Plague is a bacterial disease of rodents (and sometimes rabbits) that is transmitted from rodent to rodent through the bites of infected fleas.
The Urban Biology Division will collect dead rodents east of Tramway and the East Mountains to test for plague or tularemia. If you find a dead rodent without obvious trauma call 311.
- Any rodents such as mice, squirrels, pack rats, prairie dogs, and chipmunks may be infected with plague, but the one rodent most commonly infected in this area is the rock squirrel.
- Rodents generally die from the infection.
- Humans may become infected through the bites of infected fleas or through direct contact with infected rodent tissues.
- Direct contact cases usually involve hunters who field dress infected squirrels without wearing gloves, allowing plague bacteria to enter the body through open cuts or abrasions in the skin.
- Pets, particularly cats and occasionally dogs, may acquire infections through the bites of infected fleas or through ingesting infected rodent tissues.
- If you are experiencing symptoms described here seek medical attention;with early diagnosis and antibiotics this disease is easily treatable.
- Pets experiencing symptoms described below should be taken to a veterinarian.
Clinical Forms of Plague & Symptoms
Plague infection in humans may produce the following clinical forms and associated symptoms.
All three forms are caused by the same bacteria. The forms are used to describe the course of the infection in the human body. The only form that can be spread person to person is the Pneumonic form. Plague is treatable with antibiotics.
- Bubonic plague - This is generally the most common form and is acquired through the bites of infected fleas or by direct contact with infected tissues. Symptoms appear after a two to six day incubation period and include a rapid onset of high fever, swollen lymph nodes in the neck, armpit or groin areas, headache, and fatigue.
- Septicemic plague - If Bubonic plague is untreated the disease can progress to Septicemic Plague which is a toxic poisoning of the blood stream. Some patients, usually teenagers, may start with the Septicemic form of plague due to flea bites or direct contact with infected tissues and have no swollen lymph nodes. Symptoms include high fever, lethargy, and mental confusion.
- Pneumonic plague - If Bubonic or Septicemic plague are untreated the disease may progress to Pneumonic plague. In this form the plague bacteria invade the lung tissue. Humans may also acquire Pneumonic plague by inhaling infective droplets from another Pneumonic patient or cat. Symptoms include lung congestion, difficulty in breathing, high fever, chest pain and coughing with bloody discharge. This is the only form that is transmittable from person to person.
The Urban Biology staff:
- Conducts routine surveillance throughout the year to detect the presence of plague in the East Mountains and Western Foothills.
- Captures live rodents to collect blood and flea samples for plague analysis.
- Retrieves dead rodents in these same areas.
- If wild rodents have died for no apparent reason, take a tissue sample to be tested for plague.
- Implements follow-up surveillance, and apply flea control strategies with low toxicity to humans and animals to kill potentially infected fleas in areas plague is detected, especially if a person or a domestic pet is involved.
- Conduct educational outreach which includes literature distribution and community presentations on the prevention and control of plague.
Urban Biology strategies such as surveillance help to pinpoint areas where control is necessary and this helps to reduce the use of insecticides unnecessarily. This reduces the overall usage of insecticides in the environment.