Table of Content

04 November 2020, Volume 32 Issue 5

Previous Issue    Next Issue

The South-to-North Water Diversion Project and schistosomiasis: an overview

HUANG Yi-Xin

2020, 32(5):  441. 

Asbtract ( )   PDF (1030KB) ( )  

Related Articles | Metrics

Before and after the construction of the South?to?North Water Diversion Project, a number of studies have been conducted to assess the possibility of the northward spread of Oncomelania snails and schistosomiasis caused by the construction of the project, the survival and reproduction of snails moved north of their natural distribution, and the transmission of schistosomiasis by the survival snails moved north of their natural distribution. The effect of the South?to?North Water Diversion Project on the transmission of schistosomiasis is restricted along the Jiangsu section of the eastern route project of the South?to?North Water Diversion Project, and the Water Transfer Project from the Yangtze River to Han River of the middle route project of the South?to?North Water Diversion Project. It has been demonstrated the water diversion pattern via the pump stations and the ecological conditions in the water transfusion channels of the South?to?North Water Diversion Project are unlikely to result in the northward spread of Oncomelania snails or schistosomiasis, and no snails or schistosomiasis spread was found during the surveillance before and after the operation of the eastern route project of the South?to?North Water Diversion Project, and the Water Transfer Project from the Yangtze River to Han River of the middle route project of the South?to?North Water Diversion Project. Nevertheless, sustainable surveillance of Oncomelania snails along the South?to?North Water Diversion Project will provide scientific support and safety guarantee for the construction and operation of the subsequent projects.

Epidemiology, diagnosis, treatment and control measures of trichinellosis in China: an overview

YANG Xiao-Di, XU Chang-Yan, WANG Shu-Ying, GAO Hong-Yu, LIANG Jin-Bao

2020, 32(5):  448. 

Asbtract ( )   PDF (1019KB) ( )  

Related Articles | Metrics

Trichinellosis is a worldwide zoonotic parasitic disease, which may infect humans and a wide range of animals, including carnivores, herbivores and even birds. Humans get infections through ingestion of raw or semi?cooked meat or meat products containing live Trichinella larvae. Currently, this zoonosis is predominantly prevalent in southwestern, northeastern and central parts of China, which poses a great threat to human health and socioeconomic development. In addition, the emergent public health hazards caused by trichinellosis outbreaks greatly threaten human health and social stability. This review describes the current status, diagnosis, treatment and control measures of trichinellosis in China, so as to provide insights into trichinellosis control in the country.

Epidemic trend and control progress of soil-transmitted nematodiasis in Jiangsu Province

MAO Fan-Zhen, XU Xiang-Zhen, JIN Xiao-Lin, LIU Jian-Feng, NI Bi-Xian, DAI Yang, CAO Jun

2020, 32(5):  453. 

Asbtract ( )   PDF (1293KB) ( )  

Related Articles | Metrics

Soil?transmitted nematodiasis was once widely prevalent in Jiangsu Province, which seriously threatened human health and hindered socioeconomic development. The control efforts over decades resulted in a remarkable decline in the prevalence of soil?transmitted nematode human infections in Jiangsu Province, with a reduction from 59.32% in 1989 to 0.12% in 2019, and the human prevalence remains at < 0.5% since 2013. Since 1987, an integrated strategy has been adopted for the control of soil?transmitted nematodiasis in Jiangsu Province; however, the core interventions varies at different stages, which mainly include deworming, water and sanitation service improvement, health education, and monitoring and assessment. The criteria of effective soil?transmitted nematodiasis control had been achieved in all epidemic counties (districts) of Jiangsu Province by 2019. Further actions to strengthen health education and monitoring and implement precision control measures are required to consolidate the achievements of soil?transmitted nematodiasis control and eliminate the harm of soil?transmitted nematodiasis to humans. This review summarizes the epidemiology, control progress and evolution of control strategy of soil?transmitted nematodiasis in Jiangsu Province.

Strategies and studies of malaria vector control in Jiangsu Province

LI Ju-Lin, ZHOU Hua-Yun, TANG Jian-Xia, ZHU Guo-Ding, CAO Jun

2020, 32(5):  459. 

Asbtract ( )   PDF (1097KB) ( )  

Related Articles | Metrics

Malaria was one of the major infectious diseases in Jiangsu Province, where Anopheles sinensis and An. anthropophagus are main vectors for malaria transmission. Following the concerted efforts for decades, the goal of malaria elimination was achieved in Jiangsu Province in 2019, and the vector control strategy has played a vital role during the progress towards malaria elimination in Jiangsu Province. Hereby, we review the historical distribution and ecological features of An. sinensis and An. anthropophagus and describe vector control strategies at different stages of malaria control in Jiangsu Province. In addition, the advances in the research of vector biology and control in Jiangsu Province are discussed, including vector identification, strain colonization, susceptibility to malaria parasites and insecticide resistance.

