Nilson Giraldi1, Odilon Vidotto2, Italmar Teodorico Navarro2 and João Luis Garcia1
1. Departamento de Medicina Veterinária Preventiva e Saúde Animal da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP. 2. Departamento de Medicina Veterinária.e Preventiva da Universidade Estadual de Londrina, PR.
Abstract Coproparasitological analyses were performed on 191 daycare children and 434 elementary school children from urban and rural areas in Rolândia, Parana State, Brazil. The overall prevalence of enteroparasites was 15.2 % for daycare children and 52.5% for elementary school children. Risk factors are discussed.
Key-words: Parasitic infection. Epidemiology. Prevalence. School children. Daycare. Brazil.
Resumo Exames coproparasitológicos realizados em 191 crianças de creches e em 434 alunos da primeira à quarta série das áreas urbana e rural da rede municipal de Rolândia, PR, evidenciaram enteroparasitas em prevalência de 15,2% nas creches e de 52,5% entre os escolares. Fatores de risco são discutidos.
Palavras-chaves: Infestação parasitária. Epidemiologia. Escolares. Creches. Brasil.
From March to September of 1998, 191 children from 1 to 6 years old from 4 daycare schools of urban areas of Rolândia, were submitted to coproparasitolgic tests to evaluate the prevalence of enteroparasites. Furthermore, to evaluate the prevalence of the enteroparasitosis among children up 6 years old, there was utilized a sample of the 2589 students from urban and rural elementary schools (2300 urban and 289 from rural schools). From October to December of 1998, coproparasitologic tests were performed in 276 students from urban area and 158 rural. The magnitude of the sample from each school was dictated by soft Epi-Info 6. Students were chosen arbitrarily.
Parents and students answered a questionnaire to reveal epidemiological aspects of enteroparasitosis, such as the habit of washing hands before meals, the habit of ingesting crude milk, meat or vegetables, having a garden at home, contact with dogs and cats, keeping animals at home, water supply, fecal disposal and habit of walking barefoot. Fecal samples were brought from home, in appropriate plastic bowls and properly identified. They were immediately remitted to the laboratory, kepton at refrigerator at 4°C until processing as outlined by Faust et al9 and Hoffman et al4 methods.
The odd’s ratio (OR) was estimated to establish forces of association between studied variables and the significance determined when 95% of confidance interval did not include the 1. The association analysis between the groups were tested by Chi-square test (x2), with statistical significance determined when p<0.05.
Among daycare children it was observed that 29 (15.2%) had positive results by coproparasitologic test, by unique or mixed infections (Table1). A. lumbricoides was the most prevalent, occuring in 13 (6.8%) children, followed by Giardia lamblia in eight (4.2%), Enterobius vermicularis in five (2.6%), Ancylostomatidae in two (1%) and Strongyloides in one (0.5%), as revealed in Table 2.
One hundred and fifty two (55.1%) urban area students and 76 (48.1%) rural area students were positive. There was no significant difference in the presence of endoparasites between students of urban and rural areas (x2= 1.96 p = 0.16, Table 1). This similarity may be explained, with regard to the studied area, by the rural origin of many families. Even urban areas are under a strong rural influence, as well as migrant farm workers which can comprise part of the families of many urban students. The prevalence in urban areas is in accordance with Ferreira et al3 and Dórea et al1, in São Paulo, SP and Botucatu, SP. Although, Kobayashi et al5 reported an index of 70% in 222 habitants of rural areas in Holambra, SP, working with all ages of individuals.
Among students, there was a higher prevalence of protozoa than nematodes. G. lamblia occurred in 106 (38.6%) urban students and 43 (26.9%) rural ones. These findings are similar with previous data from São Jerômino da Serra, PR, in the same region7 Entamoeba histolitica occurred in two (0.7%) samples from urban areas and in six (3.7%) children of rural areas. In urban areas, Endolimax nana and Entamoeba coli exhibited the same prevalence, being identified in 37 (13.3%) student fecal samples. In rural areas, E. nana occurred in 13(8.1%) and E. coli in 16 (10%) samples. Hymenolepis nanawas observed in 10 (3.8%) urban students and in one (0.1%) rural. Despite the fact that urban students receive exclusively treated water, it can be noted a high prevalence of hydro-transmission parasites, as is the case of protozoans. On other hand, feces disposal in the urban area studied is provided mostly by domestic systems. These results suggest that water treatment is not a protection factor with regard to these parasites.
For nematodes, of 276 students from urban areas, A. lumbricoides was demonstrated in 17 (6.1%), Ancylostoma spp in 12 (4.3%), Enterobius vermicularis and Trichuris trichuiura in two samples (0.7%) and Strongyloides stercoralis in one (0.4%) student.
In rural areas, of 158 students, A. lumbricoides was observed in two (1.2%), Ancylostoma spp in seven (4.4%) and E. vermicularis and T. trichiura occurred in one (0.1%) child (Table 2). These results were very similar to those of Marzochi & Cavalheiro8, when performed on children ages 5-9 and 10-14, prevalences for G. lamblia of 29 and 12% were obtained, respectively.
Of 113 boys from urban areas 63 (55.8%) had positive corproparasitological tests. Among 163 girls, 89 (54.6%) presented the same result. In rural areas, 39 (52.7%) boys and 37 (44%) girls. There was no difference in verminosis distribution between sexes in both areas (x2 = 0,04 p = 0,85 in urban areas and x2 = 1.18 p = 0.27 in rural). Dórea et al1 found a higher prevalence in boys and suggest that, at this age, boys have more contact with soil when playing and a less frequent use of shoes than girls.
In students, with regard to age, there was no measurable significant difference (x2 = 5.80 p = 0,06 in urban areas and x2 = 2.56 p = 0.27 in rural Table 3).
The habit of washing hands before meals constitutes a protective factor against verminosis in rural areas (OR = 0.35 0.13 < OR < 0.93 x2 = 5.57 p = 0.01 Table 4), in accordance with other studies1 6 .
In this present study in both urban and rural areas, other evaluated factors such as the habit of eating raw vegetables, having a garden, keeping animals at home, water supply, fecal disposal, and habit of walking barefoot did not influence coproparasitological results.
The data relating to nursery school are in accordance with Ferreira et al3 who also observed a higher prevalence of ascaridiasis in children less than 6 years old, in São Paulo, SP.
The difference in the occurrence of parasites between school children and daycare children (x2 = 76.42 p < 0.01 Table 1) suggests that contact with the soil is one of the most important transmission sources for children less than 6 years old, whereas water and food contamination is most significant in ages above 6 years old.
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