Freshwater Malacological Fauna of the Ruzizi Plain, Democratic Republic of the Congo: Biodiversity and Outbreaks of Schistosomiasis

Abstract

Background: In the Ruzizi plain, intestinal schistosomiasis, caused by Schistosoma mansoni and transmitted by Biomphalaria pfeifferi, remains a significant public health challenge. This research offers insights into the diversity of molluscan species in the Ruzizi Congolese plain and the prevalence of schistosomiasis. Methods: The molluscan samples were gathered using a 0.5 mm mesh dip scoop net, sieves, and plastic containers in 2015. Data on schistosomiasis outbreaks from 2010 to 2014 were sourced from local hospitals, supplemented by cases recorded in 2015. Results: The study collected 3763 snails, representing 11 gastropod species. The most prevalent were B. pfeifferi (30.75%), Melanoides tuberculata (25.64%), and Melanoides sp. (18.89%). Ponds and agricultural irrigation canals contained a higher mollusk abundance than rivers. Schistosomiasis infestation rates were 24.5, 18.3, and 15.4% in Luvungi, Sange, and Kiliba villages, respectively. Canonical correspondence analysis (CCA) revealed positive correlations between Bulinus forskalii, Biomphalaria sp., and Bulinus globosus with pH, and Melanoides sp. with electrical conductivity. In contrast, Bellamya sp. showed a negative correlation with dissolved oxygen (DO). Conclusion: The study confirmed schistosomiasis presence across the Ruzizi Congolese plain, with Luvungi exhibiting notably high prevalence. Just B. pfeifferi was identified as shedding S. mansoni cercariae in the region. Keywords: Aquatic snail, Infestation rates, Biomphalaria pfeifferi, Physico-chemical parameters, Canonical correspondence analysis

Keywords

• aquatic snail
• infestation rates
• biomphalaria pfeifferi
• physico-chemical parameters
• canonical correspondence analysis