Table of Content

31 August 2022, Volume 34 Issue 4

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Progress of schistosomiasis control in People’s Republic of China in 2021

ZHANG Li⁃juan, XU Zhi⁃min, YANG Fan, HE Jun⁃yi, DANG Hui, LI Yin⁃long, CAO Chun⁃li, XU Jing, LI Shi⁃zhu, ZHOU Xiao⁃nong

2022, 34(4):  329. 

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This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites in the People’s Republic of China at a national level in 2021. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2021. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2021, with 27 571 endemic villages covering 73 250 600 people at risk of infections. Among the 451 endemic counties (cities, districts), 75.17% (339/451), 22.17% (100/451) and 2.66% (12/451) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2021, 29 037 cases with advanced schistosomiasis were documented in China. In 2021, 4 405 056 individuals received serological tests and 72 937 were sero⁃positive. A total of 220 629 individuals received stool examinations and 3 were positive. In 2021, snail survey was performed in 19 291 endemic villages in China and Oncomelania snails were found in 7 026 villages, accounting for 36.42% of all surveyed villages, with 12 villages identified with emerging snail habitats. Snail survey was performed at an area of 686 574.46 hm2 and 191 159.91 hm2 snail habitats were found, including 1 063.08 hm2 emerging snail habitats and 5 113.87 hm2 reemerging snail habitats. In 2021, 525 878 bovines were raised in the schistosomiasis endemic areas of China, and 115 437 received serological examinations, with 231 positives detected. Among the 128 719 bovines received stool examinations, no positives were identified. In 2021, there were 19 927 schistosomiasis patients receiving praziquantel chemotherapy, and 729 113 person⁃time individuals and 256 913 herd⁃time bovines were given expanded chemotherapy. In 2021, snail control with chemicals was performed in 117 372.74 hm2 snail habitats, and the actual area of chemical treatment was 65 640.5 hm2, while environmental improvements were performed in snail habitats covering an area of 1 244.25 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2021, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remained at a low level in China in 2021; however, the progress towards schistosomiasis elimination was slowed and the areas of snail habitats rebounded mildly. Strengthening researches on snail diffusion and control, and improving schistosomiasis surveillance and forecast are recommended to prevent reemerging schistosomiasis.

Oncomelania hupensis control strategy during the stage moving towards elimination of schistosomiasis in China

YUAN Yi, CAO Chun⁃li, HUANG Xi⁃bao, ZHAO Qin⁃ping

2022, 34(4):  337. 

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Oncomelania hupensis is the only intermediate host of Schistosoma japonicum, and O. hupensis control is an important measure for schistosomiasis control. With the progress of national schistosomiasis control program, the prevalence of schistosomiasis is low in China; however, there are still multiple challenges for O. hupensis breeding and schistosomiasis transmission risk. Considering the target of the national schistosomiasis elimination program and environmental protection in the new era, the introduction of precision identification, precision interventions and precision assessment into O. hupensis control may facilitate the progress towards elimination of schistosomiasis in China.

Measurement of morphological features of Oncomelania hupensis shells in Yunnan Province

SONG Jing, DONG Yi, DU Chun⁃hong, ZHANG Zong⁃ya, SHEN Mei⁃fen, ZHANG Yun, ZHOU Ji⁃hua, LI Shi⁃zhu

2022, 34(4):  341. 

