A serious rickettsial infection transmitted to humans by lice, fleas, or mites
There are three main forms of typhus, all of which are caused by different types of rickettsial bacteria.
Epidemic typhus is transmitted by body lice, usually in overcrowded conditions, and has resulted in hundreds of thousands of deaths in times of war or famine. Today, the disease is rare except in some areas of tropical Africa and South America. Endemic typhus, which is also known as murine typhus, is a rare disease that can be transmitted from rats to humans by fleas; a few cases occur each year in North and Central America. Scrub typhus, which is transmitted by mites, has been reported in India and Southeast Asia.
The first sign of infection with scrub typhus is a black scab over the site of the bite. In all types of typhus, flu-like symptoms may develop in 1–3 weeks of infection, followed a few days later by a widespread, blotchy pink rash. In severe cases of typhus, delirium and coma occur. If the disease is not treated, dangerous complications such as pneumonia or kidney failure are also likely to develop.
Typhus is often diagnosed from the symptoms, but a blood test may be carried out. Treatment with antibiotics is usually effective. Without treatment, the bacteria can lie dormant in the body for years before being reactivated and causing the disease to recur.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.