Table of Content

20 August 2022, Volume 20 Issue 4 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Select

Promoting visceral leishmaniasis from control to elimination in China based on One Health approach ZHANG Hong-wei, LIU Ying, YANG Cheng-yun, LU De-ling, QIAN Dan, HE Zhi-quan, WANG Dan 2022, 20 (4):  181-184.  Abstract ( 758 )   PDF (436KB) ( 960 )   Visceral leishmaniasis, also known as kala-azar, represents a zoonotic parasitic disease with sandfly as the transmission medium. WHO is advocating an increase to 64（85%） of the number of countries that have achieved the goal of eliminating visceral leishmaniasis as a public health problem by 2030. As one of the zoonosis, the transmission-chain of leishmaniasis is complex. To interrupt transmission from animal hosts to human populations, as well as the establishment of “human-animal-media” co-prevention mechanism is still facing many challenges, which requires cross-sectoral, cross-regional and cross-disciplinary collaboration. The One Health approach, which aims to jointly promote human and animal health, maintain and improve the ecological environment, has advantages in zoonosis prevention and control and can effectively solve this complex public health problem. The aim and strategy for elimination of visceral leishmaniasis according to One Health approach was proposed in this paper, with the role of systematic monitoring and intervention, as well as cross-sectoral, cross-regional and cross-disciplinary collaboration being discussed, in order to provide reference for visceral leishmaniasis control and elimination in our country.  Related Articles | Metrics

Select

Progress in the investigation of Angiostrongylus cantonensis intermediate host snails GUO Yun-hai, ZHANG Yi 2022, 20 (4):  185-190,196.  Abstract ( 540 )   PDF (851KB) ( 2505 )   This paper reviewed the related investigations on the intermediate host snails of Angiostrongylus cantonensis, and recorded a total of 199 species in 49 families, including 11 families and 87 species of freshwater snails, and a total of 112 species of 38 families of terrestrial snails. In China, 33 species of 10 families have been reported, including 2 families and 11 species of freshwater snails, and 22 species under 8 families of terrestrial snails. Although the reported cases of angiostrongyliasis have been gradually decreasing in recent years in China, with the continuous spread of Pomacea spp., more natural foci of A. cantonensis have been found, and the risk of transmission of the disease continues to exist. The findings suggest that strengthening the investigation of related intermediate host snails is significant to understanding of epidemiology of Angiostrongylus cantonensis. Related Articles | Metrics

Select

Investigation on the diffusion of snails after flood disaster in 2020 in Anhui Province DAI Bo, WANG Tian-ping, XU Xiao-juan, HE Jia-chang, WANG Hao, GAO Feng-hua, DING Song-jun, LIU Ting, ZHANG Shi-qing 2022, 20 (4):  191-196.  Abstract ( 542 )   PDF (828KB) ( 758 )   Objective To understand the status of snail distribution after flooding in Anhui Province in 2020 for evidence to formulate corresponding prevention and control measures. Methods The data on the rainfall and water level in flood season in 2020 as well as disaster information of schistosomiasis in the endemic areas in Anhui were collected and analyzed. In 2021, the snail habitats were investigated in 50 counties of 9 cities where schistosomiasis was endemic, and the information of snail breeding environment, snail distribution, newly emerging and re-emerging snails were collected to analyze the diffusion of snails in Anhui after the flood. Results In flood season of 2020, the middle and lower reaches of the Yangtze River were hit by heavy rainfall, with rainfall of 317.9 mm in July. The average water level recorded at Datong hydrological station was 15.29 m in July, and the monthly maximum water level in July and August reached 16.2 m and 15.4 m respectively, both exceeding the water line for alarming (14.4 m) at the station. A total of 71.43% of the endemic towns and 47.98% of the endemic villages in across Anhui were affected by the flood disaster, resulting in embankment breaches at 130 places. In 2021, snails were found in an area of 20 238.26 hm2, of which 16 781.86 hm2 of lake and river beach were the major snail habitats. The area of snail re-emerging was 976.84 hm2 in total, in which 685.10 hm2 was recurrent area of Oncomelania hupensis caused by the flood. The area of newly emerging snail was 611.52 hm2, of which 482.23 hm2 was associated with the flood. The areas with re-emerging or newly emerged snails were primarily in the Yangtze River and its tributaries, among which the area of snail re-emerging in the main stream of the Yangtze River was 275.65 hm2(28.22%), and the area of snail newly emerging was 223.93 hm2(36.62%). The environment with snail re-emerging or newly emerging was most seen in beaches, where snails were re-emerged in 515.54 hm2(52.78%), and newly emerged in 470.79 hm2(76.99%). In the areas with different epidemic degrees, snail re-emerging or newly emerging was found in transmission interruption areas, where Oncomelania hupensis was re-emerged in 917.45 hm2(93.92%), and newly emerged in 526.53 hm2(86.10%). Among the different epidemic types, the area of re-emerging and newly emerging snail habitats was more in the marshland and lake regions, accounting for 567.87 hm2 (58.13%) and 477.79 hm2(78.13%), respectively. Conclusion The flooding in 2020 produced serious impact on snail diffusion in Anhui Province. Therefore, it is necessary to enhance snail surveillance, risk assessment of schistosomiasis and control of the snails in key environment. Related Articles | Metrics

