Assessment of schistosomiasis transmission in the River Nile at Greater Cairo using malacological surveys and cercariometry

• DOI: 10.1007/s12639-022-01529-8
• Publication Date: 2022-09-10T07:02:41Z
• Authors: Hanaa M. M. El-Kh...; Hanan S. Mossalem; Karem El-Hommossany; Sara S. M. Sayed; Wafaa A. Mohammed; Khaled M. Zayed; Mohamed Saied; Mohamed R. Habib
• Keywords: Parasite Control; Intermediate host; Veterinary medicine; Nursing; FOS: Health sciences; Global Impact of Helminth Infections and Control Strategies; Ecological Interactions of Parasites in Ecosystems; 03 medical and health sciences; 0302 clinical medicine; Copper and Zinc in Health and Disease; Helminths; Health Sciences; Schistosomiasis; Biology; Immunology and Microbiology; Freshwater snail; Nutrition and Dietetics; Ecology; Host (biology); Life Sciences; 6. Clean water; Snail; FOS: Biological sciences; Environmental Science; Physical Sciences; Medicine; Parasitology; Zoology

Abstract Continuous field studies on the abundance and distribution of freshwater snails and cercarial populations are important for schistosomiasis control programs. In the present work, snail surveys and cercariometry were conducted for four successive seasons at 12 sites on the Nile River banks in the area of Greater Cairo to identify potential transmission foci for schistosomiasis. In addition, water physicochemical parameters were recorded. The results showed that the electrical conductivity, total dissolved solids, dissolved oxygen, and pH were within the permissible levels, except that the water temperature showed an increase, especially in the spring season. Malacological surveys identified 10 native snail species at the studied sites of the Nile River, namely Bulinus truncatus, Biomphalaria alexandrina, Lymnaea natalensis, Lanistes carinatus, Cleopatra bulimoides, Melanoides tuberculata, Helisoma duryi, Bellamya unicolor, Physa acuta, Thedoxus niloticus, and one invasive snail species, Thiara scabra. The calculated diversity index indicated that the structure of snails’ habitats was poor, while Evenness index indicated that the individuals were not distributed equally. Results of natural infection identified no schistosome cercariae in B. truncatus and B. alexandrina. However, results of the cercariometry recovered Schistosoma cercariae in all the surveyed sites during all seasons with variable distribution. The preceding data suggest that, there are still some active transmission foci for schistosomiasis infection in the Nile River. Moreover, the present finding highlights the importance of cercariomety as a complementary approach to snail samplings for the identification of transmission foci for schistosomiasis.