Plague in Cats

Plague has 3 forms, which all have slightly different presentations. The different forms of plague can coexist in the same infected cat.

Bubonic plague is the most common presentation of plague in cats. Once Yersinia pestis enters the animal's system, it enters the lymphatic vessels and causes swollen lymph nodes referred to as buboes. Subsequent abscessation, rupture, and drainage of buboes is a characteristic symptom of plague.

Septicemic plague spreads through the bloodstream and can affect several different organs (liver, heart, and lungs). Septicemic plague does not cause swollen lymph nodes.

Pneumonic plague: if septicemic plague is left untreated, it spreads and causes secondary pneumonic plague in the lungs.

Due to the high mortality rate and zoonotic potential, immediate medical attention and isolation for cats suspected of infection with Y. pestis are paramount. Confirmed cases of plague must be reported to local health authorities.

Outdoor cats in endemic areas have a higher risk of entering into contact with infected rodents and fleas.

In the United States, the majority of plague cases occur in Arizona, California, Colorado, Nevada, New Mexico, and Oregon. Worldwide, plague is present in all continents, with the exception of Antarctica and Australia.

Symptoms vary in severity depending on the form of plague.

Animals affected with pneumonic plague present the same symptoms as septicemic plague with the addition of cough and abnormal lung sounds.

Cats suffering from pneumonic plague are highly contagious.

While highly deadly when left untreated, plague is easily managed with antibiotic treatment.

Plague is caused by the Yersinia pestis bacteria.

Cats become infected by:

• Flea bites: fleas become infected by the bacteria by feeding on the blood of infected rodents (e.g., mice, rats, rabbits, squirrels, and chipmunks); flea bites from infected fleas can transmit bubonic plague
• Contact with tissue of infected rodents: contact with contaminated animals and carcasses can transmit septicemic plague
• Inhalation of infected air droplets: inhalation of saliva and air droplets can transmit primary pneumonic plague Primary pneumonic plague is very rare. Cats develop secondary primary pneumonic plague as the result of untreated septicemic plague.

Cats presenting symptoms of plague generally undergo the following diagnostics:

• Blood tests
• Lymph node biopsy
• Mouth and throat swabs
• Bacterial culture
• Antibody tests
• Skin tissue biopsy
• Cerebral fluid test

Due to the life-threatening nature of the condition, the zoonotic risks, and the rapidity of the symptom progression, cats suspected of having plague should be treated and isolated prior to definitive diagnosis.

Treatment options include:

• Isolation
• Flea removal
• Antibiotic treatment (10 to 21 days)
• IV fluids
• Vomiting and diarrhea medication
• Supplemental oxygen

Cats are considered to be non-infectious 72 hours after beginning the antibiotic course.

Plague is a reportable disease; as such veterinary staff is required to report cases to public health authorities to ensure proper prevention and contact tracing.

Prognosis for plague varies from guarded to extremely poor and is dependent on which form develops and the timing of treatment.

Untreated animals developing an acute form of plague usually die within four to six days from the onset of symptoms.

The bubonic form is least likely to be fatal. Mortality rates for the septicemic and pneumonic forms in cats are very high.

Plague is a highly contagious disease, and as such, prevention is of the utmost importance. No vaccination is available. Prevention strategies include:

• Flea control measures
• Keeping pets indoors to minimize exposure in areas with reported plague cases
• Keeping animals from hunting and roaming reduces the risk of plague infection
• Reducing rodent presence in and around the household

Plague is rare in cats, but cats are more susceptible to it than dogs. Cats present a more significant risk to humans than dogs do and are responsible for a significant percentage of human plague cases.

• Isolation
• Flea removal
• Antibiotic treatment
• IV fluids
• Vomiting and diarrhea medication
• Supplemental oxygen