RESUMO
To determine the possible risk factors for the high prevalence of Schistosomiasis in Ezbas [Satellites and hamlets] than a mother village [Ebshan], Kafr El-Sheikh Governorate. The first stage of the study was a cross sectional descriptive study. The target population were all the inhabitants above 2years [4780] of ten Ezbas and a systematic random sample from the mother village [5000]. Both were subjected to Stool analysis by Kato-Katz technique. The estimated total prevalence rate of schistosomiasis of the examined population from Ezbas was 14.7% while it was 4.3% in the mother village with a statistical significant difference between Ezbas and the mother village as regards the intensity of infection. There was a significant relationship between prevalence of schistosomiasis and GMEC by population density. The prevalence was higher among males than Females and that the peak age specific prevalence rate among the inhabitants of Ezbas was [36.5%] for males and [30.4%] for females in the age group 15-<20 years with cut upward shift in the age scale and lower prevalence in the mother village. The second stage was a case control study where Schistosoma cases from all the Ezbas [704] and age and sex matched controls [705] Porn the mother village were subjected to a questionnaire compiling sociodemographic data housing environment. Knowledge. Attitudes and Practices [KAP] about Schistosomiasis and water contact behavior. History taking and thorough clinical examination were done and abdominal ultrasonography was performed for a random sample. Malacological studies of the snail Biomphalaria Alexandrina were carried out in all water channels. The risk factors for the high prevalence of schistosomiasis in Ezbas than the mother village were illiteracy [OR=63.1], true agricultural work [79.7] low social class score [OR=2.5], low housing condition score [OR= 3.7] risky houses as regards the nearness to contaminated canals [OR=11.3] when the distance was less than 5 meters [OR=5 .3] when the distance was 5-1 Om and sewage disposal into canals [OR=48]. Among the inhabitants of Ezbas, the most risky KAP were; lack of correct knowledge and out the effective method of prevention [OR=32.1], non-avoiding direct or indirect contamination of water channels [OR=46.8], non-avoiding exposure and practicing contact to contaminated water channels even after treatment [OR=183.3] and lack of periodic screening after treatment [OR=1.38]. The most risky occupational behavior for males was irrigating fields [OR=110.3], cleaning canals [OR=77.7], washing animals [OR=23.4] and fishing [0R=22.5]. The most risky occupational behavior for males and females were rice and vegetable implantation [OR=113] and removal of harmful grass [OR=11.1]. Grain washing was a risky behavior for females [OR=38.2]. The most risky socio-cultural behavior were playing and swimming for children< 15 years [OR=36], washing utensils for females [OR=40.6] and for males; ablution [OR=16.8] and bathing [OR=10.6]. The risk increases with daily exposure [OR= 6] and with a duration >2hours in each exposure [OR=25.8] and infected B. Alexandrina snails in water channels [OR=39.4]. Most of them [85.5%] had received a previous treatment by praziquantel [PZQ]; [26.8%] of them significantly received 3 doses of PZQ in the last year. Most of the cases [86.2%] were asymptomatic. Hepatomegaly, Splenomegaly and per portal fibrosis were more significantly prevalent among the inhabitants of Ezbas compared to the control as diagnosed by abdominal ultrasound [31.1%. 23.2% and 17.9% respectively]. A modification of the National Schistosomiasis Control Project is recommended for more concern towards the numerous and bas which still have a high prevalence and intensity of schistosomiasis