Prediction of trends for fine-scale spread of Oncomelania hupensis in Shanghai Municipality based on supervised machine learning models / 中国血吸虫病防治杂志

OBJECTIVE@#To predict the trends for fine-scale spread of Oncomelania hupensis based on supervised machine learning models in Shanghai Municipality, so as to provide insights into precision O. hupensis snail control.@*METHODS@#Based on 2016 O. hupensis snail survey data in Shanghai Municipality and climatic, geographical, vegetation and socioeconomic data relating to O. hupensis snail distribution, seven supervised machine learning models were created to predict the risk of snail spread in Shanghai, including decision tree, random forest, generalized boosted model, support vector machine, naive Bayes, k-nearest neighbor and C5.0. The performance of seven models for predicting snail spread was evaluated with the area under the receiver operating characteristic curve (AUC), F1-score and accuracy, and optimal models were selected to identify the environmental variables affecting snail spread and predict the areas at risk of snail spread in Shanghai Municipality.@*RESULTS@#Seven supervised machine learning models were successfully created to predict the risk of snail spread in Shanghai Municipality, and random forest (AUC = 0.901, F1-score = 0.840, ACC = 0.797) and generalized boosted model (AUC= 0.889, F1-score = 0.869, ACC = 0.835) showed higher predictive performance than other models. Random forest analysis showed that the three most important climatic variables contributing to snail spread in Shanghai included aridity (11.87%), ≥ 0 °C annual accumulated temperature (10.19%), moisture index (10.18%) and average annual precipitation (9.86%), the two most important vegetation variables included the vegetation index of the first quarter (8.30%) and vegetation index of the second quarter (7.69%). Snails were more likely to spread at aridity of < 0.87, ≥ 0 °C annual accumulated temperature of 5 550 to 5 675 °C, moisture index of > 39% and average annual precipitation of > 1 180 mm, and with the vegetation index of the first quarter of > 0.4 and the vegetation index of the first quarter of > 0.6. According to the water resource developments and township administrative maps, the areas at risk of snail spread were mainly predicted in 10 townships/subdistricts, covering the Xipian, Dongpian and Tainan sections of southern Shanghai.@*CONCLUSIONS@#Supervised machine learning models are effective to predict the risk of fine-scale O. hupensis snail spread and identify the environmental determinants relating to snail spread. The areas at risk of O. hupensis snail spread are mainly located in southwestern Songjiang District, northwestern Jinshan District and southeastern Qingpu District of Shanghai Municipality.

Expert consensus on the strategy and measures to interrupt the transmission of schistosomiasis in China / 中国血吸虫病防治杂志

Since 2015 when the transmission of schistosomiasis was controlled in China, the country has been moving towards elimination of schistosomiasis, with the surveillance-response as the main interventions for schistosomiasis control. During the period of the 13th Five-Year Plan, the transmission of schistosomiasis had been interrupted in four provinces of Sichuan, Jiangsu, Yunnan and Hubei and the prevalence of schistosomiasis has been at the historically lowest level in China. As a consequence, the goal set in The 13th Five-Year National Schistosomiasis Control Program in China is almost achieved. However, there are multiple challenges during the stage moving towards elimination of schistosomiasis in China, including the widespread distribution of intermediate host snails and complicated snail habitats, many types of sources of Schistosoma japonicum infections and difficulty in management of bovines and sheep, unmet requirements for the current schistosomiasis control program with the currently available tools, and vulnerable control achievements. During the 14th Five-Year period, it is crucial to consolidate the schistosomiasis control achievements and gradually solve the above difficulties, and critical to provide the basis for achieving the ultimate goal of elimination of schistosomiasis in China. Based on the past experiences from the national schistosomiasis control program and the challenges for schistosomiasis elimination in China, an expert consensus has been reached pertaining to the objectives, control strategy and measures for The 14th Five-Year National Schistosomiasis Control Program in China, so as to provide insights in to the development of The 14th Five-Year National Schistosomiasis Control Program in China.

