What is Plague?
Plague is a disease caused by the bacterium Yersinia pestis. You may have recently heard about it in the news, as the first case of a dog to human transmission was reported in Colorado.
Dog Transmits Plague to Its Owner
Yersinia pestis photomicrograph, courtesy of NIAID
How is it Transmitted?
Plague is most common in the Western to Mid-Western states, and is mostly seen where there is a high incidence of infected rodents such as prairie dogs. The bacteria are carried by fleas. When an infected flea bites an animal, the bacterium is transmitted and continues to spread in this manner, by the flea taking meals from infected animals and going on to the next. Dogs or cats running around outside chasing or eating vermin are at a higher risk of getting infected as the disease is transmitted through infected bodily fluids. Cats are very susceptible and are a more common source of infection in humans.
Symptoms
In humans, symptoms can include fever, chills, headache, weakness, coughing, enlarged lymph nodes (bubos or Bubonic form) and/or the development of pneumonia. The pneumonia form (Pneumonic plague) is the most contagious as it most often occurs from inhaling bacteria due to close contact with infected people or animals. Symptoms usually occur within 1-3 days after being exposed to the disease.
In cats, the most common presentation is high fever and abscessed lymph nodes (submandibular lymphadenitis). Cats can spread plague to humans through bites, scratches, contact with fluids ( it is not recommended to aspirate the lymph nodes if plague is suspected without proper protection), or infected fleas may be brought indoors via the cat or dog.
Contact your local health authorities about how and where to send tissue samples, and make sure to use proper protection if samples are taken from an animal.
Treatment
Plague is treatable with antibiotics. However, late diagnosis can prove fatal, as the disease can be overlooked. The most common drugs used for treatment include doxycycline or gentamycin.
The CDC provides an excellent presentation on plague:
Centers for Disease Control Plague Training Module