Plague: symptoms, how it spreads and how it is treated

TravelHealthPro says plague is a severe disease and can be fatal, that symptoms usually appear one to eight days after exposure and usually start with fever. The symptoms depend on the form, which UKHSA describes by route of infection.

UKHSA describes plague as a disease caused by infection with the bacterium Yersinia pestis, usually found in small mammals and their fleas. Rodents are the main reservoir of infection. The disease is best known as the Black Death, but UKHSA is clear that it still occurs today, and that septicaemic plague causes the necrosis and gangrene in the extremities classically seen in patients with the Black Death.

TravelHealthPro says plague is no longer a risk in the UK but is still reported worldwide, and that most human cases each year are reported in Africa, with Madagascar regarded as the most affected country, with cases usually reported in specific, rural areas every year between September and April.

It depends on the form. UKHSA says Yersinia pestis can be transmitted to humans through bites from infected rodent fleas or from handling infected animals or their tissues. In higher income countries sporadic infections may be caused by exposure to infected cats, through fleas, scratches or bites, and laboratory exposure may occur.

Another important route is inhaling infectious respiratory particles from a patient with pneumonic plague. UKHSA says this usually requires close and prolonged contact with the patient. TravelHealthPro says anyone with pneumonic plague can spread the bacteria through respiratory droplets to other people. Bubonic plague is not usually spread directly from person to person.

UKHSA says all forms of plague are associated with a high mortality rate when untreated, and that antibiotic treatment can be effective but early diagnosis and treatment are vital. If there is a credible suspicion of plague based on exposure history, clinical syndrome or laboratory findings, treatment should be started immediately, before laboratory confirmation.

UKHSA gives mortality figures for untreated disease: approaching 100% for pneumonic and septicaemic forms and around 60% for bubonic plague. For pneumonic plague, it says that even with prompt recognition and treatment mortality is around 30%. TravelHealthPro says antibiotic treatment is effective against plague, but early diagnosis and treatment is vital to reduce the risk of dying.

If plague is confirmed, UKHSA says contacts and other potentially exposed people will need to be risk assessed and offered antibiotic prophylaxis if indicated. All forms of plague are statutorily notifiable.

TravelHealthPro says diagnosis requires a laboratory test to identify the bacteria. UKHSA says that in the UK, clinicians who suspect plague should seek urgent advice from UKHSA's Imported Fever Service, which operates 24 hours a day and coordinates urgent testing at UKHSA's Rare and Imported Pathogens Laboratory at Porton, where PCR testing is available.

UKHSA says any suspected case should be discussed with local infection specialists, and that the local health protection team should be notified immediately if there is a credible suspicion.

UKHSA says plague is not found in the UK and that the probability of a case occurring in a person returning to the UK is very low. TravelHealthPro says the risk for travellers to any country where plague occurs is generally regarded as very low, based on the rarity of cases, with no UK cases reported in the last 50 years, although during an unusual outbreak in Madagascar the risk rating was increased to low-moderate for the duration of the outbreak.

UKHSA says there are currently no commercially available vaccines. It lists the preventive measures below and says travellers to affected areas should be aware of the risks.

• Use a DEET-based insect repellent to protect against flea bites if travelling to an area where plague is found in animals.

• Avoid contact with dead animals, infected tissues or materials.

• Avoid crowded areas where cases of pneumonic plague have been recently reported.

UKHSA says unwell travellers who have been to areas where plague occurs, and who may have had contact with rodents or fleas or anyone with symptoms or diagnosed with pneumonic plague, should seek prompt medical advice with details of their travel history and activities.

The symptoms described above, in particular fever with painful swollen lymph nodes, or a rapidly developing cough with breathlessness and chest pain, make the travel history important. Give details of where you have been and what you did.

Plague is handled as a public health matter in the UK. UKHSA says suspected cases should be discussed with local infection specialists and the Imported Fever Service, and the local health protection team is notified. Treatment and isolation, where needed, take place in NHS hospitals, and pneumonic plague is classed as a high consequence infectious disease.

Travel advice before a trip is available from an NHS GP surgery, a pharmacy or a private travel clinic. There is no vaccine, so advice focuses on avoiding flea bites and contact with animals and on where to get help if you become unwell.