ChickenThere are very few absolutes with infectious diseases. The minute we think we are sure about something, a new angle becomes apparent.

Regarding rabies, we always say that its host range is mammals, but basically only mammals.

Maybe not.

There have been occasional (poorly corroborated) reports about rabies in birds, but when I first read headlines about this story, I figured it was some bizarre and misguided website. Then I saw that it was based on a paper in a reputable journal (Baby et al. 2015, PLOS Neglected and Tropical Diseases). It’s an interesting story that probably doesn’t really change the big picture approach but is intriguing.

The case report is about a bird that was attacked by a stray dog in India (where rabies is very common). The bird died a month after the attack, after appearing “droopy” and off-feed for a day.  Because of the history of the dog bite and the high level of rabies in the local dog population, the dead bird was (surprisingly) taken to a rabies diagnostic laboratory for testing. Here in North America, I doubt anyone would consider testing a bird for rabies. It would also be very unlikely (meaning not a chance) that I’d be able to get rabies testing done on a bird even if I wanted to.

Anyway, rabies virus was detected in the brain by two different tests.

This is an interesting scenario because it is a clearly demonstrated natural infection in a chicken, which likely was the cause of the bird’s death. The lesions in the brain were different than what is typically seen in mammals, since the classical “Negri bodies” were not identified. Regardless, the virus was there and since birds are almost never tested for rabies, it’s hard to say if this is an extremely oddball case or whether this could be more common than is realized.

Despite the fact that the bird was infected, there’s no indication that the bird was infectious (i.e. able to transmit the virus). That’s an important distinction since the odd bird dying of rabies is a minor issue (unless you’re the bird), but if there is another potential source of human infection, it’s a bigger deal. It also raises questions about whether there could be a risk from slaughtering infected birds or handling tissues from infected birds. However, most likely, the rare bird that is infected poses no risk to people.

It just goes to show how strange things can happen with infectious diseases and how we need to keep an open mind and be diligent.