ABSTRACT
In view of the known cross-reactivity of sera from patients with intestinal parasites to some Schistosoma mansoni antigens, field work was conducted in an area of Venezuela non-endemic for schistosomiasis using the routine immunoenzymatic assay (ELISA) with soluble egg antigen (SEA). False positive reactions represented 15.3% of the total population as determined by SEA-ELISA. SEA-immunoblotting of the false positive sera indicated that protein fractions of 91 and 80 kDa appear to be responsible for cross-reactivity. Sera from hookworm infected individuals produced a higher frequency and intensity of cross-reaction than other sera. SEA-fractions of 105, 54, 46, 42, 32, 25 and 15 kDa were the most specific.
Subject(s)
Hookworm Infections/epidemiology , Schistosomiasis mansoni/epidemiology , Adolescent , Adult , Animals , Antigens, Helminth/isolation & purification , Child , Child, Preschool , Cross Reactions , Enzyme-Linked Immunosorbent Assay , False Positive Reactions , Hookworm Infections/complications , Humans , Infant , Middle Aged , Prevalence , Reproducibility of Results , Schistosoma mansoni/isolation & purification , Schistosomiasis mansoni/complications , Seroepidemiologic Studies , Venezuela/epidemiologyABSTRACT
Schistosomiasis has special characteristics in Venezuela, since the majority of the infected population is asymptomatic and the elimination of eggs is very low, difficulting in this way parasitologic diagnosis. It is thus necessary to develop sensitive and specific immunologic methods to be applied in field surveys. The present study compares two serologic tests for Schistosomiasis, the enzyme linked immunosorbent assay (ELISA) with eggs (SEA) and adult (AWA) antigens and the traditional circumoval precipitation test (COPT). Sensitivity and specificity of the test were performed being 100% and 92% in COPT, 79% and 71% in ELISA-SEA and 71% and 91% in ELISA-AWA respectively. Advantages and disadvantages of each test are discussed.