Select

Investigation on the diffusion of snails after flood disaster in 2020 in Jiangxi Province XIE Jing-zi, LI Yi-feng, YUAN Min, HE Ting-ting, LI Zong-guang, LÜ Shang-biao, LIN Dan-dan 2022, 20 (4):  197-201.  Abstract ( 374 )   PDF (970KB) ( 835 )   Objective To investigate and analyze the impact of the devastating flood in Jiangxi Province in 2020 on the spread of Oncomelania snails, so as to provide scientific basis for the monitoring and control of Oncomelania snails in areas following flood disaster. Methods The data on flood disaster were collected from schistosomiasis endemic areas in Jiangxi Province in 2020. Then investigations were conducted on snail spreading in the environments with snails in history, suspected with snails, and snail-free environment bordered in that with snail prevalence after flood disaster. Software Excel 2016 was used to construct the database for the snail spreading after flood disaster, and various indicators for snail status and the nature of snail spreading were summed up and statistically analyzed. Results Snail spreading to a certain extent was found in 95 environments in 63 administrative villages in the 38 towns in 14 endemic counties (cities/districts) after the flood disaster in 2020. The spreading affected an area of 1 411.37 hm2, the diffusion area of Oncomelania snails in hill area was 240.82 hm2 （17.06%), and that in lake area was 1 170.55 hm2 (82.94%). Hilly type Oncomelania snails were found in 80.00% (76/95) of the total environment with snail diffusion, where the average density of live snails was 0.533 8 snails/0.1 m2, and significantly higher than that of the marshland and lake type(0.055 8 snails/0.1 m2). The occurrence rate by individual frame with living snails in diffusion environment of hilly type (24.63%) was significantly higher than that in lake type (2.45%). After flooding all 185 single retreated polders in Poyang Lake District, no environments were found to be suspected with snail breeding. Conclusion Catastrophic flood should be the major factor for spread of snails in the hilly environment. Therefore, it is necessary to strengthen the monitoring and control of snails after the disaster to prevent the resurgence of schistosomiasis. Related Articles | Metrics

