Evolution of Schistosomiasis Haematobium Prevalence in the Last 30 Years in a Rural Area of Assiut Governorate- Upper Egypt

Abstract

Schistosomiasis is a pressing public health problem in Egypt. The prevalence of S. haematobium increased in Upper Egypt in association with perennial irrigation since the construction of Aswan High Dam. Cross-sectional field studies were designed and conducted in 1969 and 1999 in Nazza karar village, Assiut Governorate to study socioeconomic development, changes of S.haematobium prevalence, water contact activities and the contribution of risk factors. The first survey [1969] was carried out 3 years after the introduction of perennial irrigation system with a total coverage of 3512 persons. In the second survey [1999], one-fourth of the houses [1380] were taken by systematic random sample to yield 1021 eligible persons. The data were collected by personal interview. Few questions were added in the second survey as regards households electrical appliances availability. Urine was examined by sedimentation technique in both surveys. The prevalence declined from 31.9% to 8.52% [73.3% decline]. Males had a higher prevalence than females in both surveys. The peak age was 10-19 years in the two surveys. Among males, the peak prevalence was at age group 14-19 years in the second survey. Farmers and farm laborers decreased from 37.4% to 25.2% and significantly had higher prevalence of S.haematobium than other jobs in the two surveys. Persons who had latrines increased from 48.9% to 91.9% [87.1% increase]. The houses encroached on water canal, therefore persons living close to the canal [<60 meters] increased from 19.5% to 52.3% [167.9% increase] and the prevalence increased with decreasing distance from the canal. More than one-third [37.4%] of the studied sample in 1999, had refrigerators. The prevalence decreased significantly among those who had washing machines [P=0.0153]. The prevalence among whose who had TV were 7.3% compared to 16.7% among those who did'nt have TV [P=0.0002]. The same was found for radio [6.8% vs 11.1%, P=0.0171]. There was no significant difference between those attending school or not except among females in age group 6-19 years. TV [69.4%] was the main source of knowledge followed by school [7%] then health unit [4.8%] By applying multiple regression model in the second survey, the significant risk factors were: TV absence, sex [male], occupation and washing machines absence. Although the swimming activity of males in the canal increased in the second survey particularly in <15 years old [41.2 % vs 5.8%], S. heamatobium infection was much lower [16.7% vs 100%]. In conclusion socioeconomic development had improved the schistosomiasis control program, but the introduction of single dose antischistosomiasis oral drugs and health ducation through mass media had accelerated the prevalence decline.