Prevalence and familial aggregation of schistosomal liver morbidity in Kenya: Evaluation by new ultrasound criteria

Severe periportal fibrosis is not an inevitable consequence of infection wi th Schistosoma mansoni. Genetic predisposition may be a deciding factor in the development of disease. To assess the contribution of genetic factors i n the severity of hepatic fibrosis, the degree of familial aggregation was determined in a Kenyan population. Schistosomal fibrosis was identified wit h hepatic ultrasound and newly proposed World Health Organization criteria, which include both qualitative and quantitative observations. These 2 aspe cts of the criteria correlated well with one another. The peak prevalence o f ultrasound proven fibrosis trailed 5-10 years behind peak prevalence of i nfection and declined sharply after age 50 years. This pattern was consiste nt with either resolution of severe fibrosis over 10-20 years or early deat h of those severely affected. Genetic predisposition appears to be a weak f actor in the development of severe disease in this population, since no hou sehold or familial aggregation could be identified.