Prairie dog flea control

In response to a case of plague in prairie dogs in Saskatchewan's Grasslands National Park, park officials are dusting prairie dog burrows with insecticide to try to control fleas. A single case of plague, a serious bacterial infection caused by Yersinia pestis, was identified in a prairie dog in the park earlier this summer. Plague is present in some areas of North America, but it's rare in Saskatchewan. It circulates in wild small mammals, and prairie dogs are particularly susceptible to infection. The main mode of transmission is via fleas, which feed off infected animals, then bite and infect other animals.

Prairie dog numbers at the park have dropped by 50-70% this summer, however it's not known whether plague is involved in this, as there has also been a drought. It's fair to assume, though, that if there has been one case of plague found in the park, there have probably been many other undiagnosed cases. Whether or not plague is responsible for the large drop in prairie dog numbers, measures to try to reduce plague transmission are a good idea because of the impact it can have on the prairie dog population (and those of other wild mammals), as well as people or pets that may venture into the area. Anyone or anything walking through the area could plausibly be bitten by an infected flea. The odds are probably pretty low, but park officials are trying to keep people and pets out of the park to reduce this risk.

Plague in Saskatchewan

Plague has been identified in a dead prairie dog in Grasslands National Park in Saskatchewan, Canada. This disease, caused by the bacterium Yersinia pestis, circulates in small wild mammals in some regions, and is spread by fleas. While plague is endemic in some parts of North America, it's very rare in Canada. (The last reported human case was in 1939).

Prairie dogs are highly susceptible to plague.  The most likely problem with plague occurring in prairie dogs in Grasslands National Park will be the impact on the prairie dog population itself. Outbreaks of plague in prairie dogs can be devastating, virtually wiping out entire colonies.

  • Plague can be transmitted to people, but the risk here is quite low. For people to become infected, they have to be bitten by a flea that was infected by biting an infected prairie dog (or other animal). The risk of exposure to a flea infected by wildlife is pretty low if people aren't crawling around prairie dog holes and take some basic precautions.
  • The risk to pets is similarly low. Cats are more susceptible to plague than dogs, but they have to be exposed via a flea or, more commonly, from hunting and eating infected wildlife. There presumably aren't too many pet cats in Grasslands National Park, so the risk of exposure is probably limited. Dogs are rather resistant to plague, but they are probably at increased risk of exposure in a situation like this because they are more likely to be taken into areas where infected animals and fleas may be present (e.g. with people going hiking).

The greatest public health and domestic pet concern would be if plague spread beyond prairie dogs and into other small mammal populations that live closer to people or that have more contact with pets. The likelihood of this becoming a major problem is pretty low, but it's a serious disease and this situation certainly needs to be monitored.

In response to this case, park personnel are monitoring prairie dog colonies to look for more cases. They are presumably also keeping a close eye out for any other unexpected deaths of small mammals. Park officials have recommended that people stay away from prairie dog colonies, tuck their pants into their socks (to keep out fleas) and use insect repellent on their shoes. They have also closed some areas to domestic pets.

Photo: Black-tailed Prairie Dogs atop their burrows in Grasslands National Park in Saskatchewan, Canada (source: www.canada-photos.com)