Ramy Mohamed Ghazy1, Walid Ismail Ellakany2, Mai M Badr3, Nehad E M Taktak3, Heba Elhadad4, Sarah M Abdo5, Ayat Hagag5, Abdel Rahman Hussein6, Mohamed Mostafa Tahoun7. 1. Tropical Health Department, High Institute of Public Health, Alexandria University, Alexandria, Egypt. 2. Department of Tropical Medicine, Faculty of Medicine, Alexandria University, Alexandria, Egypt. walidellakany@yahoo.com. 3. Department of Environmental Health, High Institute of Public Health Alexandria University, Alexandria, Egypt. 4. Parasitology Department, Medical Research Institute, Alexandria university, Alexandria, Egypt. 5. Department of Medical Parasitology, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, 35516, Egypt. 6. Ministry of Health and Population, Alexandria, Egypt. 7. Department of Epidemiology, High Institute of Public Health Alexandria University, Alexandria, 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.
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.
Authors: Amal Farahat Allam; Ola Kader; Adel Zaki; Amel Youssef Shehab; Hoda Fahmy Farag Journal: Trop Med Int Health Date: 2009-03 Impact factor: 2.622
Authors: Allen G P Ross; Remigio M Olveda; Delia Chy; David U Olveda; Yuesheng Li; Donald A Harn; Darren J Gray; Donald P McManus; Veronica Tallo; Thao N P Chau; Gail M Williams Journal: J Infect Dis Date: 2014-07-28 Impact factor: 5.226
Authors: Jack E T Grimes; David Croll; Wendy E Harrison; Jürg Utzinger; Matthew C Freeman; Michael R Templeton Journal: PLoS Negl Trop Dis Date: 2014-12-04
Authors: Eric C Strunz; David G Addiss; Meredith E Stocks; Stephanie Ogden; Jürg Utzinger; Matthew C Freeman Journal: PLoS Med Date: 2014-03-25 Impact factor: 11.069
Authors: Peter J Hotez; Miriam Alvarado; María-Gloria Basáñez; Ian Bolliger; Rupert Bourne; Michel Boussinesq; Simon J Brooker; Ami Shah Brown; Geoffrey Buckle; Christine M Budke; Hélène Carabin; Luc E Coffeng; Eric M Fèvre; Thomas Fürst; Yara A Halasa; Rashmi Jasrasaria; Nicole E Johns; Jennifer Keiser; Charles H King; Rafael Lozano; Michele E Murdoch; Simon O'Hanlon; Sébastien D S Pion; Rachel L Pullan; Kapa D Ramaiah; Thomas Roberts; Donald S Shepard; Jennifer L Smith; Wilma A Stolk; Eduardo A Undurraga; Jürg Utzinger; Mengru Wang; Christopher J L Murray; Mohsen Naghavi Journal: PLoS Negl Trop Dis Date: 2014-07-24
Authors: Ryan E Wiegand; Pauline N M Mwinzi; Susan P Montgomery; YuYen L Chan; Kennedy Andiego; Martin Omedo; Geoffrey Muchiri; Michael O Ogutu; Fredrick Rawago; Maurice R Odiere; Diana M S Karanja; W Evan Secor Journal: J Infect Dis Date: 2017-12-12 Impact factor: 5.226
Authors: Tayo Alex Adekiya; Raphael Taiwo Aruleba; Babatunji Emmanuel Oyinloye; Kazeem Oare Okosun; Abidemi Paul Kappo Journal: Int J Environ Res Public Health Date: 2019-12-26 Impact factor: 3.390