Utility of history, examination and laboratory tests in screening those returning to Europe from the tropics for parasitic infection

OBJECTIVES To examine the utility of the different elements of screening ex patriates and travellers returned from the tropics for parasitic disease (e xposure history, symptoms, examination and laboratory tests). METHODS In phase 1 (conducted prospectively 1990-91), 1029 asymptomatic ret urnees had a detailed questionnaire and interview on risk-behaviour, physic al examination and laboratory tests. In phase 2 (1997-98), 510 consecutive patients referred for routine screening (276 symptomatic and 234 asymptomat ic) were screened with laboratory tests. RESULTS Exposure history did not correlate reliably with parasite burden. I n phase 1 physical examination revealed 387 abnormalities, only three of wh ich indicated parasitic disease. Schistosomal serology was positive in 11% (CI 9-13) of these asymptomatic cases including patients with light or no r eported freshwater exposure. Stool microscopy was positive in 19% (CI 16-22 ) of cases not correlated with reported eating habits, and eosinophilia was present in 8% (CI 6-10). In phase 2 reported symptoms did not correlate wi th parasitic disease. Schistosomiasis was present in 15% (CI 13-24) of asym ptomatic and 18% (CI 13-22) of symptomatic individuals (OR 1.2 P = 0.46); s tool microscopy was positive in 14% of both symptomatic and asymptomatic pa tients, and eosinophilia in 9% of symptomatic and 6% of asymptomatic indivi duals. CONCLUSION Potentially serious asymptomatic infection is common in travelle rs. Detailed exposure history symptom history and physical examination adde d little to detecting cases. Stool microscopy, schistosomal serology and eo sinophil count all had good yield. Filarial serology had low yield in patie nts without eosinophilia.