Toxocariase humana e parasitoses intestinais em areas sob o risco de enchentes no municipio de Campinas, Estado de São Paulo, Brasil




Human intestinal parasitoses remain a very common public health problem, and their geographical distribution and prevalence are associated with several factors, particularly the low socio-economic status of the population. Nematodes such as Toxocara canis and Toxocara cati (parasites in dogs and cats, respectively) are the main agents of the visceral and ocular larva migrans syndrome in humans, and their frequency is often overlooked due to the occurrence of non-apparent or undiagnosed infections. The purpose of the present research was to evaluate some aspects of the transmission dynamics of intestinal parasitosis, as well as factors that may cause Toxocara infection in the population living in flood-risk areas of three boroughs (Jardim Santa Monica, Jardim Sao Marcos and Jardim Campineiro) located in the city of Campinas (State of Sao Paulo, Brazil). Between 1998 and 2000, epidemiological surveys were carried out using a probabilistic sampling of the population. Forty households were randomly selected, and parasitological examinations for feces were performed in all the residents. Moreover, blood samples were collected for an enzyme-linked immunosorbent assay (ELISA) designed to investigate anti-Toxocara antibodies and hemogram. Ali the subjects participating in the survey completed semi-structured questionnaires for the assessment of relevant epidemiological data. At the same time, samples obtained from the soil surrounding the selected households were examined for geohelminth eggs. Analysis of the data indicated that global prevalence of enteroparasites was 59.8%, and the most frequent helminth was A .lumbricoides (16.5%) and the protozoa G. duodena/is (15.9%). The infections by protozoa (46.3%) were numerically superior to those caused by helrninthoses (35.4%). The majority of helrninth parasitic burdens were mild. In 1999, anti-Toxocara antibodies were present in 23.9% of the samples, and, in 2000, the infection rate was 20.9%. On both occasions, no significant difference was found in the infection prevalence as regards the subjects ages. The samples collected in 2000, however, indicated a higher prevalence of infection among the female. Seventy-five subjects were examined in both surveys. The results showed 12 seroconversion occurrences, pointing to an incidence rate of 17.9% for toxocariasis in the population under study. It was also observed that among the subjects who had seroconversion, the age range of66.7% was less than 10 years. The 57 samples collected from the soil of the same region in December 1998 and July 1999 were examined for environmental contamination of Toxocara eggs, which were found in 12.3% and 14.0% of the samples. The presence of helminth enteroparasites was also noted, but it was numerically low. The variables that showed statistic significance from the analyses of the epidemiological questionnaries, coproparasitological examinations, as well as anti-Toxocara serology provided an account of the potential risk factors for human infection by enteroparasites and Toxocara. The results suggest that socio-economical variables play a significant role in the prevalence of human infection by such organisms under the prevailing conditions of the area investigated


parasitologia inundações - campinas (sp) epidemiologia

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