ELISA-IgM para diagnóstico da esquistossomose mansoni em área de baixa endemicidade

Abstract

An immunoenzymatic method for the detection of IgM antibodies (IgM-ELISA) against a fraction of Schistosoma mansoni adult worm antigen, soluble in trichloroacetic acid (TCA-soluble fraction), was evaluated for epidemiological purposes in low endemic areas for schistosomiasis. Blood samples on filter paper were collected from a population living in the municipality of Pedro de Toledo, São Paulo State, and submitted to IgM-ELISA. The results were compared to those obtained by the IgM-immunofluorescence test (IgM-IFT) and the Kato-Katz parasitological method. Positive rates of 36.8%, 33.5%, and 1.6% were obtained respectively by the IgM-ELISA, IgM-IFT, and Kato-Katz methods. The geometric mean obtained by the parasitological method was 40.9 eggs per gram of feces (epg). The nearly perfect agreement observed between the two serological tests (Kappa index of 0,89) indicates good diagnostic performance by the evaluated test. IgM-ELISA is a potentially useful method for diagnosis of schistosomiasis in individuals with low worm burden.

The combination of three faecal parasitological methods to improve the diagnosis of schistosomiasis mansoni in a low endemic setting in the state of Ceará, Brazil

“…Laboratory diagnosis of this parasitic disease can be performed using either direct methods, based on the identification of parasite eggs in the patient's faeces or tissues (Rabello et al 2008) or indirect methods, which include the enzyme-linked immunosorbent assay (ELISA) method for detecting circulating antigens and polymerase chain reaction (PCR)-based methods. Because the ELISA technique allows for automation and provides quantitative results, this method has been shown to be best suited for application in population studies (Oliveira et al 2003). A known limitation of this parasitological detection method is its lack of sensitivity, particularly in areas of low endemicity and in individuals infected with low parasite loads.…”

Efficacy of an enzyme-linked immunosorbent assay as a diagnostic tool for schistosomiasis mansoni in individuals with low worm burden

“…IgM-ELISA -TCA-soluble fraction of the S. mansoni adult worm antigen preparation was obtained as described earlier (Deelder & Kornelis 1980) and used as antigen for coating flat polystyrene plates (Nunc, Brand Products, Denmark), according to previous standardization (Oliveira et al 2003). Test sera diluted 1:100 in PBS-Tween-milk (phosphate buffered solution containing 0.05% of Tween-20 and 1% skimmed milk) were incubated for 1 h at 37 o C. After washings, peroxidase-conjugated anti-human IgM (Sigma Chemical Company, St Louis, US) diluted to 1:4.000 was added and incubated for 1 h at 37 o C. After another series of washings, a chromogenic mixture of H 2 O 2 and OPD (o-phenylenediamine) was added.…”

“…When the results obtained by an ELISA for detection of IgG antibodies against a crude adult worm antigen preparation (IgG-ELISA) were compared with those obtained by the IgM-IFT, in a schoolchildren population living in a low endemic area, poor index of concordance was observed, better diagnostic efficiency being observed for the IgM-IFT (Silva et al 1998). The use of a polysaccharide fraction of the S. mansoni adult worm antigen preparation, soluble in trichloroacetic acid (TCA-soluble fraction), as antigenic substrate in a ELISA method, for detection of IgM antibodies (IgM-ELISA) was evaluated by Oliveira et al (2003), in a region of low endemicity for schistosomiasis, showing good degree of concordance when compared to IgM-IFT.…”

Construcción de un Inmunosensor Amperométrico utilizando Apirasa de Solanum tuberosum para la Detección de Esquistosomiasis

“…El tratamiento con medicamentos por sí solo parece ser insuficiente para eliminar o disminuir los altos índices de positividad. El desarrollo y el refinamiento de los procedimientos convencionales de diagnósticos clínicos, tales como: Ensayo Inmunoadsorbente Ligado a Enzimas (ELISA), Inmunoensayo por Electroforesis (EI), Radio Inmuno ensayo (RIA), etc., han sido extensos (Shiguekawa et al, 2000;Oliveira et al, 2003). No obstante, la mayoría de esos métodos requieren de personal altamente calificado, de instrumentos sofisticados y mayor tiempo de análisis para su conclusión.…”