Leptospirosis

This zoonosis is caused by a Gram-negative organism, Leptospira interrogans, which is excreted in animal urine and enters the host through a skin abrasion or intact mucous membranes. Individuals who work with animals or take part in water sports which bring them in close contact with rodents (e.g. boating lakes, diving) are most at risk.


Clinical features

• Following an incubation period of about 10 days, the intiial leptospiraemic phase is characterised by fever, headache, malaise and myalgia, followed by an immune phase, which is most commonly manifest by meningism. Most recover uneventfully at this stage. A small proportion go on to develop hepatic and renal failure, haemolytic anaemia, and circulatory collapse (Weil's disease).

Investigations

• Blood or CSF culture can identify the organisms in the first week of the disease. The organism may be detected in the ruine during the second week. Serology will show specific IgM antibodies by the end of the first week.

Management

• Oral doxycycline is given for mild disease and intravenous penicillin or erythromycin for more severe disease. The complications of the disease should be treated appropriately.