Assessment of schistosomiasis transmission risk along the Yangtze River basin after the flood disaster in 2020

ZHANG Li-Juan, ZHU Hong-Qing, WANG Qiang, Lü Shan, XU Jing, LI Shi-Zhu

2020, 32(5):  464. 

Asbtract ( )   PDF (1805KB) ( )  

Related Articles | Metrics

Objective　To evaluate the impact of the flood disaster on schistosomiasis transmission along the Yangtze River basin in 2020, so as to provide insights into schistosomiasis prevention and control in flood?affected areas. Methods　The data pertaining to the endemic situation of schistosomiasis were collected from 5 provinces of Hunan, Hubei, Jiangxi, Anhui and Jiangsu from 2013 to 2019, including Schistosoma japonicum infections in humans and livestock and snail distribution, and the warning water levels and actual water status were collected in water regions locating in these 5 provinces. The cumulative numbers of S. japonicum egg?positive individuals and bovines during the period from 2013 to 2019, the area of snail habitats in 2019 and the water level on July 12, 2020 were estimated at a county level and employed as parameters for classification of schistosomiasis transmission risk. Then, the cumulative value of each risk index was calculated to assess the risk of schistosomiasis transmission risk. Results　After the flood disaster along the Yangtze River basin in 2020, there were 10, 5 and 9 counties (districts) at high risk of schistosomiasis transmission in 5 provinces of Hunan, Hubei, Jiangxi, Anhui and Jiangsu based on number of egg?positive individuals, number of egg?positive bovines and snail distribution, respectively. Based on comprehensive risk indices, there were 10 (8 in Dongting Lake regions of Hunan Province and 2 in Poyang Lake regions of Jiangxi Province) and 15 counties (districts) (4 in Hubei Province, 7 in Hunan Province and 4 in Jiangxi Province) identified at grades 5 and 4 risk of schistosomiasis transmission. Conclusions　Dongting Lake regions and Poyang Lake regions are the most severely flood?affected schistosomiasis?endemic foci of China in 2020, and the flood disaster may facilitate the transmission of schistosomiasis in affected areas. Therefore, schistosomiasis control requires to be intensified after the flood disaster to prevent the rebound of the disease.

Spatio-temporal patterns of Oncomelania hupensis snail habitats in Suzhou, Wuxi and Changzhou cities along the Taihu Lake region

LIU Mao-Mao, FENG Yun, ZHANG Jian-Feng, SHI Liang, WANG Xin-Yao, LIU Lu, ZHAO Song, XIONG Chun-Rong, DONG Xuan, YAO Yun-Yi, YANG Kun

2020, 32(5):  469. 

Asbtract ( )   PDF (1970KB) ( )  

Related Articles | Metrics

Objective　To investigate the spatio?temporal distribution characteristics of Oncomelania hupensis snail habitats in three cities of Suzhou, Wuxi and Changzhou along the Taihu Lake region, so as to provide technical supports for establishing a sensitive and highly effective surveillance and forecast system for schistosomiasis. Methods　Snail distribution data were collected from Suzhou, Wuxi and Changzhou cities from 1950 to 2018, and the changing trend for snail habitats were described over years. In addition, the clusters of snail habitats were detected using Kernel density analysis and SaTScan space?time scan analysis. Results　The number of snail habitats appeared a single?peak distribution in Suzhou, Wuxi and Changzhou cities from 1950 to 2018, which peaked in 1970 and then declined rapidly. There were 62.68% of snail habitats eliminated within 10 years after identification, of which 38.24% were eliminated at the year of identification. Kernel density analysis and SaTScan space?time scan analysis revealed that high?density clusters of snail habitats were mainly distributed in Kunshan City, Wuzhong District and Xiangcheng District from 1970 to 1980, and in Yixing City in 1990; since then, the clusters gradually shrank, and overall appeared a move from northeast to west of Taihu Lake. A total of 4 new clusters were detected after 1970, as revealed by space?time scanning of snail habitats. In current snail habitats, emerging snail habitats are mainly identified in Huqiu District (Dongzhu Town), Wuzhong District (Guangfu Town), Taicang City (Shaxi Town) and Jintan District, and re?emerging snail habitats are scattered in 7 districts. Conclusions　The distribution of snail habitats are spatio?temporal aggregation in Suzhou, Wuxi and Changzhou cities. The monitoring and prediction of emerging and re?emerging snail habitats are the key points in the future.

Prevalence of soil-borne nematode infections among residents living in urban/town areas of China in 2015

ZHU Hui-Hui, ZHOU Chang-Hai, ZHU Ting-Jun, HUANG Ji-Lei, QIAN Men-Bao, CHEN Ying-Dan, LI Shi-Zhu, ZHOU Xiao-Nong

2020, 32(5):  476. 