Prevalence of Clonorchis sinensis infections in freshwater fish in mainland China: A meta-analysis / 中国血吸虫病防治杂志

Objective To understand the real prevalence of Clonorchis sinensis infections in the freshwater fish in mainland China, so as to provide insights into clonorchiasis control and detection of freshwater fish. Methods All literatures reporting the prevalence of C. sinensis infections in the freshwater fish, the second intermediate host of the parasite, were jointly retrieved in Chinese and English electronic databases from January 1, 2010 to December 31, 2020, including Wanfang Data, CNKI, PubMed, Web of Science, Embase and Cochrane Library. All studies were screened based on inclusion and exclusion criteria, and the quality of all enrolled literatures was evaluated. The pooled prevalence of C. sinensis infections in freshwater fish and its 95% confidence interval (CI) were estimated using the software Stata version 15.0, and subgroup analyses were performed to investigate the region-, season- and sample source-specific pooled prevalence of C. sinensis infections in freshwater fish. In addition, the sensitivity and publication bias of all included studies were analyzed. Results A total of 40 eligible literatures were included in this study, including 37 Chinese literatures and 3 English literatures, and there were 10 high-quality literatures, 27 moderate-quality literatures and 3 low-quality literatures. A total of 53 species containing 37 959 freshwater fish were reported in these 40 studies, and 73.58% (39/53) of freshwater fish species were identified with C. sinensis infections. Meta-analysis showed 23.5% [95% CI: (0.19, 0.28)] pooled prevalence of C. sinensis infections in freshwater fish in mainland China, and subgroup analyses higher prevalence of C. sinensis infections in freshwater fish in northeastern China [35.7%, 95% CI: (0.22, 0.50)] than in central [25.9%, 95% CI: (0.04, 0.48)] and southern China [20.6%, 95% CI: (0.09, 0.32)], higher prevalence of C. sinensis infections in freshwater fish sampled in spring [44.1%, 95% CI: (0.35, 0.53)] than in autumn [6.7%, 95% CI: (0.05, 0.08)] and summer [3.3%, 95% CI: (−0.01, 0.07)], and higher prevalence of C. sinensis infections in freshwater fish sampled from natural water [25.2%, 95% CI: (0.17, 0.33)] than from retail trades [22.2%, 95% CI: (0.17, 0.28)] and breeding chain [12.3%, 95% CI: (0.03, 0.22)]. However, all included studies had a publication bias with a low sensitivity. Conclusions The prevalence of C. sinensis infections is high in freshwater fish in mainland China, and there are still challenges for clonorchiasis control. Reinforcement of health education, diagnostics development and food safety supervision is recommended in future clonorchiasis control programs.

Evaluation of the measures in early warning and disposal of snail environment in a forest land in Songjiang District, Shanghai / 上海预防医学

Objective To evaluate the methods in early warning of schistosomiasis and elimination of snails in an ecological public forest in Yexie Town of Songjiang District, and provide the basis for monitoring and controlling snails in forest land in the future. Methods The monitoring data of snails, schistosomiasis and snail elimination in the public forest were collected to evaluate the effect of controlling snails. Results The area with existence of snails was found to be 10.47 hm2, and it was decreased by 98.28% after three times of snail elimination.A total of 1 904 serological tests was performed (test rate of 88.76%) with the positive rate of 0.16%.Pathogenic test result was negative in 3 subjects examined.Serological samples of 11 dogs and 1 sheep were all negative for the test.None of the 1 480 live snails tested was found to be positive in infection.The awareness rate of schistosomiasis control knowledge and behavior formation in 275 students were 98.2% and 95.3%, respectively. Conclusion The snails in the public forest in Yexie Town have been effectively controlled, but there are still scattered living snails.The measures in eliminating and monitoring of snails should be continued and strengthened.

[Surveillance of schistosomiasis 34 years after transmission interruption in Songjiang District, Shanghai City].

OBJECTIVE: To analyze the surveillance data after schistosomiasis transmission interruption from 1985 to 2018, so as to provide scientific basis for the future prevention and control of schistosomiasis. METHODS: The data pertaining to snail survey, surveillance of schistosomiasis in humans and livestock, and health education were collected and analyzed in Songjiang District after schistosomiasis transmission interruption from 1985 to 2018. RESULTS: From 1985 to 2018, there were 8 townships, 68 villages and 1 462 settings with snails in Songjiang District, covering an area of 96.399 hm2. There were 4 townships and 59 villages with snails newly identified in previously schistosomiasis non-endemic areas, with emerging snail habitats of 60.161 hm2. A total of 26 148 snails were captured, and no infections were detected. The snail habitats were mainly distributed in the river course, ditches and farmlands, which accounted for 45.28%, 33.17% and 21.55% of total snail habitats, respectively. A total of 245 955 humans were subjected to the serological test, with a positive rate of 0.03%, and 37 humans were subjected to the parasitological test, with 3 positives detected. These three egg-positives were all imported chronic cases with schistosomiasis. A total of 9 109 livestock were detected using the serological test, and no infection was found. Most of the awareness rate of schistosomiasis control knowledge and the rate of correct behavior formation were over 80% in residents and students. CONCLUSIONS: The achievements of schistosomiasis control are consolidated in Songjiang District; however, there are still risk factors of schistosomiasis transmission, including residual snails, snail diffusion and importation of external source of infection. The future surveillance of schistosomiasis should focus on snails and sources of infection.