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Objective　To investigate the morphological variation of Oncomelania hupensis shells in Yunnan Province, so as to provide insights into the understanding of O. hupensis genetic evolution and control. Methods　According to the O. hupensis density, geographical location, altitude, water system and environmental type, 12 administrative villages were sampled from 10 schistosomiasis⁃endemic counties (districts) in 3 prefectures (cities) of Yunnan Province as snail collection sites. From December 2021 to January 2022, about 200 snails were collected from each collection site， among which thirty adult snails (6 to 7 spirals) were randomly selected from each site, and the 11 morphological indexes of snail shells were measured and subjected to cluster analysis and principal component analysis. Results　Of O. hupensis snails from 12 localities of Yunnan Province, the longest shell (7.33 mm) was detected in snails from Yongle Village, Eryuan County, with the shortest (4.68 mm) in Dongyuan Village, Gucheng District, and the largest angle of apex (59.47°) was measured in snails from Caizhuang Village, Midu County, with the smallest (41.40°) in Qiandian Village, Eryuan County. The mean coefficient of variation was 9.075% among O. hupensis snails from 12 localities of Yunnan Province, with the largest coefficient of variation seen in the thickness of the labra brim (29.809%). Among O. hupensis snails from 12 localities of Yunnan Province, the mean Euclidean distance was 2.26, with the shortest Euclidean distance seen between O. hupensis snails from Qiandian Village of Eryuan County and Wuxing Village of Dali City (0.26), and the largest found between O. hupensis snails from Caizhuang Village of Midu County and Cangling Village of Chuxiong County (8.17). Cluster analysis and principal component analysis classified O. hupensis snails from 12 localities of Yunnan Province into three categories, including the O. hupensis snail samples from Caizhuang Village of Midu County, O. hupensis snail samples from Cangling Village of Chuxiong County, and O. hupensis snail samples from Qiandian Village of Eryuan County, Wuxing Village of Dali City, Yangwu Village of Yongsheng County, Xiaoqiao Village of Xiangyun County, Yongle Village of Eryuan County, Xiaocen Village of Dali City, Anding Village of Nanjian County, Dongyuan Village of Gucheng District, Lianyi Village of Heqing County, and Dianzhong Village of Weishan County. The variations in these three categories of snail samples were mainly measured in the principal component 2 related to the angle of apex and the thickness of the labra brim. Conclusions　The variations in the Euclidean distance and morphological features of shells of O. hupensis from 12 localities of Yunnan Province gradually rise with the decrease in the latitude of the collection sites. The angle of apex is an indicator for the growth of O. hupensis whorl.

Bioinformatics analysis of differentially expressed genes associated with chronic schistosomiasis japonica⁃induced hepatic fibrosis

DU Zhi⁃xiang, LI Yang, WANG Zi⁃jian, ZHOU Da⁃ming, YANG Jiang⁃hua

2022, 34(4):  352. 

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Objective　To screen differentially expressed genes (DEGs) associated with chronic schistosomiasis japonica⁃induced hepatic fibrosis and analyze their functions. Methods　The dataset of gene expression profiles of patients with chronic schistosomiasis japonica⁃induced hepatic fibrosis was downloaded from the Gene Expression Omnibus (GEO) database, and DEGs were screened using R package. The biological functions of DEGs were characterized using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. In addition, the protein⁃protein interaction (PPI) network of DEGs was created to screen the hub genes. Results　A total of 62 DEGs were identified, including 12 down⁃regulated genes and 50 up⁃regulated genes. GO enrichment analysis showed that DEGs were mainly enriched in 116 biological processes, including fatty acid, sulfur compound, acyl⁃coenzyme A and thioester metabolism; 19 cellular components, including mitochondrial matrix, outer mitochondrial membrane and organelle outer membrane; and 7 molecular functions, including insulin⁃like growth factor binding and oxidoreductase activity. KEGG pathway enrichment analysis that the DEGs were significantly enriched in phosphatidylinositol⁃3⁃kinase/serine/threonine protein kinase (PI3K/Akt), mitogen⁃activated protein kinase (MAPK), calcium metabolism and cyclic adenosine monophosphate (cAMP) signaling. PPI network analysis identified six hub genes involved in the development of chronic schistosomiasis japonica⁃induced hepatic fibrosis, including ACACA, ACSL1, GPAM, THRSP, PLIN1 and DGAT2, and ACSL1, ACACA and PLIN1 were the top 3 hub genes. Conclusions　ACSL1, ACACA, and PLIN1 may be the hub genes associated with the development of chronic schistosomiasis japonica⁃induced hepatic fibrosis, and abnormal lipid metabolism mediated by these DEGs may play an important role in the development of chronic schistosomiasis japonica⁃induced hepatic fibrosis.

Effect of Toxoplasma gondii Chinese 1 genotype infections on brain iron metabolism in mice

WANG Chong, CAI Yi⁃hong

2022, 34(4):  361. 

