Table of Content

06 July 2022, Volume 34 Issue 3

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Analysis of the new WHO guideline to accelerate the progress towards elimination of schistosomiasis in China

GUO Zhao-yu, FENG Jia-xin, ZHANG Li-juan, ZHOU Yi-biao, ZHOU Jie, YANG Kun, LIU Yang, LIN Dan-dan, LIU Jian-bing, Dong Yi, WANG Tian-ping, WEN Li-yong, JI Min-jun, WU Zhong-dao, JIANG Qing-wu, LIANG Song, GUO Jia-gang, CAO Chun-li, XU Jing, LÜ Shan, LI Shi-zhu, ZHOU Xiao-nong

2022, 34(3):  217. 

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On February 2022, WHO released the evidence-based guideline on control and elimination of human schistosomiasis, with aims to guide the elimination of schistosomiasis as a public health problem in disease-endemic countries by 2030 and promote the interruption of schistosomiasis transmission across the world. Based on the One Health concept, six evidence-based recommendations were proposed in this guideline. This article aims to analyze the feasibility of key aspects of this guideline in Chinese national schistosomiasis control program and illustrate the significance to guide the future actions for Chinese national schistosomiasis control program. Currently, the One Health concept has been embodied in the Chinese national schistosomiasis control program. Based on this new WHO guideline, the following recommendations are proposed for the national schistosomiasis control program of China: (1) improving the systematic framework building, facilitating the agreement of the cross-sectoral consensus, and building a high-level leadership group; (2) optimizing the current human and livestock treatments in the national schistosomiasis control program of China; (3) developing highly sensitive and specific diagnostics and the framework for verifying elimination of schistosomiasis; (4) accelerating the progress towards elimination of schistosomiasis and other parasitic diseases through integrating the national control programs for other parasitic diseases. 　

Decoding the evolution of preventive chemotherapy schemes for schistosomiasis in China to improve the precise implementation of the WHO guideline on control and elimination of human schistosomiasis

XU Jing, LI Yi⁃feng, DONG Yi, ZHAO Zheng⁃yuan, WEN Li⁃yong, ZHANG Shi⁃qing, LIN Dan⁃dan, ZHOU Jie, LIANG Song, GUO Jia⁃gang, LI Shi⁃zhu, ZHOU Xiao⁃nong

2022, 34(3):  223. 

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Preventive chemotherapy is one of the pivotal interventions for the control and elimination of schistosomiasis, which is effective to reduce the morbidity and prevalence of schistosomiasis. In order to promote the United Nations’ sustainable development goals and the targets set for schistosomiasis control in the Ending the neglect to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021—2030, WHO released the guideline on control and elimination of human schistosomiasis in 2022, with major evidence⁃based updates of the current preventive chemotherapy strategy for schistosomiasis. In China where great success has been achieved in schistosomiasis control, the preventive chemotherapy strategy for schistosomiasis has been updated several times during the past seven decades. This article reviews the evolution of the WHO guidelines on preventive chemotherapy and Chinese national preventive chemotherapy schemes, compares the current Chinese national preventive chemotherapy scheme and the recommendations for preventive chemotherapy proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, and proposes recommendations for preventive chemotherapy during the future implementation of the 2022 WHO guideline, so as to provide insights into schistosomiasis control among public health professionals engaging in healthcare foreign aid.

Contribution to global implementation of WHO guideline on control and elimination of human schistosomiasis by learning successful experiences from the national schistosomiasis control program in China

WANG Xin⁃yao, ZHANG Jian⁃feng, GUO Jia⁃gang, LÜ Shan, JI Min⁃jun, WU Zhong⁃dao, ZHOU Yi⁃biao, JIANG Qing⁃wu, ZHOU Jie, LIU Jian⁃bing, LIN Dan⁃dan, WANG Tian⁃ping, DONG Yi, LIU Yang, LI Shi⁃zhu, YANG Kun

2022, 34(3):  230. 

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Schistosomiasis is a parasitic disease that seriously hinders socioeconomic developments and threatens public health security. To achieve the global elimination of schistosomiasis as a public health problem by 2030, WHO released the guideline on control and elimination of human schistosomiasis on February, 2022, with aims to provide evidence⁃based recommendations for schistosomiasis morbidity control, elimination of schistosomiasis as a public health problem, and ultimate interruption of schistosomiasis transmission in disease⁃endemic countries. Following concerted efforts for decades, great achievements have been obtained for schistosomiasis control in China where the disease was historically highly prevalent, and the country is moving towards schistosomiasis elimination. This article reviews the successful experiences from the national schistosmiasis control program in China, and summarizes their contributions to the formulation and implementation of the WHO guideline on control and elimination of human schistosomiasis. With the progress of the “Belt and Road” initiative, the world is looking forward to more China’s solutions on schistosomiasis control.

