Intestinal Helminthes Infections and Re-Infections with Special Emphasis on Schistosomiasis Mansoni in Waja, North Ethiopia

Abstract

To determine the status of infection and re-infection caused by Schistosoma mansoni in a small town of Waja, northern Ethiopia, stool samples were collected from primary school children in two rounds (in mid June and mid September 2004) and were examined using the Kato thick smear method. In addition, water bodies that might serve as biotopes for the intermediate host snails were located and searched using scoops. During the first survey, the prevalence of S. mansoni among the 224 children (119 male and 105 females) sampled was 27.1%. S. mansoni prevalence increased from 27.1% to 36.4% (P< 0.05), during the 2nd survey, three months following the treatment of the positive cases. Similarly, an increase in the prevalence of T. trichiura was observed (from 16 to 30.7%), whereas that of Ascaris lumbricoides decreased during the second survey (from 50 to 42.8%) (P<0.003). S. mansoni prevalence was higher in males than in females during both surveys (35.3% vs 18.1% 1st survey; and 51% vs 32.6% in the 2nd survey (P < 0.05). The profile of infection with S. mansoni in the various age groups showed a peak infection rate in the age group 15-19 years (41.2%) followed by the age group 10-14 (24%) and the least affected were the 5-9 age groups (18.5%) (P<0.002). The risk of decreasing schistosomiasis mansoni is discussed and the possible prevention and control measures are suggested.

Key words: Schistosoma mansoni, Infection, Re-infection, Intensity