Determinants of Schistosoma mansoni transmission in hotspots at the late stage of elimination in Egypt

Abstract

Background In certain settings, the prevalence and severity of schistosoma infection do not lessen despite repeated rounds of preventative chemotherapy; these areas are known as hotspots. This study aimed to investigate the role of human practices, besides environmental and malacological factors, in the maintenance of the Schistosoma mansoni infection transmission chain in hotspot areas in Egypt. Methods This cross-sectional study was conducted between July and November 2019 in Kafr El-Sheikh Governorate, Egypt. A pre-designed structured interviewing questionnaire was used to collect humanitarian data. Stool samples were collected from children aged 6–15 years on three successive days and examined using the Kato-Katz technique. Simultaneously, water and snail samples were taken from watercourses surrounding houses. Snails were identified based on their shell morphology and structure and tested for cercaria shedding. Water samples were analyzed for their physicochemical and biological characteristics. Results A total of 2259 fecal samples (1113 in summer and 1146 in fall) were collected from 861 children. About 46.9% of the participants were males, and 31.8% were aged 6–10 years. The prevalence of S. mansoni infection was higher during the summer than during the fall (19.1% vs 7.2%, respectively, P < 0.01). The intensity of infection (light, moderate, and heavy) during summer versus fall was (93.55 vs 89.38%, 6.45 vs 8.85%, and 0.00% vs 1.77%), respectively (P < 0.05). A higher prevalence of human infection was observed among males than females [OR = 1.63, 95% confidence interval (CI):1.10–2.40, P = 0.015], children aged 11–15 years than among their counterparts aged 6–10 years (OR = 2.96, 95% CI: 1.72–5.06, P < 0.001), and mothers with a low level of education (OR = 3.33, 95% CI: 1.70–6.52, P < 0.001). The main identified risk factors were contacting the main body of water-canal for washing clothes (OR = 1.81, 95% CI: 1.12–2.49, P = 0.015), land irrigation (OR = 2.56, 95% CI: 1.32–4.96, P = 0.004), water collection (OR = 2.94, 95% CI: 1.82–4.73, P < 0.001), bathing (OR = 2.34, 95% CI: 1.21–4.31, P = 0.009), and garbage disposal (OR = 2.38, 95% CI:1.38–4.12, P < 0.001). The count of Biomphalaria alexandrina was distinct between seasons (P < 0.01) in consistent with statistically significant differences in water temperature, salinity, turbidity, the total concentration of coliforms, depth, velocity, and water level (P < 0.01). The presence of grasses and duckweeds was significantly associated with snail infection (P = 0.00 l). Significant effects of water depth, pH, temperature, and total dissolved solids on snail count were also observed (P < 0.05). Conclusions The persistence of the infection is due to adoption of risky behaviors and environmental factors that enhance snail survival and infection. Schistosomiasis elimination in hotspots requires an integrated control approach that combines preventive chemotherapy with other complementary measures.

Baseline Liver Ultrasound Findings in Preschool Children From the Praziquantel in Preschoolers Trial in Lake Albert, Uganda

“…However, the finding in adjusted analysis of a relationship between maternal education and the subjective measure of periportal thickening is unexpected and contrary to the literature, in which higher maternal education is generally associated with decreased prevalence of schistosomiasis. [28][29][30] The finding may be due to chance due to the small number of children with periportal thickening. Importantly, ultrasound markers of liver morbidity were not affected by malaria seropositivity in this cohort, which makes confounding of liver morbidity by malaria status unlikely.…”

Numerical simulation of the Oncomelania snails transport attached to floating objects under different wind conditions

“…Schistosomiasis is a contagious disease that seriously endangers human health and harms socioeconomic development (Jean et al, 2022;Lo et al, 2022). Due to its high contagiousness, long communication links and wide endemic distribution (Song et al, 2017;Ghazy et al, 2022;Lv et al, 2022), schistosomiasis is listed by the World Health Organization as one of the most widely distributed parasitic diseases Liu et al, 2021). Schistosomiasis mainly infects people who have come into contact with infected water through skin and mucous membranes (Yuan et al, 2017;Zhang and Zhao, 2023).…”

Anti-fibrotic Effect of Oral Versus Intraperitoneal Administration of Gold Nanoparticles in Hepatic Schistosoma mansoni-Infected Mice

“…To limit transmission, the Egyptian Ministry of Health and Population (MoHP) improved the treatment technique far beyond what the World Health Organization (WHO) recommended. But significant transmission remained in a few loci [ 7 ].…”