Table of Content

15 August 2023, Volume 35 Issue 4

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Epidemiology of pathogenic tick-borne viruses in China: a review#br# #br#

MA Jingge, LIU Ning, LIU Ziyan, LIU Quan, WEI Feng, WANG Zedong

2023, 35(4):  325-330,348. 

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Ticks are obligate, haematophagous arthropods that are distributed across the world, which may transmit more than 200 pathogens, including viruses, bacteria and parasites. A large number of tick species are widespread in China, and their transmitting tick-borne viral diseases pose a great threat to human health in endemic foci. This review describes the epidemiology of common, emerging and potentially pathogenic tick-borne viruses in China, and recommends the assessment of public health significance and pathogenicity of emerging tick-borne viruses using reverse microbial etiology, so as to provide insights into the management of emerging tick-borne diseases in China.

Protective effect of recombinant Schistosoma japonicum cystatin against acute kidney injury associated with acute liver failure in mice

XUE Yuan, YANG Xiaodi, ZHANG Huaping, ZHANG Tingting, CHEN Weihao, CHANG Xinyue, WANG Yanhong

2023, 35(4):  331-339. 

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Objective　To evaluate the protective effect of recombinant Schistosoma japonicum cystatin (rSj⁃Cys) against acute kidney injury induced by acute liver failure and unravel the underlying mechanism, so as to provide insights into the clinical therapy of acute kidney injury. Methods　Twenty⁃four male C57BL/6J mice at ages of 6 to 8 weeks were randomly divided into the normal control group, rSj⁃Cys control group, lipopolysaccharide (LPS)/D⁃galactosamine (D⁃GaIN) model group and LPS/D⁃GaIN +rSj⁃Cys treatment group, of 6 mice each group. Mice in the LPS/D⁃GaIN group and LPS/D⁃GaIN + rSj⁃Cys group were intraperitoneally injected with LPS (10 μg/kg) and D⁃GaIN (700 mg/kg), and mice in the LPS/D⁃GaIN + rSj⁃Cys group were additionally administered with rSj⁃Cys (1.25 mg/kg) by intraperitoneal injection 30 min post⁃modeling, while mice in the rSj⁃Cys group were intraperitoneally injected with rSj⁃Cys (1.25 mg/kg), and mice in the normal control group were injected with the normal volume of PBS. All mice were sacrificed 6 h post⁃modeling, and mouse serum and kidney samples were collected. Serum creatinine (Cr) and urea nitrogen (BUN) levels were measured, and the pathological changes of mouse kidney specimens were examined using hematoxylin⁃eosin (HE) staining. Serum tumor necrosis factor (TNF)⁃α and interleukin (IL)⁃6 levels were detected using enzyme⁃linked immunosorbent assay (ELISA), and the expression of inflammatory factors and pyroptosis⁃related proteins was quantified in mouse kidney specimens using immunohistochemistry. In addition, the expression of pyroptosis⁃related proteins and nuclear factor⁃kappa B (NF⁃κB) signaling pathway⁃associated proteins was determined in mouse kidney specimens using Western blotting assay. Results　HE staining showed no remarkable abnormality in the mouse kidney structure in the normal control group and the rSj⁃Cys control group, and renal tubular injury was found in LPS/D⁃GaIN group, while the renal tubular injury was alleviated in LPS/D⁃GaIN+rSj⁃Cys treatment group. There were significant differences in serum levels of Cr (F = 46.33, P < 0.001), BUN (F = 128.60, P < 0.001), TNF⁃α (F = 102.00, P < 0.001) and IL⁃6 (F = 202.10, P < 0.001) among the four groups , and lower serum Cr [(85.35 ± 32.05) µmol/L], BUN [(11.90 ± 2.76) mmol/L], TNF⁃α [(158.27 ± 15.83) pg/mL] and IL⁃6 levels [(56.72 ± 4.37) pg/mL] were detected in the in LPS/D⁃GaIN + rSj⁃Cys group than in the LPS/D⁃GaIN group (all P values < 0.01). Immunohistochemical staining detected significant differences in TNF⁃α (F = 24.16, P < 0.001) and IL⁃10 (F = 15.07, P < 0.01) expression among the four groups , and lower TNF⁃α [(106.50 ± 16.57)%] and higher IL⁃10 expression [(91.83 ± 5.23)%] was detected in the LPS/D⁃GaIN + rSj⁃Cys group than in the LPS/D⁃GaIN group (both P values < 0.01). Western blotting and immunohistochemistry detected significant differences in the protein expression of pyroptosis⁃related proteins NOD⁃like receptor thermal protein domain associated protein 3 (NLRP3) (F = 24.57 and 30.72, both P values < 0.001), IL⁃1β (F =19.24 and 22.59, both P values < 0.001) and IL⁃18 (F = 16.60 and 19.30, both P values < 0.001) in kidney samples among the four groups, and lower NLRP3, IL⁃1β and IL⁃18 expression was quantified in the LPS/D⁃GaIN + rSj⁃Cys treatment group than in the LPS/D⁃GaIN group (P values < 0.05). In addition, there were significant differences in the protein expression of NF⁃κB signaling pathway⁃associated proteins p⁃NF⁃κB p⁃P65/NF⁃κB p65 (F = 71.88, P < 0.001), Toll⁃like receptor (TLR)⁃4 (F = 45.49, P < 0.001) and p⁃IκB/IκB (F = 60.87, P < 0.001) in mouse kidney samples among the four groups, and lower expression of three NF⁃κB signaling pathway⁃associated proteins was determined in the LPS/D⁃GaIN + rSj⁃Cys treatment group than in the LPS/D⁃GaIN group (all P values < 0.01). Conclusion　rSj⁃Cys may present a protective effect against acute kidney injury caused by acute liver failure through inhibiting inflammation and pyroptosis and downregulating the NF⁃κB signaling pathway.

