ABSTRACT
Objective To investigate the changes in the endemic situation of schistosomiasis in national surveillance sites of Sichuan Province, so as to provide the scientific evidence for formulating the schistosomiasis elimination strategy. Methods From 2015 to 2019, 63 national schistosomiasis surveillance sites were assigned in Sichuan Province, in which Schistosoma japonicum infections were monitored in humans, livestock, wild feces and snails. The monitoring data were descriptively analyzed. Results A total of 94 119 person-time local residents were serologically screened for S. japonicum infections in 63 national surveillance sites of Sichuan Province from 2015 to 2019, with sero-prevalence rates ranging from 1.28% to 3.11%, and the sero-positives were predominantly detected in local residents at ages of over 50 years and in farmers. A total of 94 119 person-time mobile populations were serologically screened for S. japonicum infections in the national surveillance sites during the 5-year period, with sero-prevalence of 1.10% to 1.59%. There were no egg-positives identified in either local residents or mobile populations. Among the 6 126 herd-time livestock detected, no egg-positives were identified, and no S. japonicum infection was detected in the 205 wild feces. Snail survey was performed covering an area of 8 484.08 hm2, and 724.80 hm2 snail habitats were identified, including 2.43 hm2 emerging snail habitats and 63.00 hm2 re-emerging snail habitats. The mean occurrence of frames with snails was 6.87% to 19.63%, and the mean density of living snails was 0.18 to 0.62 snails/0.1 m2 in the national surveillance sites of Sichuan Province from 2015 to 2019; however, no S. japonicum infection was detected in snails. Conclusions The endemic situation of schistosomiasis has reduced to the lowest level in Sichuan Province; however, there is a rise in snail habitats, and there is still a risk of schistosomiasis resurgence. Further improvements of the surveillance system for schistosomiasis are required to achieve the goal of schistosomiasis elimination in Sichuan Province as soon as possible.
ABSTRACT
ObjectiveTo analyze the influencing factors of health-related behaviors for schistosomiasis prevention and control among primary and secondary school students in Sichuan Province using a multilevel and multivariate logistic model, so as to provide the theoretical evidence for developing the schistosomiasis prevention and control strategy among primary and secondary school students in Sichuan Province. MethodsA multi-stage sampling was conducted among 63 schistosomiasis-endemic counties (districts) in Sichuan Province. Five endemic townships were sampled from each county (district), and 100 Grade 4 to 6 students in each primary school and 100 Grade 1 to 3 students in each secondary school were sampled from each township as the study subjects. The health-related behaviors for schistosomiasis prevention and control were investigated using a questionnaire survey, and factors affecting infested water contact behaviors were identified using univariate and multilevel logistic analyses. Results Among the 62 200 questionnaires distributed, there were 59 134 recovered, and 56 510 were qualified. The qualified 56 510 respondents included 22 955 secondary school students and 33 555 primary school students, and 28 297 male students and 28 213 females. A higher proportion of infested water contacts was seen in male students than in females (P < 0.001), and the students living in heavily endemic areas had a higher proportion of infested water contacts than those in mildly endemic areas (P < 0.001). In addition, there was no significant difference in the proportion of infested water contacts between primary and secondary school students (P >0.05). Multilevel and multivariate logistic analyses revealed a lower proportion of infested water contacts with the increase of knowledge, belief and self-efficacy levels (P < 0.001), and there was a cluster of infested water contacts among students at a county scale (P < 0.001). Conclusions There is a cluster of infested-water contact behaviors among primary and secondary school students at a county scale in Sichuan Province. Individual and environmental factors should be considered during the formulation of health education strategy and interventions for schistosomiasis among primary and secondary school students.
ABSTRACT
Objective To analyze the risk of re-emergence of Oncomelania snail(O.snail) from 2015 to 2019, in order to improve the effectiveness of snail control. Methods Collection of report forms and schistosomiasis surveillance data was carried out from 2015 to 2019, and analyzed retrospectively. Results The area of snail-emergence was 6 241.98 hm2 during 2015-2019, 44.29、4 610.18、813.92、446.09 and 327.50 hm2 respectively, for each corresponding year.Among the re-emergence areas, flat-ground subtype was 1 185.49 hm2(18.99%), hilly subtype was 2 536.58 hm2(40.64%), and mountain subtype was 2 519.91 hm2(40.37%).The top 5 cities with O.snail re-emergence areas were Liangshanzhou(2016), Ya′an(2016), Deyang(2016), Meishan(2016), and Meishan(2017).The top 5 disticts with O.snail re-emergence areas were Renshou, Puge, Lushan, Tianquan and Dechang. Conclusion The re-emergence of O.snail attributes to several factors, such as low quality of annual snail survey, unitary method of elimination and complexity of snail habit environment.Surveillance and supervision on the sources of infection and snail spreading should continue with exploration of new method in eliminating snails especially in hilly regions.
