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    28 February 2022, Volume 34 Issue 1
    One Health: Re⁃thinking of zoonoses control
    FEI Si⁃wei, XU Jing⁃shan, LÜ Shan, GUO Xiao⁃kui, ZHOU Xiao⁃nong
    2022, 34(1):  1. 
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    Under the dual pressure of emerging zoonoses and the difficulty in eliminating conventional zoonoses, many uncertainties in global control of infectious diseases are challenging the achievement of sustainable development goals set by the United Nations General Assembly. One Health, developed on the basis of understanding the relationship between human diseases and animal diseases, is conducive to the prevention and control of zoonoses. The connotation of “One Health” is mainly explained by three aspects, namely the systems thinking mode of “unity of environment and man”, the practice guidance of “multi⁃sectoral concert” and the economic evaluation strategy of “cost⁃effectiveness analysis”. One Health approach has been successfully applied in the control of major infectious diseases in China, such as schistosomiasis, leading to remarkable achievements; however, there are still multiple challenges. This review proposes that much attention should be paid to top⁃level design, the difference between emerging zoonoses and conventional zoonoses, and the dynamic process of One Health governance during the development and application of One Health.
    Epidemiological trends of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020 based on the Joinpoint regression model
    WU Xin⁃hua, WU Jun, XU Ren⁃mei, XIONG Ying, CHEN Zhe
    2022, 34(1):  7. 
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    Objective To analyze the dynamic changes of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020, so as to provide insight into the development of the schistosomiasis elimination strategy. Methods Schistosomiasis control data were captured from Poyang County from 2004 to 2020, and the epidemiological data of schistosomiasis were collected from national schistosomiasis surveillance sites in Poyang County from 2005 to 2020. The endemic status of schistosomiasis was analyzed in Poyang County from 2004 to 2020, and a Joinpoint regression analysis was performed to investigate the trends of schistosomiasis in Poyang County from 2004 to 2020. Results The sero⁃prevalence and egg⁃prevalence of human Schistosoma japonicum infections reduced from 24.39% (24 976/102 397) and 4.53% (259/5 721) in 2004 to 5.37% (2 421/45 100) [annual percent change (APC) = average annual percent change (AAPC) = -8.64% ] and 0 (0/3 963) in 2020 (APC = AAPC = -32.07%) in Poyang County, and the trends were both significant (both P < 0.01). The sero⁃prevalence of S. japonicum infections reduced from 1.21% (294/24 332) in bovines in 2013 to 0.58% (35/5 999) in 2020 in Poyang County, with one turning point (AAPC = -8.20%,P > 0.05). There were no townships or villages with emerging snail habitats in Poyang County from 2004 to 2020, and there were three turning points of trend in the proportion of snail areas detected in total snail areas (AAPC = -2.30%,P > 0.01).The sero⁃prevalence and adjusted prevalence of S. japonicum infections reduced from 60.82% (742/1 220) and 10.16% (124/1 220) in local residents in 2005 to 5.73% (70/1 221) and 0 in 2020 in national schistosomiasis surveillance sites of Poyang County, and the trends for sero⁃prevalence (APC = AAPC = 17.47%, P < 0.01) and adjusted prevalence of S. japonicum infections (APC = AAPC = -44.92%, P < 0.01) were both statistically significant. S. japonicum infections were identified in 10 (2005) and 2 local livestock (2007), with prevalence of 10.00% (10/100) and 13.33% (2/15), respectively, and S. japonicum infections were detected in snails in 2008 and 2009; however, no positive samples of mixed O. hupensis were detected by loop⁃mediated isothermal amplification. Conclusions The endemic situation of schistosomiasis control had remarkably reduced in Poyang County from 2004 to 2020; however, there are still challenges for consolidating schistosomiasis control achievements and even elimination of schistosomiasis.
    Prevalence of Clonorchis sinensis infections in freshwater fish in mainland China: a meta⁃analysis
    DAI Si⁃min, YU Qing, MA Xiao⁃jiang, WANG Zhen⁃yu, ZHANG Yao⁃guang, ZHU Min, ZHANG Chen⁃gang, ZHU Qian, JIANG Li, JIN Yan⁃jun, PAN Hao, WU Huan⁃yu
    2022, 34(1):  16. 
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    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.
    Analysis of lactate dehydrogenase gene polymorphisms and prediction of B cell epitopes in four human Plasmodium species
    HUANG He⁃rong, DONG Ying, DENG Yan, XU Yan⁃chun, CHEN Meng⁃ni, LIU Yan, ZHANG Cang⁃lin
    2022, 34(1):  28. 