Asbtract ( )   PDF (1470KB) ( )  

Related Articles | Metrics

Objective　To understand the prevalence of soil?borne nematode infections among residents living in urban/town areas of China, so as to provide insights into the control and elimination of soil?borne nematodiasis. Methods　A total of 5 epidemic areas were classified in China according to the prevalence of human Clonorchis sinensis infections captured from the 2014–2015 national survey on major human parasitic diseases in China, and the total sample size was estimated according to the binomial distribution and Poisson’s distribution. Then, the total sample size was allocated proportionally to each province (autonomous region, municipality) of China based on the percentage of residents living in urban and town areas, and the number of survey sites in each province (autonomous region, municipality) was proportionally assigned according to the percentages of residents living in urban and town areas. Then, stratified sampling was performed at county, township and community levels according to the number of sampling sites in each province (autonomous region, municipality), and the survey site (community) was defined as the smallest sampling unit. All permanent residents in the survey sites were selected as the study subjects, and their stool samples were collected for identification and counting of parasite egg using a Kato?Katz technique. The prevalence and intensity of each parasite species were calculated. Results　From 2014 to 2015, among the 133 231 residents detected in 31 provinces (autonomous regions, municipalities) of China, the overall prevalence of soil?borne nematode infections was 1.23% (1 636/133 231), and the prevalence rates of hookworm, Ascaris?lumbricoides and?Trichuris trichiura infections were 0.77% (1 032/133 231), 0.32% (426/133 231) and 0.17% (224/133 231), respectively. The highest prevalence of soil?borne nematode infections was seen in Jiangxi (4.03%, 82/2 034) and Chongqing (4.03%, 524/13 012), followed by in Hainan (3.47%, 72/2 075). The prevalence of soil?borne nematode infections was 1.07% (662/62 139) in men and 1.37% (974/71 092) in women, and the greatest prevalence was found in residents at ages of 65 to 70 years (2.56%, 219/8 569). With regard to occupations and education levels, herdsmen (2.47%, 2/81) and illiterate residents (3.33%, 226/6 795) were found to have the highest prevalence of soil?borne nematode infections, respectively. In addition, mild infections were predominantly identified in hookworm?, A.?lumbricoides? and?T. trichiura?infected individuals (all > 90%). Conclusions　The overall prevalence of soil?borne nematodiasis remains low in urban and town areas of China; however, human infections are widespread. According to the epidemiological features, health education combined with deworming are recommended to reduce the prevalence of soil?borne nematode infections among residents living in urban and town areas of China.

Epidemic situation of malaria in Yunnan Province from 2014 to 2019

WEI Chun, LU Na, YANG Rui, TANG Ye-Rong, Lü Quan, JIANG Jin-Yong

2020, 32(5):  483. 

Asbtract ( )   PDF (1396KB) ( )  

Related Articles | Metrics

Objective　To investigate the epidemiological characteristics of malaria and implementation of the “1?3?7” approach in malaria elimination in Yunnan Province, so as to provide the data support for the development of post?elimination surveillance interventions. Methods　All data pertaining to malaria cases in Yunnan Province from 2014 to 2019 were captured from the Notifiable Disease Reporting System of Chinese Center for Disease Control and Prevention, and the changes in the epidemic situation of malaria were analyzed during the 5?year period. In addition, the core indexes regarding the “1?3?7” approach in malaria elimination of Yunnan Province from 2014 to 2019 were retrieved from the Malaria Control System in the Parasitic Disease Information Reporting System, and all changes in the indexes were descriptively analyzed. Results　During the period from 2014 to 2019, a total of 2 283 malaria cases were reported in Yunnan Province, including 1 927 cases with vivax malaria, 326 cases with plasmodium malaria, 29 cases with other species of malaria, and one case with unidentified species. There were 64 local cases, 2 219 overseas imported cases. Among the 2 283 malaria cases, the male/female ratio was 4.58 ∶ 1, and 80.25% of the cases were aged from 15 to 50 years. Farmer (70.00%) was the predominant occupation, and 76.70% (1 751/2 283) of the cases were identified in 25 border counties (districts). Malaria cases were reported in each month during the 5?year period, and the number of malaria cases increased from April, peaked on May to July, and started to decline on August. From 2014 to 2019, the reporting rate of malaria cases within 24 hours upon diagnosis was 100%, and the detection of malaria cases was 99.69% (2 276/2 283) in the laboratory, with a 99.65% (2 275/2 283) rate of definite diagnosis. In addition, the percentage of individual epidemiological investigations within 3 days was 100.00% (2 283/2 283), and the number of epidemic foci survey and treatment within 7 days was 576 during the 3?year period from 2017 to 2019. The goal of malaria elimination was achieved in Yunnan Province on June, 2020. Conclusions　Malaria has been eliminated in Yunnan Province, and management of overseas imported malaria is the primary challenge to consolidate the malaria elimination achievements in the future. However, the approach in malaria elimination remains to be maintained, and the role of the Yunnan Provincial Malaria Diagnostic Reference Laboratory requires to be strengthened.

Prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City

NING Chao-Qun, KANG Ji-Ming, LI Yi-Ting, CHEN Hui-Hui, CHU Yan-Hong, YU Ying-Fang, WU Xiu-Ping, AI Lin, CHEN Jia-Xu, TIAN Li-Guang, LIAO Qi-Dong

2020, 32(5):  489. 

Asbtract ( )   PDF (1193KB) ( )  

Related Articles | Metrics

Objective　To investigate the prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City. Methods　A cross?sectional questionnaire survey was conducted among students sampled from a primary school in Jiangjin District, Chongqing City on April, 2018, and their stool samples were collected for microscopic examinations, in vitro culture and PCR assays to analyze the prevalence of Blastocystis infections and subtype of the parasite. In addition, the risk factors of Blastocystis infections among primary school students were identified using univariate analysis and multivariate logistic regression analysis. Results　A total of 466 primary students were surveyed, and the subjects had a mean age of (9.81±1.66) years and included 236 males (50.64%) and 230 females (49.36%). The prevalence of Blastocystis infections was 15.24% (71/466) among the study students, and there was no significance difference in the prevalence between male and female students (16.52% vs. 13.91%; [χ2] = 0.616, P = 0.433). In addition, there was a significant difference in the prevalence of Blastocystis infections among grade 1 (6.35%, 4/63), grade 2 (5.17%, 3/58), grade 3 (21.74%, 15/69), grade 4 (25.30%, 21/83), grade 5 (10.19%, 11/108) and grade 6 students (20.00%, 17/85) ([χ2] = 15.410，P = 0.009). There were four Blastocystis subtypes characterized (ST1, ST3, ST6 and ST7), in which ST6 was the most common subtype (45.07%, 32/71), followed by ST3 (25.35%, 18/71). Multivariate logistic regression analysis revealed that minority ethnicity [odds ratio (OR) = 4.259, 95% confidential interval (CI）: (1.161, 15.621)] and low maternal education level (primary school and below) [OR = 9.038, 95% CI: (1.125, 72.642)] were identified as risk factors of Blastocystis infection among primary school students in Jiangjin District, Chongqing City. Conclusions　There is a high prevalence of Blastocystis infections detected among primary school students in Jiangjin District, Chongqing City, and ST6 and ST3 are predominant subtypes. Minority ethnicity and low maternal education level (primary school and below) are risk factors for Blastocystis infections in primary school students.

Impact of "Elaphurus davidianus return home project" on the transmission of schistosomiasis in Poyang Lake areas

Lü Shang-Biao, LIU Yi-Wen, LIU Yue-Min, XU Sheng-Guo, LI Yi-Feng, YUAN Min, HE Ting-Ting, LIN Dan-Dan

2020, 32(5):  498. 

Asbtract ( )   PDF (1664KB) ( )  

Related Articles | Metrics

Objective　To investigate the prevalence of Schistosoma japonicum infections in Elaphurus davidianus released to Poyang Lake areas and evaluate the impact of the project of “E. davidianus released to wild environments for natural reproduction and growth” ( “E. davidianus return home project” ) on the transmission of schistosomiasis in Poyang Lake areas. Methods　During the period from April 2018 to December 2019, the population distribution, inhabiting activity and natural reproduction of E. davidianus released to Poyang Lake areas were investigated by means of GPS and artificial observations. The S. japonicum infection was identified in animal feces in E. davidianus inhabitats using a hatching test, and snail distribution was surveyed in E. davidianus inhabiting grass islands using a systematic sampling method. Results　A total of 51 E. davidianus were released to the Poyang Lake areas in 2018, which subsequently produced 5 E. davidianus habitats in Yinlong Lake, Longkou, Nanchi Lake, Lianzi Lake and Zhu Lake. E. davidianus was found to predominantly inhibit in grass islands, farmlands and forest lands in hilly regions around the Poyang Lake areas. The natural reproduction rate of E. davidianus was 25% in the habitats in 2019, and the mean density of snails was 0.009 to 0.039 snails/0.1 m2 in E. davidianus inhabitats; however, no S. japonicum infection was identified in snails. In addition, the mean densities of wild E. davidianus and bovine feces were 4.6 samples/hm2 and 2.1 samples/hm2, and the prevalence of S. japonicum infection was 4.35% and 13.16% (P = 0.236), respectively; however, the intensities of S. japonicum infections were “+++” and “+”, respectively. Conclusions　The E. davidianus released to Poyang Lake areas may get infections with S. japonicum, and cause schistosomiasis transmission through fecal contamination in grass islands. The impact on local schistosomiasis transmission and the response strategy requires to be investigated following the release of E. davidianus to lake regions, to ensure the achievement of the goal of schistosomiasis elimination and the successful implementation of the “E. davidianus return home project” in Poyang Lake areas.

Survey of human intestinal protozoal infections in Tibet Autonomous Region, 2015

BIANBA Zhuo-Ma

2020, 32(5):  502. 