Surveillance of schistosomiasis 34 years after transmission interruption in Songjiang District, Shanghai City / 中国血吸虫病防治杂志

Objective To analyze the surveillance data after schistosomiasis transmission interruption from 1985 to 2018, so as to provide scientific basis for the future prevention and control of schistosomiasis. Methods The data pertaining to snail survey, surveillance of schistosomiasis in humans and livestock, and health education were collected and analyzed in Songjiang District after schistosomiasis transmission interruption from 1985 to 2018. Results From 1985 to 2018, there were 8 townships, 68 villages and 1 462 settings with snails in Songjiang District, covering an area of 96.399 hm2. There were 4 townships and 59 villages with snails newly identified in previously schistosomiasis non-endemic areas, with emerging snail habitats of 60.161 hm2. A total of 26 148 snails were captured, and no infections were detected. The snail habitats were mainly distributed in the river course, ditches and farmlands, which accounted for 45.28%, 33.17% and 21.55% of total snail habitats, respectively. A total of 245 955 humans were subjected to the serological test, with a positive rate of 0.03%, and 37 humans were subjected to the parasitological test, with 3 positives detected. These three egg-positives were all imported chronic cases with schistosomiasis. A total of 9 109 livestock were detected using the serological test, and no infection was found. Most of the awareness rate of schistosomiasis control knowledge and the rate of correct behavior formation were over 80% in residents and students. Conclusions The achievements of schistosomiasis control are consolidated in Songjiang District; however, there are still risk factors of schistosomiasis transmission, including residual snails, snail diffusion and importation of external source of infection. The future surveillance of schistosomiasis should focus on snails and sources of infection.

Surveillance of schistosomiasis 34 years after transmission interruption in Songjiang District, Shanghai City / 中国血吸虫病防治杂志

Objective To analyze the surveillance data after schistosomiasis transmission interruption from 1985 to 2018, so as to provide scientific basis for the future prevention and control of schistosomiasis. Methods The data pertaining to snail survey, surveillance of schistosomiasis in humans and livestock, and health education were collected and analyzed in Songjiang District after schistosomiasis transmission interruption from 1985 to 2018. Results From 1985 to 2018, there were 8 townships, 68 villages and 1 462 settings with snails in Songjiang District, covering an area of 96.399 hm2. There were 4 townships and 59 villages with snails newly identified in previously schistosomiasis non-endemic areas, with emerging snail habitats of 60.161 hm2. A total of 26 148 snails were captured, and no infections were detected. The snail habitats were mainly distributed in the river course, ditches and farmlands, which accounted for 45.28%, 33.17% and 21.55% of total snail habitats, respectively. A total of 245 955 humans were subjected to the serological test, with a positive rate of 0.03%, and 37 humans were subjected to the parasitological test, with 3 positives detected. These three egg-positives were all imported chronic cases with schistosomiasis. A total of 9 109 livestock were detected using the serological test, and no infection was found. Most of the awareness rate of schistosomiasis control knowledge and the rate of correct behavior formation were over 80% in residents and students. Conclusions The achievements of schistosomiasis control are consolidated in Songjiang District; however, there are still risk factors of schistosomiasis transmission, including residual snails, snail diffusion and importation of external source of infection. The future surveillance of schistosomiasis should focus on snails and sources of infection.

[Historical Oncomelania hupensis snail environments in Baoshan District, Shanghai City].

OBJECTIVE: To understand the distribution and characteristics of historical Oncomelania hupensis snail environments in Baoshan District, Shanghai City, so as to provide the reference for adjusting and formulating the monitoring program of the snail situation in the future. METHODS: A retrospective survey and a field survey were conducted to collect the information of historical O. hupensis snail environments and set up the database. The distribution and characteristics of them were analyzed. RESULTS: There were 53 historical O. hupensis snail environments which distributed in three towns, and the accumulative area was 1 635 530 m2 in Baoshan District, Shanghai City. Class I, II, III and IV accounted for 73.58%, 5.66%, 16.98% and 3.77% respectively. The complete transformation (Class I and Class II) was done in 42 places which covered the area of 1 622 043 m2, in which Class I environments and Class II environments accounted for 79.25% and 99.18% of the total, respectively. CONCLUSIONS: There has been a great change in the historical O. hupensis snail environments in Baoshan District, Shanghai City. The information of the field investigation should be enriched and updated at different times to guide the investigation of O. hupensis snails in the future.