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    Objective To analyze the polymorphism of Plasmodium lactate dehydrogenase (pLDH) gene and predict B⁃cell epitopes in pLDH peptides in four species of human malaria parasites. Methods The blood samples and epidemiological characteristics were collected from malaria cases in Yunnan Province registered in the National Notifiable Disease Report System. The pLDH genes of four human Plasmodium species were amplified using nested PCR assay and sequenced. The polymorphisms of pLDH genes was analyzed using the software MEGA version 7.0.26 and DnaSP version 5.10, and the B⁃cell epitopes were predicted in pLDH peptides using the Immune Epitope Database (IEDB). Results The sequences of P. vivax LDH (PvLDH), P. falciparum LDH (PfLDH), P. ovale LDH (PoLDH) and P. malariae LDH (PmLDH) genes were obtained from 153, 29, 17 and 11 blood samples from patients with P. vivax, P. falciparum, P. ovale and P. malariae malaria, respectively, which included 15, 2, 4 and 2 haplotypes and had a nucleotide diversity (π) of 0.104. A high level of intra⁃species differentiation was seen in the PoLDH gene (π = 0.012), and the π values were all < 0.001 for PvLDH, PfLDH and PmLDH genes. Active regions of B⁃cell antigen were predicted in the pLDH peptide chain of four human malaria parasites, of 4 to 5 in each chain, and the activity score was approximately 0.430. Among these peptide chains, the “86⁃PGKSDKEWNRD⁃96” short⁃peptide was a B⁃cell epitope shared by all four species of human malaria parasites, and the “266⁃GQYGHS (T)⁃271” short⁃peptide was present in PvLDH and PoLDH peptide chains, while “212⁃EEVEGIFDR⁃220” was only found in the PvLDH peptide chain, and “208⁃LISDAE⁃213” was only seen in the PfLDH peptide chain. Conclusions The PoLDH gene polymorphism may be derived from the weak negative purification selection, while PvLDH, PfLDH and PmLDH genes may maintain a relatively conservative state. There may be two B⁃cell epitopes “212⁃EEVEGIFDR⁃220” and “208⁃LISDAE⁃213” in the proximal region of the C terminal in the pLDH peptide chain, which is feasible to differentiate between P. vivax and P. falciparum infections.
    Evaluation of efficiency of different anti⁃cysticercus antibody test kits for serodiagnosis of cysticercosis
    ZHANG Ya⁃lan, JIANG Tian⁃tian, JI Peng⁃hui, HE Zhi⁃quan, CHEN Xi, HONG Yang, ZHAO Dong⁃yang, DENG Yan, CHEN Wei⁃qi, ZHANG Hong⁃wei
    2022, 34(1):  36. 
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    Objective To evaluate the diagnostic efficiency of four anti⁃cysticercus IgG, IgG4 or IgM antibody test kits (enzyme⁃linked immunosorbent assay, ELISA) by different manufacturers, so as to provide insights into the epidemiological investigation and clinical detection of cysticercosis. Methods Forty serum samples from cerebral cysticercosis patients, 100 serum samples from healthy volunteers, 30 serum samples from paragonimiasis skrjabini patients, 17 serum samples from cystic echinococcosis and 19 serum samples from subcutaneous or cerebral sparganosis patients were collected and detected using anti⁃cysticercus IgG, IgG4 or IgM antibody test kits (brand A) and the anti⁃cysticercus IgG antibody test kit (brand B). The sensitivity, specificity and false negative rate of the four kits for detection of cysticercosis were estimated. Results The anti⁃cysticercus IgG, IgG4 or IgM antibody test kits (brand A) showed 95.00% (38/40), 87.50% (35/40), 7.50% (3/40) sensitivities and 98.00% (98/100), 100.00% (100/100) and 100.00% (100/100) for detection of cysticercosis, while the anti⁃cysticercus IgG antibody test kit (brand B) presented a 75.00% (30/40) sensitivity and 100.00% (100/100) specificity for detection of cysticercosis. The sensitivity for detection of cysticercosis was significantly higher by the anti⁃cysticercus IgG antibody test kit (brand A) than by the anti⁃cysticercus IgG antibody test kit (brand B) ([χ2] = 6.28, P < 0.05); however, no significant difference was seen in the specificity by two kits ([χ2] = 2.01, P > 0.05). The four ELISA kits showed overall false positive rates of 37.88% (25/66), 22.73% (15/66), 62.12% (41/66) and 15.15% (10/66) for detection of paragonimiasis, echinococcosis and sparganosis ([χ2] = 37.61, P < 0.05), and the anti⁃cysticercus IgG antibody test kit (brand A) presented the highest overall false positive rate for detection of paragonimiasis, echinococcosis and sparganosis ([χ2] = 7.56, P' < 0.008), while a higher overall false positive rate was seen for detection of paragonimiasis, echinococcosis and sparganosis