THE USE OF MORBIDITY QUESTIONNAIRES TO IDENTIFY COMMUNITIES WITH HIGHPREVALENCES OF SCHISTOSOME OR GEOHELMINTH INFECTIONS IN TANZANIA

Parasitic infections were investigated in Morogoro Rural District,Tanz ania, between October 1992 and June 1993. A total of 4589 schoolchildr en (aged 7-17 years) from 30 primary schools was screened for infectio n with Ascaris lumbricoides, Trichuris trichiura, hookworms (3456 chil dren only), Schistosoma mansoni and S. haematobium. The children were also asked about their recent experiences of the following: diarrhoea, abdominal pain, blood in stool, perception of suffering from schistos omiasis, and worm infection and examined for spleen and liver enlargem ent. Among schools, there were correlations between the prevalence of S. mansoni infection and bloody stools, spleen enlargement and liver e nlargement, and between S. haematobium infection and the presence of b lood in urine. To exclude ecological explanations for the correlations , logistic regression was used to estimate the adjusted odds ratio (OR ) for each infection and each sign or symptom. No si,on or symptom was significantly associated with any geohelminth infection. Reported blo od in stool was significantly associated with S. mansoni infection (OR =1.62, P=0.045). Reported blood in urine was significantly associated with S. haematobium infection (OR=7.71, P<0.001), as was reported bloo d in stool (OR=11.52, P<0.001), indicating that presence of blood in e ither form of excreta was related to the local term for schistosomiasi s. These results support the possibility of using reported blood in st ool as a means of rapid assessment for identifying communities with a high prevalence of S. mansoni infection.