What is Typhus?
Typhus is one a range of infectious diseases produced by a family of small bacteria known as Rickettsiae. These bacteria live naturally in a range of hosts (typically rats and dogs in temperate countries). The disease is spread by ticks, mites, fleas, or lice, each agent having a distinct way of spreading, but all causing a disease with a very similar clinical picture.
The disease is transmitted to humans when infected fleas and ticks on the bodies of rats or dogs jump to humans and feed by biting. Human lice also become infected by feeding on the blood of an infected person. Spreading of infected lice between people leads to onward spreading of the infection. The Rickettsiae are injected into the bloodstream of the patient who goes on to develop symptoms. Occasionally the infection may be passed on via the ticks faeces, which may get rubbed into a skin wound. Flea and tick born typhus spreads much less easily than louse borne typhus.
How common is Typhus?
Classic typhus tended to produce explosive epidemics in cooler countries at times of great stress including famine and war. It is estimated that there are more than 20 million cases globally each year. In the past, it tended to run alongside plague infection during the eras of Black Death in Europe in the 14th and 15th centuries. Typhus was a major cause of death during the Great Famine in Ireland in 1847 both in Irish households and on board ships as people fled to the US and Canada to escape the Famine. Typhus can be found in Southern and Eastern Europe, North and Central America, Sub-Saharan Africa and Australia.
How serious are Rickettsial diseases?
They range in severity from relatively mild (such as Mediterranean tick typhus and African tick bite fever) to those diseases that are potentially life threatening such as Rocky Mountain spotted fever. Untreated classical Typhus is relatively mild in children but has a high mortality rate in older people (50% in the elderly).
What are the symptoms of these diseases?
The incubation period of 7 to 14 days, but it can as long as two months. Typhus is a notifiable disease in Ireland. The symptoms begin with what feels like bad cold with a fever lasting between one and six weeks with chills severe headache and cramps in muscles. There is also a rose coloured rash (Rose Rash) that disappears on pressure. Glands close to the bite become swollen and painful.
What types of typhus are there?
Fuller information on typhus is available through the CDC's Yellow Book Chapter on Rickettsial Infections.
- Epidemic typhus (Louse Borne, European or Classical): this is prevalent across the world and is passed by infected human lice. The rash begins on the trunk and spreads to the limbs. There are concentrated pockets to be found in mountainous areas of Africa and South America. Onset of this form of typhus tends to be slow, with a fever of 400C being reached after several days.
- Tick typhus: is found in southern Africa and India and is spread from cattle and wild animal ticks.
- Scrub typhus: is spread from infected rodents and is found mainly in the Pacific islands and in southeast Asia. It has a very sudden onset. Cough is prominent and pneumonia may develop.
- Murine typhus: This is common throughout the world and is transmitted by fleas. It is similar to epidemic typhus but tends to be milder.
- Rocky Mountain spotted fever: This is a rickettsial disease related to typhus. It is endemic in the Rocky Mountains and South eastern US. The rash begins on the feet, unlike classical typhus. The mortality for untreated RMSF is high, more than 30%.
How is typhus diagnosed?
Blood tests can show antibodies to the Rickettsiae.
How can typhus and RMSF be prevented?
Avoiding flea bites is the best way to prevent typhus and RMSF when travelling. This useful information will help to protect you against biting ticks.
How can typhus and RMSF be treated?
Antibiotics such as doxycycline are very effective against Rickettsiae.
Where can I get further information?
The WHO's International Travel and Health section provides information on typhus for travellers
The UK's National Travel Health Network and Centre (NaTHNaC) provides typhus information
The Centers for Disease Control and Prevention provides information on rickettsial disease including typhus and Rocky Mountain spotted fever.
Updated 16th July 2010