Located in the Albertine Rift, the Ruzizi plain is a natural area of high freshwater molluscan Biodiversity. Unfortunately, there is very little information about the freshwater gastropods of the Ruzizi Congolese plain. In the Ruzizi plain, intestinal schistosomiasis due to Schistosoma mansoni is one of the most important public health problems and its intermediate host mollusc is Biomphalaria pfeifferi. This study provides information about molluscan biodiversity in the freshwaters of Ruzizi Congolese plain, infestation rates and the prevalence of schistosomiasis. Sampling was carried out in three representative sites, including Luvungi, Sange and Kiliba. nd nd The samples were collected from 2 May 2015 to 2 June 2015. Each of the sites included 2 ponds, 2 irrigation canals and 2 rivers. In total, 18 collecting points have been visited twice each one. The medical statistics data of outbreaks of infection of schistosomiasis were recorded from hospitals in these sites. Statistical analyses were performed using ANOVA and Kruskal Wallis tests in R software. We also used Shannon, Simpson and Fisher-alpha diversity indices in PAST software. A total of 3763 snails were collected belonging to 11 gastropod species such as Biomphalaria pfeifferi (30.75%), Melanoides tuberculata (25.64%), Melanoides sp (18.89%), Pila ovata (17.06%), Lymnaea natalensis (3.19%), Bulinus tropicus (2.84%), Bulinus globosus (1.44%), Bulinus forskalii (0.05%), Lymnaea sp (0.05%), Biomphalaria sp (0.05%) and Bellamya sp (0.03%). Of them, only B. pfeifferi was found in the Ruzizi plain as the highest abundant species. The ponds and irrigation canals dug for the agricultural needs provide a higher abundance of molluscs than rivers. There was no significant difference in the total numbers of gastropods collected these three freshwater habitats (p= 0.4819). The findings showed schistosomiasis is reported in all Ruzizi Congolese plain, but Luvungi is a locality where the prevalence of schistosomiasis becomes greatest increased (P < 0.001). Only B. pfeifferi was shedding S. mansoni cercariae in the Ruzizi Congolese plain, but B. globosus and B. forskalii were never found shedding human schistosome cercariae during our survey. The infestation rates of B. pfeifferi at Luvungi, Sange and Kiliba were 24.5%, 18.3% and 15.4% respectively.
Freshwater malacological fauna of the Ruzizi plain (South Kivu, Democratic Republic of the Congo): biodiversity, infestation rates and outbreaks of infection of schistosomiasis