Sharing the WHO guideline on control and elimination of human schistosomiasis to achieve the goal of schistosomiasis elimination in China

WANG Tian⁃ping, LÜ Shan, QIN Zhi⁃qiang, ZHOU Yi⁃biao, LIU Yang, WEN Li⁃yong, GUO Jia⁃gang, XU Jing, LI Shi⁃zhu, ZHANG Guang⁃ming, ZHANG Shi⁃qing

2022, 34(3):  235. 

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Currently, the national schistosomiasis control program of China is moving from transmission interruption to elimination, and there are multiple challenges during the stage moving towards the progression of schistosomiasis elimination, including a high difficulty in shrinking snail⁃infested areas, unstable achievements for infectious source control, imperfect surveillance system and a reduction in schistosomiasis control and administration. Based on the core suggestions proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, recommendations on schistosomiasis surveillance system building, development of novel diagnostics, adjustment of the schistosomiasis control strategy and maintaining and improvements of the schistosomiasis control capability are proposed for the national schistosomiasis control program of China in the new era according to the actual status of schistosomiasis control in China. Formulation of the national schistosomiasis control strategy and goal from One Health perspective, verification of transmission interruption and elimination of schistosomiasis, precision implementation of schistosomiasis control interventions with adaptations to local circumstances, development and application of highly sensitive and specific diagnostics are recommended for elimination of schistosomiasis in China. In addition, the implementation of the 2022 WHO guideline on control and elimination of human schistosomiasis may guide the elimination of schistosomiasis in China.

Prediction of trends for fine⁃scale spread of Oncomelania hupensis in Shanghai Municipality based on supervised machine learning models

GONG Yan⁃feng, LUO Zhuo⁃wei, FENG Jia⁃xin, XUE Jing⁃bo, GUO Zhao⁃yu, JIN Yan⁃jun, YU Qing, XIA Shang, LÜ Shan, XU Jing, LI Shi⁃zhu

2022, 34(3):  241. 

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Objective　To predict the trends for fine⁃scale spread of Oncomelania hupensis based on supervised machine learning models in Shanghai Municipality, so as to provide insights into precision O. hupensis snail control. Methods　Based on 2016 O. hupensis snail survey data in Shanghai Municipality and climatic, geographical, vegetation and socioeconomic data relating to O. hupensis snail distribution, seven supervised machine learning models were created to predict the risk of snail spread in Shanghai, including decision tree, random forest, generalized boosted model, support vector machine, naive Bayes, k⁃nearest neighbor and C5.0. The performance of seven models for predicting snail spread was evaluated with the area under the receiver operating characteristic curve (AUC), F1⁃score and accuracy, and optimal models were selected to identify the environmental variables affecting snail spread and predict the areas at risk of snail spread in Shanghai Municipality. Results　Seven supervised machine learning models were successfully created to predict the risk of snail spread in Shanghai Municipality, and random forest (AUC = 0.901, F1⁃score = 0.840, ACC = 0.797) and generalized boosted model (AUC= 0.889, F1⁃score = 0.869, ACC = 0.834) showed higher predictive performance than other models. Random forest analysis showed that the three most important climatic variables contributing to snail spread in Shanghai included aridity (11.87%), ≥ 0 ℃ annual accumulated temperature (10.19%), moisture index (10.18%) and average annual precipitation (9.86%), the two most important vegetation variables included the vegetation index of the first quarter (8.30%) and vegetation index of the second quarter (7.69%). Snails were more likely to spread at aridity of < 0.87, ≥ 0 ℃ annual accumulated temperature of 5 550 to 5 675 ℃, moisture index of > 39% and average annual precipitation of > 1 180 mm, and with the vegetation index of the first quarter of > 0.4 and the vegetation index of the first quarter of > 0.6. According to the water resource developments and township administrative maps, the areas at risk of snail spread were mainly predicted in 10 townships/subdistricts, covering the Xipian, Dongpian and Tainan sections of southern Shanghai. Conclusions　Supervised machine learning models are effective to predict the risk of fine⁃scale O. hupensis snail spread and identify the environmental determinants relating to snail spread. The areas at risk of O. hupensis snail spread are mainly located in southwestern Songjiang District, northwestern Jinshan District and southeastern Qingpu District of Shanghai Municipality.

Spatio⁃temporal distribution characteristics of Oncomelania hupensis in Anhui Province from 2011 to 2020

WANG Can, XU Xiao⁃juan, GAO Feng⁃hua, ZHANG Li⁃juan, LÜ Shan, ZHANG Shi⁃qing, XU Jing

2022, 34(3):  252. 