Asbtract ( )   PDF (1001KB) ( )  

Related Articles | Metrics

Objective　To investigate the current prevalence of human intestinal protozoal infections in Tibet Autonomous Region, so as to provide the scientific basis for the development of the future control strategy. Methods　The study sites were sampled using a stratified cluster random sampling method in different ecological zones and different geographical locations of Tibet Autonomous Region in 2015. Fecal samples were collected from the permanent residents at ages of 3 years and older for the detection of intestinal protozoa cysts and trophozoites. The region?, gender?, age?, occupation? and education level?specific prevalence of human intestinal protozoal infections was estimated and compared. Results　A total of 70 study sites were sampled from 23 counties (districts) in 3 ecological zones of Tibet Autonomous Region in 2015. Among 17 939 subjects surveyed, there were 1 117 residents infected with intestinal protozoa, with a prevalence of 6.23%. There were 9 species of intestinal protozoa identified, and Entamoeba coli (3.59%), Giardia lamblia (0.74%) and Blastocystis hominis (0.72%) were found to have a high infection rate. The prevalence of human intestinal protozoal infections was 7.20%, 6.39% and 4.48% in the southern, eastern and northern Tibetan ecological zones, respectively. Among the 23 counties (districts), the highest human prevalence was seen in Baingoin (13.56%) and Amdo counties (12.77%), and there were significant differences in the prevalence of human intestinal protozoal infections among the three ecological zones (χ2 = 33.909, P < 0.01) and 23 counties (districts) (χ2 = 580.511, P < 0.01). There was no gender?specific prevalence of human intestinal protozoal infections (men, 6.08%; women, 6.35%; χ2 = 0.542, P > 0.05); however, there was age?specific human prevalence (χ2 = 44.377, P < 0.01), and a higher prevalence was seen in residents at ages of 60－69 years (8.51%) and 50－59 years (7.67%). In addition, there were occupation? (χ2 = 37.568, P < 0.01) and education level?specific prevalence rates of human intestinal protozoal infections (χ2 = 14.659, P < 0.01), and a higher prevalence was seen in farmers (7.17%) and herdsmen (5.28%), and in residents with a primary school education (6.62% and illiterate residents (6.33%). Conclusions　The prevalence of human intestinal protozoal infections remains high in Tibet Autonomous Region. The health education pertaining to intestinal parasitic disease control requires to be intensified among farmers and herdsmen in rural areas.

Survey of snail distribution in Four-lake Basin of Hubei Province

SHAN Xiao-Wei, XIAO Ying, LIU Si, ZHONG Chen-Hui

2020, 32(5):  506. 

Asbtract ( )   PDF (1231KB) ( )  

Related Articles | Metrics

Objective　To investigate the distribution of Oncomelania snails in Four Lake Basin of Hubei Province, so as to provide scientific evidence for the development of snail control interventions. Methods　The snail distribution was surveyed by means of the retrospective study and cross?sectional survey in the Four Lake Basin in Spring of 2016. The data pertaining to the endemic situation of schistosomiasis were collected and analyzed in the Four Lake Basin from 2008 to 2018, and the associations of snail habitat areas with the prevalence of Schistosoma japonicum in humans and bovines were examined. Results　There were 16 003 snail habitats in the 9 schistosomiasis?endemic counties (districts) in the Four Lake Basin in 2016, covering an area of 246 million m2. The mean density of living snails was 0.622 5 snails/0.1 m2, which was relatively high in weed?type settings (0.688 0 snails/0.1 m2) and ditches (0.706 4 snails/0.1 m2). Type I (current snail habitats, 53.03%) and II/III (historical snail habitats, 46.97%) settings were predominant snail habitats. A big change was seen in snail habitats in dry farmland, marshland and paddy farmland, and environmental modification resulted in satisfactory snail control effectiveness. In addition, the area of snail habitats positively correlated with the changes in the prevalence of S. japonicum infections in humans (r = 0.842, P < 0.01) and livestock (r = 0.695, P < 0.01). Conclusions　The integrate strategy with an emphasis on the control of the source of S. japonicum infections results in remarkable snail control effectiveness in the Four Lake Basin; however, there is a risk of re?emerging snail habitats.

Challenges of schistosomiasis control in China during the coronavirus disease 2019 (COVID-19) epidemic

GUO Jing-Yi, ZHANG Li-Juan, CAO Chun-Li, Lü Shan, XU Jing, LI Shi-Zhu, ZHOU Xiao-Nong

2020, 32(5):  511. 