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Objective　To investigate the effect of Toxoplasma gondii Chinese 1 genotype infections on host brain iron metabolism and brain damages. Methods　Twenty C57BL/6 mice, each weighing 15 to 17 g, were randomly divided into the control and infection groups, of 10 mice in each group. Each mouse in the infection group was injected intraperitoneally with 4 000 tachyzoites of the TgCtwh3 isolate with Chinese 1 genotype, while each mouse in the control group was injected with an equal amount of sterile phosphate⁃buffered saline (PBS). All mice were sacrificed 6 day post⁃infection and brain tissues were sampled. The iron levels were measured in mouse brain specimens using inductively coupled plasma mass spectrometry (ICP⁃MS). The differentially expressed genes were determined between the experimental and control groups using RNA chips and Gene Ontology (GO) term enrichment analysis of differentially expressed genes was performed. The mRNA expression of Toxoplasma gondii surface antigen 1 (TgSAG1) gene and some Zrt⁃ and Irt⁃like protein (ZIP) family member coding genes was detected by quantitative real⁃time PCR (qPCR) assay. The ultrastructure of the hippocampus dentate gyrus in mouse brain specimens was observed using optical and electronic microscopy. The glutathione peroxidase 4 (GPx4) expression was determined using Western blotting, and malondialdehyde (MDA) level was measured using thiobarbituric acid (TBA) test. In addition, the optical density (OD) of vascular endothelial growth factor (VEGF) protein was measured using immunohistochemistry. Results　Optical microscopy showed cell necrosis in the hippocampus dentate gyrus of mouse brain specimens in the infection group, and electronic microscopy cytoplasmic vacuolization, nuclear atrophy and necrosis, disruption of cristae mitochondriales and increased autophagosome levels in the mouse brain hippocampus specimens in the infection group. The iron level was significantly greater in mouse brain specimens in the infection group than in the control group [(32.92 ± 0.90) µg/g vs. (37.72 ± 1.10) µg/g; t = 3.397, P < 0.01]. RNA chips revealed 721 up⁃regulated genes and 276 down⁃regulated genes in mouse brain specimens between the infection and control groups, and the differentially expressed genes were significantly enriched in metal ion binding ability (molecular function). Elevated expression of metal element transporter ZIP2 mRNA (t = 8.659, P < 0.05), reduced GPx4 expression [(1.046 ± 0.025) vs. (0.720 ± 0.101); t = 3.129, P < 0.01], increased MDA level [(4.37 ± 0.33) nmol/mgprot vs. (5.93 ± 0.54) nmol/mgprot; t = 2.451, P < 0.05], and up⁃regulated mean OD of VEGF protein [(0.348 3 ± 0.017 8) vs. (0.490 6 ± 0.010 5); t = 6.641, P < 0.01] were found in mouse brain specimens in the infection group than in the control group. Conclusions　Chinese 1 genotype T. gondii infection results in iron accumulation in brain tissues, reduced antioxidant ability and elevated levels of oxidative stress in mice, suggesting that T. gondii infection may cause brain damages through affecting iron metabolism in host brain tissues.

Prevalence and risk factors of Giardia lamblia infections among colorectal cancer patients in Henan Province

CHEN Hui⁃hui, DENG Yan, LI Zhi, WANG Zhen⁃lei, RUN Zeng⁃ci, ZHANG Ting, CAI Yu⁃chun, ZHANG Hong⁃wei, HU Zhu⁃hua, CHEN Jun⁃hu, TIAN Li⁃guang, LI Jian

2022, 34(4):  370. 

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Objective　To investigate the epidemiological characteristics and identify the risk factors of Giardia lamblia infections among patients with colorectal cancer in Henan Province. Methods　A cross⁃sectional study was performed for questionnaire surveys among colorectal cancer patients in Henan Cancer Hospital during the period from March to July, 2021. Patients’ stool samples were collected, and the triosephosphate isomerase (tpi) gene of G. lamblia was amplified in stool samples using nested PCR assay to characterize the parasite genotype. Univariate analysis and multivariate logistic regression analyses were employed to identify the risk factors of G. lamblia infections among colorectal cancer patients. Results　A total of 307 colorectal cancer patients were investigated, including 176 males (57.3%) and 131 females (42.7%). PCR assay detected 8.1% [95% confidential interval (CI): (0.056, 0.117)] prevalence of G. lamblia infections among the study subjects, and there was no significant difference in the prevalence between men [9.1%, 95% CI: (0.057, 0.143)] and women [6.9%, 95% CI: (0.037, 0.125)] ([χ2] = 0.495, P = 0.482). In addition, there was no age⁃specific prevalence of G. lamblia infections among the participants ([χ2] = 1.534, P = 0.675). Multivariate logistic regression analysis identified use of septic tanks [odds ratio (OR) = 3.336, 95% CI: (1.201, 9.267)], daily use of well water [OR = 3.042, 95% CI: (1.093, 8.465)] and raising livestock [OR = 3.740, 95% CI: (1.154, 12.121)] as risk factors of G. lamblia infections among colorectal cancer patients, and the prevalence of abdominal pain was significantly greater in colorectal cancer patients with G. lamblia infections than in those without infections (P = 0.017). Among the 25 patients with G. lamblia infections, assemblage A was characterized in 24 (96.0%) cases and assemblage B in one case (4.0%). Conclusions　 The prevalence of G. lamblia is high among colorectal cancer patients in Henan Province, and assemblage A is the dominant genotype of G. lamblia. Use of septic tanks, daily use of well water and raising livestock are risk factors of G. lamblia infections among patients with colorectal cancer.