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Objective　To analyze the spatial⁃temporal distribution characteristics of Oncomelania hupensis snails in Anhui Province from 2011 to 2020, to provide insights into precision control of O. hupensis snails in Anhui Province. Methods　O. hupensis snail distribution data were collected in Anhui Province from 2011 to 2020 and descriptively analyzed, including actual area of snail habitats, area of emerging snail habitats and area of Schistosoma japonicum⁃infected snails. The actual area of snail habitats and area of emerging snail habitats were subjected to spatial autocorrelation analysis, hotspot analysis, standard deviation ellipse analysis and space⁃time scanning analysis, and the clusters of snail distribution and settings at high risk of snail spread were identified in Anhui Province from 2011 to 2020. Results　The actual area of snail habitats gradually decreased in Anhui Province from 2011 to 2020. The actual area of snail habitats were 26 238.85 hm2 in Anhui Province in 2020, which were mainly distributed in marshland and lake regions. There was a large fluctuation in the area of emerging snail habitats in Anhui Province during the period from 2011 to 2020, with the largest area seen in 2016 (1 287.65 hm2), and 1.98 hm2 emerging infected snail habitats were detected in Guichi District, Chizhou City in 2020. Spatial autocorrelation and hotspot analyses showed spatial clusters in the distribution of actual areas of snail habitats in Anhui Province from 2011 to 2020 (Z = 3.00 to 3.43, all P values < 0.01), and the hotspots were mainly concentrated in the marshland and lake regions and distributed along the south side of the Yangtze River, while the cold spots were mainly concentrated in the mountainous regions of ​​southern Anhui Province. There were no overall spatial clusters in the distribution of areas of emerging snail habitats (Z = -2.20 to 1.71, all P values > 0.05), and a scattered distribution was found in local regions. Standard deviation ellipse analysis showed relatively stable distributions of the actual areas of snail habitats in Anhui Province from 2011 to 2020, which was consistent with the flow direction of the Yangtze River, and the focus of the distribution of areas of emerging snail habitats shifted from the lower reaches to upper reaches of Anhui section of the Yangtze River. Space⁃time scanning analysis identified two high⁃value clusters in the distribution of actual areas of snail habitats in lower and middle reaches of Anhui section of the Yangtze River from 2011 to 2020, and two high⁃value clusters in the distribution of areas of emerging snail habitats were identified in mountainous and hilly regions. Conclusions　 There were spatial clusters in the distribution of O. hupensis snails in Anhui Province from 2011 to 2020, which appeared a tendency of aggregation towards the south side and upper reaches of the Yangtze River; however, the spread of O. hupensis snails could not be neglected in mountainous and hilly regions. Monitoring of emerging snail habitats should be reinforced in mountainous and hilly regions and along the Yangtze River basin.

Soluble egg antigen of Schistosoma japonicum induces macrophage apoptosis in mice

YIN Guo, QI Xin, LI Ya⁃lin, XU Lei, ZHOU Sha, CHEN Xiao⁃jun, ZHU Ji⁃feng, SU Chuan

2022, 34(3):  259. 

