Rate of reinfection with S. mansoni following treatment in two newly reclaimed areas of Egypt.

This paper reports an on-going study in two newly reclaimed areas in Ismailia Governorate, El-Manayef, 10 km south-west of the city of Ismailia (area 1) and the other in Siani Peninsula, just east of the Bitter Lakes (area 2). In he baseline survey, the prevalence of infection of 49.9% and 40.1% and high intensity infection of 21.8% and 15.7% were found for S. mansoni in areas 1 and 2 respectively. Geometric mean egg counts for those found positive were 101.2 and 75.9. In a subsequent survey, a year after treatment of positives, the overall prevalence was 30.2% and 30.5% and the prevalence of high intensity infection was 8.6% and 10.5% in the two areas. The prevalence among those found positive and then treated during the first round (reinfection rate) was 31.7% and 19.2%. Geometric mean egg counts had declined from 141.3 to 63.1 and from 133.6 to 59 among those who were reinfected. The occurrence of reinfection was strongly associated with younger age in both areas. Rates of reinfection showed a strong but not significant association with male sex in area 2 (p = 0.087), but no association in area 1. These high rates of reinfection demonstrate the importance of promotion of hygiene behaviors as well as ensuring access to chemotherapy.