Exploratory Study of Schistosoma Hematobium Infection …… Fouad El Magri, et al.
Exploratory Study of Schistosoma Hematobium Infection in Derna area (2001) Foad El Magri,* Rashida Barakat,* Omar El Shourbagy,* Abstract: Health questionnaires and parasitologic examinations of urine were performed on a random sample of 1506 pupils from Derna area, Libya in (2001) to investigate the prevalence of and risk factors for infection with Schistosoma hematobium (S.h.)in the area.The prevalence of S.h. was 5.4 % (82 cases). Age- prevalence of infection was from the age of 10 onward. Males had higher infection rates than females. Risk factors for Schistosoma hematobium infection were male gender; age 10 years; swimming in Shalal water; farming and pasthistory of schistosomiasis and Blood in the urine. Control of risk factors, health education and appropriate treatment strategies should be implemented to control S.h. infection in Derna. Introduction: Many scholars and activists have suggested that the pharmaceutical industry is failing to devote sufficient effort towards finding effective cure and treatment for tropical infectious diseases such as leishmaniasis, lymphatic filariasis, Chagas’ disease, leprosy, Guinea worm, onchocerciasis and schistosomiasis. These so-called ‘neglected’ diseases predominantly affect poor populations in low-income countries, and pose particular social and economic problems for those affected.1 Moreover, the treatment already exists for many of these diseases. Schistostomiasis (bilharzia), which predominantly affects children in Africa, can be treated with praziquantel at a cost of 30 cents per child a year.2 Schistosomiasis hematobium infection is endemic in Libyan Arab Jamaheriya, although it prevails mainly in the Western part of the country, yet infection foci were reported in the Eastern part, especially Derna. Information about the extent and transmission dynamics in this area is limited to very localized previous studies.3,4,5 The World Health Organization suggested that the prevalence of Schistosoma mansoni among 7- to 14-year-olds should be used to guide treatment strategies in endemic areas. This explores how well the prevalence in that age group predicted the overall prevalence in the community. There was a strong relationship between the prevalence among 7 to 14 year of age, and the overall prevalence in the community.6
In 1971, S. hematobium infection was diagnosed in 4.1% of the 7842 pupils attending schools in Derna city. The infection was slightly higher among males (4.5%) than females (3.6%}. Regarding age, the infection rate decreased by the increase of age, being 4.4%. 3.9% and 0.5% among primary, preparatory and secondary school, respectively. The highest rate was reported among school children in El Maghar sector of the city. Furthermore, in the same year, examination of 3600 individuals living in this sector revealed infection in 2.6% of them. This finding was attributed to the fact that most of the inhabitants of El Maghar sector work in Wady Derna (the valley) where the presence of snail intermediate host of S. Hematobium in its water bodies was documented. A control program –including treatment of infected individuals, health education and application of baylocide- was implemented. Follow up examination of schoolchildren carried out in 1976, 1977 and 1979 showed a marked drop of infection (0.8%, 0.07% and 0.3% respectively). Furthermore, examination of 8390 urine samples Cin Wehda hospital. Bilharzia control center and Polyclinic) revealed S. haematobium infection in 11 individuals, only.7 A survey for urinary schistosomiasis was conducted in all schools (18 in number) of Ubari district (Sebha Governorate) of the Libyan Arab Republic (1975). Out of 1874, school pupils examined, 99 proved positive at the rate of 5.3 %. Boys were more infected
*) Pediatric and Community Dep., Derna Faculty of Medicine & WHO.
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Exploratory Study of Schistosoma Hematobium Infection …… Fouad El Magri, et al.
than girls and the peak of infection was at eleven years. The intensity of infection was light. Treatment of infected pupils started with Niridazole at the standard dose, with about 60 percent cure rate. Antisnail measures were introduced for the first time using copper sulphate with satisfactory preliminary results.7 An ELISA system showed a positive rate for Schistosoma mansoni infections of 33.4% in Tauorga school-children (1985) and qualitative stool examination detected only 6.9%. Subsequent sampling of the school population indicated that a mollusciciding programme involving the major water body in the area had prevented an overall increase in prevalence and had apparently produced a decrease in prevalence in certain locations. New housing, piped water, sanitary disposal of wastes and health education were additional favourable factors.8 In 1993, a study was conducted in 9 localities of Tauorga town, which is situated in the North-West of Libya, with the objective of finding out the trend of Schistosomiasis mansoni in general population and to plan suitable strategies for its prevention. 1544 people were selected by two stage cluster random sampling. Stool samples were collected and examined for Schistosoma mansoni eggs. The study revealed that the overall prevalence of schistosomiasis mansoni was 20.85%. Significantly higher prevalence was observed in school-age group (28.61%), in males (25.28%) and in localities situated within the area of 2 Km from the spring (55.58%).9 Recently, school children were used as indicators for the identification of schistosomiasis-positive family members in an area of low endemicity. This was to improve current schistosomiasis control programs by applying a strategy to identify schistosomiasispositive individuals in a more efficient way. The initial prevalence among school children was 8.6%. However, the prevalence among the family members of these school children increased to 15.5%. In contrast to these findings, the prevalence in family members of schistosomiasis-negative school children was 3.8%. Although the applied methodology showed a relatively low sensitivity (50.0%), the high negative predictive value (87.7%) indicates that a few positive family members of school children with a negative stool result 57
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will be missed. This shows that this method of evaluation could be a strategy for a more efficient and cheaper identification of schistosomiasis-positive individuals in areas of low endemicity.10 Objectives: To estimate the prevalence and intensity of Schistosoma haematobium infection among primary and preparatory school children in Derna.