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Objective　To investigate the dynamic changes of macrophage numbers and apoptosis during Schistosoma japonicum infection, and to investigate the possible mechanisms of macrophage apoptosis induced by S. japonicum soluble egg antigen (SEA). Methods　C57BL/6 mice at ages of 6～8 weeks were randomly divided into 4 groups, including three experimental groups and a normal control group. Each mouse in the experimental groups was infected with (12 ± 1) cercariae of S. japonicum via the abdominal skin, and all mice in an experimental group were sacrificed 3, 5, 8 weeks post⁃infection, respectively, while mice in the control group were not infected with S. japonicum cercariae and sacrificed on the day of S. japonicum infection in the experimental group. Mouse liver specimens and peritoneal exudation cells were sampled in each group, and the dynamic changes of macrophage numbers and apoptosis were detected. Mouse peritoneal macrophages were isolated, purified and treated with S. japonicum SEA, PBS and ovalbumin (OVA) in vitro, and the macrophage apoptosis was detected using flow cytometry. The mRNA and protein expression of BCL⁃2 protein family members were determined in macrophages using real⁃time quantitative PCR (qPCR) and Western blotting assays, and the activation of caspase 3 was determined using flow cytometry and Western blotting. In addition, macrophages were in vitro treated with S. japonicum SEA in presence of a caspase inhibitor, H2O2 or N⁃acetyl⁃L⁃cysteine, and the apoptosis of macrophages was detected using flow cytometry. Results　The total macrophage numbers continued to increase in mouse liver [(0.873 ± 0.106) × 106, (2.737 ± 0.460) × 106 and (3.107 ± 0.367) × 106 cells, respectively; F = 81.900, P < 0.01] and peritoneal specimens [(5.282 ± 1.136) × 105, (7.500 ± 1.200) × 105 and (12.800 ± 0.800) × 105 cells, respectively; F = 55.720, P < 0.01] 3, 5 and 8 weeks post⁃infection with S. japonicum, and the numbers of apoptotic macrophages also continued to increase in mouse liver [(0.092 ± 0.018) × 106, (0.186 ± 0.025) × 106 and (0.173 ± 0.0270) × 106 cells; F = 57.780, P < 0.01] and peritoneal specimens [(0.335 ± 0.022) × 105, (0.771 ± 0.099) × 105 and (1.094 ± 0.051) × 105 cells; F = 49.460, P < 0.01] 3, 5 and 8 weeks post⁃infection with S. japonicum. The apoptotic rate of SEA⁃treated macrophages [(24.330 ± 0.784)%] was significantly higher than that of PBS⁃ [(18.500 ± 1.077)%] and OVA⁃treated macrophages [(18.900 ± 1.350)%] (both P values < 0.01). There were no significant differences in the mRNA or protein expression of Bcl⁃2 [Bcl⁃2 mRNA expression: (1.662 ± 0.943) vs. (1.000 ± 0.000), t = 1.215, P > 0.05; BCL protein expression: (0.068 ± 0.004) vs. (0.070 ± 0.005), t = 0.699, P > 0.05], Bax [Bax mRNA expression: (0.711 ± 0.200) vs. (1.000 ± 0.000), t = 2.507, P > 0.05; Bax protein expression: (0.089 ± 0.005) vs. (0.097 ± 0.003), t = 2.232, P > 0.05] and Bak [Bak mRNA expression: (1.255 ± 0.049) vs. (1.00 ± 0.00), t = 0.897, P > 0.05; BAK protein expression: (0.439 ± 0.048) vs. (0.571 ± 0.091), t = 2.231, P > 0.05] between in SEA⁃ and PBS⁃treated macrophages. S. japonicum SEA induced macrophage apoptosis in the presence of a caspase inhibitor (F = 0.411, P > 0.05); however, SEA failed to induce macrophage apoptosis in the presence of H2O2 or NAC (F = 11.880 and 9.897, both P values < 0.05). Conclusion　S. japonicum SEA may induce macrophage apoptosis through promoting reactive oxygen species expression during S. japonicum infections in mice.

Molluscicidal activity of the secondary metabolites from Streptomyces nigrogriseolus XD 2⁃7 against Oncomelania hupensis and its preliminary mechanisms of molluscicidal actions

XING Yun⁃tian, YAO Jia⁃kai, QU Guo⁃li, ZHANG Su⁃yang, DAI Jian⁃rong, FENG Bai⁃nian

2022, 34(3):  269. 

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Objective　To evaluate the storage stability of metabolites from actinomycetes Streptomyces nigrogriseolus XD 2⁃7 and the mollcuscicidal activity against Oncomelania hupensis in the laboratory, and to preliminarily explore the mechanisms of the molluscicidal activity. Methods　The fermentation supernatant of S. nigrogriseolus XD 2⁃7 was prepared and stored at -20, 4 ℃ and 28 ℃ without light for 10 d; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation supernatant was boiled in a 100 ℃ water bath for 30 min and recovered to room temperature, and then the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The pH values of the fermentation supernatant were adjusted to 4.0, 6.0 and 9.0 with concentrated hydrochloric acid and sodium hydroxide, and the fermentation supernatant was stilled at room temperature for 12 h, with its pH adjusted to 7.0; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation product of S. nigrogriseolus XD 2⁃7was isolated and purified four times with macroporous resin, silica gel and octadecylsilane bonded silica gel. The final products were prepared into solutions at concentrations of 10.00, 5.00, 2.50, 1.25 mg/L and 0.63 mg/L, and the molluscicidal effect of the final productswas tested against O. hupensis following immersion for 72 h, while dechlorination water served as blank controls, and 0.10 mg/L niclosamide served as positive control. The adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were measured in in O. hupensis soft tissues using high performance liquid chromatography (HPLC) following exposure to the final purified fermentation products of S. nigrogriseolus XD 2⁃7. Results　After the fermentation supernatant of S. nigrogriseolus XD 2⁃7 was placed at -20, 4 ℃ and 28 ℃ without light for 10 d, immersion in the stock solution and solutions at 10⁃ and 50⁃fold dilutions for 72 h resulted in a 100% (30/30) O. hupensis mortality. Following boiling at 100 ℃ for 30 min, immersion in the stock solution and solutions at 10⁃ and 50⁃fold dilutions for 72 h resulted in a 100.00% (30/30) O. hupensis mortality. Following storage at pH values of 4.0 and 6.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2⁃7 for 72 h resulted in a 100.00% (30/30) O. hupensis mortality, and following storage at a pH value of 9.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2⁃7 for 72 h resulted in a 33.33% (10/30) O. hupensis mortality ([χ2] = 30.000, P < 0.05). The minimum concentration of the final purified fermentation products of S. nigrogriseolus XD 2⁃7 was 1.25 mg/L for achieving a 100% (30/30) O. hupensis mortality. The ATP level was significantly lower in O. hupensis soft tissues exposed to 0.10 mg/L and 1.00 mg/L of the final purified fermentation products of S. nigrogriseolus XD 2⁃7 than in controls (F = 7.274，P < 0.05), while no significant difference was detected in the ADP level between the treatment group and controls (F = 2.485，P > 0.05). Conclusions　The active mollcuscicidal ingredients of the S. nigrogriseolus XD 2⁃7 metabolites are maintained stably at -20, 4 ℃ and 28 ℃ for 10 d, and are heat and acid resistant but not alkali resistant. The metabolites from S. nigrogriseolus XD 2⁃7 may cause energy metabolism disorders in O. hupensis, leading to O. hupensis death.

