Pneumonic plague — what it is

Overview

Pneumonic plague occurs when Yersinia pestis infects the lungs. It can develop on its own or as a progression of another form of plague.

Because it affects the lungs, it is the form capable of person-to-person transmission via infectious respiratory droplets.

Symptoms

Symptoms usually develop quickly and include fever, headache, weakness, and rapidly worsening pneumonia with shortness of breath, chest pain and cough.

The cough may produce bloody or watery sputum. Without prompt treatment it can progress rapidly.

How it spreads

Person-to-person spread occurs through respiratory droplets from a person with pneumonic plague, generally after close contact.

It is not spread through casual, brief contact or, in the way seasonal flu is, through the air over long distances.

Treatment & prevention

Pneumonic plague is treatable with antibiotics, but treatment must begin as early as possible.

People in close contact with a pneumonic plague patient are typically monitored and may be given preventive antibiotics under the guidance of public-health authorities.

Important context for the Irkutsk event

The Irkutsk case is under investigation as pneumonia of unknown cause. Authorities have not confirmed pneumonic plague. This page is general medical information, not a diagnosis of that case.