What is Plague?
Plague is caused by the bacteriaYersinia pestisis. It is a serious infectious disease that affects both humans and animals. The bacteria circulate naturally among rodents and their fleas in certain parts of the world, occasionally spreading to people through infected flea bites, direct contact with infected animals, or, less commonly, through respiratory droplets from someone with plague infecting their lungs.
Plague is best known for causing the Black Death in medieval Europe, but it still occurs today in several countries across Africa, Asia, and the Americas.
There are three types of plague presentations, bubonic, septicaemic and pneumonic. The bubonic plague is the most common and causes painful swollen lymph nodes called 'buboes'. Septicaemic plague involves bacteria in the bloodstream and pneumonic plague is an infection in the lung. Without appropriate treatment, the World Health Organization (WHO) estimates a case-fatality ratio of 30% to 60% for bubonic plague. This figure is closer to 100% for pneumonic plague. Although plague can be life-threatening, it is treatable with antibiotics when recognised early.
FAQs
Which countries have plague?
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Plague continues to occur in several regions of the world. According to the World Health Organization, the countries reporting the highest numbers of cases in recent decades are the Democratic Republic of the Congo and Madagascar. Sporadic cases are also reported in other parts of Africa, Asia, and the Americas.
Travellers visiting rural areas where plague occurs should be aware of the disease, particularly if their activities involve contact with wildlife or remote environments.
How do travellers become infected with plague?
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Most people who develop plague are infected after being bitten by fleas that have previously fed on infected rodents. Infection can also occur through handling infected animals, particularly rodents and other small mammals.
Pneumonic plague, which affects the lungs, can spread between people through respiratory droplets during close contact with an infected individual.
Is there a vaccine available for travellers?
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There is currently no widely available plague vaccine routinely recommended for Australian travellers. Protection relies on avoiding flea bites, limiting contact with rodents and other potentially infected animals, and seeking prompt medical attention if symptoms develop after possible exposure.
Is plague a concern for most tourists?
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For most travellers, the risk of acquiring plague remains low. The likelihood of exposure is generally highest among those visiting rural or remote areas where infected rodents and fleas are present, particularly if camping, trekking, hunting, or working closely with animals. Understanding how the disease is transmitted and taking sensible precautions can reduce the risk even further.
What should I do if I develop symptoms after travel?
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Anyone who develops fever, swollen lymph nodes, severe illness, or unexplained respiratory symptoms after visiting a region where plague occurs should seek urgent medical assessment and advise the treating doctor about their travel history. Early diagnosis and antibiotic treatment are important for preventing serious complications.
What to Know
Plague symptoms
Symptoms of plague usually appear between one and seven days after exposure. The exact symptoms depend on which form of the disease develops. The most common form, bubonic plague, typically begins suddenly with fever, chills, headache, weakness, fatigue, and body aches. A characteristic feature is the development of one or more painful, swollen lymph nodes known as 'buboes', which most often occur in the groin, armpit, or neck.
In some cases, the infection spreads directly into the bloodstream, causing septicaemic plague. This form may present with fever, profound weakness, abdominal pain, nausea and vomiting. Severe infections can result in bleeding beneath the skin and impaired blood flow to the fingers, toes, nose, or ears.
A less common but particularly serious form is pneumonic plague, where the bacteria infect the lungs. Symptoms may include sudden fever, cough, chest pain, difficulty breathing, and bloody sputum. Without prompt treatment, pneumonic plague can deteriorate rapidly and may spread to close contacts through respiratory droplets.
Plague diagnosis and treatment
Diagnosing plague requires both clinical suspicion and laboratory testing. A doctor may suspect plague in a traveller who develops compatible symptoms after visiting an area where the disease occurs, particularly if there has been exposure to rodents, fleas, or sick animals. Travel history is therefore an important part of the assessment.
Laboratory testing may involve samples of blood, sputum, or fluid taken from an affected lymph node. These specimens can be examined and cultured to identifyYersinia pestis. Additional testing may be performed depending on the clinical presentation.
Importantly, treatment should not be delayed while waiting for test results if plague is strongly suspected. Modern antibiotics are highly effective when started early, and prompt therapy dramatically improves the likelihood of recovery. Patients with severe illness often require hospitalisation for monitoring, intravenous medications, and supportive care. Delayed treatment significantly increases the risk of complications and death.
Plague prevention
Preventing plague largely comes down to reducing exposure to infected fleas, rodents, and other animals. When travelling in regions where plague occurs, avoid touching, feeding, or handling wild rodents or other animals that appear sick or have died unexpectedly. Hunters, campers, and travellers spending time in remote rural areas should be particularly cautious.
Using an insect repellent containing DEET or picaridin can help reduce flea bites, particularly in rural settings. Long sleeved clothing, enclosed footwear, and avoiding sitting or sleeping directly on the ground may provide additional protection in areas where fleas are present.
Accommodation should be kept free of rodents wherever possible. Food should be stored securely, rubbish disposed of appropriately, and rodent infestations reported to management if staying in rural lodgings or camps. Travellers should avoid handling animal carcasses and should never touch dead rodents with bare hands.
Because pneumonic plague can spread between people, travellers should also avoid close contact with anyone known or suspected to have plague affecting the lungs. Medical attention should be sought promptly if symptoms develop during travel or after returning home, as early recognition and treatment remain the most effective defence against severe disease.