Age and gender effects in self‐reported urinary schistosomiasis in Tanzania

Abstract

Summaryobjectives To characterize age-gender prevalence profiles of urinary schistosomiasis according to the questionnaire responses, compare the profiles to field survey data from selected regions, and determine if the profiles varied spatially throughout Tanzania.methods In 2004, a national school-based questionnaire survey for self-reported schistosomiasis and blood in urine (BIU) was conducted in all regions of mainland Tanzania, to assist targeted mass distribution of praziquantel. Field survey data were collected in six north-western and five coastal regions using microscopic examination of urine samples for the presence of Schistosoma haematobium eggs and assessment of micro-haematuria with chemical reagent strips. Bayesian logistic regression models were created to calculate age-gender profiles adjusted for demographic and ecological covariates and spatial correlation in the questionnaire data. Separate odds ratios (OR) for age-gender effects were calculated in each administrative area.results Data were obtained from > 2.5 million schoolchildren. Boys had higher prevalence of selfreported schistosomiasis and BIU than girls. In boys, prevalence according to the questionnaire and field surveys followed similar age profiles. However, in girls, prevalence according to the field surveys increased in older age groups, but flattened out or decreased according to the questionnaire, indicating the latter underestimated prevalence in older girls. In the models, little spatial correlation was evident in the OR for the age-gender effects, suggesting that these did not vary spatially.conclusion Age-gender patterns of urinary schistosomiasis were consistent in different geographical areas of Tanzania. Because the questionnaire underestimated prevalence in older girls, we propose that upward calibration of observed prevalence is done for older females only.

Preparing for national school‐based deworming in Kenya: the validation and large‐scale distribution of school questionnaires with urinary schistosomiasis

“…The lower prevalence of reported blood in urine and the poor performance of reported blood in urine in identifying infected individuals, especially among older girls, corroborate with previous studies (Red Urine Study Group 1995; Lengeler et al 2002; Clements et al 2008a). For instance, a survey among Tanzanian school children found that 28.2% of girls reported blood in urine compared with 48.6% of boys and that reported blood in urine had a sensitivity of 51.5% and a specificity of 79.2%, but sensitivity was significantly lower in girls than in boys (39.6% vs. 61.9%) (Guyatt et al 1999).…”

“…Also in Tanzania, a 2004 national questionnaire survey was administered to over 2.5 million children in 12 399 schools across the country (Clements et al 2008b). Analysis of differences of reported blood in urine by age and sex found that whilst the prevalence of S. haematobium increased with age among girls, the prevalence of reported blood in urine either flattened out or decreased, indicating the latter underestimated prevalence in older girls (Clements et al 2008a). It has been suggested that the onset of menses influences girls’ willingness to report blood in urine.…”

“…To identify schools with a high prevalence of S. haematobium , school-based questionnaires administered by teachers reliably identified high prevalence schools in a number of settings (Lengeler et al 2002; Brooker et al 2009a). Questionnaire surveys are now therefore recommended as a first step in implementing national schistosomiasis control (WHO 1995) and have to date been implemented at national or sub-national scales in Cote d’Ivoire (N’Guessan et al 2007) and Tanzania (Clements et al 2008a, b). In implementing a questionnaire survey, it is essential that parasitological validation should precede any large-scale use of questionnaires (WHO 1995, 2006).…”

Profile of bacterial and parasitic urinary infections in Saint Louis Senegal between 2000 and 2010

“…However, other investigations did not show any difference in the prevalence of schistosomiasis according to the sex (Dabo et al, 2011). It appears that the prevalence of S. haematobium changes following the season and would be higher the raining season because of ecoclimatic conditions promoting parasite transmission (Clements et al, 2008).…”

Self-Reported Prevalence and Socio-Demographic Determinants of Multiple Parasitic Infection among Schooling Adolescents in Nigeria

“…To achieve our objective, we adopted the proposition of Moestue et al [10] that the information given by students in a questionnaire is diagnostically reliable, so long as any under-or over-reporting is systematic and consistent, it could be used to identify schools where a health problem is common and where curative or preventive measures could be effectively directed. This notion has been well studied and validated for urinary schistosomiasis [16]- [18].…”