Effect of household water treatment with chlorine on diarrhea among children under the age of five years in rural areas of Dire Dawa,eastern Ethiopia:a cluster randomized controlled trial

Background:Diarrheal disease is a leading cause of child mortality and morbidity worldwide.Household water treatment with chlorine significantly reduces morbidity due to waterborne diseases.However,the effect of point-ofuse(POU)water treatment in improving the quality of water in areas where POU is not provided free of charge and the effectiveness of home visits in inspiring household members to use POU regularly have not been studied.The objective of this study was to evaluate the effectiveness of drinking water disinfection by chlorination on diarrheal disease reduction among children under the age of 5 years in rural eastern Ethiopia.Methods:A cluster randomized controlled trial was carried out in rural Dire Dawa from October 2018 through January 2019.The 405 households were randomized to intervention and control arms and intervention materials were distributed after conducting a baseline survey.This trial evaluated the effectiveness of household drinking water disinfection by chlorination in reducing incidence of diarrhea among children under the age of 5 years.Intervention households received 1.2%sodium hypochlorite with demonstration of its proper use.Participants in the control households continued with their usual habits of water collection and water storage.Generalized estimation equations(GEE)with log link Poisson distribution family and exchangeable correlation matrix was used to compute crude incidence rate ratio(IRR),adjusted IRR and the corresponding 95%confidence intervals.Results:In the intervention households,in total,281 cases of diarrhea were documented(8.7 cases per 100 personweeks observation);in the control households,in total 446 cases of diarrhea were documented(13.8 cases per 100 person-weeks observation).A 36.0%(adjusted IRR=0.64,95%CI:0.57–0.73)reduction in incidence of diarrhea was observed in the intervention arm when compared with the control arm.The highest and the lowest reductions were obtained in children of age ranges 1 to 2 years and 3 to 4 years,42.7 and 30.4%,respectively.Adherence to the intervention was 81.3%as measured by free residual chlorine test.Conclusions:In rural areas where diarrhea is the second leading cause of morbidity,water chlorination at the household level using liquid bleach considerably reduced episodes of diarrhea among children under the age of 5 years.Therefore,chlorinating drinking water at the household level may be a valuable interim solution for reducing the incidence of diarrheal diseases until potable water is made accessible to the majority of the population in Dire Dawa Administration and other Ethiopian communities.

Environmental determinants of distribution of freshwater snails and trematode infection in the Omo Gibe River Basin,southwest Ethiopia

Background:Determination of infection rates of snail populations is one of the basic tools for epidemiological studies of snail borne diseases.In this study,we opted to determine the trematode infection of freshwater snails in the Omo-Gibe River Basin,southwest Ethiopia.Methods:We collected snail samples from 130 observation sites in lakes,wetlands,rivers,reservoirs and irrigation canals surveyed during the dry season(March to May)in 2016.The snail samples were examined for trematode infections by cercarial shedding immediately after collection.Habitat conditions,water quality,human water contact practices and other human activities were assessed at each survey site.A redundancy analysis(RDA)was used to examine the relationship between cercarial infection and environmental variables.The statistical significance of eigenvalues and cercariae-environment correlations generated by the RDA were tested using Monte Carlo permutations at 499 permutations.Results:A total of 3107 snails belonging to five species were collected.The most abundant species was Biomphalario pfeifferi,representing 66%of the total collection.Overall,109(3.6%)of the snails were found infected with trematodes(cercariae).Biompholario pfeifferi was found to be the most highly infected,accounting 85%of all infected snails.A total of eight morphologically different types of cercariae were recorded,which included:Echinostoma cercariae,brevifurcate apharyngeate distome cercariae,amphistome cercariae,brevifurcate apharyngeate monostome cercariae,xiphidiocercariae,longifurcate pharyngeate distome cercariae,strigea cercariae and unidentified cercariae.Brevifurcate apharyngeate distome cercariae,and Echinostoma cercariae were the most abundant cercariae,accounting for 36 and 34%of all infection,respectively.The mean concentration of water conductivity and 5 days biological oxygen demand were higher in irrigation canals and lake sampling points.Human activities such as open field defecation,urination,livestock grazing,farming,and swimming were highly correlated with trematode infection.Conclusions:The abundance,occurrence and infection rates of snail species were largely influenced by water physicochemical quality,sanitation and water contact behaviour of the inhabitants.Human activities,such as open field defecation and urination,livestock grazing,farming,and swimming were important predictors of the abundance of cercariae.Therefore,awareness creation should be implemented for proper containment of excreta(urine and faeces)and reducing human and animal contacts with surface waters to reduce snail-borne disease transmission.