A severe infection appearing most often in the lymph nodes in the groin or axilla (bubonic), or lungs (pneumonic). It is caused by the Yersinia pestis microrganism.

The condition occurs mainly in wild rodents, (e.g., rats, mice, squirrels, etc.), and it may be acute, subacute, or chronic in nature. In the U.S., it has most recently been seen in southwestern states. The bubonic type occurs more often. The transmission is from rodent to humans by the bite of an infected flea. Human-to-human transmission occurs by the inhalation of droplet nuclei, and by the cough of infectious patients with pulmonary lesions. In areas where the disease is more prevalent, cases have been linked with household pets, especially cats. Cats transmit the disease by biting, or, if the cat has pneumonic plague, by the inhalation of contaminated droplets.

The incubation period in bubonic plague is approximately 2 to 5 days. However, it can vary from a few hours to 12 days. There is an abrupt onset frequently linked with chills and fever. The heart rate may be rapid and irregular, and low blood pressure may occur. Inflamed lymph nodes (buboes) emerge along with or shortly before the fever. The lymph nodes located at the femoral or the inguinal area are most commonly affected; followed by the axillary, cervical, or a small percentage may involve multiple nodes. The nodes become very tender and firm, with swelling. Skin eruptions vary from a small, fluid-filled lesion with slight locally inflamed lymph nodes to dead tissues seen at the bite site. Neurological effects may include: restlessness, delirium, confusion, and lack of coordination. The incubation period for primary pneumonic plague is 2 to 3 days. This is followed by a quick onset of high fever, chills, increased heart rate, and headache. Cough occurs within 20 to 24 hours. Sputum is mucoid at first, swiftly showing blood specks, and then becoming pink or bright red and frothy. Increased respirations and dyspnea are common.

Diagnosis is based on retrieval of the organism. Needle aspiration of a bubo is the preferred method. The organism can be cultured from blood, sputum, or lymph node samples. Complement fixation, passive hemagglutination, and immunofluorescent staining are the serologic tests performed.

Instant treatment reduces chance of death to less than 5%. When microorganisms are found in the blood, or in the case of pneumonic plague, treatment with antibiotics within 24 hours is indicated.

The mortality rate for patients who do not get treated for bubonic plague is about 60%. Deaths most often occur from organisms in the blood within 3 to 5 days. Death occurs within 48 hours of the onset of symptoms for untreated patients with pneumonic plague. Septicemic plague may cause death before bubonic or pulmonary manifestations prevail.

1. May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% and/or other requirements/qualifications under 38 CFR 3.350 [Special monthly compensation ratings]. Also reference 38 CFR 3.155(d)(2).   

2. This disease shall be granted service connection as a result of tropical service, although not otherwise established as incurred in service if manifested to a compensable degree within the applicable time limits under §3.307 or §3.308 following service in a period of war or following peacetime service provided the rebuttable presumption provisions of §3.307 are also satisfied [38 CFR 3.309 (b)).Disease subject to presumptive service connection].

3.  Consider service connection on a presumptive basis as a tropical disease (38 CFR §3.307; §3.308; §3.309 (b)).

As active disease rate as 100%, thereafter rate under the appropriate body system any residual disability of infection.