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

Abstract

SummaryOBJECTIVES To examine the utility of the different elements of screening expatriates and travellers returned from the tropics for parasitic disease (exposure history, symptoms, examination and laboratory tests). METHODS In phase 1 (conducted prospectively 1990-91), 1029 asymptomatic returnees had a detailed questionnaire and interview on risk-behaviour, physical examination and laboratory tests. In phase 2 (1997-98), 510 consecutive patients referred for routine screening (276 symptomatic and 234 asymptomatic) were screened with laboratory tests. RESULTS Exposure history did not correlate reliably with parasite burden. In phase 1 physical examination revealed 387 abnormalities, only three of which indicated parasitic disease. Schistosomal serology was positive in 11% (CI 9-13) of these asymptomatic cases including patients with light or no reported 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 with parasitic disease. Schistosomiasis was present in 15% (CI 13-24) of asymptomatic and 18% (CI 13-22) of symptomatic individuals (OR 1.2 P ϭ 0.46); stool microscopy was positive in 14% of both symptomatic and asymptomatic patients, and eosinophilia in 9% of symptomatic and 6% of asymptomatic individuals. CONCLUSION Potentially serious asymptomatic infection is common in travellers. Detailed exposure history, symptom history and physical examination added little to detecting cases. Stool microscopy, schistosomal serology and eosinophil count all had good yield. Filarial serology had low yield in patients without eosinophilia.keywords health screening, parasites, tropics correspondence Dr P. L. Chiodini,

Schistosomiasis in non-endemic countries

“…Travellers may not remember their freshwater contact, so this is not a reliable screening question; in asymptomatic travellers from Africa, up to 11% have been reported as infected. 2,3 Two species of human schistosomiasis predominate; Schistosomiasis haematobium, which mainly affects the bladder and urogenital system, and S mansoni, which mainly affects the liver and gut. The much rarer species, which are S intercalatum, S japonicum and S mekongi, all present similarly to S mansoni, with the latter two being found in Asia.…”

Post-Travel Screening of Asymptomatic Long-Term Travelers to the Tropics for Intestinal Parasites Using Molecular Diagnostics

“…Two sizeable studies have been performed, in which people from highly industrialized countries were screened for parasitic infections, after having stayed in the tropics. Whitty and others 1 determined the use of posttravel screening in the United Kingdom. They studied two cohorts, totaling over 1,000 symptomatic and asymptomatic travelers and expatriates who stayed in the tropics or subtropics for at least 3 months.…”

Evaluation of Eight Serological Tests for Diagnosis of Imported Schistosomiasis

“…Therefore, direct parasitological methods often fail (11). For this patient group, serological tests detecting antischistosomal antibodies are an important diagnostic tool (26,38,44), although the "seronegative window" has to be considered in very early infections (9,25,43).…”