Schistosomiasis mansoni and geo-helminthiasis in school children in the Dembia plains, Northwest Ethiopia

Abstract: A cross sectional survey was conducted in twelve elementary schools in the Dembia Plains, Northwest Ethiopia, in 1995. Faecal specimens of 1282 pupils were examined for schistosoma mansoni and the major soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura, the hookworms) by the Kato thick smear technique. Infection due to A. lumbricoides was registered in all schools and was the most prevalent (41.3%, range:4.4%-70.8%)followed by Schistosoma mansoni (35.8%, range:19.5%-62.2%),the hookworms (22.8%, range:2.5%-35.1%), and Trichuris trichiura infection (16.5%, range:9.2%-31.6%). Double, triple and quadruple infections were encountered in 693 (54.0%), 90 (7.1%) and 4 (0.3%) specimens, respectively. Most of the double infections were a combination of S. mansoni and A. lumbricoides (20.3%). The highest prevalence for a single infection was recorded for A. lumbricoides (139=10.9%). Infection was found in all ages and appeared to increase with age in schistosomiasis and ascariasis cases only. There was no significant difference in infection rates between the sexes. The intensity of infection was generally higher for A. lumbricoides and S. mansoni. The rate of heavy infection was high for A. lumbricoides (32.4%) and 23.7% of the infected children harboured moderate S. mansoni infection. Neither age nor sex was related to egg output except for S. mansoni which showed a marked agerelated difference (F=3.13, p<0.005). The relationships between prevalence and intensity of infection gave a positive linear relationship for S. mansoni (r=0.84) and A. lumbricoides (r=0.93). The high infection rate observed in this study signifies the need for timely control measures in the area. [Ethiop. J. Health Dev. 1998;12(3):237-244]