Prevalence and intensity of the schistosomiasis situation along the Zimbabwean urban and peri-urban shoreline of lake Kariba.

OBJECTIVE To determine the prevalence and intensity of schistosomiasis in urban and peri-urban Kariba. DESIGN A cross sectional schistosomiasis survey involving screening people for infection and searching for intermediate host snails. SETTING Lake Kariba Research Station, Zimbabwe. SUBJECTS One thousand and seventy three people living in four residential areas of Kariba were screened for both Schistosoma haematobium and Schistosoma mansoni. Seventeen water contact sites along the shoreline close to the residential areas were surveyed for snails. MAIN OUTCOME MEASURES Prevalence and intensity of both S. haematobium and S. mansoni and abundance of intermediate host snails at potential transmission sites. RESULTS The prevalence of S. haematobium and S. mansoni were 7.2% and 2.1% respectively. More males (8.4%) were infected with S. haematobium than females (5.7%). There was no difference in prevalence of S. mansoni between males (2.2%) and females (2.0%). Most infections of S. haematobium were in the age group of 15 to 19 years while the age distribution pattern for S. mansoni was patchy. Most of the infections detected were light i.e. one to 100 eggs per gram of faeces or less than 50 eggs per 10 ml of urine. Few intermediate host snails for schistosomiais were collected and none of them were infected with human schistosomes. CONCLUSION Prevalence and intensity of schistosomiasis were low and therefore, the disease was not considered to be a major public health problem.