Application of an ELISA test using Schistosoma bovis adult worm antigens in travellers and immigrants from a schistosomiasis endemic area and its correlation with clinical findings

Abstract

We have recently evaluated an ELISA for the diagnosis of human schistosomiasis using S. bovis adult worm antigens (AWA Sb), showing a sensitivity of 94% and a specificity of 97% for patients diagnosed by egg detection. Nevertheless, the comparison of this AWA Sb ELISA with direct parasitological findings as the gold standard could introduce a selection bias, due to the well-known lack of sensitivity of direct methods in the detection of acute schistosomiasis and of low burden infections. The objective of the present work is to compare it with parasitological methods and commercial indirect haemagglutination test using S. mansoni antigens (WA Sm IHA) in 254 immigrants and travellers with different clinical settings; in addition, to find specific bands in the EITB of different phases of schistosomiasis. The AWA Sb ELISA showed 72% of seropositivity in patients with Katayama fever, while patients with eosinophilia and genito-urinary complaints showed 27% and 93%, respectively. The diagnosis yield was globally higher than direct egg detection or WA Sm IHA test with regard to the clinical setting. Finally, the utilization of EITB with S. bovis AWA permits the confirmation of diagnosis in chronic and acute phases of the disease.