Prevalence and Intensity of Intestinal Parasitic Infections and Factors Associated with Transmission among School going Children

Objective: To determine the prevalence and intensity of intestinal parasitic infections and factors associated with transmission among primary school going children.Design: Cross-sectional descriptive study.Setting: Muthithi Location situated in Murang'a County; Kenya.Subjects: Multi-stage sampling was used to select 418 children. Stool specimens were examined using Kato-katz technique to determine the number of helminthes eggs per gram of stool and formol ether concentration technique to detect the different protozoan cysts. Data were analysed using Statistical Package format (SPSS version 20.0). Pearson's Chi-square test was used to establish the association between categorical variables. Multivariate analysis was used to determine the factors associated with the infections.Results: The study established that 53.8% (225 out of 418) were infected with one or more of intestinal parasite. Five species of helminthes were identifiedwith prevalence of 11.5%; the predominant helminth parasite identified was Ascaris lumbricoides 9.1% (38 cases). Intestinal protozoan identified in this population was Entamoeba histolytica with prevalence of 42.3% (177 cases). The factors established to be independently associated with presence of intestinal parasitic infection were: age 11-15 years P0.001; use of plain water for hand washing P0.05; eating food without spoon P0.05; consuming raw vegetables P0.001; untrimmed finger nails P0.001 and source of drinking water [river P0.001 and mixed sources (river; well and tap) P0.05]. Conclusion: This study revealed that intestinal parasites still pose a public health problem to school going children. Despite lack of school based deworming programme in this area; treatment combined with health education and other interventions in school age children is recommended as a way of controlling transmission

Identification of schistosome-infected snails by detecting schistosomal antigens and DNA sequences

Cercarial shedding tests do not provide species identification of the shistosomes concerned and cannot detect prepatent schistosomal infections. We have demonstrated that both immunodetection by ELISA of schistosomal antigens in snail hemophlymph, and dot hybridization of snail extracts by DNA probe representing highly repeated sequences, proved suitable for detecting infected snails during prepatnecy as well as patency. A group-specific monoclonal antibody was found to be suitable for detecting Schistosoma mansoni infection in Biomphalaria sp., but not for positive identification of S. haematobium in Blulinus sp. Comparative evaluation of the diagnostic qualities, and technical aspects and cost of these tests, point to the superiority of the immunodetection approach for large scale detection of snails prepatently infected with S. mansoni. This approach is potentially useful for providing extended information on schistosome-snail epidemiology that may facilitate rapid evaluation of the danger of post-control reinfection, and help make decisions on the time and place of supplementary control measures. In this context the potential usefulness of the immunodetection or DNA probing approach for facilitating catalytic model representation of schistosome-snail epidemiology warrants further evaluation. Specific identification of S. haematobium in Bulinus by either of these approaches may be possible depending on the development of suitable antibodies or DNA probes