General Information

Plague is an acute bacterial infection caused by the organism Yersinia pestis.

What are the symptoms?

There are 5 forms of plague, all of which are uncommon and 3 of which are very rare.

Usually, plague takes the form known as bubonic plague. The bacteria invade the body and cause fever. The lymph nodes swell up and become very painful (this is the bubo). The buboes can range in size from1-10cm in length.

Less frequently, the organism causes pneumonic plague, a form of pneumonia with severe respiratory symptoms, rapidly developing cough and difficulty in breathing. The other very rare presentations of plague include meningitis, septicaemic and pharyngeal plague.

Plague can be very effectively treated with antibiotics, meaning that in treated cases deaths occur in fewer than 5% of cases. If left untreated the infection can result in death in 90% or more of cases.

How do you catch plague?

The natural hosts are small animals such as wild rats, and man is an incidental host. In certain parts of the world the organism is known to circulate in animals. Plague is still reported consistently from several countries in Africa, Asia, South America and rural parts of the USA. The organism is usually passed to humans through the bite of a flea which has previously fed on an infected animal. In other words, the flea acts as a "vector" which passes the organism from animals to man.

Bubonic plague is generally not spread from person-to-person, except through direct contact with any fluids from the swellings. Pneumonic plague can be passed from person to person through the inhalation of droplets from the cough or sneeze of an infected individual.

How long can you have the infection before developing symptoms?

The incubation period for plague is usually between 1 and 7 days. For plague pneumonia following inhalation it is shorter at 1-4 days.

How can plague be prevented or treated?

Provided the disease is identified in its early stages, it can be treated very effectively with antibiotics. Antibiotics can also be given to close contacts of patients to help prevent them from developing the disease.

How common is plague?

Today, we do not have indigenous plague in the UK - the last outbreak of plague acquired here was in 1918. However, plague is still found in many countries around the world, particularly in Africa and Asia, but also the USA. 2118 cases were reported to the WHO in 2003; more than 90% of all cases were notified from African countries.