ABSTRACT
Objective To investigate the epidemic factors of schistosomiasis in wetlands in Sichuan Province, so as to provide scientific evidence for the prevention and control of schistosomiasis in wetlands. Methods The artificial and natural wetlands were selected from Sichuan Province, and the relevant data regarding wetlands were collected. Routine snail survey, investigation on human morbidity due to schistosomiasis, snail diffusion experiments, questionnaire survey, determination of water infectivity and retrospective survey were conducted. Results In Sichuan Province, the mean densities of living snails were 0.003 snails/0.1 m2 and 2.033 snails/0.1 m2 in the upper and lower reaches of the Meiwan Reservoir wetlands, 0.08 snails/0.1 m2 in the Jinyan Lake of Guanghan City, 0.21 snails/0.1 m2 in Muhe River of Guanghan City, and 0.02 snails/0.1 m2 prior to the construction of Qiong-hai wetland park in Xichang City in 2015. Artificial simulation experiments showed that the largest distance of snail diffusion in water was 2 000 m. There were 8.80% (41/466) of subjects that lived neighboring wetlands, worked in wetlands and visited wet-lands having infested water contact behaviors. A total of 690 sentinel mice were assigned, and no Schistosoma japonicum infection was detected in the 677 mice dissected. Retrospective survey showed that the construction of the Meiwan Reservoir caused the spread of schistosomiasis in Dailing County, and snails were found in the ditches entering the Jinyan Lake and in Jinyan Lake areas 5 years following the construction of the Jinyan Lake in Guanghan City, with S. japonicum -infected snails detected in the ditches entering the Jinyan Lake. Conclusions O. hupensis snails are found in some wetlands in Sichuan Province. Protection of wetlands and snail control with environmental improvements are recommended for the prevention of snail importation in natural wetlands, while in artificial wetlands, thorough snail control is recommended during the construction of the wetlands because of the likelihood of snail importation via water systems. In addition, both natural and artificial wetlands require long-term systematic surveillance of schistosomiasis.
ABSTRACT
Objective To build a schistosomiasis transmission risk surveillance system in Sichuan Province, so as to provide technical support for facilitating the progress towards schistosomiasis elimination in the province. Methods The surveillance sites for schistosomiasis transmission risk were assigned in 63 endemic counties (districts) of 11 cities (prefectures) in Sichuan Province. During the period from 2015 through 2018, wild feces contamination, the sources of Schistosoma japonicum infections (fever patients, livestock and wild animals), water infectivity in key settings, snail distribution in key settings, and snail breeding risk (snail importation and spread, floating debris carrying snails and snail breeding in ecological wetlands) were monitored in the surveillance sites. Results From 2015 to 2018, a total of 1 636 wild faces were detected in Sichuan Province, and 3 faces were positive for S. japonicum, with a 0.18% positive rate; among 3 995 livestock and 59 wild mice monitored, no S. japonicum infection was detected. A total of 49 414 fever patients were monitored in 2018, and 493 were seropositive for S. japonicum infection; then, 445 seropositives were subjected to stool examinations, and no egg-positives were found. From 2010 to 2018, a total of 93 sentinel sites were assigned, and 3 994 sentinel mice were placed for monitoring the water infectivity, with one S. japonicum-infected mouse detected. Between 2015 and 2018, a total of 4 156 key settings were investigated covering an area of 1 998.46 hm2, and 668 settings were detected with snails (16.07%), covering an area of 193.26 hm2; 497 suspected settings with a likelihood of snail importation with plant introduction were monitored from 2017 to 2018, and 65 settings with snails were found with 2 673 snails captured; 593 sites were assigned to collect the floating debris from 2017 to 2018, and 9 191.39 kg floating debris were collected with 186 snails captured; 4 wetlands were monitored for the risk of schistosomiasis transmission from 2013 to 2015, and snail breeding was found in 2 wetlands. No S. japonicum infection was identified in snails captured from all surveillance sites. Conclusions A sensitive and effective schistosomiasis transmission risk surveillance system has been successfully established in Sichuan Province. There is still a risk of schistosomiasis transmission risk in local areas of Sichuan Province. Therefore, the integrated schistosomiasis control measures with emphasis on the control of the source of S. japonicum infections should be further intensified, and snail monitoring and control and monitoring and control of schistosomiasis in wetlands should be also intensified.