Preparation and characterization of a recombinant poly⁃epitopic vaccine EgG1Y162⁃2 (4) against cystic echinococcosis based on the linker GSGGSG

ZHENG Jia, ZHANG Dong⁃jun, ZHAO Shang⁃qi, LI Yan⁃min, ZHOU Yan⁃xia, ZHOU Wen⁃tao, ZHOU Xiao⁃tao

2022, 34(4):  378. 

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Objective　To perform prokaryotic expression and preliminary characterization of the recombinant poly⁃epitope vaccine EgG1Y162⁃2 (4) against cystic echinococcosis. Methods　The recombinant poly⁃epitope vaccine EgG1Y162⁃2 (4) against Echinococcus granulosus based on the linker GSGGSG was subjected to structural three⁃dimensional (3D) modeling using immunoinformatics to analyze the structural changes and evaluate the antigenicity of the vaccine. The pET30a⁃EgG1Y162⁃2 (4) recombinant plasmid was generated using double digestion with EcoR I and Sal I, and then transformed into competent cells. Following protein induction with isopropyl⁃β⁃D⁃thiogalactoside (IPTG), the prokaryotic expression proteins were characterized using Western blotting, and the antigenicity of the recombinant protein was analyzed using sera from cystic echinococcosis patients and health volunteers. Results　The four EgG1Y162⁃2 proteins coupled by the 3D structure of the recombinant vaccine EgG1Y162⁃2 (4) presented independent and effective expression and good antigenicity. The highest protein expression was detected in the supernatant following induction of the recombinant plasmid pET30a⁃EgG1Y162⁃2 (4) by 0.2 mmol/L IPTG at 37 ℃ for 4 h, and a pure protein component was seen following elution with 60 mmol/L imidazole. Western blotting analysis of the recombinant multi⁃epitope protein HIS⁃EgG1Y162⁃2 (4) showed a band at approximately 39 kDa, and this band was recognized by sera from cystic echinococcosis patients. Conclusion　A recombinant poly⁃epitope vaccine EgG1Y162⁃2 (4) against cystic echinococcosis has been successfully constructed, which provides a preliminary basis for researches on recombinant multi⁃epitope vaccine against cystic echinococcosis.

Evaluation of the effectiveness of malaria control health education among overseas enterprise employees

DU Yan⁃qiu, LIANG Cheng, GU Ya⁃ping, ZHOU Hua⁃yun, HUANG Jia⁃yan, CAO Jun

2022, 34(4):  383. 

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Objective　To evaluate the effectiveness of health education on knowledge, attitude and practice (KAP) relating to malaria control among overseas enterprise employees. Methods　In September 2019, on⁃site malaria control health education was conducted among all Chinese employees of a China⁃funded mining enterprise in the Democratic Republic of Congo. The KAP questionnaire for malaria control was generated on the Questionstar website, and the participants were subjected to two questionnaire surveys prior to and 14 months after health education. After the questionnaires were recovered, all valid questionnaires were divided into 4 groups, including the baseline group (the questionnaires filled out by respondents who received health education and participated in two questionnaire surveys before health education), the loss⁃to⁃follow⁃up group (the questionnaires filled out by respondents who received health education but only participated in the questionnaire survey after health education), the retest group (the questionnaires filled out by respondents who received health education and participated in two questionnaire surveys after health education) and the new group (questionnaires filled out by respondents who did not receive health education and only participated in the questionnaire survey after health education) according to subjects’ receiving health education and participation in two questionnaire surveys. The correct rate of malaria control knowledge, the proportion to good attitudes towards malaria control and the proportion of good practices towards malaria control were compared between the baseline group and the loss⁃to⁃follow⁃up group, between the baseline group and the retest group, and between the retest group and the new group. Results　A total of 110 and 142 valid questionnaires were recovered during the two surveys, and the recovery rates were 90.9% and 70.3%, respectively. There were 77, 77, 33, and 65 valid questionnaires recovered from the baseline group, the loss⁃to⁃follow⁃up group, the retest group, and the new group, respectively. There were no significant differences in respondents’ gender, age and educational levels between the baseline group and the loss⁃to⁃follow⁃up group (all P values > 0.05), and there were no significant differences between the two groups in terms of the mean score of malaria control knowledge (Z = 2.011, P > 0.05), the mean score of attitudes towards malaria control (t = -0.787, P > 0.05) and the mean score of practices towards malaria control (t = -0.787, P > 0.05). There were significant differences between the retest group and the baseline group in terms of the mean score of malaria control knowledge (10.83 vs. 9.79; Z = -4.017, P < 0.05), the mean score of attitudes towards malaria control (29.48 vs. 28.61; Z = -1.981, P < 0.05) and the mean score of practices towards malaria control (6.43 vs. 5.91; Z = -2.499, P < 0.05). There were no significant differences between the retest group and the new group in terms of gender, age or education levels (all P values > 0.05), and a higher mean score of malaria control knowledge was found in the retest group than in the new group (10.83 vs. 9.81; Z = -2.962, P < 0.05), while no significant differences were seen in the mean score of attitudes towards malaria control (29.48 vs. 30.17; Z = -1.158, P > 0.05) and the mean score of practices towards malaria control (6.43 vs. 6.37; Z = -0.048, P > 0.05) between the two groups. Conclusion　Malaria control health education may significantly improve the understanding of malaria control knowledge, positive attitudes towards malaria control and the compliance of practices towards malaria control among overseas enterprise employees.

