Trematode infections of the freshwater snail Biomphalaria pfeifferi from a south-east Nigerian community with emphasis on cercariae of Schistosoma

Abstract

Knowledge of trematode infections in Biomphalaria pfeifferi from south-eastern Nigeria is scarce, due to the absence of Schistosoma mansoni infection in the region. Therefore, the present study sought to describe trematode infections in B. pfeifferi from the River Uzuru in the Nigeria Cement Factory area, Nkalagu, south-eastern Nigeria. Four hundred and sixty snails were checked for trematode infections, and mice were exposed to the Schistosoma cercariae shed from the snails. Adult worms were harvested from the mice 13 weeks post-infection, while sections of the liver and spleen were examined. Primary school children living in the area were screened for S. mansoni infection and assessed for activities involving water contact. The edges of the river were also searched for burrows and rodents. The five cercaria morphotypes found were armatae xiphidiocercariae, echinocercariae, Schistosoma cercariae, cystophorous cercariae and cercariaeum cercariae. The overall prevalence and mean intensity of trematode infections were 39.78% and 195.46, with the prevalence and mean intensity of most cercaria morphotypes higher in the hot-dry than in the cool-dry season. The infected mice showed S. mansoni-like characteristics but the stool samples of the schoolchildren were negative for S. mansoni eggs. Water-contact activities in the River Uzuru were minimal. Burrows were seen at the river edges but no Schistosoma eggs were recovered from captured rats. This is the first report of Schistosoma cercariae and other cercaria morphotypes in B. pfeifferi from south-eastern Nigeria. Additional molecular investigations are needed to identify correctly these Schistosoma cercariae, due to their public health implication.

Distribution and seasonal abundance of Biomphalaria snails and their infection status with Schistosoma mansoni in and around Lake Tana, northwest Ethiopia

“…Significant variation of Biomphalaria infection with S. mansoni was observed across the study seasons. The highest infection rate was observed during the dry season as compared to the wet season, which is in line with reports from Tanzania 56 , Sudan 43 , 57 and Nigeria 58 . High levels of open-field defecation, human-water contact activities, and stable water conditions are observed during the dry seasons of the year in Ethiopia.…”

Abundance, Distribution, and Diversity of Freshwater Snail and Prevalences of Their Infection by Cercaria of Fasciola gigantica and Schistosoma spp at Mayo-Vreck River, Far North Region of Cameroon

“…Te infection rate of Biomphalaria by S. mansoni is higher during the hot (23.03%) and cold (20.49%) dry seasons than during the rainy season (16.72%). Similar results have been reported from Tanzania [93], Sudan [55,94], and Nigeria [95], indicating that schistosomiasisinfected B. pfeiferi molluscs were elevated during a dry season. Bekana et al [26] reported higher B. pfeiferi infection rates in Ethiopia (28.9%) after the rainy season (October to December), followed by the dry season between January and March (12.3%), while no infected snails were observed during the rainy season from June to September.…”

A Search for Snail-Related Answers to Explain Differences in Response of Schistosoma mansoni to Praziquantel Treatment among Responding and Persistent Hotspot Villages along the Kenyan Shore of Lake Victoria

“…Not unexpectedly, and as reported from previous studies, Biomphalaria snails shedding other trematode cercariae were also frequently collected. [49][50][51][52] Although non-schistosome infections exceeded S. mansoni infections by a factor of 2.9, we noted no significant positive or negative associations with any of the groups of trematodes with S. mansoni infections. The three villages that yielded the most S. mansoni snail infections (PHS villages Kanyibok and Usenge and RESP Kotieno) also yielded by far the most infections with other trematodes, suggesting they are general "trematode-transmitting hotspots."…”