The role of parenteral antischistosomal therapy in the spread of hepatitisC virus in Egypt

Background The population of Egypt has a heavy burden of liver disease, mos tly due to chronic infection with hepatitis C virus (HCV). Overall prevalen ce of antibody to HCV in the general population is around 15-20%. The risk factor for HCV transmission that specifically sets Egypt apart from other c ountries is a personal history of parenteral antischistosomal therapy (PAT) . A review of the Egyptian PAT mass-treatment campaigns, discontinued only in the 1980s, show a very high potential for transmission of blood-borne pa thogens. We examine the relative importance of PAT in the spread of HCV in Egypt. Methods The degree of exposure to PAT by cohort was estimated from 1961-86 Ministry of Health data. A cohort-specific exposure index for PAT was calcu lated and compared with cohort-specific HCV prevalence rates in four region s. Findings HCV prevalence was calculated for 8499 Egyptians aged 10-50 years. A significant association between seroprevalence of antibodies to HCV and the exposure index (1.31 [95% CI 1.08-1.59]; p=0.007) was identified across four different regions. In all regions cohort-specific HCV prevalence was lowest in children and young adults than in older cohorts. These lower prev alence rates coincided with the gradual and final replacement of PAT with o ral antischistosomal drugs at different points in time in the four regions. Interpretation The data suggest that PAT had a major role in the spread of HCV throughout Egypt. This intensive transmission established a large reser voir of chronic HCV infection, responsible for the high prevalence of HCV i nfection and current high rates of transmission. Egypt's mass campaigns of PAT may represent the world's largest iatrogenic transmission of blood-born e pathogens.