Distribution of mosquito species and associated viruses in Hami City of Xinjiang Uygur Autonomous Region from 2019 to 2020

GAO Zhen⁃guo, WANG Dong, MAHE Mu⁃ti, CAO Zhi⁃xin, LIU Yan, Lina Turxunbayi, HUANG Rui⁃fang, MA Xin

2022, 34(4):  392. 

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Objective　To investigate the distribution of mosquito species and their associated viruses, and identify Culex pipiens subspecies in Hami City, Xinjiang Uygur Autonomous Region. Methods　Mosquitoes were captured using mosquito trapping lamps method in Yizhou District, Yiwu County, and Balikun County of Hami City in mi⁃July, 2019 and 2020. The species and subspecies of all captured mosquitoes were characterized. In addition, the flavivirus, alphavirus, bunyavirus, Japanese encephalitis virus, Liaoning virus, Tahyna virus, tick⁃borne encephalitis virus and West Nile virus were detected using reverse⁃transcription PCR assay in captured mosquitoes. Results　A total of 1 496 mosquitoes were captured from Yizhou District, Yiwu County, and Balikun County of Hami City, belonging to 3 genus and 3 species. Cx. pipiens was the dominant mosquito species (986 mosquitoes, 65.91%), followed by Aedes caspius (457 mosquitoes, 30.55%), while Culiseta alaskaensis had the lowest number (53 mosquitoes, 3.54%). All captured Cx. pipiens mosquitoes were identified as Cx. pipiens pipiens based on the terminalia of male mosquitoes. RT⁃PCR assay tested negative for flavivirus, alphavirus, bunyavirus, Japanese encephalitis virus, Liaoning virus, Tahyna virus, tick⁃borne encephalitis or West Nile virus in captured Cx. pipiens mosquitoes. Conclusions　There were 3 species of mosquitoes in Hami City from 2019 to 2020, including Cx. pipiens, Ae. Caspius and C. alaskaensis, with Cx. pipiens as the dominant mosquito species, and all captured Cx. pipiens mosquitoes were Cx. pipiens pipiens; however, no arboviruses were detected.

Molluscicidal effect of immersion with 50% wettable powder of niclosamide ethanolamine salt against Oncomelania hupensis on the soil surface and inside the soil layer in winter

WANG Wei⁃chun, ZHAN Ti, FAN Ze⁃han, XIANG Ke⁃xia, ZHU Ying⁃fu, DUAN Yong⁃mei, CAO Zhi⁃guo

2022, 34(4):  396. 

