Spatial distribution and habitat characterization of schistosomiasis host snails in lake and land habitats of western Kenya

Abstract

Intermediate host snails of schistosomiasis were surveyed in this study to determine their abundance and distribution in the lake and land aquatic habitats of Lake Victoria basin of Kenya. Several sites were sampled at eight locations, both in the lake and on the land. The habitat and/or vegetation type (i.e. open water, hippo grass, hyacinth, ambatch trees, other vegetation, stream, swamp, pond, dam) of the sampled aquatic sites within the locations were also differentiated, water physicochemical parameters were determined, and the abundance of different species or taxa of phytoplankton and zooplankton were enumerated and correlated with the abundance of schistosomiasis snails in the sites. The results indicated significantly more Biomphalaria sudanica snails than Bulinus africanus snails in different physical habitats on land (Student's t-test, P < 0.05), as well as in different locations on land (Student's t-test, P = 0.026). Regression analyses revealed that several physicochemical parameters, including dissolved oxygen (R 2 = À0.659; n = 8; P = 0.014), pH (R 2 = 0.728; n = 8; P = 0.007) and turbulence (R 2 = À0.616; n = 8; P = 0.02), were predictive of Biomphalaria spp. abundance, while pH (R 2 = 0.610; n = 8; P = 0.02) and turbulence (R 2 = À0.578; n = 8; P = 0.028) were predictive of Bulinus spp. abundance in different locations in the lake. Cyanobacteria (R 2 = 0.638; n = 8; P = 0.02) and chlorophyceae (R 2 = À0.50; n = 8; P = 0.05) were shown to be predictive of both Biomphalaria spp. and Bulinus spp. abundance in different locations in the lake. Zooplankton abundance varied significantly between different locations in the lake (One-way ANOVA, P < 0.001). Bosmina spp. were found to be predictive of both Biomphalaria spp. (R 2 = À0.627; n = 8; P = 0.01) and Bulinus spp. (R 2 = À0.50; n = 8; P = 0.05) in different locations in the lake. The results from this study will help inform policy regarding control measures for schistosomias and intermediate snail hosts in Lake Victoria waters, as well as in adjacent terrestrial aquatic habitats and even beyond.

Distribution of Biomphalaria Snails in Associated Vegetations and Schistosome Infection Prevalence Along the Shores of Lake Victoria in Mbita, Kenya: A Cross-Sectional Study

“…On the contrary, more snails have been shown to be found in Echinochloa stagnina mixed with E. crassipes along the shoreline of Lake Victoria. 5 Rather than feeding directly on higher plants, snails are known to feed by grinding the decaying plants matter, microflora, algae and bacteria that covers the vegetation. 26 Therefore C. gracilis being soft grass, the rate of drying and decaying is high and the growth of algae and other microflora on the decaying materials will be on the increase.…”

“…Only Biomphalaria host snails were collected using hand held standard flat wire mesh scoop (2 mm mesh size), according to previously described method. 5,10,13 The sampling site was measured 20m long, along the lake shore and 2m long into the main water body. The total area of the site scooped was 40 m 2 and scooping was performed in each and every site between 7:00 am and 9:30 am.…”

“…3 Schistosomiasis caused by S. mansoni and S. haematobium are the 2 species found along the Kenyan lake Victoria region, 4 with the intermediate host being snails of the genus Biomphalaria and Bulinus and respectively. 5 S. mansoni infection continues to be among the most important and widespread of the neglected tropical diseases in Kenya, especially among communities living around the shores of Lake Victoria in western Kenya. 4 More than 6 million people in Kenya are infected with the disease.…”

Schistosoma mansoni proctocolitis with polyposis

“…S. mansoni prevalence in Kenya is stated as 13%. This is due to Biomphalaria species of snails found around Lake Victoria (11,12). Our patient came from Homa Bay, along the shores of the lake.…”

Influence of physico-chemical parameters on the intermediate host of Schistosoma haematobium and Schistosoma mansoni in Makwaye and Kubanni Reservoirs, Zaria, Nigeria

“…The symptoms developed by the disease included fever, headache, abdominal pain, malaise, urticarial and diarrhea (Awobode et al, 2016). Transmission of schistosomiasis depends on the extent and duration human-water contact (Ofulla et al, 2013). The women working frequently in water and domestic chores are at greater risk (Awobode et al, 2016).…”