by the anti⁃cysticercus IgG antibody test kit (brand A) than by the anti⁃cysticercus IgG antibody test kit (brand B) ([χ2] = 8.75, P' < 0.008). The four ELISA kits showed false positive rates of 40.00% (12/30), 16.67% (5/30), 76.67% (23/30) and 13.33% (4/30) for detection of paragonimiasis ([χ2] = 32.88, P < 0.05) and 21.05% (4/19), 26.32% (5/19), 73.68% (14/19) and 15.79% (3/19) for detection of sparganosis ([χ2] = 19.97, P < 0.05), and the highest false positive rates were found by the anti⁃cysticercus IgM antibody test kit (brand A) for detection of paragonimiasis and sparganosis (all P' < 0.008). However, the four ELISA kits showed comparable false positive rates of 52.94% (9/17), 29.41% (5/17), 23.53% (4/17) and 17.65% (3/17) for detection of echinococcosis ([χ2] = 8.24, P > 0.05). In addition, the anti⁃cysticercus IgM antibody test kit (brand A) showed false positive rates of 76.67% (23/30), 23.53% (4/17) and 73.68% (14/19) for detection of paragonimiasis, echinococcosis and sparganosis ([χ2] = 14.537, P < 0.05), with the lowest false positive rate seen for detection of echinococcosis ([χ2] = 14.537, P' < 0.014), while no significant differences were seen in the false positive rate for detection of paragonimiasis, echinococcosis and sparganosis by other three ELISA kits (all P > 0.05). Conclusions The four anti⁃cysticercus IgG, IgG4 or IgM antibody test kits exhibit various efficiencies for serodiagnosis of cysticercosis. The anti⁃cysticercus IgG antibody test kit (brand A) has a high sensitivity for serodiagnosis of cysticercosis; however, it still needs to solve the problems of cross⁃reaction with other parasitic diseases and stability.
    Preliminary study on differentially expressed proteins in a mouse model of secondary cystic echinococcosis based on data independent acquisition proteomics
    HAN Shuang, MA Jun⁃ying, ZHANG Xue⁃fei, WANG Hu, SUN Xi, MA Xiao, LIU Jia, GUO Shuai, HAN De⁃hong, SI Xiao⁃mei
    2022, 34(1):  41. 
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    Objective To identify the differentially expressed proteins in different liver tissues in the mouse model of cystic echinococcosis (CE), so as to provide insights into the research and development of therapeutic drugs targeting CE. Methods Female Kunming mice at ages of 6 to 8 weeks were randomly assigned into the CE group and the control group. Mice in the CE group were intraperitoneally infected with 2 000 Echinococcus multilocularis protoscoleces, while mice in the control group were injected with the same volume of physiological saline. All mice in both groups were sacrificed after breeding for 350 d, and the lesions (the lesion group) and peri⁃lesion specimens (the peri⁃lesion group) were sampled from the liver of mice in the CE group and the normal liver specimens (the normal group) were sampled from mice in the control group for data independent acquisition (DIA) proteomics analysis, and the differentially expressed proteins were subjected to Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Results A total of 26 differentially expressed proteins were identified between the lesion group and the normal group and between the peri⁃lesion group and the normal group, including 8 up⁃regulated proteins and 18 down⁃regulated proteins. GO term enrichment analysis showed that these differentially expressed proteins were predominantly enriched in endoplasmic reticulum membrane (biological components), oxidoreductase activity (molecular function) and oxoacid metabolic process and monocarboxylic acid metabolic process (biological processes). KEGG pathway enrichment analysis revealed that the differentially expressed protein Acyl⁃CoA oxidase 1 (Acox1), which contributed to primary bile acid biosynthesis during the fatty acid oxidation, was involved in peroxisome signaling pathway, and the differentially expressed protein fatty acid binding protein 1 (Fabp1), which contributed to fatty acid transport, was involved in the peroxisome proliferator⁃activated receptor (PPAR) signaling pathway. Conclusion Differentially expressed proteins are identified in the liver specimens between mouse models of CE and normal mice, and some differentially expressed proteins may serve as potential drug targets for CE.
    Preliminary study on differentially expressed proteins in a mouse model of secondary alveolar echinococcosis based on data independent acquisition proteomics
    SI Xiao⁃mei, MA Jun⁃ying, ZHANG Xue⁃fei, WANG Hu, SUN Xi, MA Xiao, WANG Wei, LIU Yu⁃fang, LIU Jia, GUO Shuai, HAN De⁃hong, HAN Shuang
    2022, 34(1):  52. 