Select

Investigation on the diffusion of snails after flood disaster in 2020 in Hubei Province WANG Hui, SHAN Xiao-wei, ZHONG Chen-hui, LIU Si, YANG Jun-jing, LIU Jian-bing 2022, 20 (4):  202-205,209.  Abstract ( 421 )   PDF (810KB) ( 1069 )   Objective To understand the status of snail diffusion in Hubei Province after the flood disaster in 2020 for scientific evidence to control snail spreading in flood season. Methods By systematic sampling and environmental sampling method, we conducted survey on the snail diffusion, based on the water system in individual county, in the snail habitats together with the materials/facilities with snails lodged after the flood in 2020, and the captured snails were subjected to laboratory test. Results A total of 933 environments in 63 counties with schistosomiasis endemic and the neighboring areas were investigated in Hubei Province, which covered an environmental area of 6 965.77 hm2 involved in more than 30 water systems. Snail diffusion was found in an area of 4 350.74 hm2 in 20 counties with schistosomiasis endemic. In total, 1 360.39 hm2 was expanded from the original environment with snails. Snail re-emerging was found in 1 856.19 hm2, and newly emerging was seen in 1 134.16 hm2. The 159 997 snails were captured, in which 149 928 were live snails. No infected snails were found. A total of 85 458 snails were captured from the materials/facilities in the 20 endemic counties, and the snails were most found in the trees (33 326 snails) and on the walls of infrastructure (35 581 snails), yet infected snails were free. Conclusion Although the flood disaster in 2020 led to a large area of snail spread in the schistosomiasis endemic area of Hubei Province. Nevertheless, control of snail spread in flood season should be the focus of schistosomiasis control in the future. Related Articles | Metrics

Select

Investigation on the diffusion of snails after flood disaster in 2020 in Hunan Province TANG Ling, CHENG Xiang-hui, LIAN Hua, ZHOU Jie, LI Sheng-ming, WANG Hui-lan, JIANG Qiong, LI Guang-ping 2022, 20 (4):  206-209.  Abstract ( 400 )   PDF (801KB) ( 736 )   Objective To investigate on snail spread in schistosomiasis endemic areas of Hunan Province after flood disaster in 2020 for proposals in planning the prevention and control measures throughout the province. Methods The Oncomelania snails were investigated in the schistosomiasis endemic areas affected by flood disaster in the province by environmental sampling and systematic sampling. All snail samples collected were crushed to undergo microscopic examination for determining whether they were alive or dead and status of schistosomiasis infection. In addition, the area with snail spreading, occurrence of frame with snails and density of live snails were statistically analyzed. Results Snail spread occurred in 96 environments in 11 of the 41 schistosomiasis endemic counties (cities and districts) in Hunan Province of the snail survey in 2021. The area with snail spreading, a frame with snails and density of live snails were 1 084.09 hm2, 7.41%, and 0.183 4 snails/0.1m2, respectively. No infected snails were found. Snail spread was seen in the basins of Xiangjiang River, Zishui River, Lishui River and Dongting Lake, and most serious in the basins along Lishui River, with a total of 81 environments that accounted for 970.44 hm2 (89.52%).The diffusion nature is dominated by the newly developed environment, with the newly developed snail area of 754.54 hm2 (69.60%).The diffusion environments were primarily associated with beach (968.74 hm2, 89.36%), and the vegetation with snail diffusion was dominated by weeds (883.76 hm2, 81.52%). Conclusion Flood disasters can increase the risk of Oncomelania snails spreading in endemic areas. In order to consolidate the achievements of schistosomiasis control in the whole province, efforts should be made to check and control snails, improve the environment and monitor the diffusion status of snails. Related Articles | Metrics

