Impact of the current National Bilharzia Control Programme on the epidemiology of schistosomiasis mansoni in an Egyptian village.

In a population-based study in the Nile Delta of Egypt, the modified Kato thick smear technique was used to study the epidemiology of Schistosoma mansoni. After 2 years of implementation of the National Bilharzia Control Programme by the Ministry of Health, the general prevalence dropped from 47.2% to 21.9%. The peak prevalence rate has shifted downwards in magnitude (40.4% compared to 72.1%) and backwards over the age scale (5-14 in contrast to 15-19 years age group). Redistribution of various infection grades has taken place. More than three-quarters (75.6%) of the infected individuals have light infections in contrast to only one-fifth (20%) 2 years ago. The mean egg count for the entire sample population has dropped significantly (P < 0.05) from 128 to 17 eggs/g stools with no significant difference between males and females. This positive impact can be attributed largely to the case finding and treatment component of the programme. However, the incidence rate remained nearly the same before and 2 years after implementation of the programme (18.7 and 18.1%, respectively). The non-changing high incidence rate indicates that the knowledge, attitude and practice (KAP) of the population concerning water contact have not yet changed. Insufficient improvement in environmental sanitation may be a contributing factor. Continuation of serious efforts in case finding and treatment is recommended, with special emphasis on schoolchildren. This should be coupled with an intensive health education programme.