When most people hear the word “plague”, they picture medieval Europe. In reality, plague still exists today, and its most dangerous form is pneumonic plague. It is rare, and it can be treated with antibiotics, but only if it is recognised early. This guide explains what international health agencies such as the World Health Organization (WHO) and the European Centre for Disease Prevention and Control (ECDC) say about how pneumonic plague spreads, what the symptoms look like, and how it is treated and prevented.
Pneumonic Plague at a Glance
- Cause: the bacterium Yersinia pestis
- What it affects: the lungs
- How it spreads: through infected respiratory droplets, including from coughing
- Incubation: usually one to three days
- Treatment: antibiotics, which work best when started early
- Vaccine: no widely licensed vaccine at present
What Is Pneumonic Plague?
Plague is caused by the bacterium Yersinia pestis. The WHO describes two main clinical forms: bubonic and pneumonic. Pneumonic plague, the lung-based form, is the most virulent of the two.
It usually begins in one of two ways. Bubonic plague, which is spread by infected fleas, can advance to the lungs and become pneumonic. It can also begin directly in the lungs when a person breathes in the bacteria from someone who already has the pneumonic form.
How Does Pneumonic Plague Spread?
Unlike bubonic plague, the pneumonic form can pass from person to person. The WHO explains that it spreads through infected respiratory droplets, including when a patient coughs. The ECDC adds that people with pneumonic plague are most infectious in the final hours before death.
Person-to-person spread is not the usual way plague reaches people, but it is the main reason pneumonic plague is taken so seriously by health authorities.
Symptoms and How Quickly They Develop
According to the ECDC, primary pneumonic plague has a short incubation period of one to three days. Symptoms can include:
- Fever
- Cough, sometimes with bloody or wet mucus
- Chest pain
- Difficulty breathing
- Weakness and a rapidly developing pneumonia
Without treatment, the illness usually progresses to respiratory failure, shock and rapid death. The WHO notes that untreated pneumonic plague can be fatal within 18 to 24 hours of onset, which is why speed matters so much.
How Is It Diagnosed?
Symptoms alone cannot confirm plague. The WHO states that confirmation requires laboratory testing. Doctors also take a patient’s history into account, such as recent travel to an area where plague occurs or contact with a plague patient.
Treatment
Pneumonic plague is serious, but it is curable when treated early. The WHO says common antibiotics can cure the disease if they are given early. The Institut Pasteur lists fluoroquinolones, tetracyclines and streptomycin among the antibiotics of choice. Treatment must always be directed by a medical team. Suspected plague should never be treated at home.
How Outbreaks Are Controlled
Public health teams rely on a small set of well-established measures:
- Isolation: patients are isolated and cared for by trained staff wearing personal protective equipment.
- Masks: masks may help limit the spread when they are worn correctly by patients and by health workers.
- Contact tracing: close contacts are identified, monitored and offered a seven-day course of preventive antibiotics.
Reducing Your Risk
For most people, the risk is very low. During an outbreak, the WHO advises avoiding close contact (within 2 metres) with anyone who is coughing and spending less time in crowded places. If you develop symptoms after travelling to an affected area, or after contact with a plague patient, seek medical care immediately and tell the doctor about your travel. The ECDC recommends that plague should be considered in symptomatic travellers returning from risk areas.
Is There a Vaccine?
There is no widely licensed plague vaccine at present. Public health fact sheets state that none is available, and the Institut Pasteur notes that older vaccines do not protect against the pneumonic form. Research into newer vaccines, including one aimed at pneumonic plague, is ongoing.
Where Does Pneumonic Plague Occur?
Plague is still found in parts of Africa, Asia and the Americas. Pneumonic outbreaks have been recorded in India in 1994, in the Democratic Republic of the Congo in 2004 and 2006, and in Madagascar in 2017, where several regions and major cities were affected. These outbreaks were brought under control through early detection, isolation, contact tracing and antibiotics.
Frequently Asked Questions
Is pneumonic plague contagious?
Yes. Unlike bubonic plague, it can spread between people through respiratory droplets.
Can pneumonic plague be cured?
Yes, with prompt antibiotic treatment. Without early treatment it is almost always fatal, so urgent medical care is essential.
How soon do symptoms appear?
Usually within one to three days of exposure.
Should I be worried about catching it?
The risk is very low for most people. If you have been in contact with a plague patient or travelled to an affected area and feel unwell, seek medical help straight away.
The Bottom Line
Pneumonic plague is dangerous, but it is also rare and treatable. It spreads between people through respiratory droplets, it develops quickly, and early antibiotic treatment saves lives. If you develop fever, cough, chest pain or difficulty breathing after a possible exposure, get medical help immediately.
Related reading: Salmonella: Everything You Need to Know
Sources
- World Health Organization: Plague fact sheet
- World Health Organization: Plague Q&A
- ECDC: Disease information about plague
- Institut Pasteur: Plague disease fact sheet
This article is for general information only and is not medical advice.
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