Select

The effect analysis of comprehensive governance for schistosomiasis in Yunnan Province from 2004 to 2021 SONG Jing, SHEN Mei-fen, DONG Yi 2022, 20 (4):  210-214,220.  Abstract ( 427 )   PDF (956KB) ( 708 )   Objective To analyze the effect of comprehensive treatment of schistosomiasis in Yunnan Province from 2004 to 2021 for providing a basis to formulate control strategies in following stage. Methods The surveillance reports and preventive and control reports of schistosomiasis as well as the relevant data of agriculture, water conservancy, forestry and data maintained in the state land administration for comprehensive control of schistosomiasis were collected in Yunnan Province from 2004 to 2021. The control effect was evaluated based on statistical analysis of the annual control expenditure, comprehensive control measures, and the changes of population, cattle disease and snail situation. Results From 2004 to 2021, molluscide was applied to a total area of 100 061.87 hm2 in Yunnan Province. 4 146 548 people and 1 823 871 cattle underwent extended chemotherapy, and 293 731 innocuous-sanitary toilets were built. 4 277 980 cattle were raised in pens, 13 371 cattle were eliminated and 96 181 cattle were replaced by machines. In total, 64 624.40 hm2 of water area was replaced with dry land, and 925.16 km of irrigated areas were transformed. 1.266 5 million people were access to safe drinking water. 14 464.14 hm2 forests were planted for snail suppression and disease prevention, and 56.99 hm2 of land was leveled. In 2004, the positive rate of human blood test was 21.10%, the corrected infection rate was 2.51%. The infection rate of cattle and Oncomelania hupensis was 3.76% and 0.70%, respectively. Infected snails were found in 771 sites, and the area with snails was 4 364.79 hm2. The occurrence rate of snail in individual frame and live snail density were 4.71% and 0.256 0 snails/0.1 m2, respectively. In 2021, the positive rate of human blood test was 2.21%, and the corrected infection rate and cattle infection rate were both zero. No infected snails were detected after 2013. In 2021, the area with snails was 1 058.59 hm2, and the rate of snails occurred in individual frame and live snail density were 1.21% and 0.034 3 snails /0.1 m2 respectively. 3.986 715 2 billion yuan was used for comprehensive control of schistosomiasis in Yunnan Province from 2004 to 2021. The average annual investment was 199.832 6 million yuan from 2004 to 2008; 253.001 6 million yuan from 2009 to 2015; and 202.756 8 million yuan from 2016 to 2021, respectively. Conclusion The comprehensive control measures primarily based on control of the transmission sources of schistosomiasis in Yunnan Province have achieved remarkable results, and lead to obviously decreased infection rate of schistosomiasis in population and cattle, as well as greatly reduced areas with snails. However, some difficulties still exist, including the bottleneck in further cutting down the snail area, and prevention and control of the infection sources in livestock. Following measures should include continuously ensuring the investment of funds to further improve the comprehensive control measures and consolidate the results of schistosomiasis control.  Related Articles | Metrics

