Guidance for Personnel Working with Wild Rodents at Texas A&M University-Kingsville

What is plague?

Plague is caused by infection with the bacterium Yersinia pestis, which is carried by rats, other rodents, and their fleas. The disease is manifested in bubonic and pneumonic forms. Human infections are initially transmitted from rodents by rat fleas, but later the disease may shift into the pneumonic form and continue by direct person-to-person spread.

How is plague spread?

Plague is transmitted to humans primarily by the bite of infected rat fleas. It is also possible to contract bubonic plague when cuts or other breaks in the skin come into direct contact with the body fluids or tissues of infected animals. In bubonic plague, the bacilli spread from a local abscess at the flea bite site to draining lymph nodes. Human to human transmission can occur through fleas, but much more commonly occurs via respiratory droplets once in the pneumonic form.

Who is at risk for infection?

Anyone who is exposed to fleas from diseased rodents is at risk for infection, as is anyone who has close contact with infected animals. This includes travelers to rural areas with large numbers of plague-infected rats, and laboratory workers who have close contact with infected or potentially infected animals, or who work with the Yersinia pestis bacterium itself.

Is plague infection serious?

Plague infection is extremely serious, and early clinical diagnosis is essential. If untreated, the fatality rate is 60% (bubonic) to 100% (septicemic or pneumonic); with antibiotic treatment, the chances of survival are greatly increased.

How can I protect myself?

The best way to protect yourself against plague is to become fully aware of its signs and symptoms. It is also important to avoid wild rodents and to be aware that some species may be more susceptible to infection with Yersinia pestis than others.

What are the signs of plague infection?

Manifestations of plague include general malaise, high fever, pain or tenderness at the regional lymphnodes. The lymphnodes become hot, swollen, tender, and hemorrhagic, giving rise to the characteristic black buboes. This swelling of the lymphnodes, along with skin blotches and delirium can occur within a few days of infection. Once the infection enters the bloodstream, the liver, spleen, and lungs are affected. The patient develops a severe bacterial pneumonia. Septicemia can also develop, with or without lymph node involvement.

 What do I do if an exposure or injury occurs?

Exposure to aerosols, bites or scratches involving animals or injuries from objects contaminated with body fluids from animals require immediate first aid and medical attention. Notify your supervisor! Then, contact the University Police Department at 593-2611 or dial 911.