Plague Found Again in Desert Southwest May 2015

On May 13, 2015 I received an update from the Arizona Veterinary Medical Association warning veterinarians that plague was diagnosed in Jerome, Arizona. A cat tested positive for Yersinia pestis and it is suspected in three other cats. Y.pestis is endemic to the southwestern United States as well as semiarid areas of Asia and Africa. The virus is found in rodents with rock squirrels, prairie dogs and ground squirrels being the most susceptible in the U.S. Fleas carried by the rodents transmit the bacteria to other animals and humans through their bites. An interesting fact is that dogs are much more resistant to the bacteria than cats. Hunters may contract the disease after exposure to infected tissues. Veterinarians have contracted the disease when caring for infected cats. The unsuspecting doctor fails to take appropriate precautions because they think they are treating a cat fight abscess.

Once infected, plague manifests itself in three different syndromes depending upon the route the bacteria entered the animal’s body. 1) Bubonic- After a flea bite, the bacteria is carried to the nearest lymph node (gland) where the bacteria replicates until it forms a bubo. The center of the swollen lymph node (bubo) forms an abscess. It will eventually break open and drain. 2) Septicemic- If the bacteria is able to enter the bloodstream, it will spread around the body causing sepsis. 3) Pneumonic- In the pneumonic form, bubos form in the patient’s lungs. This occurs when the bacteria is inhaled. The bubonic form carries the best prognosis.

Clinical signs of plague start with fever, anorexia, lethargy and enlarged lymph nodes. In cats, the lymph nodes under the jaw are the most commonly affected. Since abscess all look alike, take precautions before treating any animal with an abscess. Use masks and gloves to prevent transmission of the bacteria.

To prevent plague, the Arizona Department of Health Services recommends flea prevention for all pets. I recommend using flea and tick repellant.  The Brown Dog Tick found in Arizona carries Erhlichia canis which causes tick fever.


-Morgan, R. Plague(Zoonotic) Vin Canine Associate 10/11/2003, Revised by Rothrock, K. 3/5/2013.                                                              -Plague in Jerome, AZ, Email from Arizona Veterinary Medical Association, May 13, 2015.


Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.