Identifying and Evaluating Field Indicators of Urogenital Schistosomiasis-Related Morbidity in Preschool-Aged Children

Abstract

BackgroundSeveral studies have been conducted quantifying the impact of schistosome infections on health and development in school-aged children. In contrast, relatively little is known about morbidity levels in preschool-aged children (≤5 years) who have been neglected in terms of schistosome research and control. The aim of this study was to compare the utility of available point-of-care (POC) morbidity diagnostic tools in preschool versus primary school-aged children (6–10 years) and determine markers which can be used in the field to identify and quantify Schistosoma haematobium-related morbidity.Methods/Principal FindingsA comparative cross-sectional study was conducted to evaluate the performance of currently available POC morbidity diagnostic tools on Zimbabwean children aged 1–5 years (n=104) and 6–10 years (n=194). Morbidity was determined using the POC diagnostics questionnaire-based reporting of haematuria and dysuria, clinical examination, urinalysis by dipsticks, and urine albumin-to-creatinine ratio (UACR). Attributable fractions were used to quantify the proportion of morbidity attributable to S. haematobium infection. Based on results of attributable fractions, UACR was identified as the most reliable tool for detecting schistosome-related morbidity, followed by dipsticks, visual urine inspection, questionnaires, and lastly clinical examination. The results of urine dipstick attributes showed that proteinuria and microhaematuria accounted for most differences between schistosome egg-positive and negative children (T=-50.1; p<0.001). These observations were consistent in preschool vs. primary school-aged children.Conclusions/SignificancePreschool-aged children in endemic areas can be effectively screened for schistosome-related morbidity using the same currently available diagnostic tools applicable to older children. UACR for detecting albuminuria is recommended as the best choice for rapid assessment of morbidity attributed to S. haematobium infection in children in the field. The use of dipstick microhaematuria and proteinuria as additional indicators of schistosome-related morbidity would improve the estimation of disease burden in young children.

Assessing the prevalence of urogenital schistosomaisis and transmission risk factors amongst school-aged children around Mapé dam ecological suburbs in Malantouen district, Cameroon

“…Our reported schistosomiasis prevalence of 16.6% was similar to Akouala et al [7, 22], but low compared to Nkengazong et al at Barombidam [23–25] in 2013 (69.17%). This study is consistent previous studies in addition to school absentiesm and poor performance [3, 5, 15, 21, 22, 26–28]. Our findings revealed that epidemio-ecological factors responsible for persistent transmission dynamics included the presence/contact with the dam, traditional fisherman culture, interation between animal-human contaminated Mape dam source of water driking, favourable subtropical climate, landscape of region, residence for at least one year and 2 km surrounding villages, and no access to Praziquantel or other antihelmintic agents for the last 2 months [2, 9, 15, 18, 22, 28, 29].…”

Putting the treatment of paediatric schistosomiasis into context

“…In studies involving preschool-aged children in sub-Saharan Africa, including our own in Zimbabwe (for example [11, 16]), the challenge during treatment of infants and younger children has been the lack of an appropriate child-size praziquantel tablet. When treating young children with the currently available commercial praziquantel tablets, there is a need to break them to get the correct dosage, followed by crushing them to avoid chocking, and then finally dissolving or mixing with a sweetener to reduce the bitter taste.…”

“…Therefore, disease control is still needed in the post-transmission period, in which at-risk populations are monitored. This is a problem in post-mass treatment for schistosomiasis control in the post-transmission period and so surveillance and suitable intervention are needed in areas where transmission is interrupted [10, 11]. In addition, further studies on the pathogenesis of post-transmission schistosomiasis are necessary.…”

“…In such low endemic areas, there is a need to establish new cut-offs/thresholds for diagnosis in regard to low prevalence. In addition, new diagnostic tools to support control programmes leading to and evaluating transmission interruption or even elimination of schistosomiasis need to be evaluated and scaled up in the form of an up-converting phosphor technology-based lateral flow antigen assay [11]. …”

Polymorphisms in IL-10 (-1082) and IFN-𝛾, (+874) cytokine genes associated with resistance or susceptibility to Schistosoma haematobium infection in primary school children of Mount Darwin, Zimbabwe

“…Schistosomiasis also causes anaemia by inducing pro-inflammatory cytokinemediated dyserythropoiesis, a common feature seen in anaemia associated with inflammation (Leenstra et al, 2006). Available tools to identify point-of-care diagnostics for morbidity in the pre-school age group during urogenital schistosomiasis still need to be validated (Wami et al, 2015). The pro-inflammatory cytokines such as tumour necrosis factor α (TNF-α), interleukin-1 b (IL-1b), IL-6 regulate the acute phase response which has detrimental effects if acute phase proteins such as Creactive protein are produced continuously especially during infection (Coutinho et al, 2006).…”