How do plagues spread

Contact with contaminated fluid or tissue. Humans can become infected when handling tissue or body fluids of a plague-infected animal. For example, a hunter skinning a rabbit or other infected animal without using proper precautions could become infected with plague bacteria. This form of exposure most commonly results in bubonic plague or septicemic plague.

Infectious droplets. When a person has plague pneumonia, they may cough droplets containing the plague bacteria into air. If these bacteria-containing droplets are breathed in by another person they can cause pneumonic plague.

Typically this requires direct and close contact with the person with pneumonic plague. Transmission of these droplets is the only way that plague can spread between people. This type of spread has not been documented in the United States since , but still occurs with some frequency in developing countries.

Cats are particularly susceptible to plague, and can be infected by eating infected rodents. Sick cats pose a risk of transmitting infectious plague droplets to their owners or to veterinarians. Several cases of human plague have occurred in the United States in recent decades as a result of contact with infected cats.

Skip directly to site content Skip directly to page options Skip directly to A-Z link. Section Navigation. It is caused by the bacterium Yersinia pestis. This bacterium is found in rodents and their fleas and occurs in many areas of the world, including the United States.

Even so, when released into air, the bacterium will survive for up to one hour, although this could vary depending on conditions. Pneumonic plague is one of several forms of plague. Depending on circumstances, these forms may occur separately or in combination:. With pneumonic plague, the first signs of illness are fever, headache, weakness, and rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery sputum.

The pneumonia progresses for 2 to 4 days and may cause respiratory failure and shock. Without early treatment, patients may die. Early treatment of pneumonic plague is essential. To reduce the chance of death, antibiotics must be given within 24 hours of first symptoms. Streptomycin, gentamicin, the tetracyclines, and chloramphenicol are all effective against pneumonic plague. Antibiotic treatment for 7 days will protect people who have had direct, close contact with infected patients.

Wearing a close-fitting surgical mask also protects against infection. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Plague outbreaks are most common in rural and semirural areas that are overcrowded, have poor sanitation and have a high rodent population. The greatest number of human plague infections occur in Africa, especially the African island of Madagascar. Plague has also been transmitted to humans in parts of Asia and South America. In the United States, plague is rare, but it has been known to occur in several western and southwestern states — primarily New Mexico, Arizona, California and Colorado.

Veterinarians and their assistants have a higher risk of coming into contact with domestic cats and dogs that may have become infected with plague. People who work outdoors in areas where plague-infected animals are common are also at higher risk of getting plague.

Camping, hunting or hiking in areas where plague-infected animals reside can increase your risk of being bitten by an infected flea. No effective vaccine is available, but scientists are working to develop one. Antibiotics can help prevent infection if you're at risk of or have been exposed to plague. Take the following precautions if you live or spend time in areas where plague outbreaks occur:.

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Overview Plague is a serious bacterial infection that's transmitted primarily by fleas. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references AskMayoExpert. Rochester, Minn.