Volume 9 Number 2 August 1995
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MethodsThe investigation was made in conjunction with countrywide surveys of schistosomiasis nlansoni conducted between 1979 and 1993. The survey covered a total of 93 colnInunities in various parts of the country .Stool specinlens were procured fronl both school and non-school populations by a systenlatic sampling nlethod, i.e., where the sanlpling units were school children, the first child was selected by casting lots while the second child, the third child, and so on had been chosen by adding a constant factor until the required nunlber _________________________ 1From the Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. of children was obtained. In non- school population the same sampling procedure was applied to collect stool specimens. Schistosomiasis survey and accessibility of the communities to highways were the two factors that governed the survey coverage. About one- third 10% fomlalin-fi11ed 10ml labelled vials were handed out to the selected individuals who were instructed to transfer about 2 gram of freshly voided stool into the vials. On handing over the specinlen vials to the technicians, they were interviewed to provide information on their sex, age, and occupation. The preserved specimens were then carried to the laboratory of the Institute of Pathobiology where they were processed and examined by qualified technicians using the Formol-Ether-Concentration (FEC) technique (10). ResultsThe infection rates of Giardia Lamblia by age and sexes are presented in Table 1 while prevalence of infection by altitude are presented in Table 2. The overall prevalences of giardiasis among the school children (5-19 years of age) and residents were 8.9% and 3.1%, respectively. The corresponding prevalence among the non- school children (5 -19 years of age) was 4.4%, showing that school children are more significantly infected than their non-school s counterparts (P < 0.005). The overall difference in infection rates between males and l females in both the school population and residents is not statistically significant (P>0.01). Table 1: Giardia lamblia infction by age and sex among school children in Ethiopia
Both sexes combined, there is a general tendency of decline in prevalence of giardiasis with rise in age both the school and residents, although more pronounced in the former . Among residents, females had the highest infection rate in 0-4 years of age while in males, highest infection rate was observed in the age group 5-14 years. Communities surveyed were located at altitudes of 380 and 3000 m above sea level. A closer observation of giardial infection at various altitudes shows that giardiasis is almost equally prevalent at all elevations.
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