Schistosoma haematobium infection is reported to facilitate the development of urogenital diseases. Its symptoms include haematuria, dysuria and tiredness, and it may cause cognitive decline in children. The prevalence of S. haematobium infection needs to be known in endemic areas and a mass treatment programme against the disease implemented. The aim of this study was to investigate the prevalence and intensity of S. haematobium infection in ILembe and uThungulu health districts, using the major symptom, haematuria, as an indicator. A total of 6 265 urine samples, from 96 rural schools, was collected for analysis using dipsticks. The prevalence of haematuria in the ILembe health district was 37% (95% CI, 35–39%) for boys and 39% (95% CI, 37–41%) for girls. The prevalence of haematuria in the uThungulu health district was 56% (95% CI, 53– 59%) and 53% (95% CI, 50–56%) for girls and boys, respectively. Light-intensity infection was the most common infection level in both health districts. A negative relationship was observed between prevalence and altitude (r = −0.262, p = 0.009); whereas, we found a slight, though significant, positive association with mid-summer temperatures (r = 0.234, p = 0.021). Associations between prevalence and distance of school to the nearest river were non-significant.

Environmental factors such as pollution, pesticide exposure and socio-demographic location have been implicated as a pressure capable of altering genetic make-up. Altered genetic sequence of genes encoding enzymes may result in single nucleotide polymorphism (SNP). Of peculiar interest is the genetic variance on the paraoxonase-1 gene induced by pre- and postnatal exposure to pesticides. SNP have been reported on the paraoxonase-1 gene and post-xenobiotic exposure and are presumed to alter gene sequence and ultimately enzymatic activity. The altered enzymatic activity may facilitate neurodevelopment disorders. Autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) are among the neurodevelopment disorders of which prevalence is concurrently associated with increasing environmental xenobiotic exposure. The variance on xenobiotic metabolising genes is associated with altered neurodevelopment outcome and ultimately altered neurobehavioural outcome. Prime interests of this systematic review were to establish an understanding of the sequences on the paraoxonase-1 gene associated with adverse neurobehavioural outcome. An in-depth literature search was conducted using the term combination “pesticide exposure, pre- and postnatal exposure, organophosphates/organophosphorus, single nucleotide polymorphism, paraoxonase-1 (PON-1), neurodevelopment/neurobehavioural outcome in child/infant”. Articles published from the year 2000 to 2018 were considered for review. The result showed that variance on the PON1-108 and 192 alleles could be implicated in the development of altered neurobehavioural outcomes.

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