Historical Oncomelania hupensis snail environments in Baoshan District, Shanghai City / 中国血吸虫病防治杂志

Objective To understand the distribution and characteristics of historical Oncomelania hupensis snail environ-ments in Baoshan District,Shanghai City,so as to provide the reference for adjusting and formulating the monitoring program of the snail situation in the future.Methods A retrospective survey and a field survey were conducted to collect the information of historical O.hupensis snail environments and set up the database.The distribution and characteristics of them were analyzed.Re-sults There were 53 historical O.hupensis snail environments which distributed in three towns,and the accumulative area was 1 635 530 m2in Baoshan District,Shanghai City.Class Ⅰ,Ⅱ,Ⅲ and Ⅳ accounted for 73.58％,5.66％,16.98％and 3.77％re-spectively.The complete transformation(Class Ⅰ and Class Ⅱ)was done in 42 places which covered the area of 1 622 043 m2,in which Class Ⅰ environments and Class Ⅱ environments accounted for 79.25％and 99.18％of the total,respectively.Conclu-sions There has been a great change in the historical O.hupensis snail environments in Baoshan District,Shanghai City.The information of the field investigation should be enriched and updated at different times to guide the investigation of O.hupensis snails in the future.

[Risk analysis of imported schistosomiasis in Shanghai City from 2005 to 2015].

OBJECTIVE: To understand the risk situation of imported schistosomiasis and its main influencing factors in Shanghai City from 2005 to 2015. METHODS: A retrospective survey was performed, and the database was established based on the data collection of imported schistosomiasis, Oncomelania hupensis snail situation and mobile population in Shanghai City from 2005 to 2015. RESULTS: From 2005 to 2015, the mobile population in Shanghai City increased by 123.92%, which reached about 9 816 500, and 54.70% of them were located in the inner suburban districts. The accumulated areas with snails of 7.13 hm2 were found in 16 towns of 4 outer suburbs (excluding Chongming District). A total of 23 cases of imported schistosomiasis were found in Shanghai City, and the number of the imported schistosomiasis cases was on the downward trend (rs = -0.782, P = 0.004). From 2005 to 2009, 11 out of 13 imported schistosomiasis cases (84.62%) were distributed in the inner suburban districts where no O. hupensis snails were found at the same time. From 2010 to 2015, 9 out of 10 imported schistosomiasis cases (90%) were distributed in the outer suburban districts where O. hupensis snails were found at the same time. CONCLUSIONS: The number of imported schistosomiasis cases in Shanghai is on the downward trend. However, the threat of imported schistosomiasis to the prevention and control of schistosomiasis in Shanghai City should not be ignored.

[Effects of atrial excitable period on the stability of atrial fibrillation in goats].

OBJECTIVE: To investigate the effects of atrial excitable period (EP) on the stability of atrial fibrillation (AF) in goats. METHODS: Ten female goats were instrumented with epicardial electrodes patches on the left atrium (LA) free wall. AF was induced and maintained by a home-made stimulator with frequency of 50 Hz at a 1-second duration and a 2-seconds interval. The stimulator was disconnected regularly. AF-induced duration, average AF cycle length (AFCL), and atrial effective refractory period during AF (ERP(AF)) were measured; EP was calculated by AFCL-ERP(AF). RESULTS: Eight goats were studied. Persistent AF (> 24 h) could be induced in all the 8 goats within 6-16 days. When the induced AF lasted for 3-10 min or 24 h, the AFCL was 98.3 ms +/- 11.0 ms and 84.9 ms +/- 5.2 ms (P < 0.05), respectively, ERP(AF) was 90.5 ms +/- 13.2 ms and 63.0 ms +/- 4.8 ms (P < 0.05), respectively, and EP was 7.8 ms +/- 2.4 ms and 21.9 ms +/- 3.5 ms (P < 0.05), respectively. CONCLUSION: The decrease in ERP(AF) is more significant than the shortening in AFCL, resulting in the gradually widening of EP which may contribute to the perpetuation of AF.