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    Objective To identify the differentially expressed proteins in different liver tissues in the mouse model of alveolar echinococcosis using high⁃resolution mass spectrometry with data independent acquisition (DIA), and to identify the key proteins contributing to the pathogenesis of alveolar echinococcosis. Methods Protoscoleces were isolated from Microtus fuscus with alveolar echinococcosis and the experimental model of alveolar echinococcosis was established in female Kunming mice aged 6 to 8 weeks by infection with Echinococcus multilocularis protoscoleces. Mice were divided into the experimental and control groups, and animals in the experimental group was injected with approximately 3 000 protoscoleces, while mice in the control group were injected with the same volume of physiological saline. Mouse liver specimens were sampled from both groups one year post⁃infection and subjected to pathological examinations. In addition, the lesions (the lesion group) and peri⁃lesion specimens (the peri⁃lesion group) were sampled from the liver of mice in the experimental group and the normal liver specimens (the normal group) were sampled from mice in the control group for DIA proteomics analysis, and the differentially expressed proteins were subjected to bioinformatics analysis. Results A total of 1 020 differentially expressed proteins were identified between the lesion group and the normal group, including 671 up⁃regulated proteins and 349 down⁃regulated proteins, and 495 differentially expressed proteins were identified between the peri⁃lesion group and the normal group, including 327 up⁃regulated proteins and 168 down⁃regulated proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that these differentially expressed proteins were involved in peroxisome, peroxisome proliferator⁃activated receptor (PPAR) and fatty acid degradation pathways, and the peroxisome and PPAR signaling pathways were found to correlate with liver injury. Several differentially expressed proteins that may contribute to the pathogenesis of alveolar echinococcosis were identified in these two pathways, including fatty acid binding protein 1 (Fabp1), Acyl⁃CoA synthetase long chain family member 1 (Acsl1), Acyl⁃CoA oxidase 1 (Acox1), Enoyl⁃CoA hydratase and 3⁃hydroxyacyl CoA dehydrogenase (Ehhadh) and Acetyl⁃Coenzyme A acyltransferase 1B (Acaa1b), which were down⁃regulated in mice in the experimental group. Conclusion A large number of differentially expressed proteins are identified in the liver of the mouse model of alveolar echinococcosis, and Fabp1, Acsl1, Acox1, Ehhadh and Acaa1b may contribute to the pathogenesis of alveolar echinococcosis.
    Morphological and molecular identification of trematode isloates from laying ducks in Nanchang City
    WANG Pei, PU Wen⁃jing, TAN Hui⁃zhen, WANG Ping, CHEN Xiao⁃qing
    2022, 34(1):  59. 
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    Objective To identify the species of trematodes isolated from laying ducks in Nanchang City using morphological and molecular approaches. Methods Trematodes were isolated from the hepatobiliary duct, gallbladder and large intestine of market⁃sold laying ducks in Nanchang City. Following morphological characterization, total DNA was extracted from all trematode specimens, and internal transcribed spacer region (ITS) and cytochrome C oxidase subunit 1 (Cox1) genes were amplified using PCR assay and sequenced. Sequence alignment was performed using the Blast software, and homology and phylogenetic analyses were done in the trematode isolates based on ITS and Cox1 gene sequences. Results The morphological characteristics of two trematode isolates from the large intestine of laying ducks were similar to those of Echinostoma revolutum and E. miyagawai, and the morphological characteristics of eight trematode samples isolated from the hepatobiliary duct and gallbladder of laying ducks were similar to those of Amphimerus anatis. The ITS and Cox1 gene sequences of the two trematode isolates from the large intestine of laying ducks had 99.3% and 98.9%-99.4% homology with E. miyagawai, and the phylogenetic analysis showed that two trematode isolates had the closest genetic relationship with E. miyagawai based on ITS and Cox1 gene sequences. The ITS gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 95.1%-95.5% with Opisthorchis sudarikovi and Clonorchis sinensis, while the Cox1 gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 86.3%-86.4% and 85.5%-85.7% with O. viverrini and O. sudarikovi. ITS gene sequence⁃based phylogenetic analysis showed that the duck⁃derived trematode isolates had the closest genetic relationship with C. sinensis, and Cox1 gene sequence⁃based phylogenetic analysis showed that the duck⁃derived trematode isolates had the closest genetic relationship with Metorchis orientalis and O. viverrini. Conclusions The trematode isolates from the large intestine of laying ducts in Nanchang City may be E. miyagawai, and the trematode isolates from the hepatobiliary duct and gallbladder may be an unidentified trematode species of the family Opisthorchiidae.
    Epidemiological characteristics of imported Plasmodium ovale malaria in Jiangsu Province from 2012 to 2020
    WANG Wei⁃ming, CAO Yuan⁃yuan, YANG Meng⁃meng, LU Yan, GU Ya⁃ping, XU Sui, ZHOU Hua⁃yun, ZHU Guo⁃ding
    2022, 34(1):  66. 