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Objective　To evaluate the molluscicidal effect of 50% wettable powder of niclosamide ethanolamine salt (WPNES) against Oncomelania hupensis on the soil surface and inside the soil layer by immersion method in winter. Methods　O. hupensis snails were placed on the soil surface and 2, 5 cm and 10 cm under the soil layer outdoors in winter, and then immersed in 50% WPNES at concentrations of 1 mg/L and 2 mg/L for 1, 3 d and 7 d, while dechlorinated water served as controls. Snail mortality was observed following immersion with 50% WPNES on the soil surface and inside the soil layer. Results　Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 3-day corrected snail mortality rates were 98.0% and 76.0% on the soil surface, and the 7-day corrected snail mortality rate was both 100.0%. Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 7-day corrected snail mortality rates were 95.5% and 85.6% 2 cm below the soil layer, 66.0% and 6.4% 5 cm below the soil layer. However, the 7-day snail mortality rate swere comparable between the 50% WPNES treatment group (at 2 mg/L and 1 mg/L) and controls 10 cm below the soil layer (both P > 0.05). Conclusion　Immersion of 50% WPNES at a concentration of 2 mg/L for 7 days presents a high molluscicidal efficacy against O. hupensis on the soil surface and 5 cm within the soil layers in winter.

Establishment of an animal model of Sparganum mansoni infection and study on therapeutic methods II Establishment of a mouse model of sparganosis mansoni via oral administration of procercoids

TANG Xian⁃shi, XU Yong⁃liang, WANG Qiang, ZHANG Ying, TONG De⁃sheng

2022, 34(4):  400. 

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Objective　To establish an animal model of sparganosis mansoni through oral administration of Cyclops infected with procercoids. Methods　Domestic cats were infected with Sparganum mansoni under laboratory conditions, and fresh cat stool samples were collected, washed in dechlorinated water, and filtered. Spirometra mansoni eggs were collected and prepared into suspensions. Twenty C57BL/6j mice were randomly divided into the experimental group (n = 15) and the control group (n = 5). Wild Cyclops were infected with Spirometra mansoni coracidia to allow 3 to 5 procercoids in each Cyclop. Then, each mouse in the experimental group was given 15 Cyclops infected with procercoids by gavage, while mice in the control group were orally administered with the same volume of dechlorinated water. All mice were sacrificed after 5 months, and dissected, and suspicious Sparganum mansoni worms were collected. The serum specific IgG antibody against Sparganum mansoni was measured in mice using enzyme⁃linked immunosorbent assay (ELISA). Genomic DNA was isolated from suspicious Sparganum mansoni worms, and the specific Sparganum mansoni cytochrome oxidase I (COI) gene was amplified using PCR assay. Results　Among the 15 mice in the experimental group, six were positive for the serum specific IgG antibody against Sparganum mansoni, and milky white worms were found and collected from the subcutaneous regions of 4 out of 6 mice. Only one worm was detected in each mouse, and the worm morphology was similar to Sparganum mansoni. Capillary electrophoresis of the PCR amplification products of COI gene presented a specific band with 151 bp in size, and sequencing analysis revealed 100% homology with Sparganum mansoni. Conclusions　A mouse model of sparganosis mansoni is successfully created through oral administration of Cyclops infected with Spirometra mansoni procercoids.

Molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate in hilly schistosomiasis⁃endemic regions

ZHU Ze⁃lin, LUO Bing⁃rong, LIU Yu⁃hua, HAO Yu⁃wan, TIAN Tian, WANG Qiang, DUAN Li⁃ping, LI Shi⁃zhu

2022, 34(4):  404. 

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Objective　To evaluate the molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate (WPPS) against Oncomelania snails in hilly schistosomiasis⁃endemic regions and test its toxicity to fish. Methods　In October 2020, a snail⁃infested setting which had been cleared was selected in Nanjian County, Yunnan Province and divided into several blocks, and the natural snail mortality was estimated. 25% WPPS was prepared into solutions at concentrations of 1 and 2 g/L, and 25% wettable powder of niclosamide ethanolamine salt (WPNES) was prepared into solutions at a concentration of 2 g/L. The different concentrations of drugs were sprayed evenly, and the same amount of water was used as blank control. Snails were surveyed using the systematic sampling method 1, 3 and 7 days post⁃treatment, and snail survival was observed. A fish pond was selected in Nanjian County, and 2 kg 25% WPPS was evenly sprayed on the water surface to allow the effective concentration of 20 g/L. Fish mortality was estimated 8, 24, 48 and 72 h post⁃treatment. Results　One⁃day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 97.99%, 97.99% and 94.11% adjusted snail mortality rates ([χ2] = 3.509 and 3.509, both P values > 0.05）, and the adjusted snail mortality was all 100% 3 d post⁃treatment with 1 and 2 g/L WPPS and 2 g/L WPNES, while 7⁃day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 91.75%, 86.57% and 57.76% adjusted snail mortality rates （[χ2] = 14.893 and 42.284, both P values < 0.05）. Treatment with 2 g/L WPPS for 72 h resulted in a 0.67% cumulative mortality rate of fish. Conclusion　25% WPPS is effective for snail control and highly safe for fish, which is feasible for use in hilly schistosomiasis⁃endemic regions.

