Acute schistosomiasis in a cluster of travelers from Rwanda: diagnostic contribution of schistosome DNA detection in serum compared to parasitology and serology.
BACKGROUND
Diagnosis of acute schistosomiasis is often elusive in travelers. Serum schistosome DNA detection is a promising new diagnostic tool. Its performance is compared with current diagnostic procedures in a cluster of travelers recently infected in Rwanda.


METHODS
Recent infection with schistosomiasis was suspected in 13 Belgian children and adults, within 2 months after swimming in the Muhazi Lake, Rwanda. All were subjected to clinical examination, eosinophil count, feces parasite detection, schistosome antibody tests [enzyme-linked immunosorbent assay (ELISA) and hemagglutination inhibition assay (HAI)], and schistosome DNA detection in serum by real-time polymerase chain reaction.


RESULTS
All 13 patients, between 6 and 29 years old, had a high eosinophil count (median 2,120 µL(-1) ; range 1,150-14,270). Seven of nine persons exposed for the first time developed symptoms compatible with acute schistosomiasis. Eggs of Schistosoma mansoni were found in a concentrated feces sample of 9/13 (69%), with low egg counts (median 20 eggs per gram; range 10-120). Antischistosome antibodies (ELISA and/or HAI) were present in serum of 10/13 (77%) patients. Combining schistosome antibody tests and fecal microscopy demonstrated schistosomiasis in 11/13 (85%) patients. Schistosome-specific DNA was isolated in all 13 (100%) serum samples.


CONCLUSIONS
In this cluster of travelers with acute schistosomiasis, schistosome DNA detection in serum was able to confirm infection in all exposed persons. It clearly outperformed antibody tests and microscopic parasite detection methods as a qualitative diagnostic test.
Department of Clinical Sciences, Institute for Tropical Medicine Antwerp, Antwerp, Belgium. jclerinx@itg.be
Jan
J
Clerinx
Emmanuel
E
Bottieau
Dominic
D
Wichmann
Egbert
E
Tannich
Marjan
M
Van Esbroeck
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000032:analysis*; D000947:Antigens, Helminth; D001530:Belgium / Q000453:epidemiology; D002648:Child; D018509:DNA, Helminth / Q000032:analysis* / Q000097:blood; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000469:parasitology*; D005260:Female; D006801:Humans; D008297:Male; D010270:Parasite Egg Count; D060888:Real-Time Polymerase Chain Reaction; D012432:Rwanda / Q000208:ethnology; D012550:Schistosoma mansoni / Q000235:genetics* / Q000276:immunology; D012552:Schistosomiasis / Q000175:diagnosis* / Q000208:ethnology / Q000469:parasitology; D012680:Sensitivity and Specificity; D014195:Travel; D055815:Young Adult
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D018509:DNA, Helminth