Prevalence of comorbid depression and anxiety and effect of psychological interventions among schistosomiasis patients in China: a meta⁃analysis

WANG Meiti, JIN Guixiang, CHENG Ying, ZHENG Jinxin, TIAN Liguang, ZHANG Shunxian, HONG Wu

2023, 35(4):  340-348. 

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Objective　To investigate the prevalence of comorbid depression and anxiety and to evaluate the effect of psychological interventions among schistosomiasis patients in China, so as to provide insights into improvements of psychological health among schistosomiasis patients. Methods　Publications pertaining to comorbid depression and anxiety and psychological interventions among Chinese schistosomiasis patients were retrieved in electronic databases, including CNKI, Wanfang Data, PubMed, Web of Science, and Embase. The prevalence of comorbidity, psychological interventions, and scores for the Self⁃Rating Depression Scale (SDS) and Self⁃Rating Anxiety Scale (SAS) before and after psychological interventions among Chinese schistosomiasis patients were extracted. The prevalence of comorbid depression and anxiety was investigated among Chinese schistosomiasis patients using a meta⁃analysis, and the effect of psychological interventions for depression and anxiety was evaluated. Results　A total of 231 publications were retrieved, and 14 publications that met the inclusion and exclusion criteria were included in the final analysis, including 2 English publications and 12 Chinese publications. Meta⁃analysis showed that the prevalence rates of comorbid depression and anxiety were 61% [95% confidential interval (CI): (48%, 72%)] and 64% [95% CI: (42%, 81%)] among Chinese schistosomiasis patients. Both the SDS [1.45 points, 95% CI: (1.30, 1.60) points] and SAS scores [2.21 points, 95% CI: (2.05, 2.38) points] reduced among Chinese schistosomiasis patients after psychological interventions than before psychological interventions, and the SDS [−0.47 points, 95% CI: (−6.90, −0.25) points] and SAS scores [−1.30 points, 95% CI: (−1.52, −1.09) points] reduced among Chinese schistosomiasis patients in the case group than in the control group. Conclusions　The comorbid anxiety and depression are common among Chinese schistosomiasis patients, and conventional psychological interventions facilitate the improvements of anxiety and depression among schistosomiasis patients.

Spatial distribution of Oncomelania hupensis spread in Hubei Province from 2020 to 2022

CHEN Yanyan, XIAO Ying, WEI Fenghua, YANG Junjing, DAI Lingfeng, ZHONG Chenhui, LIU Jianbing

2023, 35(4):  349-357. 

