The ongoing H5N1 avian flu pandemic in wild birds (and all its various spillovers into domestic poultry, cattle, wildlife and sometime people) has led to a lot of questions about how we handle situations that increase human or domestic mammal contacts with wild birds. This includes a range of activities and animals, including:

• Backyard bird feeders
• Backyard chickens
• Hunting dogs
• Off-leash dog walks in areas with waterfowl
• Indoor-outdoor cats
• AND petting zoos / public farms

There aren’t a lot of petting zoos where people can have direct contact with birds (birds can be pretty flighty, and there’s the pecking risk among other things) but some operations do allow it. Even when direct contact is not permitted, people at petting zoos or on these open farms can certainly be in close proximity to birds, and have contact with mammals that live with birds.

What’s the risk of exposure to avian flu at a petting zoo or open farm?

It’s hard to say. It’s probably quite low but non-zero. A recent outbreak of H5N1 avian flu on a petting farm in British Columbia has highlighted some of the issues. The outbreak resulted in approximately 50 ducks and chickens being euthanized (presumably after one or more got sick or died, and were tested and found to be infected with the flu virus). Local public health is “advising anyone who visited the farm on Oct. 26 or 27 to monitor for symptoms associated with avian flu, including but not limited to cough, fever, sore throat, runny nose or red, watery, itchy or painful eyes”.

Anyone with signs of illness should contact public health ASAP for testing. The health unit has also been in touch with school groups and other known visitors who were on the property during this time period.

Bird-to-human transmission of this virus is still pretty rare, and is typically associated with direct close contact with (usually a large number of ) birds. Given the low incidence of transmission, likelihood that there was no or limited direct contact with the birds, and maybe limited risk of people and birds being in small enclosed airspaces together, the risk to the public is probably still very low even in this situation. The risk for farm personnel would presumably be higher. Regardless, the risk still isn’t zero so it’s good to raise awareness and have testing available to see if there was any transmission to farm visitors or staff.

The risk of severe disease in people in this case is very low, since the currently circulating H5N1 strain has typically caused mild infections in people. But, every bird-to-human (or bird-to-any-mammal) transmission creates more risk for adaptation of the virus to mammals. We want to limit that as much as possible, and identify transmission to better understand the virus and help reduce the risk of subsequent human-to-human spread.

At this point, we should be past the risk period for human illness since it’s been over 2 weeks from the last potential exposure to the birds on this petting farm. Hopefully no news is good news. (The recent case of H5 influenza infection in a teenager in BC does not appear to be linked to this petting farm, as it was later reported that the individual had no known exposure to any infected animals or birds.)