First report of invasive Pomacea snails in Shandong Province

WANG Long-jiang, XU Yan, SUN Hui, ZHANG Ben-guang, KONG Xiang-li, HAN Hai-tao, LI Jin, LI Yue-jin, YANG Li-min, GUO Yun-hai, WANG Yong-bin

2022, 34(4):  407. 

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Objective　To characterize the species of invasive Pomacea snails that were discovered for the first time in Shandong Province. Methods　Pomacea snails samples were collected in the field of Jining City, Shandong Province on October 2021 for morphological identification. Pomacea snails were randomly sampled and genomic DNA was extracted from foot muscle tissues of Pomacea snails for multiplex PCR amplification. The PCR amplification product was sequenced. Then, the sequence was aligned and a phylogenetic tree was created using the software MegAlign 7.1.0. In addition, Angiostongylus cantonensis infection was detected in Pomacea snails with the lung microscopy. Results　A total of 104 living Pomacea snails were collected, and all were characterized as Pomacea spp. based on morphological features. Of 12 randomly selected adult Pomacea snails, multiplex PCR assay and sequencing identified eleven snails as P. canaliculata and one as P. maculata. No A. cantonensis infection was detected in 104 Pomacea snails. Conclusion　This is the first report of invasive Pomacea snails in Shandong Province, where P. canaliculata and P. maculata are found.

Endemic situation of schistosomiasis in Suzhou City from 2010 to 2020

SHI Qian⁃wen, SHEN Ling⁃e, ZHOU Jing, ZHANG Jun, WU Jing⁃zhi

2022, 34(4):  412. 

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Objective　To analyze the endemic status of schistosomiasis in Suzhou City from 2010 to 2020, so as to provide the evidence for formulating the future schistosomiasis control strategy. Methods　The data pertaining to the endemic status of schistosomiasis in Suzhou City from 2010 to 2020 were retrieved from the annual schistosomiasis control report, the information management platform of schistosomiasis (parasitic diseases) in Jiangsu Province and the Parasitic Diseases Control Information Management System of Chinese Center for Disease Control and Prevention, including snail survey data, snail control data and schistosomiasis examination data, and were retrospectively reviewed. Differences of proportions were tested for statistical significance with chi⁃square test, and the trends in proportions were evaluated using the chi⁃square test for trends. Results　Elimination of schistosomiasis was achieved in Suzhou City in 2018, and there were 3.528 9 million residents living in schistosomiasis⁃endemic villages of 81 townships in 9 counties. A total of 707 600 labor⁃days were used for snail survey in 11 586 village⁃times in Suzhou City from 2010 to 2020, covering 18 572.73 hm2, and snail habitats were detected with an area of 68.61 hm2, including emerging snail habitats of 37.30 hm2. A total of 23 144 snails were dissected, and no Schistosoma japonicum infection was detected. Reemerging and emerging snail habitats were predominantly found in inlands. During the period from 2010 to 2020, snail control was performed in Suzhou City for 71 000 labor⁃times, and snail control was done covering 269.34 hm2 through chemical treatment and covering 3.48 hm2 through environmental improvements. A total of 674 002 person⁃times received serological tests for S. japonicum infections in Suzhou City from 2010 to 2020, with seroprevalence of 0.38%, and a total of 33 835 person⁃times received stool examinations, with no egg⁃positives identified. The sero⁃prevalence of S. japonicum infections appeared an overall tendency towards a rise in Suzhou City from 2010 to 2020 ([χ2] = 129.48, P < 0.001). The sero⁃prevalence of S. japonicum infections appeared high among local residents in 2016, and remained stable in other years, while the sero⁃prevalence of S. japonicum infections appeared an overall tendency towards a rise among mobile populations ([χ2] = 54.11, P < 0.001). There were 278 800 and 175 202 serological tests among local residents and mobile populations in Suzhou City from 2013 to 2020, and 0.50% and 0.35% sero⁃prevalence rates were detected, respectively. The sero⁃prevalence of S. japonicum infections was significantly higher among local residents than among mobile populations in Suzhou City ([χ2] = 54.76, P < 0.001). Conclusions　There is a risk of rebound of schistosomiasis in Suzhou City. Integrated control should be reinforced to prevent the risk of rebound of schistosomiasis in Suzhou City.

