Parasitic contamination of waste stabilization ponds effluent, prevalence and risk factors associated with transmission of soil-transmitted helminthiasis among school-aged children in the surrounding community in Dares Salaam

Abstract

Background: Waste water can be treated by waste stabilization ponds (WSPs) toremove the parasites that might cause infectious diseases when released into environment. Partially or untreated waste water poses risk of transmitting potential infectious diseases like soil-transmitted helminths (STH) to the surrounding communities, the higher risk groups being irrigating farmers, vegetables consumersand children. Aim/ broad objective: To determine the level of parasitic contamination in waste stabilization ponds effluent, prevalence and risk factors associated with STH among school-aged children surrounding two municipal waste stabilization ponds in Dar es Salaam. Materials and methods: A descriptive cross-sectionalstudy with a quantitative approach was used. A multistage sampling technique was used to select five primary schools located in area about 3 km in which a total of 342 pupils were enrolled in a study done in June 2017. Wastewater effluent was analysed by using modified Bailenger method, whereas stool specimen were examined by using Kato-Katz technique. Demographic data and hygienic practices information were collected by using a structured questionnaire and respective proportions calculated. Results: Study respondents were 319 pupils and response rate was 93.3%.The mean concentration of nematode eggs in Vingunguti WSP was 1.1eggs/litre specifically hookworm eggs (1.13 eggs/litre) and Ascaris spp. egg (1.1 eggs /litre). No parasitic egg was seen in Buguruni effluent. Overall prevalence of STH was (1/319) 0.3% Trichuris trichiura infection (0.7% in Buguruni and 0.0% in Vingunguti). Conclusion: The concentration of nematode eggs in effluent from Vingungutiwasabove WHO limits while effluent from Buguruni WSP abides by the guideline. There is very low prevalence of STH among school-aged children surrounding municipal WSPs in Dar es Salaam which might be due to high coverage of school deworming program. Recommendation: There is a need for technical maintenance and monitoring of Vingunguti WSP to improve pond performance and complete treatment of waste water. Health education and behavior change programsshould be provided to urban farmers and inhabitants surrounding WSPs to improve awareness and knowledge on modes of transmission and preventive measures of STH.