ULTRASONOGRAPHY IN A SENEGALESE COMMUNITY RECENTLY EXPOSED TO SCHISTOSOMA-MANSONI INFECTION

Inhabitants of Ndombo (n = 614), a village in an area recently infecte d with Schistosoma mansoni in Northern Senegal, were examined clinical ly, parasitologically, and ultrasonographically to investigate the pre sence and degree of S. mansoni-related hepatosplenic morbidity after a few years of exposure to schistosomal infection of regional canals. D espite previous praziquantel treatment of 56% of the inhabitants prior to bur investigation,the prevalence of S. mansoni infection in 1993 w as 90%, and 42% of the villagers excreted more than 1,000 eggs per gra m of stool. Previously untreated individuals were found to have signif icantly higher egg counts than treated ones. Despite the high intensit ies of infection, ultrasonographically detected severe periportal thic kening of the liver was infrequent. Grading according to body length-d ependent normal values of cross-section diameter of peripheral portal vein branches of a European control group correlated with intensities of infection. Of the total, group of patients, 30% (n = 182) had mon s evere thickening of portal vein branch diameters above the 97th percen tile and 70% of these had a splenomegaly. The highest egg counts and t he most frequent development of periportal thickening were found in 11 -20 year-old individuals. Periportal thickening was less frequent in p raziquantel-treated adolescents than in untreated ones. This suggests that early antischistosomal medication may be useful to limit schistos omiasis-induced hepatic morbidity especially in children, even though reinfection seems inevitable.