Asbtract ( )   PDF (1379KB) ( )  

Related Articles | Metrics

Objective　To investigate the implementation of schistosomiasis control activities in China during the coronavirus disease 2019 (COVID?19) epidemic, so as to evaluate the impact of COVID?19 epidemic on the national schistosomiasis control program in China. Methods　On April 2020, 3 counties (districts) were randomly selected from each of the 12 schistosomiasis?endemic provinces (municipality, autonomous region), and a questionnaire survey was conducted to investigate the implementation of schistosomiasis control activities in these counties (districts) from January to March 2020. Then, the impact of the COVID?19 epidemics on the national schistosomiasis control program of China was evaluated using a comparative analysis approach. Results 　Among the 36 counties (cities, districts) sampled from 12 provinces (municipality, autonomous region), 66.67% were at a high and medium risk of COVID?19 epidemics. The implementation of schistosomiasis control activities assignment, human schistosomiasis examination and treatment, snail control with chemical treatment and health education reduced by 44.26% to 91.56% as compared to 2019 during the same time period, and the schistosomiasis control program was more affected by COVID?19 in transmission?controlled provinces. The gross funds invested into the schistosomiasis control program reduced by 23.39% in relative to the expected, while the total expenditure increased by 41.22%. In addition, all 36 surveyed counties (districts) considered that the COVID?19 epidemic had a short?term impact on the schistosomiasis control program, with the most predominant impact on schistosomiasis control activities assignment, human resources and monitoring of endemic situation of schistosomiasis. Conclusions　The COVID?19 epidemics affect the routine schistosomiasis control program across the endemic?foci of China. Policy and financial support should be strengthened to ensure the completion of the schistosomiasis control program.

Genes associated with Wolbachia-induced cytoplasmic incompatibility in natural populations of Culex pipiens pallens: a preliminary study

WANG Ying-Fan, HE Kun, GUO Wei, WANG Hai-Fang, ZHANG Dong-Hui, GONG Mao-Qing, JI Min-Jun, CHEN Lin

2020, 32(5):  517. 

Asbtract ( )   PDF (1162KB) ( )  

Related Articles | Metrics

Objective　To investigate the genes involved in Wolbachia?induced cytoplasmic incompatibility among three natural populations of Culex pipiens pallens in eastern China, so as to provide insights into the development of preventive and control measures for mosquito?borne diseases based on Wolbachia. Methods　The cytoplasmic incompatibility was tested among three natural populations of C. pipiens pallens collected from Nanjing and Wuxi of Jiangsu Province and Tangkou of Shandong Province using reciprocal crosses. Wolbachia infection was detected in C. pipiens pallens using a PCR assay, and the expression of Wolbachia wsp and WD0513 genes was quantified using a fluorescent quantitative real?time PCR (qPCR) assay. Results　Bidirectional compatibility was found between the natural populations of C. pipiens pallens collected from Nanjing and Wuxi of Jiangsu Province (t = 0.57 and 0.15, both P values > 0.05), while bidirectional incompatibility was seen between the natural populations of C. pipiens pallens collected from Tangkou of Shandong Province and Wuxi of Jiangsu Province (t = 63.81 and 43.51, both P values < 0.01), and between the natural populations of C. pipiens pallens collected from Nanjing of Jiangsu Province and Tangkou of Shandong Province (t = 39.62 and 43.12, both P values < 0.01). Wolbachia wsp gene was amplified in all three natural populations of C. pipiens pallens, and qPCR assay detected no significant difference in the Wolbachia wsp gene expression among the three natural populations of C. pipiens pallens (F = 2.15, P > 0.05). In addition, there was no significant difference in the WD0513 gene expression between the natural populations of C. pipiens pallens collected from Tangkou of Shandong Province and Nanjing of Jiangsu Province (q = 8.42, P < 0.05) or between the natural populations of C. pipiens pallens collected from Tangkou of Shandong Province and Wuxi of Jiangsu Province (q = 7.84, P < 0.05); however, there was a significant difference detected in the WD0513 gene expression between the natural populations of C. pipiens pallens collected from Nanjing and Wuxi of Jiangsu Province (q = 0.40, P > 0.05). Conclusions　Different Wolbachia numbers are detected in natural populations of C. pipiens pallens collected from Nanjing and Wuxi of Jiangsu Province and Tangkou of Shandong Province and, and WD0513 gene may be involved in the Wolbachia?induced cytoplasmic incompatibility among three natural populations of C. pipiens pallens.

Flood disasters and schistosomiasis control

ZHANG Shi-Qing

2020, 32(5):  522. 

Asbtract ( )   PDF (1017KB) ( )  

Related Articles | Metrics

Currently, the endemic situation of schistosomiasis has dropped to the lowest level in China; however, there are still factors affecting the transmission of schistosomiasis. Flood disasters may pose a great impact on the transmission of schistosomiasis and even affect the progress of schistosomiasis control and the consolidation of schistosomiasis control achievements. In 2020, major flood disasters occur across China. This paper analyzes the current status of schistosomiasis and the impact of flood disasters on the transmission of schistosomiasis in China, and systematically describes the assessment of and response to schistosomiasis transmission risk before flood disasters, the prevention of Schistosoma japonicum infections during flood disasters and the assessment of the endemic situation of schistosomiasis and surveillance of schistosomiasis after flood disasters. It is considered that schistosomiasis control is an important part of conventional schistosomiasis control activities and an important part of anti?flood and schistosomiasis?preventive activities in flood disaster?affected areas. It is recommended that emergence response interventions are implemented in a scientific and well?organized manner to avoid or reduce the risk of schistosomiasis transmission caused by flood disasters. In addition, the research on early surveillance and forecast approaches for schistosomiasis should be emphasized and reinforced to provide the scientific and precise tools for achieving the goal of the 13th Five?year Plan for Schistosomiasis Control and elimination of schistosomiasis in China.

