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Arizona Prairie Dog Deaths Caused by the Plague

Posted April 08, 2015 in A Vet's Life

Prairie Dogs standing up

According to Brooks Hays of, Arizona health officials became concerned when a large number of prairie dogs were found to be dying or dead. Several burrows were tested and were found to be infested with fleas that tested positive for Yersinia pestis. “Nearby burrows are now being cleared and disinfected, in an effort to stem any possible outbreak of the disease,” said UPI. The article went on to report that it’s actually not a new occurrence. “The plague isn't new to Arizona. The disease has been firmly established in the Grand Canyon State, as well as Colorado and New Mexico, for some time now. Every year, a handful of people are infected with the disease.” Still, with plague headlines in the news, you may well be wondering if your pet is at risk.

What causes the plague?
Yersnia pestis, the bacteria that causes plague, is commonly carried by small rodents such as ground squirrels, rats, mice and even rabbits. Unfortunately, small rodents and rabbits not only can carry Yersnia pestis, but can also become affected by it. Prairie dogs are very vulnerable to plague due to their social nature, and outbreaks can decimate the population.

This naturally occurring bacteria survives due to a cycle between rodents and fleas1. Plague is found in upland forests and grasslands in rural to semi-rural areas of the western part of the United States (especially the southwest regions)1. There is a higher incidence of plague during cooler summers that follow wet winters1, during the months of May to October. Wherever you expect rodents to live, that’s where this bacteria can survive. The more exposure to rodents or fleas, the higher the risk of exposure to Yersnia.

How can the plague spread to dogs and cats?    
Rarely, dogs, cats and humans can be infected. The CDC says this may happen one of three ways:

  • Flea bites: This is the most common way that Yersnia is transmitted. During plague outbreaks (e.g., dying prairie dogs), the host dies, causing fleas to abandon that source of blood and seek other creatures. When dogs, cats and humans visit places where rodents have recently died of plague, they risk being exposed through flea bites1.
  • Exposure to contaminated fluid or tissue: Exposure to infected tissue can result in plague.  Hays reports, back in 2012, a cat guardian was exposed after his cat bit him while he was trying to pull a partially-eaten mouse from the cat’s throat; unfortunately, this person developed a severe infection and lost several fingers due to Yersnia. Another cause of exposure may be hunting. While skinning a rabbit or another infected animal, there is the risk of becoming exposed to the plague bacteria1.
  • Infectious droplets: While this route is less common, aerosol transmission of plague can occur in someone who has plague pneumonia. Inhalational exposure can occur resulting in pneumonic plague. While this is rare (as it typically requires intimate exposure to a person with pneumonic plague), it can result in human-to-human exposure1.

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Justine has more than 18 years of experience in the veterinary industry and is a board-certified emergency critical care veterinary specialist and toxicologist as well as the CEO and founder of Vetgirl. She is also a founding member of IDEXX’s Pet Health Network team.

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