Food and waterborne protozoan parasites: The African perspective

Abstract

Parasitic food-borne diseases, particularly those caused by the protozoan parasites Cryptosporidium, Giardia, Cyclospora cayetanensis and Entamoeba are increasingly becoming common and have received considerable attention in the last two decades. The ability of the transmission stages of the parasites to survive in the environment for prolonged periods, globalization of the food industry and changes in eating habits have contributed to the numbers of human infections. This systematic scoping review highlights these important water- and foodborne parasites in the African context, detailing the burden in African water sources, wastewater/effluents and fresh produce. A scoping review search targeting African countries was conducted in Medline, Web of science and African journals online as well as back referencing from included studies covering the period 1990 to January 2020. Out of 1134 studies, 68 were included in the review. The articles covered 17 out of 54 African countries. There were 39/68 studies reporting on water sources while the rest reported on fresh produce. Cryptosporidium prevalence ranged from 6 to 100% in surface water, 4 to 100% in tap water and up to 100% in wastewater and sludge. In fresh produce, Cryptosporidium was reported from five countries with prevalence of 0.8–75%. Giardia was reported in 47 out of 68 articles; prevalence ranged from 2.4% in surface water; 1% to over 70% in tap water; 28–100% in wastewater and 2% - 99% in fresh produce. Prevalence of Cyclospora cayetanensis was lower. Prevalence of Entamoeba was 78% in surface water; 100% in wastewater and up to 99% in fresh produce. This study finds that Africa is no exception to the risk presented by the subject parasites from water and/or food sources. Routine screening for these parasites particularly at household level and provision of adequate and safe drinking water would help to control the parasites.