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Objective　To identify the spatial distribution pattern of Oncomelania hupensis spread in Hubei Province, so as to provide insights into precision O. hupensis snail control in the province. Methods　Data pertaining to emerging and reemerging snails were collected from Hubei Province from 2020 to 2022 to build a spatial database of O. hupensis snail spread. The spatial clustering of O. hupensis snail spread was identified using global and local spatial autocorrelation analyses, and the hot spots of snail spread were identified using kernel density estimation. In addition, the correlation between environments with snail spread and the distance from the Yangtze River was evaluated using nearest⁃neighbor analysis and Spearman correlation analysis. Results　O. hupensis snail spread mainly occurred along the Yangtze River and Jianghan Plain in Hubei Province from 2020 to 2022, with a total spread area of 4 320.63 hm2, including 1 230.77 hm2 emerging snail habitats and 3 089.87 hm2 reemerging snail habitats. Global spatial autocorrelation analysis showed spatial autocorrelation in the O. hupensis snail spread in Hubei Province in 2020 and 2021, appearing a spatial clustering pattern (Moran’s I = 0.003 593 and 0.060 973, both P values < 0.05), and the mean density of spread snails showed spatial aggregation in Hubei Province in 2020 (Moran’s I = 0.512 856, P < 0.05). Local spatial autocorrelation analysis showed that the high⁃high clustering areas of spread snails were mainly distributed in 50 settings of 10 counties (districts) in Hubei Province from 2020 to 2022, and the high⁃high clustering areas of the mean density of spread snails were predominantly found in 219 snail habitats in four counties of Jiangling, Honghu, Yangxin and Gong’an. Kernel density estimation showed that there were high⁃, secondary high⁃ and medium⁃density hot spots in snail spread areas in Hubei Province from 2020 to 2022, which were distributed in Jingzhou District, Wuxue District, Honghu County and Huangzhou District, respectively. There were high⁃ and medium⁃density hot spots in the mean density of spread snails, which were located in Jiangling County, Honghu County and Yangxin County, respectively. In addition, the snail spread areas negatively correlated with the distance from the Yangtze River (r = –0.1089, P < 0.05). Conclusions　There was spatial clustering of O. hupensis snail spread in Hubei Province from 2020 to 2022. The monitoring and control of O. hupensis snails require to be reinforced in the clustering areas, notably in inner embankments to prevent reemerging schistosomiasis.

Bioinformatics analysis of the RNA binding protein DDX39 of Toxoplasma gondii

YANG Zhenke, WANG Jinghui, QI Yiming, TIAN Xiaowei, MEI Xuefang, ZHANG Zhenchao, WANG Shuai

2023, 35(4):  358-365,373. 

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Objective　To analyze the RNA binding protein of Toxoplasma gondii (TgDDX39) using bioinformatics technology, and to evaluate the immunogenicity of TgDDX39, so as to provide insights into development of toxoplasmosis vaccines. Methods　The amino acid sequences of TgDDX39 were retrieved from the ToxoDB database, and the physicochemical properties, transmembrane structure domain, signal peptide sites, post⁃translational modification sites, coils, secondary and tertiary structures, hydrophobicity, and antigenic epitopes of the TgDDX39 protein were predicted using online bioinformatics tools, incluiding ProtParam, TMHMM 2.0, SignalP 5.0, NetPhos 3.1, COILS, SOPMA, Phyre2, ProtScale, ABCpred, SYFPEITHI and DNASTAR. Results　TgDDX39 protein was predicted to be an unstable hydrophilic protein with the molecular formula of C2173H3458N598O661S18, which contained 434 amino acids and had an estimated molecular weight of 49.1 kDa and a theoretical isoelectric point of 5.55. The protein was predicted to have an extremely low possibility of signal peptides, without transmembrane regions, and contain 27 phosphorylation sites. The β turn and random coils accounted for 39.63% of the secondary structure of the TgDDX39 protein, and a coiled helix tended to produce in one site. In addition, the TgDDX39 protein contained multiple B and T cell antigenic epitopes. Conclusions　Bioinformatics analyses predict that TgDDX39 protein has high immunogenicity and contains multiple antigenic epitopes. TgDDX39 protein is a potential candidate antigen for vaccine development.

Effect of Echinococcus multilocularis infection on Tim3 expression in spleen natural killer cells of mice

SHI Yang, ABIDAN Ainiwaer, LI Dewei, ZIBIGU Rousu, WANG Maoling, ZHENG Xuran, KANG Xuejiao, WANG Hui, LI Jing, ZHANG Chuanshan

2023, 35(4):  366-373. 