ABSTRACT
Objective To explore the integrated schistosomiasis control model in mountainous and hilly endemic regions, so as to provide insights into the development of the schistosomiasis elimination strategy. Methods Five hilly and mountainous areas endemic for schistosomiasis were selected as the integrated control demonstration areas in Sichuan Province from 2011 to 2015. According to the epidemic characteristics, economic levels and overall development planning of the demonstration areas, the goals, strategies and measures were developed, and the effectiveness of schistosomiasis control was evaluated following implementation of the integrated control. Results The support system of the integrated schistosomiasis control model was built in the integrated control demonstration areas in Sichuan Province from 2011 to 2015, and five ecological, industrialized and sustainable development models of integrated schistosomiasis control were developed, including integration of balancing rural and urban development, systematic ecological improvement, intensified ecological agriculture, scientific management and health education of schistosomiasis control and ecological ethnic circular economy. Since the implementation of the integrated schistosomiasis control model, the snail habitats were completely changed. Until 2015, 92.0% of all historical areas with snails were managed, the coverage of safe drinking water was 100.0%, and more than 95.0% of the livestock were fenced. The coverage of sanitary toilets increased by 93.0%, 96.8%, 78.8%, 87.1% and 82.0% from 2011 to 2015, respectively, and the farmers’mean yearly income increased by 32.7% in the demonstration areas. From 2011 to 2015, the seroprevalence of human Schistosoma japonicum infections reduced from 3.1% in 2011 to 1.6% in 2015 in the demonstration areas, and no egg-positives were identified. In addition, the number of fenced bovines reduced year by year, and no egg-positives were detected. The areas of snail habitats were 398.7, 108.2 hm2 and 52.9 hm2 in the demonstration areas from 2011 to 2013, with no infected snails found, and no snails were detected since 2014. The awareness of schistosomiasis control knowledge and percentage of correct behavior formation increased year by year among residents in the demonstration areas from 2011 to 2015. Conclusions The five integrated schistosomiasis control models meet the needs of the current schistosomiasis control activities in mountainous and hilly endemic areas of Sichuan Province, and achieve the goals of controlling the sources of S. japonicum infections, economic development, social progress and improving the ecological environment, which provides new insights into schistosomiasis elimination in the country.
ABSTRACT
Transmission control and interruption of schistosomiasis has been gradually achieved in the mountainous and hilly endemic areas with the implementation of the schistosomiasis control programmes, which are moving towards the progress of schistosomiasis elimination. As an important measure of schistosomiasis control, health education is experiencing new challenges and problems in the new situation, and conventional health education of schistosomiasis control has already failed to meet the needs of socioeconomic and cultural development and the increasing changes of human production and life styles in the endemic areas. Therefore, a precision health education model for schistosomiasis control is of great need to be established to highly effectively promote the implementation of schistosomiasis control measures. This review summarizes the important role of health education in schistosomiasis control in mountainous and hilly endemic areas, and describes the new health education model based on optimization of the policy environment and creation of the community atmosphere according to the changes in the endemic situation of schistosomiasis and requirements of the schistosomiasis control target, so as to promote the precision and sustainable implementation of health education and health promotion in schistosomiasis control.
ABSTRACT
Objective To investigate the epidemic factors of schistosomiasis in wetlands in Sichuan Province, so as to provide scientific evidence for the prevention and control of schistosomiasis in wetlands. Methods The artificial and natural wetlands were selected from Sichuan Province, and the relevant data regarding wetlands were collected. Routine snail survey, investigation on human morbidity due to schistosomiasis, snail diffusion experiments, questionnaire survey, determination of water infectivity and retrospective survey were conducted. Results In Sichuan Province, the mean densities of living snails were 0.003 snails/0.1 m2 and 2.033 snails/0.1 m2 in the upper and lower reaches of the Meiwan Reservoir wetlands, 0.08 snails/0.1 m2 in the Jinyan Lake of Guanghan City, 0.21 snails/0.1 m2 in Muhe River of Guanghan City, and 0.02 snails/0.1 m2 prior to the construction of Qiong-hai wetland park in Xichang City in 2015. Artificial simulation experiments showed that the largest distance of snail diffusion in water was 2 000 m. There were 8.80% (41/466) of subjects that lived neighboring wetlands, worked in wetlands and visited wet-lands having infested water contact behaviors. A total of 690 sentinel mice were assigned, and no Schistosoma japonicum infection was detected in the 677 mice dissected. Retrospective survey showed that the construction of the Meiwan Reservoir caused the spread of schistosomiasis in Dailing County, and snails were found in the ditches entering the Jinyan Lake and in Jinyan Lake areas 5 years following the construction of the Jinyan Lake in Guanghan City, with S. japonicum -infected snails detected in the ditches entering the Jinyan Lake. Conclusions O. hupensis snails are found in some wetlands in Sichuan Province. Protection of wetlands and snail control with environmental improvements are recommended for the prevention of snail importation in natural wetlands, while in artificial wetlands, thorough snail control is recommended during the construction of the wetlands because of the likelihood of snail importation via water systems. In addition, both natural and artificial wetlands require long-term systematic surveillance of schistosomiasis.