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    Objective To analyze the epidemiological characteristics of imported cases with Plasmodium ovale infections in Jiangsu Province from 2012 to 2020, so as to provide insights into the development of the imported malaria control strategy in the province. Methods All data pertaining to cases with definitive diagnosis of P. ovale malaria in Jiangsu Province from 2012 to 2020 were captured from the National Notifiable Disease Report System and the Information Management System for Parasitic Disease Control in China, including the date of going abroad and returning to China, time of malaria infections overseas, date of malaria onset, initial diagnosis and definitive diagnosis. All data pertaining to epidemic status were descriptively analyzed. Results A total of 347 cases of P. ovale malaria were reported in Jiangsu Province from 2012 to 2020, with the highest number seen in 2015 (71 cases). All cases were laboratory⁃confirmed overseas imported malaria cases, accounting for 14.32% of all reported malaria cases in Jiangsu Province during the period from 2012 to 2020. The 5 cities with the highest number of imported P. ovale malaria cases included Lianyungang City (53 cases, 15.27%), Nantong City (44 cases, 12.68%), Huai’an (44 cases, 12.68%), Taizhou City (44 cases, 12.68%) and Yangzhou City (36 cases, 10.37%). The highest number of imported P. ovale malaria cases was reported in October (39 cases, 11.24%), and the lowest number was seen in December (21 cases, 6.05%). P. ovale infections mainly occurred in were Equatorial Guinea (97 cases, 37.95%), Angola (60 cases, 17.29%) and Nigeria (40 cases, 11.53%). The median duration between returning to China and malaria onset was 64 (144) days, and 7.49% (26/347) of all cases developed malaria one year after returning to China. The initial diagnosis of P. ovale malaria was mainly made at county⁃level medical institutions (117 cases, 33.72%), and the definitive diagnosis was mainly made at city⁃level medical institutions (122 cases, 35.16%). The correct rate of initial diagnosis of P. ovale malaria increased from 0 in 2012 to 78.26% in 2020, appearing a tendency towards a rise year by year ([χ2] = 50.90, P < 0.01). Conclusions Imported P. ovale malaria cases were reported in Jiangsu Province each year from 2012 to 2020, and P. ovale infections predominantly occurred in Africa. Initial and definitive diagnoses of P. ovale malaria were mainly made at city⁃ and county⁃level medical institutions. Training on the detection ability of malaria parasites is recommended among grassroots microscopists to improve the diagnostic ability of P. ovale malaria, and consolidate the achievements of malaria elimination in Jiangsu Province.
    Effectiveness of integrated schistosomiasis control in Changzhou City from 2015 to 2020
    HE Ming⁃zhen, XIE Yi⁃qing, ZOU Yong⁃gen, ZHU Shi⁃ying, GUO Yan⁃li
    2022, 34(1):  72. 
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    Objective To evaluate the effectiveness of the integrated schistosomiasis control measures in Changzhou City from 2015 to 2020, so as to provide insights into the formulation of the strategy used to consolidate the schistosomiasis elimination achievements. Methods The annual schistosomiasis control working report and integrated schistosomiasis control data were collected in Changzhou City from 2015 to 2020, and the prevalence of Schistosoma japonicum infections in humans and livestock and snail status were analyzed to evaluate the effectiveness of the integrated schistosomiasis control measures. Results  During the period from 2015 to 2020, a total of 112 061 person⁃time individuals received serological tests for S. japonicum infections in Changzhou City, and the sero⁃prevalence was 0.15% to 1.09% during the 6⁃year period, with a significant difference seen among years ([χ2] = 288.11, P < 0.05). From 2015 to 2020, a total of 13 435 person⁃time individuals received stool examinations, with no egg⁃positives identified; among 5 840 herd⁃time livestock receiving schistosomiasis examinations, no positives were detected, while a 100% coverage of fencing livestock was seen each year. During the 6⁃year period, a total of 38.40 hm2 snail habitats were found, including 8.97 hm2 emerging snail habitats, and among the 2 344 snails dissected, no S. japonicum infection was found. Chemical treatment covered an area of 385.71 hm2, and environmental improvements covered an area of 200.39 hm2. The mean density of living snails was less than 0.1 snails/0.1 m2 in snail habitats found in Changzhou City each year from 2015 to 2020, and the coverage of harmless toilets was 100% in 2020. During the 6⁃year period, a total of 3.740 6 million person⁃time individuals were given schistosomiasis health education in Changzhou City. Conclusions Changzhou City is now at the post⁃elimination surveillance stage; however, there are still factors affecting schistosomiasis transmission. The schistosomiasis surveillance system remains to be improved to consolidate the schistosomiasis elimination achievements in Changzhou City.
