Controle da esquistossomose mansônica em área de baixa transmissao

Abstract

The schistosomiasis is transmitted by Biomphalaria tenagophila in our study area (Pedro de Toledo, São Paulo, Brazil). From 1980 to 1990 epidemiological surveys in a population of 4,000 inhabitants, has shown that: prevalences by Kato-Katz (KKT), immunofluorescence (FT) and intradermal (IDT) techniques were 22.8%, 55.5% and 51.8%, respectively; intensity of infection was low, 58.5 eggs per gram of faeces (epg); there were no symptomatic cases; prevalences were higher in mates, children and rural zone; index of potential contamination was 57.5% in the age group 5 to 20 years; 2/3 of patients were autochthonous; cases were no-randomly aggregated; transmission was focal and only 0.4% of snails were infected; water contacts through recreation showed the most important odds ratio; knowledge, attitudes and practices were satisfactory. From the epidemiological findings a control programme was carried out: yearly faeces exams, chemotherapy, molluscocide, health education and sanitation. Thus, the prevalence decreased sharply to 3.3% and intensity of infection to 30.3 epg; the incidence rates ranged between 0.4% and 2.5% annually; the sanitation became better and the youngsters were the main target in prophylaxis. To improve control, immunodiagnosis has to be conducted and the involvement of the population should be increase. However, we cannot forget that re-infection, therapeutic failure, etc, could play a major role in the maintenance this residual prevalence.

Immunodiagnostic Methods: What Is Their Role in Areas of Low Endemicity?

“…We are currently in a diagnostic dilemma for S. mansoni —the direct parasitological major technique (Kato-Katz) have become relatively insensitive due to widespread chemotherapy that results in generally low worm burdens, which leads to less efficiency in low transmission settings and in post-treatment situations [2, 8, 10, 14, 25, 27, 30, 37]. Other diagnostic alternatives include detection of antibodies or circulating antigens in serum and/or urine samples.…”