ABSTRACT
Objective To build a schistosomiasis transmission risk surveillance system in Sichuan Province, so as to provide technical support for facilitating the progress towards schistosomiasis elimination in the province. Methods The surveillance sites for schistosomiasis transmission risk were assigned in 63 endemic counties (districts) of 11 cities (prefectures) in Sichuan Province. During the period from 2015 through 2018, wild feces contamination, the sources of Schistosoma japonicum infections (fever patients, livestock and wild animals), water infectivity in key settings, snail distribution in key settings, and snail breeding risk (snail importation and spread, floating debris carrying snails and snail breeding in ecological wetlands) were monitored in the surveillance sites. Results From 2015 to 2018, a total of 1 636 wild faces were detected in Sichuan Province, and 3 faces were positive for S. japonicum, with a 0.18% positive rate; among 3 995 livestock and 59 wild mice monitored, no S. japonicum infection was detected. A total of 49 414 fever patients were monitored in 2018, and 493 were seropositive for S. japonicum infection; then, 445 seropositives were subjected to stool examinations, and no egg-positives were found. From 2010 to 2018, a total of 93 sentinel sites were assigned, and 3 994 sentinel mice were placed for monitoring the water infectivity, with one S. japonicum-infected mouse detected. Between 2015 and 2018, a total of 4 156 key settings were investigated covering an area of 1 998.46 hm2, and 668 settings were detected with snails (16.07%), covering an area of 193.26 hm2; 497 suspected settings with a likelihood of snail importation with plant introduction were monitored from 2017 to 2018, and 65 settings with snails were found with 2 673 snails captured; 593 sites were assigned to collect the floating debris from 2017 to 2018, and 9 191.39 kg floating debris were collected with 186 snails captured; 4 wetlands were monitored for the risk of schistosomiasis transmission from 2013 to 2015, and snail breeding was found in 2 wetlands. No S. japonicum infection was identified in snails captured from all surveillance sites. Conclusions A sensitive and effective schistosomiasis transmission risk surveillance system has been successfully established in Sichuan Province. There is still a risk of schistosomiasis transmission risk in local areas of Sichuan Province. Therefore, the integrated schistosomiasis control measures with emphasis on the control of the source of S. japonicum infections should be further intensified, and snail monitoring and control and monitoring and control of schistosomiasis in wetlands should be also intensified.
ABSTRACT
Objective To explore the integrated schistosomiasis control model in mountainous and hilly endemic regions, so as to provide insights into the development of the schistosomiasis elimination strategy. Methods Five hilly and mountainous areas endemic for schistosomiasis were selected as the integrated control demonstration areas in Sichuan Province from 2011 to 2015. According to the epidemic characteristics, economic levels and overall development planning of the demonstration areas, the goals, strategies and measures were developed, and the effectiveness of schistosomiasis control was evaluated following implementation of the integrated control. Results The support system of the integrated schistosomiasis control model was built in the integrated control demonstration areas in Sichuan Province from 2011 to 2015, and five ecological, industrialized and sustainable development models of integrated schistosomiasis control were developed, including integration of balancing rural and urban development, systematic ecological improvement, intensified ecological agriculture, scientific management and health education of schistosomiasis control and ecological ethnic circular economy. Since the implementation of the integrated schistosomiasis control model, the snail habitats were completely changed. Until 2015, 92.0% of all historical areas with snails were managed, the coverage of safe drinking water was 100.0%, and more than 95.0% of the livestock were fenced. The coverage of sanitary toilets increased by 93.0%, 96.8%, 78.8%, 87.1% and 82.0% from 2011 to 2015, respectively, and the farmers’mean yearly income increased by 32.7% in the demonstration areas. From 2011 to 2015, the seroprevalence of human Schistosoma japonicum infections reduced from 3.1% in 2011 to 1.6% in 2015 in the demonstration areas, and no egg-positives were identified. In addition, the number of fenced bovines reduced year by year, and no egg-positives were detected. The areas of snail habitats were 398.7, 108.2 hm2 and 52.9 hm2 in the demonstration areas from 2011 to 2013, with no infected snails found, and no snails were detected since 2014. The awareness of schistosomiasis control knowledge and percentage of correct behavior formation increased year by year among residents in the demonstration areas from 2011 to 2015. Conclusions The five integrated schistosomiasis control models meet the needs of the current schistosomiasis control activities in mountainous and hilly endemic areas of Sichuan Province, and achieve the goals of controlling the sources of S. japonicum infections, economic development, social progress and improving the ecological environment, which provides new insights into schistosomiasis elimination in the country.