Select

Analysis on the epidemiological and etiological characteristics of imported dengue fever cases in Kunming in 2019 WANG Xue-fei, TIAN Rong, CHEN Zhi-hui, YANG Ming-dong, GUO Xiao-fang 2022, 20 (4):  215-220.  Abstract ( 333 )   PDF (3017KB) ( 603 )   Objective To analyze the epidemiological and etiological characteristics of imported dengue fever cases in Kunming City in 2019 for evidences in planning prevention and control measures for this infection. Methods The epidemiological information was collected from the imported dengue fever cases in Kunming City in 2019 according to the National Dengue Surveillance Program in China. Serum samples were obtained from part of the imported dengue fever cases reported between January and June of 2019, and subjected to serotyping of the dengue virus (DENV) by RT-PCR. In addition, E gene sequence of the virus was amplified for phylogenetic analysis. Results A total of 400 imported cases were reported in Kunming in 2019, in which 297 (74.25%) were imported from foreign countries such as Cambodia (187 cases), Myanmar (38 cases) and Laos (28 cases). Ninety-nine cases (24.75%) were from mainland China, and most of them (93 cases) were from Xishuangbanna of Yunnan Province. The cases were reported all year round, and peaked from May to October of the year. The male to female ratio was 2.01∶1. The cases were distributed in every age group, yet most were young adults aged from 20 to 50 years (84.25%). The occupation of the reported cases was associated with house-workers and currently unemployed (19.5%), traders (14%), government staffs (13%), famers (11.5%) and workers (10.75%). Between January and June of 2019, a total of 60 aliquots of serum samples were collected from the imported dengue fever cases that were from Cambodia (n=49), Laos (n=1), Myanmar (n=3), Vietnam (n=3), Thailand (n=1) and African countries (n=3). Of the 60 samples, 29 and 5 were respectively positive for DENV-1 and DENV-2. The cases imported from Cambodia were involved in DENV-1 (n=28) and DENV-2 (n=4), and DENV-2 and DENV-1 were seen in one case from Vietnam and another one from Thailand. Eight E gene sequences of DENV were amplified from 34 samples, 6 of which were DENV-1 from Cambodia, and 2 of which were DENV-2 from and Thailand. Phylogenetic tree analysis showed that 6 strains of DENV-1 belonged to genotype Ⅰ, and nucleotide sequence identities among the 6 sequences were 96.63% -100.00%. Of six sequences, one (imported from Thailand) was highly homologous with the epidemic strained identified in 2019 in Thailand, and the other 5 sequences (imported from Cambodia) had the highest homology with the strain reported in Guangdong (imported from Cambodia in 2019) and in Nanchang in 2019 (imported from Cambodia and Laos). DENV-2 sequences amplified from two strains of the cases imported from Cambodia belonged to Asian Ⅰ genotype, with a nucleotide sequence identity being 99.73%. Both strains were in high homology with those reported in Guangdong imported from Cambodia in 2019. Conclusion In 2019, most dengue cases in Kunming City were imported from Southeast Asian countries, and the imported dengue virus strains were highly homologous with the strains epidemic in and imported from Southeast Asian countries. The results suggest that it is necessary to improve early detection and report of the imported cases in order to prevent local outbreaks caused by imported cases.  Related Articles | Metrics

Select

Investigation on the current situation of schistosomiasis health education in primary students in urban area of Yueyang City ZHOU Rui-hong, ZHOU Jie, WEI Lan-jun, ZHANG Hui, FU Jing, LIU Jia-xin, ZHANG Lu, YU Liang-qing, JIANG Ying, CHEN Ling, ZHANG Mi, ZHANG Ling 2022, 20 (4):  221-224.  Abstract ( 291 )   PDF (535KB) ( 637 )   Objective To investigate the current situation of knowledge and behavior towards schistosomiasis prevention and health education needs in students from the primary schools in urban area of Yueyang City, Hunan Province, so as to provide evidence for formulating scientific and effective health education program on schistosomiasis prevention in the primary school students. Methods By stratified cluster sampling, students from four classes were recruited from grade 5 and 6 from two schools, respectively, in the urban area and around the Lake of Yueyang City, and underwent questionnaire survey for the relevant knowledge and behavior towards schistosomiasis prevention as well as health education needs. Then the results were statistically analyzed. Results A total of 353 pupils from primary schools located near the Dongting Lake and 363 pupils in the urban center of Yueyang City underwent the survey. There was no significant difference in the age, gender and grades between students from the two schools (t=-0.494, χ2gender=1.615, χ2grade=2.152, both P>0.05). The total knowledge awareness rate of schistosomiasis prevention and control was 42.60% (305/716), and was higher in pupils from the schools located near the Dongting Lake than those from the school in urban center (52.97% vs. 32.51%, χ2=30.661, P<0.05).The total rate of correct preventive behavior was 76.68% (549/716), and the correct rate was higher in students with better knowledge towards schistosomiasis prevention and control than those with poorer awareness (81.31% vs. 71.24%, χ2=6.384, P<0.05).Students' knowledge of schistosomiasis control mostly was from their teachers (47.49%). 91.90% of students were willing to learn more about the knowledge of schistosomiasis control, and their favorite way to learn the knowledge of schistosomiasis prevention and control was to participate in extracurricular activities (50.42%). Conclusion The rate of overall knowledge and preventive behavior towards schistosomiasis prevention and control appears relatively lower in the pupils in Yueyang City, which suggests that it is necessary to improve the health education on schistosomiasis prevention in the students through different means in order to enhance students' awareness of schistosomiasis control and improve their ability in self-protection.  Related Articles | Metrics

