ABSTRACT
Objectives of the Study:An Epidemiological Research, a cross-sectional study, was conducted to determine the magnitude of human contamination of irrigation canal perimeter as it relates to the prevalence and intensity of schistosome cercarial infection in snail vectors.Place and Duration of Study:The study was conducted along water canal located within an irrigation area, Kano River Project Phase I, Kadawa, between January and June, 2012.Methodology:The study area was categorized into Zone of Heavy Contamination (ZHC), Zoneof Light Contamination (ZLC) and Zone of Free Contamination (ZFC) based on the density of faecal lumps observed along the canal perimeter using 1m2quadrat sampling technique. Snail vectors of schistosomiasis were collected from these zones, identified and subjected to cercarial shedding. Brevifurcate apharyngeate cercariae were identified as schistosome cercariae.Results:Of the 827 snails collected 28.54% shed schistosome cercariae. The breakdown of infection prevalence was 31.37%, 27.69% and 26.26% for ZHC, ZLC and ZFC respectively. Three snail species recovered in the study area, Bulinus globosus, B. rohlfsi and Biomphalaria pfeifferi had infection intensity of 8.6, 5.67 and 3.94 respectively, with total mean intensity of 4.67. A Chi-squared analysis did not show any significant difference in infection prevalence in the three zones (χ2cal.0.025, χ22, 0.05= 5.99). However, infection intensity was significantly different in the three zones and among the three snail species using analysis of variance (P<0.05). Conclusion:Human environmental contamination with faeces and urine around irrigation canals remains the source of infection to snail hosts and then to humans. It is presumed that contact control through avoidance of defaecation in the open and building of pit latrines near water contact points along irrigation canals will be effective means of drawing a barrier to infection with schistosomes in the study area
ABSTRACT
O impacto do uso de agrotóxicos sobre a saúde humana é um problema que tem merecido atenção da comunidade científica em todo o mundo, sobretudo nos países em desenvolvimento. Sua avaliação demanda o conhecimento e a visualização da importância/magnitude relativa de cada uma das vias de contaminação. Inúmeros fatores, tais como as dificuldades metodológicas relacionadas com o monitoramento da exposição ocupacional aos agrotóxicos, as elevadas taxas de subnotificação de casos, a não-consideração de determinantes sociais e econômicos na avaliação de riscos relacionados a estes agentes químicos e a influência da pressão da indústria produtora de agrotóxicos no perfil do consumo destes agentes no meio rural brasileiro. No presente trabalho discute-se a importância destes fatores como determinantes da situação de saúde do homem do campo, a partir dos resultados de pesquisas de campo realizadas em regiões agrícolas do Estado do Rio de Janeiro.
The impact of pesticides' use on human health is a problem that has deserved attention of the scientific community around world, especially in the developing countries. Its evaluation demands the knowledge and the visualization of the relative importance/magnitude of all the contamination routes. Innumerable factors, such as methodological difficulties related with the evaluation of occupational exposition to pesticides, the high taxes of cases subnotification, the non-consideration of the influence of social and economic determinants in risks assessment approaches and the influence of chemical industry pressure in the pesticides' consumption profile in Brazilian agricultural areas. The present work discusses the importance of these factors as determinants of rural workers health status, by analyzing the results of field researches performed in agricultural regions of Rio de Janeiro State.