ABSTRACT
Transmission control and interruption of schistosomiasis has been gradually achieved in the mountainous and hilly endemic areas with the implementation of the schistosomiasis control programmes, which are moving towards the progress of schistosomiasis elimination. As an important measure of schistosomiasis control, health education is experiencing new challenges and problems in the new situation, and conventional health education of schistosomiasis control has already failed to meet the needs of socioeconomic and cultural development and the increasing changes of human production and life styles in the endemic areas. Therefore, a precision health education model for schistosomiasis control is of great need to be established to highly effectively promote the implementation of schistosomiasis control measures. This review summarizes the important role of health education in schistosomiasis control in mountainous and hilly endemic areas, and describes the new health education model based on optimization of the policy environment and creation of the community atmosphere according to the changes in the endemic situation of schistosomiasis and requirements of the schistosomiasis control target, so as to promote the precision and sustainable implementation of health education and health promotion in schistosomiasis control.
ABSTRACT
Objective To improve the classic Vannucci method for establishing a model of hypoxic-ischemic brain damage in the neonatal mice. Methods Postnatal day 11 KM mice were randomly assigned into normal control group ( N group, n=20) and hypoxic-ischemic brain damage group (HIBD group, n=160). For the HIBD group, the left common carotid artery of mice was ligated and exposed to hypoxia according to different conditions in the groups C1-C8, then com-pared the mortality and the success rates of all groups. TTC staining and relative infarct volume was measured to select the most stable conditions of modeling. In all groups, the growth and development of mice were evaluated by body weight growth curve at different time points after modeling. Longa test, grip test and hanging test were porformed to assess the neu-romotor function. HE staining was used to detect cerebral neuronal pathological changes. Results Neonatal mouse models of hypoxic-ischemic brain damage were established by the left common carotid artery ligation and hypoxia for 45 min under conditions of 8% O2 and 35℃, which resulted a low mortality rate (8. 3%) and high success rate (47. 92%). Compared with the normal group, mice of the HIBD group grew slowly in body weight and showed severe motor dysfunction. The liga-tion side of cerebral artery showed infarction area which accounted for 7. 76 ± 0. 70% of the total brain. The cortex and hip-pocampus of ligated brain tissue showed neuron degeneration and necrosis. Conclusions The neonatal mouse model of hy-poxic-ischemic brain damage is successfully established by our modified method , i. e. to ligate the left common carotid ar-tery and to expose the mice to hypoxia at 8% O2 and 35℃ for 45 min. This model provides a liable and stable experimental animal model for research of neonatal hypoxic-ischemic brain damage.
ABSTRACT
Objective To improve the classic Vannucci method for establishing a model of hypoxic-ischemic brain damage in the neonatal mice. Methods Postnatal day 11 KM mice were randomly assigned into normal control group ( N group, n=20) and hypoxic-ischemic brain damage group (HIBD group, n=160). For the HIBD group, the left common carotid artery of mice was ligated and exposed to hypoxia according to different conditions in the groups C1-C8, then com-pared the mortality and the success rates of all groups. TTC staining and relative infarct volume was measured to select the most stable conditions of modeling. In all groups, the growth and development of mice were evaluated by body weight growth curve at different time points after modeling. Longa test, grip test and hanging test were porformed to assess the neu-romotor function. HE staining was used to detect cerebral neuronal pathological changes. Results Neonatal mouse models of hypoxic-ischemic brain damage were established by the left common carotid artery ligation and hypoxia for 45 min under conditions of 8% O2 and 35℃, which resulted a low mortality rate (8. 3%) and high success rate (47. 92%). Compared with the normal group, mice of the HIBD group grew slowly in body weight and showed severe motor dysfunction. The liga-tion side of cerebral artery showed infarction area which accounted for 7. 76 ± 0. 70% of the total brain. The cortex and hip-pocampus of ligated brain tissue showed neuron degeneration and necrosis. Conclusions The neonatal mouse model of hy-poxic-ischemic brain damage is successfully established by our modified method , i. e. to ligate the left common carotid ar-tery and to expose the mice to hypoxia at 8% O2 and 35℃ for 45 min. This model provides a liable and stable experimental animal model for research of neonatal hypoxic-ischemic brain damage.