Study on mechanisms of Th17/Treg imbalance in patients with cystic echinococcosis based on miRNA expression profiles

LU Di, SONG Jia⁃hui, MA Zi⁃jian, ZHANG Peng⁃yue, XU Lei, WEI Chuan, CHEN Ying, ZHOU Sha, ZHU Ji⁃feng, LI Ya⁃lin, ZHAO Jia⁃qing, ZHU Ming⁃xing, ZHAO Rui, WANG Hai, CHEN Xiao⁃Jun, ZHAO Wei, SU Chuan

2022, 34(3):  277. 

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Objective　To investigate the serum microRNA (miRNA) expression and examine the impact of miRNA expression profiles on T helper type 17 (Th17)/regulatory T cells (Treg) imbalance among patients with cystic echinococcosis, so as to provide insights into the illustration of the mechanisms underlying chronic Echinococcus granulosus infections, and long⁃term pathogenesis. Methods　Total RNA was extracted from the sera of cystic echinococcosis patients and healthy controls, and subjected to high⁃throughput sequencing with the Illumina sequencing platform. Known miRNAs were annotated and new miRNAs were predicted using the miRBase database and the miRDeep2 tool, and differentially expressed miRNAs were identified. The target genes of differentially expressed miRNAs were predicted using the software miRanda and TargetScan, and the intersection was selected for Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Among the differentially expressed miRNAs with the 20 highest fold changes, miRNAs that targeted genes relating to key transcription factors RORC and FOXP3 that determine the production of Th17 and Treg cells or their important regulatory pathways (PI3K⁃Akt and mTOR pathways) were matched. Results　A total of 53 differentially expressed miRNAs were screened in sera of cystic echinococcosis patients and healthy controls, including 47 up⁃regulated miRNAs and 6 down⁃regulated miRNAs. GO enrichment analysis showed that these differentially expressed miRNA were involved DNA transcription and translation, cell components, cell morphology, neurodevelopment and metabolic decomposition, and KEGG pathway analysis showed that the differentially expressed miRNA were mainly involved in MAPK, PI3K⁃Akt and mTOR signaling pathways. Among the differentially expressed miRNAs with the 20 highest fold changes, there were 3 miRNAs that had a potential for target regulation of RORC, and 15 miRNAs that had a potential to target the PI3K⁃Akt and mTOR signaling pathways. Conclusions　Significant changes are found in serum miRNA expression profiles among patients with E. granulosus infections, and differentially expressed miRNAs may lead to Th17/Treg imbalance through targeting the key transcription factors of Th17/Treg or PI3K⁃Akt and mTOR pathways, which facilitates the long⁃term parasitism of E. granulosus in hosts and causes a chronic disease. 

Eukaryotic expression and antigen epitope prediction of the LRRC15 protein in excretory secretory antigens of Taenia solium cysticercus

LI Li⁃zhu, ZHOU Bi⁃ying

2022, 34(3):  286. 

