About This Disease

Plague is a serious illness caused by bacteria called Yersinia pestis. The disease is carried by rodents (rats and mice) and their fleas, which can then spread the disease to humans as well as to other animals. Plague is very rare in the United States, but cases are sometimes reported in the southwestern states. The most common form of plague is bubonic plague which affects the body’s lymph glands. When the infection involves the lungs, the disease is called pneumonic plague. Plague could be used as a bioterrorist weapon.

Signs and Symptoms

The symptoms of bubonic plague begin 1 to 7 days following the bite of an infected flea. For pneumonic plague, symptoms begin 1 to 4 days after contact with an infected person or animal. The first symptoms of bubonic plague include the sudden onset of fever with painful swelling of the lymph glands, called buboes, in the areas closest to the flea bite (typically, in the groin, armpit, or neck). Chills, muscle aches, weakness, fatigue, nausea, and headache may also occur. If the infection spreads to the lungs, it causes pneumonia that is highly contagious and often fatal.

Pneumonic plague is causes fever, swelling of the lymph glands, cough, and chest pain. Persons with this form of plague may cough up blood.


Bubonic plague is spread to humans from the bite of infected fleas, or by being scratched or bitten by infected animals. Bubonic plague is not directly spread from person to person. Pneumonic plaque can be spread through the air (through coughing or sneezing) and through direct and close contact with an infected person or animal.


Your physician will take samples to test for the bacteria if he or she suspects you have plague. Depending on which type of plague is suspected, samples may be taken from swollen lymph nodes, a blood sample, or respiratory samples.


Antibiotics can be prescribed by a doctor to treat plague. It is very important to detect and treat the disease early in its course. If not treated, about half of those with bubonic plague will die. Prompt treatment can greatly reduce the chance of dying from plague. Persons who are infected with pneumonic plague should be isolated from well people for 3 full days after the start of antibiotic treatment.

Risk in Hawaii

There have been no reported cases of locally transmitted plague in humans since 1949.


If you travel to an area endemic for plague and you think that you could be exposed to rodent fleas during activities such as camping, hiking, or working outdoors, use an insect repellent containing DEET. Repellents containing DEET and permethrin can be also applied to clothing for better protection. Visit the CDC site to learn more about prevention.

Information for Clinicians

Plague is an URGENT notifiable condition and must be reported by phone to the Disease Outbreak Control Division, Disease Investigation Branch on Oahu, or to the District Health Office on the neighbor islands as soon as a provisional diagnosis is established.

Disease Reporting Phone Numbers (24/7)

Oahu (Disease Investigation Branch): (808) 586-4586
Maui District Health Office: (808) 984-8213
Kauai District Health Office: (808) 241-3563
Big Island District Health Office (Hilo): (808) 933-0912
Big Island District Health Office (Kona): (808) 322-4877
After hours on Oahu: (808) 600-3625
After hours on neighbor islands: (800) 360-2575 (toll free)

For more information: Centers for Disease Control and Prevention (CDC)



Last Reviewed: August 2019