Role of institutional cultural building in the schistosomiasis control program of Jiangsu Province

PAN Li, LI Na, XUE Jun, SHI Liang, LI Wei, HUANG Yi-Xin, BIAN He-Juan

2020, 32(5):  526. 

Asbtract ( )   PDF (910KB) ( )  

Related Articles | Metrics

Jiangsu Province was once one of the provinces that are hyperendemic for schistosomiasis in China. Following the concerted efforts for nearly 70 years, the transmission of schistosomiasis was interrupted in the province in 2019, which is the first province to achieve the national criteria of interruption of schistosomiasis transmission among the 5 provinces locating in the marshland and lake regions. In addition to political, economic and scientific and technical factors that greatly contribute to the huge achievements from schistosomiasis control in Jiangsu Province, the spiritual implication of Jiangsu schistosomiasis control culture that is mainly characterized by dedication, rigorousness, truth?seeking and innovation play a vital role in the schistosomiasis control program of Jiangsu Province, which encourages generations of schistosomiasis control professionals working in Jiangsu Province to fight against the “God of plague”.

Endemic situation of schistosomiasis in a national surveillance site of Yangzhong City from 2015 to 2018

XIAO Min, WU Rong-Feng, YAN Hui-Zhong, BAI Lin

2020, 32(5):  529. 

Asbtract ( )   PDF (1016KB) ( )  

Related Articles | Metrics

Objective　To analyze the endemic situation of schistosomiasis in a national surveillance site of Yangzhong City, so as to provide the scientific evidence for adjusting the local schistosomiasis control strategy and consolidating the control achievements. Methods　According to the National Schistosomiasis Surveillance Scheme (2014 version), the snail status, Schistosoma japonicum infections in humans and livestock and wild feces contamination were monitored in Zhinan Village, a national schistosomiasis surveillance site in Yangzhong City from 2015 to 2018. Results　The areas of snail habitats reduced from 8.10 hm2 in 2015 to 2.72 hm2 in 2018, and the mean density of living snails decreased from 0.27 snails/0.1 m2 in 2015 to 0.07 snails/0.1 m2 in 2018 in Zhinan Village; however, no S. japonicum infections were identified in snails during the period from 2015 to 2018. Serological testing for S. japonicum infections was performed in 2 034 local populations and 858 mobile populations from 2015 to 2018, and the sero?prevalence of S. japonicum human infections was 0.59% to 1.98%, with no egg?positives detected. A total of 79 goats were detected for S. japonicum infections from 2015 to 2018, and no egg?positives were found. In addition, no other livestock was found in Zhinan Village from 2015 to 2018, and no wild feces were found in snail habitats. Conclusion　A great success has been achieved in schistosomiasis control in Yangzhong City; however, there are still snails breeding in the city. Monitoring of the risk factors pertaining to schistosomiasis transmission should be further intensified to consolidate the control achievements.

Assessment of schistosomiasis transmission risk in Nanjian County of Yunnan Province in 2019

DU Chun-Hong, YANG Hui, YANG Meng-Xian, ZHANG Yun, SUN Jia-Yu, WANG Li-Fang, YAN Jia-Qi, SHEN Mei-Fen, DONG Yi

2020, 32(5):  531. 

Asbtract ( )   PDF (1202KB) ( )  

Related Articles | Metrics

Objective　To assess the schistosomiasis transmission risk in Nanjing County, so as to provide the scientific evidence for the development of the schistosomiasis control strategy and consolidation of the control achievements. Methods　On May 2019, the Deqiu Village in Deqiu Town and Baiyun Village in Nanjing Town of Yunnan Province, where schistosomiasis were historically relatively highly endemic, were selected to assess the risk of transmission of schistosomiasis by means of a retrospective review of the data pertaining to the historical endemic situation and schistosomiasis control, combined with a cross?sectional survey of snail and wild feces distribution. Results　During the period between 2017 and 2018, the mean sero?prevalence rates of Schistosoma japonicum infections were 6.76% (202/2 990) and 2.86% (142/4 971) in humans and 0 (0/1 160) and 10.65% (31/291) in bovines in Deqiu and Baiyun villages of Nanjian County, respectively; however, no egg?positives were identified; in addition, there were 21.06 hm2 snail habitats found, but no S. japonicum infections were detected in snails. In 2019, there was 6.17 hm2 snail habitats detected, with 2.17% (245/11 298) occurrence of frames with snails and a 0.06 snails/0.1 m2 density of living snails; however, no positives for nucleic acid detection were seen in snails; among the 136 wild fecal samples captures from 23 settings, no S. japonicum infections were identified. Conclusions　The risk of schistosomiasis transmission remains at a low level in Nanjian County; however, the factors affecting the transmission of schistosomiasis have not been completed eliminated. The integrated schistosomiasis control strategy with an emphasis on the control of the source of S. japonicum infections requires to be reinforced to consolidate the control achievements.

