The epidemiology of schistosomiasis in Egypt: Qalyubia Governorate

The primary objectives of this study, carried out in Qalyubia Governorate i n Egypt (south-central Nile Delta), were to continue tracking historical tr ends of infection prevalence of Schistosoma mansoni and S. haematobium, det ermine whether satellites (ezbas) of mother villages differed significantly with respect to schistosomiasis transmission, and to asses schistosomiasis -induced morbidity on a population basis using ultrasonography. Our study r evealed that S. haematobium has virtually disappeared from Qalyubia,governo rate, and that S. mansoni prevalence continues to decline slowly (17% in 19 91 compared with 19% in 1990). The prevalence of intestinal schistosomiasis was actually higher in the mother villages than in the ezbas of the same v illages, indicating that prevalence based on surveys of villages alone did not (at least for Qalyubia) cause underestimates of hue prevalence. (A moth er village is the large village in an area that includes hamlets or ezbas. In many areas, the infection rate in ezbas is significantly higher than in the larger central village.) Ultrasonographic studies revealed that less th an 3% of the population had stage 2 or stage 3 periportal fibrosis, commonl y associated with chronic schistosomiasis mansoni. This low level of morbid ity was consistent with earlier data from Qalyubia, which also showed a low level of S. mansoni-induced morbidity in this governorate.