Morbidity due to Schistosoma mansoni among sugar-cane cutters in Zimbabwe

Quantitative determination of Schistosoma mansoni infection was carried out on 1995 cane cutters of the Hippo Valley and Triangle Sugar Estates. A total of 315 cutters were chosen for the study on the basis of S. mansoni infection and lack of anti-schistosomal chemotherapy during the previous three years. Stool consistency and blood and mucus in stool were determined for all the infected cutters. Overt and occult blood in stool was detected in a significantly high number of infected people compared to the control subjects (chi 2 p less than 0.001). However, the blood loss was found to have no anaemia-producing effect as determined by haemoglobin and red blood cell counts. Watery stool was prevalent among people with egg output exceeding 500 eggs per gram of stool. Mucus in stool was found to be more prevalent among infected people compared to the control subjects but the difference was not significant (p greater than 0.05). Symmer's periportal fibrosis (PPF) of various degrees of severity was detected in 47% of the infected people and grade one liver fibrosis was found in 7.5% of the control subjects (p less than 0.0001). Some 54.5% of those infected complained of abdominal pains compared to 35% of uninfected controls (p less than 0.01). There was a significant difference in the rate of absenteeism from work due to abdominal pains and diarrhoea among the infected and uninfected cane cutters (p less than 0.02).