Pattern Of Schistosoma Mansoni Infection After Intervention In Mwea Irrigation Scheme In Kenya.

Abstract

A longitudinal study of Schistosoma mansoni reinfection rate was carried out in an endemic area of Kenya, after intervention. Intervention measures applied involved chemotherapy, community mobilization to effect change in water contact habits and faecal disposal. This paper focuses on S. mansoni reinfection pattern over a two-year period. The age group 5-19 years showed an increasing trend of reinfection as compared to the 30-59 years age group. More than 50% in the 5-19 year age group had been reinfected by twelve months of follow-up. They were also responsible of 91% of all the egg-load and 83% of all the infections at the end of the study period. Since majority of the 5-19 year age group comprises school children, there is an urgent need of including issues related to schistosomiasis in the school curriculum especially in the endemic areas. PIP:

Schistosomiasis is a parasitic disease caused by blood flukes which live in the mesenteric and/or vesical veins of humans over a life span of several years. Cercariae are released by infected intermediate snail hosts into fresh water whose larvae then penetrate the skin of man when the individual contacts infected fresh water. Schistosomiasis is debilitating, setting in slowly and causing concern in its chronic stages. Chronic infection results in complications such as liver fibrosis and portal hypertension for Schistosoma mansoni and ureteric obstruction, bacterial infection, and cancer of the bladder for S. haematobium. In endemic areas, children have the highest prevalence and intensity of infection due to their more extensive contact with water relative to adults. Chemotherapy helps to control the disease, but population immigration, untreated pregnant women and very young children, and the selectiveness of control strategies make reinfection inevitable. This paper reports findings on the rate of reinfection with S. mansoni in Kirinyaga district, Kenya, between September 1983 and December 1988, after a prevention and control intervention. Schistosomiasis is endemic in that area of Kenya. Measures applied during the intervention included chemotherapy and community mobilization to effect change in water contact habits and faecal disposal. Individuals aged 5-19 years showed an increasing trend of reinfection compared to individuals aged 30-59 years, with more than 50% of subjects in the 5-19 year old age group being reinfected by twelve months of follow-up. The young age group also accounted for 91% of the egg-load and 83% of all infections at the end of the study period. The majority of the 5-19 year old age group comprises school children. An urgent need therefore exists to cover schistosomiasis-related issues in schools.