A house cat in the Eagle, Colorado area has been diagnosed with pneumonic plague. Plague, caused by the bacterium Yersinia pestis, is a disease that still strikes fear into people. While we are long since removed from the period where the "black death" killed a large percentage of the population in Europe, plague still has a foothold is some regions of the world like the southwestern US. It is present in some wildlife (mainly rodents) and periodically infects people or domestic animals through transmission by infected fleas or direct contact.

Plague is periodically identified in cats – it’s almost always outdoor cats that are affected since they have more interaction with wildlife and are at greater risk of flea infestation. Several forms of the disease can occur, including pneumonic, septicemic and bubonic plague. Pneumonic plague is a severe lung infection caused by the plague bacterium which is highly fatal.  This form is of particular concern because infected cats can spread the infection to people through aerosols produced by coughing and sneezing, or through contact with respiratory secretions. People caring for sick cats are at risk of developing plague (especially pneumonic plague, which is almost invariably fatal if untreated). Veterinary personnel are at particularly high risk. One study reported that 20% of people who contracted plague from cats worked in vet clinics. Of these, 25% of them died. 

If you live in an area where plague is present in wildlife, keep your cat indoors, avoid contact with wild rodents, keep wild rodents out of your house and make sure that you have a flea prevention program for you pets. If these things are done, the risk of disease transmission is very low.

Image source: www.northernsun.com

  • Suzanne Barnes DVM

    I am the owner of the cat that contracted plague. She did NOT have pneumonic plague as incorrectly reported by the Eagle County Health Department. She is a 14 yr old F(S)DLH that is diabetic and has fairly well developed cataracts. She receives monthly flea and tick prevention with topical Frontline Plus (Merial). She had septicemic plague and contracted it by eating the head and neck of a pack rat (wood rat)in the daytime, creating some suspicion because pack rats are strictly nocturnal. 36 hours later she presented with extreme lethargy, anorexia and a high fever only, and she was hospitalized for treatment of a suspected rodent-borne illness including plague. 24 hours after hospital admission (Day 2), she developed a single enlarged submandibular lymph node and an aspirate yielded the typical closed pin appearing Yersinia pestis bacteria and neutrophils that had phagocytised the bacteria. Her WBC count dropped to