Urban Schistosoma mansoni near Enyau river in Arua town, Uganda.

Using the Kato Katz method for quantification of parasitic eggs in faeces, 500 individuals aged between 4 and 50 years, living along River Enyau, half a kilometre from Arua town, were studied to assess the prevalence of Schistosoma mansoni in the population. The overall prevalence of Schistosoma mansoni infection was 62%. The infection was highest among school children (71.1%, i.e. 199 out of 280). Villagers who lived along the immediate vicinity of the river had a 62.8% prevalence of infection (98 out of 156). School teachers and the members of their families had the lowest infection rate (20.3% i.e. 13 out of 64). The geometric mean egg output for males and females in the community studied was 203 and 179 eggs per gram of stool, respectively. 206 (41%) out of 500 individuals had mixed infections of S. mansoni and hookworms. The rate of orally transmitted intestinal helminths like Trichuris trichiura was very low (0.8%). Ascaris lumbricoides eggs were not found.

Transmission of Schistosoma mansoni in Rhino Camp, Uganda.

Non-participant observations totalling 204 hours relevant to the transmission of Schistosoma mansoni infection were carried out in Rhino Camp at the shores of Albert Nile in North Uganda. A cross-sectional study of 636 individuals from Rhino Camp revealed a prevalence of S. mansoni infection of 77.8%. Occupational and domestic purposes were the most important reasons for water contact, whereas recreational purposes ranked lower and mainly concerned children. Both sexes were equally active in water contacts. A distinct preference of Nile water was noted despite availability of borehole water in the area. It is concluded that control measures against schistosomiasis have to take into consideration that water contact for recreational purposes might be minimized, whereas it is expected to be extremely difficult to reduce occupational and domestic water contacts.

PIP: Rhino Camp is one of the most important fishing and farming villages along the shores of Albert Nile in West Nile Province, Uganda. Ajagoro and Diova water contact sites were selected to observe water contact activities in November 1991 for 17 days during the rainy season. Cumulatively, 204 hours of observations during all times of the day were done by 2 experienced persons. The observation period covered 12 hours a day. Water contact activities were recorded up to 10 times per hour, 11-20 times per hour, and more than 20 tines per hour. A total of 157 individuals, 5-50 years old, were interviewed about tribal origin, reasons for water contact, previous status in exile, and attitudes towards Nile water. 636 individuals consisting of 155 school children, 208 fishermen and families, 247 individuals seeking admission to the study and 26 officials provided up to 2 stool samples. Fishing and water fetching was the most frequent reason for water contact at the sites. Water activities were highest in the morning and early afternoon and decreased markedly towards the evening. Children, fishers, subsistence cultivators, business people, and civil servants were involved in water activities. Children 5-9 years old were few, but individuals 10-39 years old had the highest frequencies of water contacts. A considerable proportion of observed water contacts were made by people who had been exiled from Zaire or Sudan. Individuals 10-39 years old made water contacts almost exclusively for domestic and economic reasons. Those below 5 years old came for recreational purposes. Prevalence of S. mansoni infection was 77.8% in the cross-sectional survey performed in 636 individuals. 5.5% of those had more than 500 eggs per gram stool. Little is known about the impact of water contact activities on the intensity of schistosomiasis in the area. Therefore, further ecological research is needed for future control of schistosomiasis at the community level along the river Nile.