Morbidity of Schistosoma intercalatum: A controlled population based study in Edea, Cameroun
Description
The objectives of this study were to assess morbidity from Schistosoma intercalatum infection, identify associated risk factors and evaluate the relative sensitivity of alternate diagnostic methods in the known focus of Edea, Cameroon The study design combined a population-based cross-sectional survey with case control and double blind features. Cases identified in the survey by Kato-thick smear analysis of stool samples were matched, by age groups, to randomly selected stool negative subjects Repeated fecal examinations were more sensitive (51 positive) than rectal biopsy (45 positive), which has the disadvantage of discomfort, and caused severe bleeding in three subjects The sex difference was significant only in age group 10-19. Only subjects aged 10-19 had a positive physical sign (splenomegaly) associated with infection, (OR = indefinite; P =.02), although for all below age 20 there was some evidence of association (OR = 6.13; p =.06) Cases sought medical consultation during the previous year more often than did controls (P =.01). Among those who had curtailed activities within 21 to 28 days, cases had longer periods of absence from normal activities (3.0 days vs 1.76) A history of abdominal pain in the past 21 to 28 days was positively associated with infection (OR = 2.63; P =.04), with the relationship stronger below age 20 (OR = 5.89; P =.004). This relationship was much stronger among cases free of ascaris and ancylostoma (OR = 10; P =.03). A history of abdominal pain increased infrequency with intensity of infection. Under age 20, nausea and blood in stool were more frequent in cases than controls (OR respectively 2.83 and 2.25). The absolute (and relative) eosinophil count mean was higher in cases (987.7 $\pm$ 915.2) than in controls (609.3 $\pm$ 765.6)(P =.06) Rectal mucosal lesions were associated with infection (P =.02). Only cases had sand paper and/or multiple lesions (19%). Eggs were found mostly in the submucosa, but also in the mucosa of cases passing over 400 eggs per gram of stool. Follicular colitis was associated with infection (OR = 3.38; P =.01). No evidence of peri-portal fibrosis was found among 57 cases examined by ultrasonography. (Abstract shortened with permission of author.)