A recently published University of Guelph study evaluating pet poultry flocks found (unsurprisingly) high rates of shedding of certain concerning bacteria (Brochu et al, J Vet Diagn Invest 2019).
- Campylobacter, an important cause of gastrointestinal disease in people, was present in 36% of tested chickens. Salmonella was less common but present in 3% of chicken fecal samples.
- The Campylobacter shedding rate was actually higher than has been reported in commercial chickens at slaughter plants. This is in contrast to some statements you see about people not worrying about infectious diseases with small-flock chickens because they’re not from a “factory farm.” As far as Campylobacter and Salmonella are concerned, chickens are chickens.
As the authors state, “Fecal shedding can lead to the spread of the pathogen within the environment, leading to contamination of food, tools, and materials coming into contact with people, flies, and other flocks. Given that small flock poultry are often kept as pets, close contact (e.g. kissing, petting) could increase the risk of exposure further, especially for people at higher risk (e.g. children). These results underscore the importance of proper sanitation and hand hygiene measures for flock owners to protect both flocks and the public from these pathogens.”
In a related note, the CDC has updated their Outbreaks of Salmonella infections linked to backyard poultry investigation notice.
- As of August 30th, a total of 1003 people from 49 US states have been affected. Alaska is the only mainland state where cases have not been identified (the Alaskan climate probably not being great for outdoor poultry).
- 23% of affected people are children under the age of 5, as is common in outbreaks like this, both because of their close contact with animals and their increased susceptibility to disease.
- Two people have died and over 25% of diagnosed cases have been hospitalized. So, this isn’t just a case of having to spend a couple days running to the bathroom. It can cause serious disease, a fact that’s often overlooked.
- Multiple Salmonella strains are involved, and affected people have reported getting chicks from a wide range of sources, including agricultural supply stores, websites and hatcheries.
- Outbreak strains of Salmonella have been isolated from the backyard poultry environments at multiple homes, showing the potential for exposure without direct bird contact. This also highlights the potential for spreading Salmonella beyond the yard by other routes such as wildlife and runoff.
I’m not anti-backyard chickens. However, I’m against doing things illogically (or downright stupidly). Some basic common sense and infection control practices can limit (though never eliminate) the risk, but use of these precautions is likely inadequate. It’s a complex situation that doesn’t just deal with the chicken owners. It also relates to household visitors and even neighbours, since the potential for transmission of things from yard to yard can’t be dismissed. Ultimately, we need good guidance for backyard chicken owners and good compliance, and a realization that there are always risks and therefore necessary control measures. We’re working on this area but it’s not going to be a quick fix.