Effect of schistosoma haematobium infection on the cognitive functions of preschool age children and benefits of treatment from an endemic area in Zimbabwe

BACKGROUND: Schistosomiasis is known to affect the cognitive functions of children, however, but there is paucity of information on its impact on early childhood development in developing countries where the disease is endemic. This study aimed at determining the effects of schistosomiasis due to Schistosoma haematobium on early childhood development in children below 5 years old from Murewa District, Zimbabwe, including the benefits of treatment. METHODS: Preschool age children (PSAC) under the age of 5 years were screened at baseline and at 6 months post-treatment for S. haematobium infections diagnosed using the urine filtration method. Cognitive domains were assessed using the Griffith Mental Developmental Scales III on 136 PSAC. Multivariate logistic regression was used to determine the level of association between S. haematobium infection and performance in the cognitive domains adjusting for confounding factors (i.e. nutrition, hemoglobin levels, gender and age). Median Development Quotient scores of each cognitive domain at baseline and at 6 months post-treatment were compared and quantified. RESULTS: After adjusting for confounding factors, PSAC infected with S. haematobium had greater odds of having lower scores in the Foundation of Learning Domain (OR = 3.9, p = 0.008), Language and Communication Domain (OR = 3.2, p = 0.017), Eye-Hand Coordination Domains (OR = 10.7, p = 0.001), Personal-Social-Emotional Domain (19.3, p = 0.001) and in the Overall General Development Domain (7.2, p = 0.011). Improvement of cognitive performance was observed at 6 months post treatment in the following Domains; Language and Communication Domain (p = 0.003), Eye-Hand Coordination Domain (p = 0.02) and General Development Domain (p = 0.006). CONCLUSION: The study showed that S. haematobium infection in PSAC is associated with lower cognitive scores in the Foundation of Learning, Language and Communication, Eye-Hand Coordination, Personal-Social-Emotional and in the Overall General Development domains. Our results strengthen the call for inclusion of PSAC in routine deworming programs for the control of urinary schistosomiasis and the need to develop locally validated tools to monitor early child development in endemic areas where resources are limited

The association of systemic inflammation and cognitive functions of pre-school aged children residing in a Schistosoma haematobium endemic area in Zimbabwe.

BACKGROUND: Cognitive function is negatively impacted by schistosomiasis and might be caused by systemic inflammation which has been hypothesized to be one of the mechanisms driving cognitive decline, This study explored the association of systemic inflammatory biomarkers; interleukin (IL)-10, IL-6, IL-17, transforming growth factor (TGF-β), tumor necrosis factor (TNF-α), C-reactive protein (CRP) and hematological parameters with cognitive performance of preschool-aged children (PSAC) from an Schistosoma haematobium endemic area. METHODS: The Griffith III tool was used to measure the cognitive performance of 136 PSAC. Whole blood and sera were collected and used to quantify levels of IL-10, TNF-α, IL-6, TGF-β, IL-17 A and CRP using the enzyme-linked immunosorbent assay and hematological parameters using the hematology analyzer. Spearman correlation analysis was used to determine the relationship between each inflammatory biomarker and cognitive performance. Multivariate logistic regression analysis was used to determine whether systemic inflammation due to S. haematobium infection affected cognitive performance in PSAC. RESULTS: Higher levels of TNF-α and IL-6, were correlated with lower performance in the Foundations of Learning domain (r = -0.30; p < 0.001 and r = -0.26; p < 0.001), respectively. Low cognitive performance in the Eye-Hand-Coordination Domain was observed in PSAC with high levels of the following inflammatory biomarkers that showed negative correlations to performance; TNF-α (r = -0.26; p < 0.001), IL-6 (r = -0.29; p < 0.001), IL-10 (r = -0.18; p < 0.04), WBC (r = -0.29; p < 0.001), neutrophils (r = -0.21; p = 0.01) and lymphocytes (r = -0.25; p = 0.003) The General Development Domain correlated with TNF-α (r = -0.28; p < 0.001) and IL-6 (r = -0.30; p < 0.001). TGF-β, L-17A and MXD had no significant correlations to performance in any of the cognitive domains. The overall general development of PSAC was negatively impacted by S. haematobium infections (OR = 7.6; p = 0.008) and (OR = 5.6; p = 0.03) where the PSAC had higher levels of TNF-α and IL-6 respectively. CONCLUSION: Systemic inflammation and S. haematobium infections are negatively associated with cognitive function. We recommend the inclusion of PSAC into mass drug treatment programs

Recovery of enteroviruses and poliovirus in Harare sewage using the bag-mediated filtration system at the introduction of the inactivated polio vaccine in Zimbabwe

Environmental surveillance is a sensitive method for detecting circulating virus in the absence of clinical cases and is important for monitoring progress for poliovirus (PV) eradication. This study used the bag-mediated filtration system (BMFS) to determine PV and enterovirus (EV) prevalence in sewage at the transition from oral polio vaccine type 2 (OPV2) use to inactivated polio vaccine (IPV) use in Zimbabwe, and examined the correlation between environmental surveillance results and vaccination coverage of OPV. A total of 18 BMFS samples from 6 sampling sites were analysed for the presence of EV and PV via direct RT-qPCR, direct ITD (intratypic differentiation), and the WHO algorithm. EV prevalence in Harare wastewater was 88.9% (16/18) using direct RT-PCR, 61.1% (11/18) using direct ITD, and 77.8% (14/18) using the WHO algorithm. Of the 18 samples analysed using the WHO algorithm, 10 samples (55.6%) were positive for Sabin-like PV type 3 (SL3). Of these 10 samples, 2 were also positive for non-polio enteroviruses (NPEV), resulting in a total of 6 (33.3%) samples positive for NPEV and 4 negative. The sensitivity of isolation in detecting EVs in sewage was 92.9% when comparing direct RT-qPCR results to the WHO algorithm. Using direct ITD, two high-density, low-income sampling sites were negative for SL3 and one low-density, high-income sampling point was negative for SL3 using the WHO algorithm. There was a strong association between relative EV concentration and the number of OPV3 vaccine recipients (r = 0.8590; p = 0.0284) in sampled areas. This study demonstrated the ability of BMFS to detect PVs circulating in Harare wastewater at the beginning of the OPV–IPV switch and can be used to monitor potential reintroduction of wild PV or vaccine-derived PVs from endemic areas