University of Khartoum

Studies on Transmission and Control of Schistosomiasis in Irrigation Schemes in Khartoum State, Sudan

Studies on Transmission and Control of Schistosomiasis in Irrigation Schemes in Khartoum State, Sudan

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Title: Studies on Transmission and Control of Schistosomiasis in Irrigation Schemes in Khartoum State, Sudan
Author: El Badri El Amin, Osman
Abstract: This study was carried out in two villages, kiryab in Seilate scheme, East Nile province and Baraka in Gamooeya scheme, Omdurman province where schistosomiasis is endemic. The aim of the study was to provide base-line information on Schistosomiasis transmission pattern and to the possibility of using plant molluscicides for snail control. Transmission was studied in canals neighbouring the two villages over different seasons. Aquatic plants were collected and tested in the laboratory for their molluscicidal activity. Aqueous extract of the fruit of B. aegyptiaca (Laloap) was used and evaluated in the field in comparison with Bayluscid synthetic molluscicide for the control of snails transmitting Schistosomiasis. The study was carried out during the period from August 1994 to August 1997. Both types of Schistosomiasis were recorded in Kiryab village while only the intestinal S. mansoni was found in Baraka village. Prevalence and intensity of S. haematobium infected people living in Kiryab village were 33.5% and 122.5 eggs/l0 ml. Prevalence of S. mansoni infection were 17.6% and 199.6 eggs/g in Kiryab and 40.8 % eggs/g in Baraka. The overall prevalence and intensity indices of both types of schistosomes between the two villages of the study and in each of the two villages varied significantly by age reaching a peak in the age group 10-19 years. Seven different snail species were found in sampling sites around the two villages. The snail species were the Pulmonates, Biomphalaria pfeifferi, Bulinus truncatus, Lymnaea natalensis, Physa acuta and Bulinus and the Prosobranchs, Cleopatra bulimoides and Melanoides tuberculata. Over the three years of the study, snails were observed to vary in distribution and density according to factors such as type of canal water depth .presence of aquatic vegetation and seasonal changes in temperature. However, Pulmonates including Biomphalaria pfeifferi, Bulinus truncatus were more sensitive to the effect of changes of these factors than Prosobranchs. Transmission of schistosomiasis was found to be mainly focal and seasonal taking the period from March to June. 43 different plant species belonging to 33 different families were identified in the irrigation of Khartoum and Gezira-Managil schemes. Most of the plant species collected from the families Graminae and Compositae. Of the 43 species collected and tested molluscicidal activity, only 11 species showed some molluscicidal activity. These were: A cacia niloticus, Tephrosia sp. Sesbania sesban, Ricinus communis, Cassia eldus, Ipomoea aquaica, Balanites aegyptiaca, Ziziphus spina christi, Cyperus rotundis, Mimosa pigra and Jussiaea repens. However, only three species showed an LC90 less than 500, and those are Acacia nilotica, Tephrosia sp and Sesbania sesban. From the field experiments, the LC90 of the aqueous extract of the fruit of B. aegyptiace estmated by probit was 95.4 ppm. The findings of the study when applying the aqueous of the fruit of B. aegyptiaca at this concentration in transmission sites are encouraging snail were eliminated from transmission sites and incidence rates were significantly reduced in the two villages where snail control using Bayluscide and B. aegyptiaca aqueous extract were used These findings point to the possibility of use to the plant B. aegyptiaca in the field. Further field trials for improvement of extraction methods and field application techniques together with further testing for the plant properties are needed.
URI: http://khartoumspace.uofk.edu/handle/123456789/15846
Date: 2015-07-01


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