. research and education) this spring, but the emergence of COVID-19 doesn’t mean all other infectious disease issues have disappeared. Some problems will be reduced by the precautions put in place to control COVID-19, but other problems may actually get worse. Backyard chickens continue to be popular and I anecdotally may actually be more common now, at least in some areas, as people spend more time at home (and others worry (unnecessarily) about ongoing access to eggs and chicken at grocery stores).

I’m not anti-backyard chickens. I’m anti-“spending the weekend on the toilet” and anti-“seeing people hospitalized unnecessarily” and, I guess, just anti-Salmonella and anti-Campylobacter in general. I can’t see any redeeming qualities of those bacteria, at least in people.

That’s a rambling lead-in to a CDC investigation notice about Salmonella Hadar infections linked to backyard chickens. As always, these investigations markedly underestimate the scope of the outbreak, since most people who get sick don’t get tested, and chicken-associated infections with other strains that don’t cause enough widespread disease to get tracked don’t get any attention.

Regardless, it’s a reminder that this remains a significant problem.  As of the May 20, 2020 update:

  • 97 people had been diagnosed with the outbreak strain, with disease starting between February 26 and May 1 (see graph below).
  • People from 28 states have become sick (see map below).
  • 34% were hospitalized. None died.
  • 30% were kids younger than 5 years of age.
  • It looks like 4% of Salmonella Hadar isolates were extended spectrum cephalosporinase (ESC) producers – this is characteristic of certain bacteria that leads to resistance to some important and commonly used antibiotics (e.g. 3rd generation cephalosporins).
  • The likely source of the outbreak strain is backyard poultry, both chickens and ducks. These were often purchased at places like agricultural stores, directly from hatcheries or (probably worst case scenario for various reasons) over the internet.

The bias towards young kids is totally expected since that group is more susceptible to infection and probably more likely to be tested if they get sick. It’s also a group for which there is clear messaging: kids less than 5 years of age (and elderly people, pregnant women and people with compromised immune systems) should not have contact with young poultry. That’s a major education and/or compliance gap that’s seen in most animal-associated Salmonella outbreaks.

I won’t get into a full discussion of preventive measures, but the CDC notice includes a good list. They’re all common sense and very practical, but compliance is probably variable and often bad.

Wash your hands and don’t eat poop. Good general advice, but even more relevant if you have backyard birds.  And don’t make chicken diapers your sole infection control plan.