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Objective　To conduct eukaryotic expression of the leucine⁃rich repeat containing 15 (LRRC15), a differentially expressed protein in excretory secretory antigens of Taenia solium cysticercus, and predict its antigen epitope. Methods　The molecular weight, stability, amino acid sequence composition, isoelectric point and T lymphocyte epitope of the LRRC15 protein were predicted using the bioinformatics online softwares ExPASy⁃PortParam and Protean. The full⁃length splicing primers were designed using PCR⁃based accurate synthesis, and the LRRC15 gene was synthesized. The recombinant pcDNA3.4⁃LRRC15 plasmid was constructed and transfected into HEK293 cells to express the LRRC15 protein. In addition, the LRRC15 protein was characterized by sodium dodecyl sulphate⁃polyacrylamide gel electrophoresis (SDS⁃PAGE) and Western blotting. Results　The recombinant pcDNA3.4⁃LRRC15 plasmid was successfully constructed, which expressed the target LRRC15 protein with an approximately molecular weight of 70 kDa. Bioinformatics prediction with the ExPASy⁃PortParam software showed that LRRC15 was a hydrophilic protein, which was consisted of 644 amino acids and had a molecular weight of 69.89 kDa and an isoelectric point of 5.6. The molecular formula of the LRRC15 protein was C3073H4942N846O953S28 and had an instability coefficient is 50.3, indicating that LRRC15 was an instable protein. Bioinformatics prediction with the Protean software showed that the dominant T⁃cell antigen epitopes were located in 292 to 295, 353 to 361, 521 to 526 and 555 to 564 amino acids of the LRRC15 protein, and the T⁃cell antigen epitopes with a high hydrophilicity, good flexibility, high surface accessibility and high antigenicity index were found in 122 to 131, 216 to 233, 249 to 254, 333 to 343, 358 to 361, 368 to 372, 384 to 386, 407 to 412, 445 to 450, 469 to 481, 553 to 564, 588 to 594, 607 to 617 and 624 to 639 amino acids. Following transfection of the recombinant pcDNA3.4⁃LRRC15 plasmid into HEK293 cells, SDS⁃PAGE and Western blotting identified LRRC15 proteins in cell secretory culture media, cell lysis supernatants and sediments. The LRRC15⁃His fusion protein was purified from the cell culture medium, and SDS⁃PAGE identified a remarkable band at approximately 70 kDa, while Western blotting successfully recognized the band of the recombinant LRRC15 protein. Conclusions　The eukaryotic expression and antigen epitope prediction of the LRRC15 protein in the excretory secretory antigens of T. solium cysticercus have been successfully performed, which provides insights into further understandings of its biological functions.

Analysis of the equity of health human resource allocation for echinococcosis control based on Gini index

XIAO Jie, YU Hong⁃mei, YANG Yi, LIU Lei, ZHONG Bo, ZHAO Jun⁃sheng

2022, 34(3):  292. 

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Objective　To analyze the current status and evaluate the equity of health human resource allocation for echinococcosis control in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, so as to provide the empirical evidence for optimizing the health human resource allocation for echinococcosis control. Methods　A questionnaire survey was performed to collect the numbers of health human sources for echinococcosis control, including health workers, healthcare professionals, certified/assistant physicians and registered nurses, per 1 000 permanent residents, per 1 000 m2, per 1 000 residents screened using B⁃mode ultrasonography and per 1 000 echinococcosis patients in two highly endemic counties and three lowly endemic counties in Ganzi Tibetan Autonomous Prefecture, Sichuan Province from 2016 to 2019. The equity of health human resource allocation for echinococcosis control was evaluated by permanent residents and geographical areas using Lorenz curve and Gini index in Ganzi Tibetan Autonomous Prefecture from 2016 to 2019. Results　The numbers of health workers, healthcare professionals, certified/assistant physicians and registered nurses per 1 000 permanent residents, per 1 000 permanent residents, per 1 000 m2, per 1 000 residents screened using B⁃mode ultrasonography and per 1 000 echinococcosis patients were 0.99⁃, 1.06⁃, 1.78⁃ and 1.88⁃fold; 3.38⁃, 3.67⁃, 6.00⁃ and 6.00⁃fold; 1.64⁃, 1.74⁃, 3.22⁃ and 3.18⁃fold; and 64.92⁃, 70.39⁃, 139.34⁃ and 117.44⁃fold more in lowly endemic counties than in highly endemic countries in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, 2019. The Gini indexes of health human resource allocation for echinococcosis control were 0.371 to 0.397 by permanent residents and 0.477 to 0.591 by geographical areas in Ganzi Tibetan Autonomous Prefecture from 2016 to 2019, and the Gini indexes (0.469 to 0.730) for allocation of certified/assistant physicians and registered nurses were both higher than those of health workers and healthcare professionals (0.302 to 0.451) by both permanent residents and geographical areas. Conclusion　The health human resource allocation for echinococcosis control showed general equity by permanent residents and poor equity by geographical areas in Ganzi Tibetan Autonomous Prefecture, Sichuan Province from 2016 to 2019.

