PREVALENCE OF INTESTINAL PROTOZOAN PARASITES IN DIVERSE COMMUNITIES AND DRINKING WATER BODIES IN ZIMBABWE AND WATER DISINFECTION METHODS AGAINST Giardia duodenalis AND Entamoeba histolytica/dispar.
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A prevalence study of parasitic infections in 1 260 school pupils living in urban, rural tribal trust land and commercial farming environments of Zimbabwe was done. Stool specimens were collected on 3 alternative days and examined for parasitic infections and a questionnaire was administered. Giardia duodenalis and Cyclospora cayetanensis were most prevalent in the rural area, the risk factor of being infected with G. duodenalis being, not washing fruits before eating and drinking water from deep protected wells. Parasites most prevalent in the farming enviroment were Entamoeba histolytica/dispar, Cryptosporidium parvum and the helminths. The risk factor of being infected with E. histolytica/dispar was not taking measures to make water safe for drinking. Rare protozoan parasites such as Entamoeba polecki and Enteromonas hominis were also identified in the rural and farming environments respectively. Blastocystis hominis was prevalent in the urban environment. In order to ascertain whether drinking water bodies could be a possible source of infection for intestinal parasites, stool samples from 113 participants and their drinking water samples from 30 different water bodies in Chiweshe rural area were collected. Physico-chemical analysis of water and the same techniques used for stool were also carried out for the water samples. Five participants had similar parasites identified in their drinking water source and stool samples and 4 of these had diarrhoea. Deep protected wells yielded a significant association (p < 0.05) with occurrence of G. duodenalis, E. histolytica/dispar, C. cayetanensis and unidentified water flagellates. Sand filtration using both metal and plastic buckets and course and fine activated charcoal were tested for their capability in removing protozoan parasite cysts from contaminated water. A sand filter was designed, that using a combination of river sand and local activated wood charcoal and this was capable of capturing 99.9 % protozoan parasite cysts. Fine activated charcoal from baobab fruit shells and macadamia nut shells were capable of 99.9 % reduction of protozoan parasite cysts from water. Solar radiation was tested for its capability of inactivating G. duodenalis and E. histolytica/dispar. After 7 hr of sunlight exposure, 99.9 % of parasite cysts were inactivated. Lastly, 268 pupils of Musarara Primary School were involved in the solar disinfection (SODIS) study whereby these pupils were each given 2 l PET containers painted black on one side. Half the pupils exposed their containers daily to sunlight, whilst the other half kept them indoors. Monthly follow up was done for 2 months. Solar disinfection was effective in reducing parasitic infections caused by G. duodenalis, E. coli and I. butschlii in a field setting.