Yersinia infection can cause plague or yersiniosis, both of which are notifiable conditions. Plague may be naturally occurring, or may potentially be the result of a bioterrorist attack.
Plague may be suggested by characteristic clinical findings together with a history of potential exposure in an endemic area. Microbiological studies are used to confirm the diagnosis. Rapid antigen tests may be recommended in some settings.
Plague has a high case fatality rate if left untreated (particularly pneumonic plague), but is treatable with antibiotic therapy and supportive care. Patients with pneumonic plague should be isolated immediately and placed on standard and droplet precautions. Pre-exposure or post-exposure prophylaxis may be required in people exposed to plague.
Yersiniosis generally presents as a self-limiting gastroenteritis. The mainstay of management is supportive care; however, antibiotics may be required in invasive infection.
In humans, Yersinia pestis causes plague and Yersinia enterocolitica causes yersiniosis. Infection with Yersinia pseudotuberculosis is uncommon and causes similar symptoms to yersiniosis.
The plague bacillus Y pestis is transmitted to people mainly by the bites of infected fleas. Infection is characterised by the sudden onset of systemic symptoms such as fever and painful swelling of lymph nodes (buboes) in bubonic plague; systemic features, but without buboes, in septicaemic plague; and chest pain, dyspnoea, and haemoptysis in pneumonic plague. Pharyngeal and meningeal plague are less common. Y pestis is categorised as a tier 1 bioterrorism select agent due to its low infectious dose, high case fatality rate, and history of use as an agent of bioterrorism.
Y enterocolitica and Y pseudotuberculosis are mainly acquired by consuming contaminated food and water. Symptoms are mostly confined to the gastrointestinal tract (self-limiting gastroenteritis), but reactive arthritis is a common complication.
History and exam
Key diagnostic factors
- constitutional symptoms
- lymphadenitis (bubonic plague)
- haemoptysis (pneumonic plague)
- diarrhoea (yersiniosis)
- abdominal pain (yersiniosis)
Other diagnostic factors
- pleuritic chest pain (pneumonic plague)
- dyspnoea (pneumonic plague)
- exposure to fleas (plague)
- residence in, or travel to, an endemic area (plague)
- contact with infected animals (plague)
- bioterrorism (plague)
- young children (yersiniosis)
- consumption of raw or undercooked pork products (yersiniosis)
- exposure to people with plague (plague)
- iron-overload syndromes (yersiniosis)
- chronic liver disease, diabetes, alcoholism (yersiniosis)
1st investigations to order
- blood culture (plague)
- bubo aspirate culture (bubonic plague)
- sputum culture (pneumonic plague)
- cerebrospinal fluid culture (septicaemic plague)
- throat swab specimen culture (pharyngeal plague)
- antigen detection (plague)
- WBC count (plague)
- chest x-ray (pneumonic plague)
- stool culture (yersiniosis)
Investigations to consider
- serology (plague or yersiniosis)
- polymerase chain reaction (plague)
pneumonic or septicaemic plague: non-pregnant adults and children
bubonic or pharyngeal plague: non-pregnant adults and children
pneumonic, septicaemic, bubonic, or pharyngeal plague: pregnant
- Gram-negative sepsis
- Bacterial pneumonia
- Cat scratch disease
- Plague: resources for clinicians
- Antimicrobial treatment and prophylaxis of plague: recommendations for naturally acquired infections and bioterrorism response
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