Diagnostic efficacy of indirect haemagglutination assay for detection of Schistosoma japonicum infections among boatmen and fishermen in the Dongting Lake region

MEI Zhong⁃qiu, ZENG Ting, CAI Xin⁃ting, HU Ben⁃jiao, LI Sheng⁃ming, ZHOU Jie, JIA Tie⁃wu

2022, 34(3):  300. 

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Objective　To evaluate the diagnostic efficacy of indirect haemagglutination assay (IHA) for detection of Schistosoma japonicum infections among boatmen and fishermen in Dongting Lake region, so as to provide insights into improving the schistosomiasis surveillance program among boatmen and fishermen. Methods　The boatmen and fishermen were detected for S. japonicum infections using IHA and Kato⁃Katz technique or miracidium hatching test nylon gauze simultaneously at schistosomiasis testing sites in the anchor sites for boatmen and fishermen in the Dongting Lake region during the period from 2014 to 2016, and using IHA for serological screening followed by parasitological testing of seropositives during the period from 2017 to 2019. The sensitivity and specificity of IHA were evaluated for detection of S. japonicum infections among boatmen and fishermen, with the 2014—2016 parasitological testing results as a gold standard. In addition, the seroprevalence of S. japonicum infections was compared among boatmen and fishermen with different characteristics and among years. Results　A total of 306 schistosomiasis testing sites were assigned for boatmen and fishermen, and a total of 143 360 person⁃time boatmen and fishermen were tested for S. japonicum infections in the Dongting Lake region from 2014 to 2019. The sensitivity and specificity of IHA were 69.9%, 97.3% and 96.1% ([χ2] = 74.6, P < 0.05), and 70.9%, 74.5% and 71.9% for detection of S. japonicum infections from 2014 to 2016 ([χ2] = 29.4, P < 0.05), respectively. The seroprevalence of S. japonicum infections reduced from 30.3% in 2014 to 1.8% in 2019 among boatmen and fishermen, appearing an overall tendency towards a decline (Z = 1 552.4, P < 0.05). In addition, male, individuals at ages of 45 to 60 years, full⁃time boatmen and fishermen were more likely to be seropositive for S. japonicum infections (all P values < 0.05). Conclusions　The seroprevalence of S. japonicum infections appeared a tendency towards a decline among boatmen and fishermen in the Dongting Lake region year by year from 2014 to 2019. IHA presented a high efficacy for screening of S. japonicum infections among boatmen and fishermen in the Dongting Lake region.

Analysis of causes of death among advanced schistosomiasis patients in Jiaxing City from 2010 to 2020

HUANG Jing, ZHANG Hao⁃ran, CAI Chen⁃xiao, WU Yi⁃ming

2022, 34(3):  307. 

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Objective　To analyze the cause of death among patients with advanced schistosomiasis in Jiaxing City of Zhejiang Province from 2000 to 2020. Methods　The medical records of 167 dead patients with advanced schistosomiasis that were registered in Jiaxing First Hospital and received national medical assistance program from 2010 to 2020 were collected, and compared with the data of advanced schistosomiasis patients without national medical assistance program in the same city from 1998 to 2008. Results　Among the 167 advanced schistosomiasis patients in Jiaxing City during the period from 2010 to 2020, the four most common causes of death included liver failure (22.16%), upper gastrointestinal hemorrhage (17.37%), hepatic encephalopathy (14.97%) and liver cancer (14.37%), and the dead patients were predominantly at ages of 70 to 74 years, with a mean age of 74.8 years. The four most common causes of death included upper gastrointestinal bleeding (34.16%), hepatic encephalopathy (22.28%), unexplained causes (22.28%) and liver failure (4.46%) among advanced schistosomiasis patients without national medical assistance in Jiaxing City from 1998 to 2008, and the dead patients were predominantly at ages of 60 to 69 years, with a mean age of 69.3 years. There were significant differences between patients detected from 2010 to 2020 and from 1998 to 2008 in terms of causes of death ([χ2] = 63.42, P = 0.00) and age of death ([χ2] = 50.09, P = 0.00). Conclusion　There are significant changes in the cause of death among patients with advanced schistosomiasis in Jiaxing City from 2010—2020, which may be attributed to the implementation of the national medical assistance program.

Clinical characteristics of biliary obstruction patients with Clonorchis sinensis infections

FANG Wen⁃juan, LI Xiang, JIANG Xu, DUAN Shan⁃shan, DINGJian, ZUO Li⁃jiao, ZHANG Xue⁃li, ZHANG Xiao⁃li, HAN Su

2022, 34(3):  311. 