    Effects of praziquantel isomers on the proliferation and activation of the LX⁃2 human hepatic stellate cell line
    YUAN Xuan, ZHANG Su⁃yang, YAO Jia⁃kai, XING Yun⁃tian, QU Guo⁃li, LIANG You⁃sheng, DAI Jian⁃rong
    2022, 34(1):  75. 
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    Objective To compare the effects of levo⁃praziquantel (L⁃PZQ) and dextro⁃praziquantel (D⁃PZQ) on the proliferation and activation of the human hepatic stellate cell line LX⁃2 in vitro. Methods LX⁃2 cells were stimulated with transforming growth factor⁃β (TGF⁃β). LX⁃2 cell proliferation was measured using the CCK⁃8 assay after 24 h stimulation with 0 to 50 μg/mL concentrations of praziquantel, and the gene and protein expression of typeⅠcollagen (collagenⅠ), type Ⅲ collagen (collagen Ⅲ) and α⁃smooth muscle actin (α⁃SMA) was quantified in LX⁃2 cells using quantitative real⁃time PCR (qPCR) and Western blotting assays 24 h and 48 h following stimulation with 15 μg/mL praziquantel to detect LX⁃2 cell activation. Results There were significant differences in the survival rate of LX⁃2 cells between L⁃PZQ and D⁃PZQ treatments at all concentrations (F = 6.119 and 79.180, both P values < 0.05). Either L⁃PZQ or D⁃PZQ at a concentration of < 30 μg/mL showed no remarkable effects on the LX⁃2 cell proliferation (both P values > 0.05), and L⁃PZQ at a concentration of > 50 μg/mL and D⁃PZQ at a concentration of > 40 μg/mL inhibited the LX⁃2 cell proliferation (both P values < 0.05), while D⁃PZQ at concentrations of 40 μg/mL and 50 μg/mL showed greater inhibition on LX⁃2 cell proliferation than L⁃PZQ (t = 3.419 and 8.776, both P values < 0.05). There were significant differences in the collagenⅠ, collagen Ⅲ and α⁃SMA expression in LX⁃2 cells at both transcriptional (F = 21.55, 79.99 and 46.70, all P values < 0.05) and translational levels (F = 20.12, 30.29 and 32.93, all P values < 0.05) among the blank control group, TGF⁃β stimulation group, L⁃PZQ treatment group and D⁃PZQ treatment group. L⁃PZQ treatment resulted in remarkable inhibition on collagen Ⅲ and α⁃SMA gene expression in LX⁃2 cells (both P values < 0.05); however, the treatment showed no remarkable inhibition collagenⅠ gene expression or collagenⅠ, collagen Ⅲ or α⁃SMA protein expression in LX⁃2 cells (all P values > 0.05). In addition, D⁃PZQ treatment resulted in significant inhibition on collagenⅠ, collagen Ⅲ and α⁃SMA expression in LX⁃2 cells at both translational and transcriptional levels (all P values < 0.05), and D⁃PZQ showed higher inhibition on collagenⅠ, collagen Ⅲ and α⁃SMA gene expression in LX⁃2 cells than L⁃PZQ (all P values < 0.05). Conclusions Both L⁃PZQ and D⁃PZQ inhibit the proliferation and activation of LX⁃2 cells, and D⁃PZQ shows a higher inhibitory activity than L⁃PZQ.
    Performance of loop⁃mediated isothermal amplification (LAMP) assay for detection of Schistosoma japonicum infection in Oncomelania snails in schistosomiasis transmission⁃interrupted regions
    CHEN Feng, LI Ke⁃rong, LI Wen⁃bao, TIAN Shu⁃hui, LI Ping, ZHAO Yin⁃jiao, YANG Jing, YANG Hua, LUO Bing⁃rong, MA Jun⁃hua, HAO Ming⁃ming, CHEN Shao⁃rong, LIU Yu⁃hua, LUO Tian⁃peng
    2022, 34(1):  81. 
