Bilharziasis in Swedish military personnel returning from the Democratic Republic of the Congo.

People from temperate climates often underestimate the danger of contracting bilharziasis in tropical areas. Since 1960, Swedish soldiers have served on UN duty in the Democratic Republic of the Congo and all have been frequently warned of the danger of contact with fresh water. These warnings have sometimes been ignored on the grounds that the likelihood of blood-fluke infection is minimal. The normal health check-up-examination of stools and urine for the presence of eggs and differential count for eosinophilia-had previously led to the diagnosis of only five cases in 5500 men examined. In a more detailed examination of 382 soldiers returning to Sweden from the Congo, 10 of them gave positive reactions to tests for bilharziasis.The value of serological screening has been amply demonstrated, since only one of these cases would have been detected if only conventional methods had been used. If antigens for serological tests are not available, follow-up examination for eosinophilia can provide a valuable aid in the detection of schistosome infections.