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Objective　To analyze the clinical characteristics of biliary obstruction patients with Clonorchis sinensis infections, so as to provide insights into the clinical diagnosis and therapy of this comorbidity. Methods　A total of 45 biliary obstruction patients with C. sinensis infections that were admitted to the Second Affiliated Hospital of Harbin Medical University from October 2012 to September 2019 were enrolled, and 45 patients with biliary obstruction alone at the hospital during the same study period were recruited as controls. Univariate analysis was performed to analyze the epidemiological characteristics, clinical manifestations, laboratory examination results and imaging manifestations related to C. sinensis infection, and the statistically significant univariate was used as an independent variable for multivariate logistic regression analysis. Results　Compared with biliary obstruction alone, males (91.11% vs. 46.67%; [χ2] = 20.737, P < 0.01) and rural areas (62.22% vs. 22.22%; [χ2] = 14.757, P < 0.01) showed a significantly higher proportion in biliary obstruction patients with C. sinensis infections. The major clinical symptoms involved in had jaundice (45 cases, 100%) and abdominal pain (40 cases, 88.89%) in C. sinensis⁃infected patients. Logistic regression analysis showed that males [odds ratio (OR) = 10.717，95% confidential interval (CI): (2.571, 44.662)] and drinking alcohol [OR = 4.474，95% CI: (1.019, 19.642)] were risk factors for biliary obstruction patients with C. sinensis infections, while living in city [OR = 0.128，95% CI: (0.038, 0.435)] was a protective factor. Additionally, in biliary obstruction patients with C. sinensis infections, lower total bilirubin (Z = -2.566, P < 0.05) and direct bilirubin (Z = -3.454, P < 0.05), higher indirect bilirubin (Z = -3.821, sive diagnosis requires to be made based on clinical symptoms, laboratory and imaging examinations, in order to improve the diagnosis of biliary obstruction patients with C. sinensis infections.

Cystic echinococcosis of the abdominal wall: a case report

XU Zhao⁃Jun, LIU Tao, CHEN Xiao⁃Bin, JIANG Shu⁃Yun, WANG Xin⁃Le, LIU Guang⁃Zhao, WANG Ya⁃Feng, MA Xiao⁃Ming

2022, 34(3):  315. 

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Cystic echinococcosis of the abdominal wall is relatively rare. Here, a 54⁃year⁃old patient with cystic echinococcosis of the abdominal wall was reported, who was admitted to hospital due to presence of abdominal mass for one year complicated by skin ulceration of the mass for 5 days. The case was initially diagnosed as cystic echinococcosis of the abdominal wall and given sub⁃abdominal echinococcosis cystectomy. Post⁃surgical pathological examinations revealed cystic echinococcosis (type of a single locule and multiple daughter cysts). This case report aimed to provide insights into the clinical diagnosis and treatment of cystic echinococcosis of the abdominal wall.

Advances in studies on schistosome⁃host interactions mediated by extracellular vesicles

Yang Rui⁃bing, Li Yun⁃zhen, Su Kun⁃hua, Wang Li⁃fu, Li Ling

2022, 34(3):  318. 

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Extracellular vesicles (EVs) are minute particles secreted by the cells of living organisms, which can encapsulate various bioactive molecules for long⁃distance transport to present biological functions. With the recent studies on parasite⁃host interactions, EVs, as a carrier for long⁃distance transport of worm⁃derived molecules, have been paid much attention during the across⁃species regulation of hosts. During schistosome infections, adult worms and eggs have been found to mediate hosts via secretion of EVs. This review presents the advances in the studies on schistosome⁃host interactions mediated by EVs.

Relationship and coordination between water pollution control and mosquito breeding

LI Xin⁃ran, HUANG Min⁃sheng

2022, 34(3):  322. 

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Change of water environment is strongly associated with mosquito breeding. Because of long⁃term effectiveness, low cost and high environmental compatibility, ecological pollution control systems have been widely used in water pollution control projects. However, the potential effects of mosquito breeding are likely to cause expansion of mosquito populations and an increase in the risk of transmission of vector⁃borne diseases, which may become an urgent problem to be solved during the water environment “post⁃remediation” period. This review summarizes the physical, chemical and biological factors affecting mosquito breeding caused by water environment changes and analyzes the effects of water pollution control approaches on mosquito breeding and the underlying mechanisms, so as to promote the interdisciplinary connections between water pollution control and vector control, and avoid secondary disasters caused by ecological environment restoration, such as mosquito infestation. This review may provide insights into the use of technology combinations and water pollution control approaches in vector control.