Avaliação clínico-epidemiológica da esquistossomose mansoni em uma área da periferia de Belo Horizonte, Minas Gerais

Abstract

An epidemiological study of schistosomiasis mansoni was undertaken in two suburbs on the periphery of Belo Horizonte, with the aim of describing the distrubuition of the disease in the population; as well as to study the signs and/or symptoms, sociodemographic characteristcs and reasons for water contact associated with the Schistosoma mansoni infection, in this area. The sample analysed, was selected randomly from 658 dwellings, visited, with a total of 3,290 inhabitants. Of the total sample, 3,049 (92.7%) were submitted to two parasitological fecal exams (Kato- Katz method), performed on different days. The prevalence of the infection was 20% and the geometrical mean of the number of eggs per gram of feces was 70 (IC-95%=7,4-679,7). Infection was morefrequent in men (28.8%) than women (11.9%) and highest in the15-19 (42.1%), 20-24 (34%) and 25-29 (35.1%) age groups. The geometrical mean of egg number was highest in the 15-19 (109,IC95%=6.0-4786.3) and 20-24 (104.7, lC95%=6.0-2238.7) agegroups. From the 12 sites where snails were collected monthly, in 11 were found specimens of Biomphalaria glabrata. In Only 6 of thesesites, the snails were found eliminating S. mansoni cercaria at leastonce a year. All 609 individuals eliminating S.mansoni eggs in the feces (cases) and 609 individuals selected as a random sample from those who ` were not eliminating eggs (control) were selected for analytic study.509/609 (83.6%) positive individuals and 579 (95.1%) control wereexamined. Bloody feces (ORadj=5.6, IC-95%=l.84-17.32) and palpablehardened liver (left and right lobes) (ORadj=l,76, IC-95%=l,04-2,96 and ORadj=l,67, IC-95%=1,00-2,81, respectively) were theclinical signs associated with the infection. The sociodemographiccharacteristics and reasons for water contact associated with the ,infection were: age (l0-29, OR adj=8.l, IC95%=5.3l-12.31 and 230 OR adj=4.9 IC95%=3.l4-7.59), sex=ma|e (OR adj=2.9IC95%=2.l9-3.78), piped water (OR adj=0.5 IC95%=O.34-0.86),swimming as a reason of water contact (OR adj=2.3 IC95%=l.65-3.23). Migration was not associated with S.mans0ni infection inthis area. These results show that schistosomiasis is endemic in this area with low egg counts in the feces and low morbidity. Factors associated with infection were bloody feces, swimming as a reason of water contact, palpable hardened liver (let} and right lobes) and pipedV water; this protecting against S. mansoni infection.Key words: schistosomiasis mansoni, urban schistosomiasis,epidemiology.