Plague (Black Death) is Yersinia pestis infection. Initial symptoms are fever, chills, nausea, myalgia, sore throat, prostration & headache followed by intensely painful buboes (regional lymphadenitis). Inguinal nodes are involved in cases of flea bites to the legs. Rats are the natural reservoirs.

30 (US); 20,830 (Global)
Yersinia pestis infection; Black Death; Primary pneumonic plague (inhalation of bacteria); Secondary pneumonic plague (complication of bubonic or septicemic plague);
2-6 days (bubonic plague); 1-3 days (primary pneumonic plague); [Cecil, p. 1957]
Fever, chills, nausea, myalgia, sore throat, prostration & headache followed by intensely painful buboes (regional lymphadenitis); Inguinal nodes are involved in cases of flea bites to the legs. Septicemia occurs with/without prior lymphadenopathy. [CCDM]
Standard; "Bubonic plague is not usually transmitted directly unless there is contact with pus from suppurating buboes." [CCDM, p. 459] For pneumonic plague: Droplet until after 48 hours of effective Rx; Antimicrobial prophylaxis for exposed HCW; [CDC 2007 Guideline for Isolation Precautions]
The three main types of plague are bubonic, septicemic, and pneumonic. In bubonic plague, some patients have a papule, pustule, or ulcer at the site of the flea bite. Some distinguishing features of bubonic plague versus other causes of acute lymphadenitis are rapid onset, severe systemic symptoms, exquisite tenderness of buboes, and absence of cellulitis or lymphangitis. Secondary pneumonic plague develops in some cases with a grave prognosis. [Guerrant, p. 279-80] Flea bite lesions (papules, vesicles, or pustules distal to the affected lymph nodes) are occasionally found. Some patients have prominent gastrointestinal symptoms including nausea, vomiting, diarrhea, and abdominal pain. [PPID, p. 2782, 2783] Febrile seizures are common in children. [PPID 7th Ed., p. 2946] Leukocytosis is expected, but leukopenia may occur. [Harrison ID, p. 574]

Complications of septicemia include pneumonia, meningitis, shock, and disseminated intravascular coagulation (DIC). [CCDM, p. 456-65] Platelet counts are usually normal, but are low in the presence of DIC. [ID, p. 1457] Oculoglandular plague occurs after inoculation through the conjunctiva. [Cohen, p. 1083] "Localized infection is unlikely to be observed in the lungs of patients with secondary pneumonic plague because the lung tissues are infected initially through circulatory spread, which results in a diffuse interstitial pneumonitis." [Cecil, p. 1957]

Mortality rate as high as 50% for untreated patients; [Gorbach, p. 317] Cats and dogs may carry rodent fleas into households. Plague bacilli can also be transmitted by handling the tissues of infected animals and, rarely, by inhaling droplets from infected patients or animals with plague pneumonia or pharyngitis. Natural reservoirs are wild rodents; also rabbits, hares, cats, and wild carnivores may become infected. [CCDM] Ingestion of meat from an infected animal can cause pharyngeal plague. [Harrison ID, p. 573]
Gram stain (bipolar staining like safety pin); Culture (Notify lab that Y. pestis is suspected.); DFA and serology EIA for F1 capsular antigen; [ABX Guide]
Endemic in rural areas of central and southern Africa (eastern Democratic Republic of Congo, northwestern Uganda, Madagascar), central Asia, Indian subcontinent, northeastern South America, and southwestern USA; [CDC Travel]
  • >arthralgia
  • >fatigue, weakness
  • >fever
  • >myalgia
  • E pharyngitis
  • G abdominal pain
  • G diarrhea
  • G hepatomegaly
  • G liver function test, abnormal
  • G nausea, vomiting
  • H leukocytosis
  • H lymphadenopathy
  • H splenomegaly
  • H thrombocytopenia
  • N confusion, delirium
  • N headache
  • N seizure
  • O oculoglandular syndrome
  • R chest pain
  • R cough
  • R dyspnea
  • R hemoptysis
  • R sputum production
  • S entry wound with lymph nodes
  • S lymphadenitis, acute
  • S papules or plaques
  • S petechiae and ecchymoses
  • S pustule
  • S skin blister or vesicles
  • S ulcer of skin
  • X cystic or cavitary lesions
  • X lung infiltrates
  • X pleural effusions
  • *acute renal failure
  • *ARDS
  • *bleeding tendency
  • *mediastinitis
  • *meningitis
  • *pneumonia
  • *pneumonitis
  • *sepsis
  • *shock




Inhalation, Ingestion, Skin or Mucous Membranes (Includes Conjunctiva), Animal Bite
Person-to-Person, Animal Tissue, Eating Contaminated or Infected Meat
Cats, Dogs, Rabbits, Rodents, Wild Animals
  • Eat undercooked meat or fish
  • Handle animal carcasses or placentas
  • Handle dog or cat (bite or scratch)
  • Handle domestic animals
  • Handle infected rodents (bite)
  • Handle infected rodents (not bite)
  • Travel to endemic area
  • Work in a medical or research lab
  • Work in building infested with rodent fleas or mites
Antibiotic treatment is highly effective if begun early. [CCDM] No commercially available vaccine in the U.S.; [Cecil, p. 1957]
1. (US) Published in MMWR 2011 =3; Use correction factor of 10 for reported diseases: 3 X 10 = 30;
2. (Global) 12,503 cases reported to WHO between 2004 and 2009 (2083 cases per year); 80-95% of plague is bubonic plague with a 10-20% mortality rate; [Harrison ID, p. 570] WHO statistics for 2010-2015: 96.2% of cases in Africa (Democratic Republic of Congo, Madagascar, Uganda, and others); [Cecil, p. 1955] Use correction factor of 10 for reported diseases: 2083 X 10 = 20,830;