Schistosoma haematobium infection and uropathies in hyperendemic and hypoendemic communities in the extreme northern province of Cameroon: Ultrasonographic, chemical reagent strip and bacteriologic correlates of morbidity
Description
The present study, carried out in heavily infected communities in northern Cameroon, was designed to determine the prevalence of urinary tract lesions and their association with Schistosoma haematobium (S.h.) infection and to assess the validity functional, parasitologic and bacteriologic parameters in the identification of persons at high risk for these lesions Schistosoma haematobium infection status, morphologic changes in the urinary tract (as detected by ultrasonography), functional and bacteriologic changes in the urine were determined on 980 persons selected randomly after stratification by age, sex and intensity of infection. Inclusion of egg-free controls from a hypoendemic area further facilitated measurement of association of lesions with bilharzial infection Lesions of the lower urinary tract were very frequent in the study population living in hyperendemic communities. Bladder wall hypertrophies (78%), bladder wall irregularities (67%) and bladder wall tumor/s (34%) were observed. History of persistent hematuria, level of current S.h. egg output, and massive proteinuria ($<$99 mg/dl) were the best predictors of these lesions. Large bladder tumors were, however, also strongly associated with excretion of nitrites (bacterial metabolites) in the urine and/or presence of significant bacteriuria. On the other hand, S.h. infection was associated with increased prevalence of positive excretion of urinary nitrites (14% in infected versus 2% in controls) and with increased risk for bacteriuria among children 5-14 year old (8% in infected versus 3% in the controls) Congestion of the upper urinary tract (UUT) was less frequent (4% for Hydroureter and 14% for hydronephrosis) and more confined to bilharzian patients (Less than 1 percent of controls were affected). The group at the highest risk included persons with combined LUT hyperplasia and evidence of bacterial superinfection, for whom prevalence of UUT congestion was more than 10 times higher than in controls Pathologic changes in LUT or UUT were very rare in persons with neither past history of chronic hematuria nor with current S.h. infection, most of whom were found in the control group from the hypoendemic area Observation of circadian variation in both S.h. urinary egg output and related functional changes (hematuria, proteinuria) have lead field investigators to focus their attention on midday voided urine. The present study has shown that testing first morning urine specimens could provide additional information (nitrite and bacteriuria) shown to be of high predictive value for severe uropathies. (Abstract shortened by UMI.)