Tick Typhus

The organism: cause is the spirochaete Rickettsia conori.

Distribution: It is present throughout Sub-saharan Africa but most cases seen in Britain seem to have originated in Zimbabwe and South Africa. There is also a more severe form of typhus spread by mites which occurs in South-East Asia, oceania, northern Australia and South east Siberia.

The vector: The bite of the Ixodid tick which is common in scrub land although it can be brought into the home by animals such as dogs.

The illness: After a few days fever, followed by mild maculopapular rash and lymphadenopathy can occur. The illness is usually mild and self limiting but responds to tetracyclines. Complications are rare. Scrub typhus is more severe with continuing fever, malaise, lymphadenopahty, hepatosplenomegaly and death can occur if untreated after 1-2 weeks.

Diagnosis: Treatment is usually started after a clinical diagnosis. Serology may only be helpful later in the illness.

Treatment: Tetracyclines are the drugs of choice.

Prevention is through avoiding tick bites or through their prompt removal.

Recommended for more information: 'Lecture Notes in Tropical medicine' . Dion R. Bell. Blackwell Publications ISBN 0-632-02445-0 or ' Mansons textbook of Tropical Diseases' Ed.G.C.Cook WB Sanders Company Ltd. ISBN 0-7020-1764-7.