Cat World > Cat Health > Yersinia Pestis (Plague) in Cats

Yersinia Pestis (Plague) in Cats

yersinia pestis

The plague is an extremely serious zoonotic (transmissible from animals to humans) infection caused by the bacteria Yersinia pestis. This is the bacteria that is believed to have been responsible for the Black Death which wiped out a 30-60% of the population of Europe from 1346.

The natural reservoirs of plague are rats, mice, prairie dogs and squirrels. Cats and dogs are accidental hosts. Y. pestis can be found worldwide but is most prevalent in Africa, Asia, and South America. It is extremely rare in the USA and when it does occur, it is in regional areas of the western states - where it is on the increase in recent years. Dogs are more resistant to the disease than cats, and it is self-limiting.

The plague comes in three clinical forms (below), symptoms may vary depending on which form your cat has.

  • Bubonic plague: Infection of the lymph nodes. This is the most common, and least fatal form of plague.
  • Septicemic plague: Infection of the blood. The second most common form of plague.
  • Pneumonic plague: Infection of the lungs. This is the most severe form of the plague with a 90% mortality rate if left untreated.

How is the plague transmitted?

yersinia pestis in cats

The disease can be transmitted in several ways.

Bubonic and septicemic plague are transmitted via the bite of an infected flea. This is by far the most common mode of transmission. Cats can become infected via the bite of a flea, which can also be brought into the home on the cat, biting and infecting humans.

Pneumonic plague can be spread by coughing and sneezing. This is the only mode of transmission from person to person and hasn't occurred in the USA since 1924.

In some instances, you can also become infected when handling an infected animal who bites or scratches you or from coming into contact with bodily fluids of an infected animal (such as a hunter handling a dead animal). Cats can become infected by hunting/eating infected rodents.

What are the symptoms of plague in cats?

The incubation period of the plague is 2-6 days. Symptoms vary depending on the "type" of plague, but may include:

  • Loss of appetite (anorexia).
  • Dehydration.
  • Lethargy.
  • Fever.
  • Bubonic plague - Swollen, tender lymph nodes, which become abscessed. When cats develop this form of the plague, the lymph nodes in the head and neck are most commonly affected. 
  • Pneumonic plague - Coughing and sneezing.

How is plague diagnosed?

The plague is diagnosed by culturing the organism from discharges. If your veterinarian suspects the plague, treatment will begin prior to confirmation.

A chest x-ray may also be performed.

Differential diagnosis:

FIP and FeLV tests may be performed to rule out these diseases.

How is plague treated?

Antibiotics (usually streptomycin or gentamicin)are used to treat the plague in cats (and humans). Tetracyclines may also be used, particularly for prophylaxis.

Great care must be taken while treating a cat with the plague. Strict handling and isolation will be required to prevent the spread of infection.

All cases of the plague should be reported to the relevant authorities. Veterinarians and pet owners are at risk of developing an infection if they have been exposed to an infected cat and should seek advice from their doctor. Antibiotics may be prescribed as a precaution.

Diligent flea control should be observed in cats who live in at-risk areas.

Image courtesy of NIAID