Seroprevalence of Toxoplasma gondii and Toxocara infections among pregnant women in Hangzhou City

YU Shu-Li, QIAN Chun-Yan

2020, 32(5):  534. 

Asbtract ( )   PDF (979KB) ( )  

Related Articles | Metrics

Objective　To investigate the prevalence of Toxoplasma gondii and Toxocara infections among pregnant women in Hangzhou City, so as to provide baseline data for decreasing birth defects and improving the population quality. Methods　A total of 235 pregnant women receiving prenatal diagnosis at the First People’s Hospital of Yuhang District during the period between February 2018 through December 2019 were recruited as the observation group, and 235 age?matched, non?pregnant healthy women at the same hospital during the same period served as the control group. The subjects’ medical records were captured from the hospital management information system. Blood samples were collected from the observation and control groups and detected for the presence of IgG antibodies against T. gondii and Toxocara using an enzyme?linked immunosorbent assay (ELISA). The seroprevalence of the IgG antibodies against T. gondii and Toxocara was compared between the observation and control groups. Results　The subjects in the observation group had a mean age of 26.5 ± 4.3 years (range, 23 to 31 years), and gestational ages of 10 to 27 weeks, and the subjects in the control group had a mean age of 26.1 ± 5.7 years (range, 20 to 30 years). The seroprevalence rates of IgG antibodies against T. gondii (28.51% vs. 4.68%; [χ2] = 34.85, P < 0.01) and Toxocara (24.26% vs. 5.11%; [χ2] = 25.77, P < 0.01) were both significantly higher in the observation group than in the control group, and the seroprevalence of T. gondii and Toxocara co?infections was also significantly greater in the observation group than in the control group (13.19% vs. 2.13%; [χ2] = 17.49, P < 0.01). Conclusions　The seroprevalence rates of T. gondii and Toxocara infections and their co?infections are all high among pregnant women in Hangzhou City. Screening of T. gondii and Toxocara infections is strongly recommended during pregnancy.

Advances in research of protein kinase A in parasites: a review

FAN Jun-Jie, LI Kai, TAN Qing-Qing, CAO Wen-Qiao, YE Bin

2020, 32(5):  538. 

Asbtract ( )   PDF (921KB) ( )  

Related Articles | Metrics

Protein kinase A (PKA) is an important intracellular substance that regulates substance metabolism and biological functions, which exerts a wide range of biological effects through phosphorylation of specific serine/threonine residues in specific proteins. PKA plays an important role in the cAMP signaling pathway, and is involved in various life activities of parasites. Therefore, investigating the role of PKA in the life activities of parasites may provide insights into the development of novel anti?parasitic targets. The review mainly describes the structure and function of PKA and its role in life activities of parasites.

Advances in research on aquaporins in medical helminthes

WANG Fen, YE Bin

2020, 32(5):  542. 

Asbtract ( )   PDF (1792KB) ( )  

Related Articles | Metrics

Aquaporins (AQPs) are a class of membrane intrinsic proteins in medical helminthes that specifically mediate the transmembrane transport of water or other solute molecules. Previous studies have demonstrated that AQPs play a critical role in promoting the transmembrane transport of water, osmoregulation, uptake of nutrients, release of toxic metabolic products and transport of antiparasitic drugs, which may serve as promising vaccine candidates and drug targets for parasitic diseases. This review describes the structural characteristics of AQPs in medical helminthes, and discusses the feasibility of these AQPs as anti-helminth vaccine candidates and drug targets, so as to provide insights into the development of novel vaccines and drugs against parasitic diseases.

Alveolar echinococcosis metastatic to the brain: a case report

LUO Yun-Xing, DU Chao-Nan, YANG Ming-Fei, ZHANG Qiang, WEI Xiao-Xing

2020, 32(5):  548. 

Asbtract ( )   PDF (1114KB) ( )  

Related Articles | Metrics

This paper reports a case with alveolar echinococcosis metastatic to the brain. This case underwent 10?year anti?echinococcosis treatment and operations of the liver, right kidney and brain. Following multiple operations and oral administration of albendazole, the case still had recurrence and distant metastasis of hepatic echinococcosis. It is suggested that early prevention, early diagnosis, early regular treatment and surgical radical treatment are critical to the treatment of alveolar echinococcosis.