Fever as the presenting complaint of travellers returning from the tropics.

We investigated prospectively the cause of fever in patients requiring hospitalization after returning from the tropics. All consecutive admissions (n = 195) with oral temperature > 37.0 degrees C at the time of admission were enrolled. Final diagnosis as recorded on the discharge summary by the attending physician and results of any relevant laboratory or radiological investigations were recorded on standard proforma. Malaria accounted for 42% of admissions; two patients had returned to Britain more than 6 months before presentation. The second largest group was assumed to have a non-specific viral infection (25%). Cosmopolitan infections (urinary tract infection, community-acquired pneumonia, streptococcal sore throat, etc.) accounted for 9%. Coincidental infections (schistosomiasis, filariasis, intestinal helminths) were found in 16%. Serology was positive for HIV infection in 3%. The most useful investigation was a malaria film, which was positive in 45% of cases in which it was performed. The combination of thrombocytopaenia (platelet count < 100 x 10(9)) and hyperbilirubinaemia (bilirubin > 18 IU/ml) were useful predictive markers of malaria: all 23 patients with both abnormalities had positive malaria films. Malaria must be excluded in any febrile patient returning from the tropics. In the absence of a positive malaria film, the combination of a low platelet count and raised bilirubin may suggest the need for an empirical course of therapy.