Application of the small private online course⁃based blended teaching model in Human Parasitology teaching

FAN Yan⁃ting, LIU Yan⁃qing, YANG Yang

2022, 34(4):  417. 

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Small private online course (SPOC), an emerging network⁃based, student⁃centered blended teaching model, combines the advantages of online teaching and flipped classroom, aiming to effectively improve students’ autonomous learning ability and learning efficiency. Considering a remarkable decline in the course of Human Parasitology, we built an SPOC⁃based blended teaching model for Human Parasitology, covering pre⁃course learning, intra⁃course leaning, post⁃course consolidation and evaluation, and such a model was applied among grade 2019 students with specialty of clinical medicine. Following the application of the SPOC⁃based blended teaching model, most students had improvements in autonomous learning ability and activity, and understanding of human parasitology knowledge, and the examination score disparity was avoided.

Taxonomic rank of human parasites

JIA Tie⁃wu, WANG Wei, ZHOU Yi⁃biao, ZHOU Jie, MEI Zhong⁃qiu, LI Shi⁃zhu

2022, 34(4):  420. 

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Biological category is effective to indicate the evolution of organism populations between past and present. Conventional taxonomy of human parasites mainly depends on important morphological features, which suffers from a problem of categorizing related⁃genera species with similar morphological characteristics. With recent advances in molecular biological technologies, the effective applications of mitochondrial and ribosomal biomarkers and sequencing greatly improve the development of the taxonomic rank of human parasites. Worldwide, the classification of human parasites have been continuously revised and improved. Hereby, we re⁃categorize parasitic Protozoa, Trematoda, Cestoda and Nematoda, so as to provide insights into the researches on molecular systematics and genetic evolution of human parasites.

Primary liver cancer complicated by hepatic cystic echinococcosis: a case report

LIU Tao, XU Zhao⁃jun, JIANG Shu⁃yun, LIU Guang⁃zhao, WANG Xin⁃le, XIONG Zi⁃chao, WANG Cheng

2022, 34(4):  429. 

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A primary liver cancer patient complicated by hepatic cystic echinococcosis was reported. The case was admitted to the hospital due to intermittent upper abdominal discomfort for more than half a month, and an auxiliary examination revealed primary liver cancer complicated by hepatic cystic echinococcosis. Then, hepatic artery infusion and chemoembolization was performed, and no treatment was given to cystic echinococcosis lesions. Following treatment, the patient had remarkable improvements in the liver functions.

Progress of researches on schistosomiasis⁃associated pulmonary arterial hypertension

ZHU Yong⁃hui, CAI Yu, JIANG Yuan⁃dong, DENG Wei⁃cheng

2022, 34(4):  432. 

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Schistosomiasis⁃associated pulmonary arterial hypertension (Sch⁃PAH) is categorized as WHO Group I PAH because its clinical manifestations, laboratory and hemodynamic features share with PAH of other etiologies, such as idiopathic, heritable, HIV and autoimmune disorders. Sch⁃PAH is usually a life⁃threatening complication of hepatosplenic schistosomiasis characterized by changes in the vascular wall, remodeling and vasoconstriction with lesions primarily located in the precapillary segments of the pulmonary vasculature, which may result in a marked and sustained increase in pulmonary vascular resistance, right ventricular failure and ultimately death. Although egg deposition into lung and subsequent inflammatory cascades are key factors in the pathogenesis of Sch⁃PAH, the exact pathogenesis, course of disease and treatment of Sch⁃PAH remain largely uncertain. This review mainly discusses the pathophysiological and immunological mechanisms of Sch⁃PAH, so as to provide insights into the clinical diagnosis and treatment of Sch⁃PAH.

Role of alternative activation of macrophages in hookworm therapy for inflammatory diseases: a review

YANG You⁃gui , DAI Yang

2022, 34(4):  438. 

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As a type of highly plastic innate immune cells, macrophages may be differentiated into M1 and M2 macrophages upon different stimuli, and M2 macrophages are involved in immune regulation, tissue remodeling and regeneration, and wound healing. Previous epidemiological studies have shown a significant negative correlation between the prevalence of helminth infections and the incidence of inflammatory diseases, such as allergy and autoimmune diseases. As a common type of intestinal helminths, hookworm infection may trigger high levels of type II host immune responses, with alternative activation of macrophages, which are effective to inhibit the development and progression of inflammatory diseases. This review summarizes the advances in alternative activation of macrophages in hookworm therapy for inflammatory diseases.