University of Khartoum

Types of Trematode Cercariae(Infecting Freshwater Snails) and Molecular Identification of Bulinus truncatus/tropicus Complex Using Cytochrome Oxidase Subunit I in Khartoum State

Types of Trematode Cercariae(Infecting Freshwater Snails) and Molecular Identification of Bulinus truncatus/tropicus Complex Using Cytochrome Oxidase Subunit I in Khartoum State

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Title: Types of Trematode Cercariae(Infecting Freshwater Snails) and Molecular Identification of Bulinus truncatus/tropicus Complex Using Cytochrome Oxidase Subunit I in Khartoum State
Author: Mohammed, Nidal Ahmed Ibrahim
Abstract: The planorbid freshwater snails of the two genera, Biomphalaria and Bulinus -have been vigorouslystudied due to the role they play as intermediate hosts of schistosomiasis. In Sudan specifically, most studies havefocused on the chemical and ecological control of the two genera, but few studies have looked at their biologicalcontrol. This study explored the coexistence of other species of freshwater snails and the two genera in five localities of Khartoum state. Freshwater snails from 34 sites at irrigation canals (abueshreens) and the White Nile river basin were sampled monthly from January 2104 to December 2105. The snails were examined for trematode infections by cercarial emergence immediately after collection and thenweekly for an additional four weeks to allowthe maturation of prepatent infections. A total of 17,367 snails, representing twelve snail species, ten genera, and seven families, were collected. The most abundant species wasBiomphalariapfeifferi, representing 49.4% of the samples. Overall, 3.1% of the snails were found to be sheddingsome type of cercariae. Five species were found to have infections; among these Bulinus truncatus specieswas found to be the most heavily infected during the two successive years of the study; 2014 and 2015, with an overall prevalence of 75.0% and 45.6% respectively. Double infections were recordedin only oneMelanoides tuberculatasnail and one Cleopatra bulimoides snail. Twenty- four different morphotypes of cercariae wererecorded, six of which appeared not to conform to previously described cercariae from Africa and nine were new country record.Xiphidiocercariae type 1 was the most common type of cercariae recovered, accounting for 38.8% of allinfections. The density of the schistosome intermediate host and Physa acuta snails tended to be lower during the secondyear than the first year, while the density of Lanistes ovumandPila wernei remained the same during the two years of the study. Three snail species;Lanistes carinatus,Gabbiella senaariensis and Bellamya unicolor were recorded only during the second year of the study. The findings of this study indicate that besides schistosomes, other larval trematodes are found, andsome use the same intermediate hosts as the schistosomes. Further studies should be conducted to determine whethersome of these trematodes could be manipulated for the biological control of schistosomiasis.In the present study, using Cytochrome Oxidase Subunit I (COI) marker as a molecular tool in the identification of the snails belonging to Bulinustruncatus/tropicus complex, revealed nine strains of a single species; B. truncatus. Some of these strains are susceptible to schistosome infections and some are not. These findings may to some extent help in determining the foci of the susceptible strains and thus help in the focal mollusciciding. Future work may aid in identifying the other three groups of the genus Bulinus and the species belonging to the genus Biomphalaria using molecular tools, for this will not only help in solving the problem of documenting the actual present species but also will serve in the focal mollusciciding.
URI: http://khartoumspace.uofk.edu/123456789/26069


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