[Quality control during ultrasonographic evaluation of morbidity due to Schistosoma haematobium in Niger]. / Contrôle de qualité lors de l'évaluation échographique de la morbidité due à Schistosoma haematobium au Niger.

Within the framework of a campaign to control urinary schistosomiasis in Niger, a quality control audit was performed on ultrasonographic assessment of morbidity due to Schistosoma haematobium. The purpose of this audit was to determine variance and reproductibility of epidemiological data provided by two trained independent observers. Three parameters were studied, i.e.,: interobserver variability on matched data, interobserver variance at the community level on the same or different subjects, including some after treatment with praziquantel, and intra-observer variance. A total of 1750 ultrasound examinations were carried out on 1416 inhabitants from 10 hyperendemic villages (70 p. 100 schoolchildren) according to a slightly modified version of the WHO Cairo protocol. Inter-observer variance at the individual level was high for some elementary abnormalities of the bladder. Variance was around 20 p. 100 for the 2 main indicators, i.e. presence of at least one bladder lesion and dilatation of the upper urinary tract. At the community level, inter-observer variance was moderate and the two observers' global assessment of morbidity due to Schistosoma haematobium was the same. Variations of morbidity related to level of endemicity were given perceived in parallel. Similar findings were noted for the intra-observer variability at the individual or community level. Ultrasound examination is supposed to furnish reliable morbidity data for selecting communities at risk and scheduling treatments during schistosomiasis control programs. The results of this study show that the level of inter- and intra-observer variance in ultrasonographic assessment in Niger is compatible with this critical role.

[Preliminary evaluation of usable indicators during a control program for urinary bilharziosis in Niger]. / Evaluation préliminaire des indicateurs utilisables au cours d'un programme de lutte contre la bilharziose urinaire au Niger.

The performance of several indirect screening tests was evaluated during the start-up phase of a urinary schistosomiasis control program in Niger. Urine tests were carried out on a total of 354 children attending 3 primary schools on five consecutive days. Tests included filtration of 10 ml of urine, search for microscopic hematuria using reagent strips, and gross examination of urine. In addition a questionnaire was administered on the first day to identify signs of dysuria and hematuria. Repeat testing had a strong effect on the epidemiological profile of urinary schistosomiasis in the 3 schools. Although day-to-day counts varied greatly, egg excretion could be considered as high in all infected subjects. The screening sensitivity of urine filtration was low when the level of endemicity was moderate (up to 55 p. 100). Microscopic hematuria was common. However the sensitivity of this method was overestimated in comparison with urine filtration alone and use of reagent strips can be inconvenient. Using carefully defined diagnostic criteria, gross examination of urine was as effective as urine filtration and easier to perform. The value of the questionnaire for evaluation of morbidity was low despite relatively good performance of the diagnostic techniques. The children's responses concerning hematuria were not objective and questions concerning dysuria were poorly understood and time-consuming. In the next phase of study, these findings will be validated by ultrasound imaging.

[Continued ultrasonic follow-up of children infected with Schistosoma haematobium after treatment with praziquantel]. / Suivi échographique prolongé d'enfants infestés par Schistosoma haematobium après traitement par praziquantel.

During a Schistosoma haematobium morbidity control program in Niger, we conducted a survey to describe rhe resolution of lesions after treatment with praziquantel. to determine reinfection rates and to define retreatment schedules. 114 schoolchildren (7-15 years old) living in an hyperendemic village underwent 10 successive examinations over 34 months following an initial evaluation and the administration of 40 mg/kg of praziquantel. All children, whether apparently infected with S. haematobium or not, were treated. Egg output, microhaematuria, visual aspect of urine and abnormalities of the urinary tract by ultrasound were assessed. The initial prevalence tif infection was 74.5%. Reinfection began 5 months after treatment and the final prevalence was 47.1%. Bladder abnormalities decreased rapidly, but incompletely, probably due to reinfestation: initial prevalence: 89.5%). Their prevalence increased 8 months after treatment to 72.4% at month 34. Dilatations of the upper urinary tract regressed more slowly but constantly until the end of the study (initial prevalence: 43%; 4.6% at month 34), Three years after treatment, despite reinfection, the general morbidity level (prevalence and severity of lesions) was lower than at baseline in our cohort, which would suggest the advantage of a long interval between mass treatments in the epidemiological context of our survey.