Parasitological loads of rivers crossing the city of Bukavu, Democratic Republic of Congo

Assessing the parasite loads in rivers crossing cities is important for identifying the potential risks for humans and livestocks, and for selecting suitable risk reduction measures. The aim of this study was to determine parasite loads in four rivers (Bwindi, Kahwa, Tshula, and Wesha) crossing the city of Bukavu and flowing to the Lake Kivu. For each of the rivers data were collected at points located upstream of the lake embouchure during 2013-2014, and analysed through a modified Bailenger method. Our results showed that all the rivers were characterized by a rather high TDS content, an alkalinity above 7.7 and temperatures above 22°C, on average. Moreover, a diversity of parasites including nematodes, cestodes, protozoa and trematodes, was observed: Entamoeba coli, Ascaris sp., Hymenolepis diminuta, Taenia saginata, Giardia lamblia, Ankylostoma sp., Strongyloides stercoralis, Schistosoma mansoni, Entomoeba histolytica, Hymenolepis nana, and Trichuris trichura. Nematodes represented the most common parasites in Kahwa, Tshula and Wesha rivers (57% to 71% of species
recorded), while cestodes were predominant in Bwindi river (77% of species recorded). Additionally, high parasite loads were observed during the rainy season. The results highlight the health risks to people who use water from these rivers for various needs (bathing, irrigation, dishes, and laundry). The use of the modified method of Bailenger would be of great interest for the characterization of urban waste waters and the promotion of public health because of the simplicity of its implementation and its low cost.