To determine the morbidity of S. haematobium infection - as measured by hematuria (blood in urine) - among the studied group.
To investigate the association between different demographic and social factors and S. hematobium infection among studied group. Study design: Study population: Children of primary and preparatory school in Derna area. A stratified random sample of 1506 children was randomly selected from primary and preparatory schools in Al-maghar and Bo-mansour sectors. Methods: 1. Personal and demographic data was collected through filling a pre-designed, pre-coded questionnaire. 2. A urine sample was collected - in a labeled disposable container from each child. Screening of all urine samples for the presence of hematuria, proteinuria, and haemoglobin was done using reagent strips. 3. Parasitological diagnosis of Schistosoma hematobium infection: Detection and counting of Schistosoma eggs using nuclepore filtration technique.(11). 10 ml of urine was withdrawn into a syringe, the urine was pushed through a nuclepore filter (25 mm diameter and 12u pore size) held in a filter support. Then 20 ml of air was pushed through the filter. Finally, the filter was removed, placed upside down on a clean slide and kept in a slide box. Before microscopic examination, a drop of saline was added and the slide examined for detection and counting of Schistosoma haematobium eggs. 4. Treatment of infected individuals: All infected individuals received Praziquantel,
Exploratory Study of Schistosoma Hematobium Infection …… Fouad El Magri, et al.
in a single oral dose of 40-mg/Kg-body weight unless contraindicated. Statistical analysis: Collected data was recorded in special forms. EPI INFO package was used for entering and analyzing the data. Data regarding Schistosoma hematobium infection was recorded as number of eggs per 10ml of urine. Infection data was presented, as prevalence rate. Relevant tests of significance were used in testing the relation between different proportions. Results: Health questionnaires and parasitologic examinations of urine were performed upon a random sample of 1506 pupils from Derna area, Libya in 2001 to investigate the prevalence of and risk factors for infection with Schistosoma hematobium in the area. The prevalence of S.H. was 5.4 % (82 cases). In the present study, the age ranged from 6 to 16 years with a mean value of 10.7 + 2.6 years.
Males were 417 representing 27.7% of cases, and females were 1089 representing 72.3% of all cases. Libyan cases represented a 69.8% of the studied cases. Frequency of the education level of the father among the studied cases shows that the illiterates were 156 representing 10.4%, those who could read and write were 225(14.9%), Preparatory/Secondary-educated were 903(60%) and University-educated were 222(14.7%). Frequency of the occupation level of the father among the studied cases shows that the employees were 900, representing 59.8%, teachers were 120 (8%), the skilled were 180 (12%), the retired were 60 (4%), the privateworking were 144 (9.6%), waives were 48 (3.2%) and professionals were 54 (3.6%). Tables (1 and 2) show the frequency distribution of pupils and their educational grades from the randomly selected schools from Derna area.
Table (1) Frequency distribution of pupils from randomly selected schools from Derna area. School Name El Kholoud El Nahda El Khansaa El Wahda Total
No. of pupils 888 300 180 138 1506
Percent 59% 19.9% 12% 9.2% 100%
Table (2) School Grade Distribution among studed students. School Grade Primary six G. Primary fivth G. Preparatory first.G. Preparatory third G. Preparatory second G. Primary fourth G. Primary first.G. Primary secondG. Total
No. of pupils 420 372 288 156 138 108 18 6 1506
Table (3) shows the odds ratio and 95% confidence limits for risk factors for infection with Schistosoma hematobium in Derna. Risk factors significantly associated with S. hematobium infection in Derna were among
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Percent 27.9% 24.7% 19.1% 10.4% 9.2% 7.25 1.2% 0.45% 100%
those of 10 years old onwards, males living in Almaghar, those who help in farming, children who swim or play in Shalal water; and a history of schistosomiasis. A history of schistosomiasis was associated with morbidity.
Exploratory Study of Schistosoma Hematobium Infection …… Fouad El Magri, et al.
Table (3): Odds ratio and 95% confidence limits of risk factors for infection with Schistosoma hematobium in Derna. Risk Factor Age: 6 years 7 years 8 years 9 years 10 years 11 years 12 years 14 years Gender: Male Female Pasthistory of Bilharz Helping in farmming Swimming in Shalal Bomansur hematuria Almaghar hematuria Bomansur proteinuria
Total No. 105 114 114 115 241 222 220 84 417 1089 82 82 82 285 51 285
Table (4) shows the cross-tabulation analysis as regards gender and the infection with S. hematobium ova. There was a significant difference between males and females (χ 2 = 8.2 P
