Association of schistosomiasis and risk of prostate cancer development in residents of Murehwa rural community, Zimbabwe

Schistosomiasis transmission in Zimbabwe: Modelling based on machine learning

Zimbabwe, located in Southern Africa, faces a significant public health challenge due to schistosomiasis. We investigated this issue with emphasis on risk prediction of schistosomiasis for the entire population. To this end, we reviewed available data on schistosomiasis in Zimbabwe from a literature search covering the 1980-2022 period considering the potential impact of 26 environmental and socioeconomic variables obtained from public sources. We studied the population requiring praziquantel with regard to whether or not mass drug administration (MDA) had been regularly applied. Three machine-learning algorithms were tested for their ability to predict the prevalence of schistosomiasis in Zimbabwe based on the mean absolute error (MAE), the root mean squared error (RMSE) and the coefficient of determination (R2). The findings revealed different roles of the 26 factors with respect to transmission and there were particular variations between Schistosoma haematobium and S. mansoni infections. We found that the top-five correlation factors, such as the past (rather than current) time, unsettled MDA implementation, constrained economy, high rainfall during the warmest season, and high annual precipitation were closely associated with higher S. haematobium prevalence, while lower elevation, high rainfall during the warmest season, steeper slope, past (rather than current) time, and higher minimum temperature in the coldest month were rather related to higher S. mansoni prevalence. The random forest (RF) algorithm was considered as the formal best model construction method, with MAE = 0.108; RMSE = 0.143; and R2 = 0.517 for S. haematobium, and with the corresponding figures for S. mansoni being 0.053; 0.082; and 0.458. Based on this optimal model, the current total schistosomiasis prevalence in Zimbabwe under MDA implementation was 19.8%, with that of S. haematobium at 13.8% and that of S. mansoni at 7.1%, requiring annual MDA based on a population of 3,003,928. Without MDA, the current total schistosomiasis prevalence would be 23.2%, that of S. haematobium 17.1% and that of S. mansoni prevalence at 7.4%, requiring annual MDA based on a population of 3,521,466. The study reveals that MDA alone is insufficient for schistosomiasis elimination, especially that due to S. mansoni. This study predicts a moderate prevalence of schistosomiasis in Zimbabwe, with its elimination requiring comprehensive control measures beyond the currently used strategies, including health education, snail control, population surveillance and environmental management.

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.

Interleukin-13 rs1800925/-1112C/T promoter single nucleotide polymorphism variant linked to anti-schistosomiasis in adult males in Murehwa District, Zimbabwe

Background

Chronic schistosomiasis is predominantly induced through up-regulation of inflammatory cytokines such as interleukin (IL)-13. IL-13 may contribute to the disease outcomes by increasing eosinophil infiltration thereby promoting fibrosis. IL-13 may act as an immunosuppressive inflammatory cytokine that may promote carcinogenesis and also may offer protection against schistosomiasis thereby reducing risk of schistosome infections. Our study evaluated the frequency of the IL-13 rs1800925/-1112 C/ T promoter single nucleotide polymorphisms (SNPs) among schistosomiasis infected individuals and assessed the association of the variants on IL-13 cytokine levels. We also investigated IL-13 rs1800925 polymorphisms on prostate-specific antigen levels as an indicator for risk of prostate cancer development.

Methodology

The study was cross-sectional and included 50 schistosomiasis infected and 316 uninfected male participants residing in Murehwa District, Zimbabwe. IL-13 rs1800925 SNPs were genotyped by allele amplification refractory mutation system-polymerase chain reaction. Concentrations of serum prostate-specific antigens and plasma IL-13 were measured using enzyme-linked immunosorbent assay.

Results

Frequencies of the genotypes CC, CT and TT, were 20%, 58% and 22% in schistosomiasis infected, and 18.3%, 62.1% and 19.6% in uninfected participants with no statistical differences. There were significantly (p<0.05) higher IL-13 cytokine levels among both infected and uninfected participants with the genotypes CC and CT; median 92.25 pg/mL and 106.5 pg/mL, respectively, compared to TT variant individuals; 44.78 pg/mL. Within the schistosomiasis uninfected group, CC and CT variants had significantly (p<0.05) higher IL-13 levels; median 135.0 pg/mL and 113.6 pg/mL, respectively compared to TT variant individuals; 47.15 pg/mL. Within the schistosomiasis infected group, CC, CT and TT variant individuals had insignificant differences of IL-13 level. Using logistic regression, no association was observed between prostate-specific antigen levels, IL-13 cytokine levels and IL-13 rs1800925 variants (p>0.05).

Conclusion

IL-13 rs1800925 C variant individuals had the highest IL-13 cytokine levels among the schistosomiasis uninfected suggesting that they may be protective against Schistosoma infections. There was no association between IL-13 concentrations or IL-13 rs1800925 variants and risk of prostate cancer indicating that IL-13 levels and IL-13 rs10800925 may not be utilised as biomarker for risk of prostate cancer in schistosome infections.