Select

Evaluation results of quality control and monitoring ability of schistosomiasis laboratories in Hunan Province in 2021  ZHAO He-qin-hao, XIA Meng, ZHOU Jie, YU Xin-ling, LI Guang-ping, DENG Yi, LUO Zhen-hua, LI Sheng-ming, WANG Hui-lan 2022, 20 (4):  225-227,234.  Abstract ( 264 )   PDF (837KB) ( 259 )   Objective To evaluate the detection capacity of schistosomiasis laboratories at the surveillance sites in Hunan Province for reference in improving the capacity of schistosomiasis surveillance system. Methods By stratified sampling, 12 diagnostic network laboratories were selected from the 57 laboratories designated in 41 count-level schistosomiasis epidemic areas in Hunan Province, and underwent evaluation for the detection ability using standard quality control samples that consisted of serum, Kato-Katz thick smear and egg suspension. The assessment included qualitative and titer determination of the standard sample serum by using indirect hemagglutination assay (IHA), qualification and counting of the schistosome eggs using modified Kato-Katz thick smear, and qualitative detection of the egg suspension using egg hatching method after nylon mesh bag concentration. The tested results at each county-level laboratory were compared with the standard quality control samples based on the coincidence rate and qualification rate of qualitative samples, and evaluated by final scores. Results Qualitative coincidence rate was 96.67% (58/60), 83.33% (50/60) and 91.67% (33/36), respectively for IHA, modified Kato-Katz thick smear and egg hatching method after nylon mesh bag concentration. All tested results met the quality control requirements. The total qualified rate of titer detection of the positive reference by IHA was 54.17% (13/24), and the qualified rate for egg count by modified Kato-Katz thick smear was 30.00% (6/20). Of the 12 diagnostic laboratories at surveillance sites, 7 were rated as "excellent", 2 as "good" and 3 as "qualified". Conclusion The assessment results demonstrate that the ability of schistosomiasis detection at county level in Hunan Province can basically meet the needs of the laboratory diagnosis, yet the quantitative diagnosis of schistosomiasis such as serum titer and egg count requires strengthening. Related Articles | Metrics

Select

Advances in the study of medical helminth infection on host gut microbiome HU Yue, ZHAN Rong-jian, LÜ Zhi-yue 2022, 20 (4):  228-234.  Abstract ( 456 )   PDF (869KB) ( 2440 )   Medical helminth parasitizing in the intestines of mammals and humans can interact with and regulate gut microorganisms, alter the homeostasis and balance of host's intestinal microenvironment, and affect the development, progression and prognosis of diseases. In this paper, the study of medical helminth infection on host gut microbiota before and after treatment were summarized from the aspects of intestinal microecology, immune response and metabolic reaction, in order to provide a new perspective and theoretical basis of intestinal flora on the pathogenesis, diagnosis and treatment of parasitic diseases. Related Articles | Metrics

Select

Research progress in the mechanisms and effects of biological insecticides for mosquitoes LEI Jing-jing, GONG Mao-qing, LIU Li-juan 2022, 20 (4):  235-240.  Abstract ( 508 )   PDF (865KB) ( 1436 )   Mosquitoes not only annoy human beings, but also spread many diseases, seriously threatening human health. Transmission and prevalence of mosquito-borne diseases, such as malaria and dengue fever, are also a serious threat to human health, drive people to pay more attention to the importance of mosquito control. Nowadays, wider use of chemical insecticides makes the problem of drug resistance increasingly serious. However, biological control technology can counteract the drug resistance on the premise of protecting the ecological environment, and has shown favorable application prospect. This paper reviewed the insecticidal mechanism and efficacies of biological insecticides such as bacteria, fungi and viruses for control of mosquitoes. Related Articles | Metrics