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    Objective To compare the effectiveness of loop⁃mediated isothermal amplification (LAMP) assay and microscopic examinations for detection of Schistosoma japonicum infections in Oncomelania hupensis in transmission⁃interrupted regions, so as to provide insights into the optimization of snail surveillance tools in these regions. Methods Four hilly schistosomiasis⁃endemic villages where transmission interruption was achieved were selected in Heqing County of Yunnan Province as the study villages, including Xinzhuang and Gule villages in hilly regions and Lianyi and Yitou villages in dam regions. Snail survey was performed by means of systematic sampling combined with environmental sampling in July 2018. All captured snails were identified for S. japonicum infections using microscopy. In addition, 10 to 20 snails were randomly sampled from each snail habitat following microscopy, numbered according to environments and subjected to LAMP assay. The positive rate of settings with S. japonicum⁃infected snails was compared among villages. Results A total of 7 949 living snails were captured from 83 snail habitats in 4 villages, and no S. japonicum infection was detected in snails. There were 22 mixed samples containing 1 786 snails subjected to LAMP assay, and positive LAMP assay was found in 3 mixed samples from 3 snail habitats in 2 dam villages. The positive rates of settings with S. japonicum⁃infected snails were comparable between Lianyi Village (one setting) and Yitou Village (2 settings) (5.89% vs. 14.29%, P = 0.344). However, the overall positive rate of settings with S. japonicum⁃infected snails was significantly higher in dam villages (9.67%, 3/31) than in hilly villages (0) (P = 0.048). Conclusions LAMP assay is more sensitive to detect S. japonicum infections in O. hupensis than conventional microcopy method, which may serve as a supplementary method for detection of S. japonicum infections in O. hupensis in high⁃risk snail habitats in hilly transmission⁃interrupted regions.
    Effects of nitroquine on the development of Plasmodium yoelii at different stages in Anopheles stephensi
    TAN Nie, ZHU Feng, DING Yan, XU Wen⁃yue, ZHANG Jian
    2022, 34(1):  85. 
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    Objective To investigate the effects of nitroquine on the development of different stages of Plasmodium yoelii in Anopheles stephensi. Methods An. stephensi mosquitoes were fed with conventional sucrose water or sucrose water containing 100 μmol/L nitroquine one day prior to P. yoelii infection. Following starvation for 24 hours, mosquitoes were fed with the blood of Kunming mice infected with P. yoelii, and the number of oocysts was observed in the stomach of An. stephensi. After 6 days and 14 days of infection, the mosquitoes were starved for 24 hours, and then fed with conventional sucrose water or nitroquine treated sucrose water. The An. stephensi mosquitoes were starved for 24 hours 6 and 14 days post⁃infection with P. yoelii, and then fed with conventional sucrose water or nitroquine⁃containing sucrose water, the numbers of P. yoelii sporozoites were examined in the hemolymph and salivary glands of An. stephensi. Results Following exposure to nitroquine⁃containing sucrose water one day prior to P. yoelii infections, the number of P. yoelii oocysts was significantly lower in the An. stephensi stomach on day 7 (119.2 ± 16.1 vs. 207.3 ± 21.8; t = 3.207, P < 0.05). After conventional sucrose water was ceased for 24 hours on day 6, and An. stephensi was fed with nitroquine⁃containing sucrose water, the number of P. yoelii sporozoites peaked in the hemolymph on day 14 in the nitroquine treatment group (952.3 ± 22.7) and on day 12 in the sucrose water treatment group (1 287.0 ± 39.0), and there was a significant difference in the number of sporozoites in the salivary glands between the nitroquine treatment group and the sucrose water treatment group (9 467.0 ± 1 304.0 vs. 10 533.0 ± 758.7; t = 0.707, P = 0.506) on day 17. After conventional sucrose water was ceased for 24 hours on day 14, and An. stephensi was fed with nitroquine⁃containing sucrose water, the number of sporozoites in the salivary glands was significantly greater in the nitroquine treatment group than in the sucrose water treatment group (21 900.0 ± 2 613.0 vs. 10 533.0 ± 732.3; t = 4.188, P < 0.05). Conclusions Nitroquine treatment exhibits diverse effects the development of different stages of P. yoelii, and nitroquine treatment may reduce the transmission of P. yoelii in uninfected An. stephensi.
    Surveillance of human soil⁃transmitted nematodiasis in Jurong City from 2016 to 2020
    ZHAO Qing⁃hua, CAO Jun, LI Shui⁃ming, HOU Jin⁃hua, WU Dan, ZHANG Yu⁃han, JIANG Cheng⁃gong
    2022, 34(1):  89. 
