Reinfection of School children with Schistosoma mansoni in the Finchaa Valley, Western Ethiopia

Abstract

Abstract:

Reinfection of school children with Schistosoma mansoni and factors thought to be responsible were studied in Finchaa Valley during 1993-95. A cohort of school children treated and cured of schistosome infection were followed for 12 months for reinfection studies. The annual reinfection rate and intensity were 26% and 374 EPG (eggs per gram of stool), respectively. Pretreatment intensity level was regained faster than pre-treatment prevalence 12 months posttreatment. Reinfection rate was associated with age, sex and seasonality of infection in snail hosts. Peak in snail population density and associated cercarial infection was observed in the dry season when high reinfection rate was found among school children. Rainfall appeared to have a pronounced effect in governing snail population density and cercarial infection. Detailed investigations involving all age groups on immunological response and water contact activities are necessary to assess the role of immunity and exposure on schistosome reinfection patterns. The implication of the findings to the control strategies are discussed. [Ethiop. J. Health Dev. 1997;11(3):269-274]