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    Objective To investigate the prevalence of soil⁃transmitted nematode human infections in Jurong City from 2016 to 2020, so as to provide the scientific evidence for formulating the control strategy. Methods During the period from 2016 to 2020, the permanent residents at ages of over 3 years living in Jurong City were selected as the study subjects. Stool samples were collected for the detection of soil⁃transmitted nematode eggs using the modified Kato⁃Katz thick smear method (two detections for one stool sample), and the species of hookworm was identified in stool⁃positive stool samples using the culture method. The prevalence and intensity of soil⁃transmitted nematode infections were calculated, and the change of the infection prevalence among years was examined using the Cochran⁃Armitage test for trend. Results A total of 10 011 people⁃time populations were detected for soil⁃transmitted nematode infections in Jurong City from 2016 to 2020, and 56 egg⁃positives were identified, with mean prevalence of 0.56%. The prevalence of soil⁃transmitted nematode human infections appeared a tendency towards a decline year by year in Jurong City ([χ2]trend = 5.15, P < 0.01). The mean prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infections was 0.44%, 0.11% and 0.20% in Jurong City from 2016 to 2020, respectively, and individuals with hookworm infections accounted for 78.57% of all cases with soil⁃transmitted nematode infections. Single parasite (98.21%) and mild infection were predominant in individuals with soil⁃transmitted nematode infections, and no multiple infections were seen after 2016. Conclusions The prevalence of human soil⁃transmitted nematodiasis is low in Jurong City. Based on reinforcement of soil⁃transmitted nematodiasis surveillance, an increase in the health education investment is required to consolidate the control achievements.
    Surveillance of soil⁃borne nematodiasis in Yancheng City from 2016 to 2020
    SUN Bo⁃chao, YAO Xue⁃jun, XU Zhong⁃mei
    2022, 34(1):  92. 
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    Objective To understand the prevalence of soil⁃transmitted nematode infections in Yancheng City from 2016 to 2020, so as to provide insights into the development of the scheme for further soil⁃transmitted nematodiasis surveillance. Methods Soil⁃borne nematode infections were detected using the modified Kato⁃Katz method (two slides for one sample) among the permanent residents living in Yancheng City from 2016 to 2020, and Enterobius vermicularis infection was additionally detected among children at ages of 12 years and lower using the adhesive cellophane⁃tape perianal swab method. The prevalence and intensity of human soil⁃borne nematode and E. vermicularis infections were descriptively analyzed. Results A total of 51 259 person⁃time residents were detected for soil⁃borne nematode infections in Yancheng City from 2016 to 2020, and 48 egg⁃positives were identified, with a 0.09% prevalence. The soil⁃borne nematodes infecting residents included Ascaris lumbricoides, hookworm and Trichuris trichiura, with 0.04%, 0.05% and 0.002% prevalence rates of infections, and all infections were mild. There was a region⁃specific prevalence of soil⁃borne nematode infections in Yancheng City ([χ2] = 18.21, P = 0.02), with the highest prevalence seen in Funing County (0.21%), while no infections were detected in Dafeng District for five successive years. The overall prevalence of E. vermicularis infections was 0.22% among children at ages of 12 years and lower in Yancheng City. Conclusions The prevalence of soil⁃borne nematode infections appears a gradual decline in residents living in Yancheng City from 2016 to 2020, and is at an extremely low level. Further surveillance of soil⁃transmitted nematodiasis requires to be intensified targeting key regions and populations to consolidate the control achievements.
    Progress of researches on approaches for estimating the burden of vector⁃borne diseases
    LI Qin, ZHOU Xiao⁃nong
    2022, 34(1):  95. 
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    The burden of vector⁃borne diseases refers to the loss and impact of healthy life and social economy due to disability and early death caused by vector⁃borne diseases, including economic burden and family burden. Disability⁃adjusted life year (DALY) is a comprehensive measure of the burden of disease. The economic burden of disease is classified into direct economic burden, indirect economic burden and intangible economic burden. Currently, the estimates of direct economic burdens include micro⁃cost and macro⁃cost models, and the estimates of indirecteconomic burdens include human resources and friction cost methods, while the intangible economic burden is generally estimated by willingness to pay. The currently available health economics approaches mainly include cost⁃utility analysis, cost⁃benefit analysis and cost⁃effectiveness analysis. This review summarizes the approaches for estimating the burden of malaria and other vector⁃borne diseases.
    Progress of researches on anti⁃infective properties of epigallocatechin⁃3⁃gallate
    DU Wei⁃qin, XUE Ting
    2022, 34(1):  102. 
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    (⁃)⁃epigallocatechin⁃3⁃O⁃gallate (EGCG) is the most abundant polyphenol in green tea, which has shown antioxidant, anti⁃inflammatory, anti⁃thrombotic, anti⁃radiation, anti⁃mutant, anti⁃cancer and anti⁃fibrotic actions, and has shown improvements of diabetes, obesity, asthma, cancer, cardiovascular diseases and central nervous system disorders. In addition, EGCG is reported to enhance the human immunity. Recently, EGCG has been found to play a vital role in infectious diseases caused by pathogenic microorganisms, including bacteria, fungi, viruses and parasites. The review summarizes the progress of researches on anti⁃infective properties of EGCG, so as to elucidate the potential role of EGCG in the prevention and treatment of infectious diseases.