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Objective　To investigate the effect of Echinococcus multilocularis infection on Tim3 expression and its co⁃expression with immune checkpoint molecules 2B4 and LAG3 in spleen natural killer (NK) cells of mice. Methods　C57BL/6 mice, each weighing (20 ± 2) g, were randomly divided into a high⁃dose infection group (15 mice), a low⁃dose infection group (13 mice), and a control group (11 mice). Mice in the high⁃ and low⁃dose infection groups were inoculated with 2 000 and 50 Echinococcus multilocularis protoscolices via the hepatic portal vein, while animals in the control group was injected with an equivalent amount of physiological saline via the hepatic portal vein. Mouse spleen cells were harvested 12 and 24 weeks post⁃infection, and Tim3 expression and its co⁃expression with 2B4 and LAG3 in NK cells were detected using flow cytometry. Results　There were significant differences in the proportions of Tim3 expression (F = 13.559, P < 0.001) and Tim3 and 2B4 co⁃expression (F = 12.465, P < 0.001) in mouse spleen NK cells among groups 12 weeks post⁃infection with E. multilocularis, and the proportion of Tim3 expression was significantly higher in mouse spleen NK cells in the low⁃dose infection group [(23.84 ± 2.28)%] than in the high⁃dose infection group [(15.72 ± 3.67)%] and the control group [(16.14 ± 3.83)%] (both P values < 0.01), while the proportion of Tim3 and 2B4 co⁃expression was significantly higher in mouse spleen NK cells in the low⁃dose infection group [(22.20 ± 2.13)%] than in the high⁃dose infection group [(14.17 ± 3.81)%] and the control group [(15.20 ± 3.77)%] (both P values < 0.01). There were significant differences in the proportions of Tim3 expression (F = 5.243, P < 0.05) and Tim3 and 2B4 co⁃expression (F = 4.659, P < 0.05) in mouse spleen NK cells among groups 24 weeks post⁃infection with E. multilocularis infection, and the proportions of Tim3 expression and Tim3 and 2B4 co⁃expression were significantly lower in mouse spleen NK cells in the high⁃dose infection group [(20.55 ± 7.04)% and (20.98 ± 7.12)%] than in the control group [(31.38 ± 3.19)% and (31.25 ± 3.06)%] (both P values < 0.05), and there were no significantly difference between the proportions of Tim3 expression and Tim3 and 2B4 co⁃expression in splenic NK cells in the low⁃dose infection group [(26.80 ± 6.47)% and (26.48 ± 6.48)%]and the control group(both P > 0.05). There were no significant differences in the proportions of Tim3 and LAG3 co⁃expression in mouse spleen NK cells among groups 12 (F = 2.283, P > 0.05) and 24 weeks post⁃infection (F = 0.375, P > 0.05). In the low⁃dose infection group, there were no significant differences in the proportions of Tim3 expression or Tim3 and 2B4 co⁃expression in mouse spleen NK cells 12 (t = −1.137, P > 0.05) or 24 weeks post⁃infection (t = −1.658, P > 0.05), and the proportion of Tim3 and LAG3 co⁃expression increased in mouse spleen NK cells 24 weeks post⁃infection relative to 12 weeks post⁃infection (t = −5.261, P < 0.01). In the high⁃dose infection group, there was no significant difference in the proportion of Tim3 expression in mouse spleen NK cells 12 and 24 weeks post⁃infection (t = −1.546, P > 0.05); however, the proportions of Tim3 co⁃expression with 2B4 and LAG3 increased in mouse splenic NK cells 24 weeks post⁃infection relative to 12 weeks post⁃infection (t = −2.425 and −4.745, both P values < 0.05). Conclusions　The Tim3 expression and Tim3 co⁃expression with LAG3 and 2B4 on spleen NK cells is affected by doses of E. multilocularis infection and disease stages, and present different phenotypes during the course of alveolar echinococcosis. NK cells tend to form an immunosuppressive phenotype with the progression of E. multilocularis infection, which facilitates immune escape and chronic parasitism of E. multilocularis.

Construction of a schistosomiasis transmission risk assessment system in Wuhan City based on analytic hierarchy process

ZUO Yuting, XU Mingxing, LI Yang, WANG Shuai, ZHOU Shuimao, LUO Huatang

2023, 35(4):  374-378. 

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Objective　To construct a schistosomiasis transmission risk assessment system in Wuhan City and preliminary evaluate its application effect, so as to promote the rational allocation of schistosomiasis control resources and accelerate the progress towards schistosomiasis elimination. Methods　The schistosomiasis risk assessment indicators were collected through referring schistosomiasis surveillance data of Wuhan City from 2014 to 2020, literature review and expert interviews. Indicators within each criterion and sub⁃criterion were screened using the Delphi method, and a hierarchical structure model was created based on analytic hierarchy process. Quantitative assignment of each indicator was conducted according to relative importance, and the weight and combination weight of each criterion were calculated in each analytic hierarchy framework to create a schistosomiasis transmission risk assessment system, which was used for the schistosomiasis transmission risk assessment in 12 national schistosomiasis surveillance sites in Wuhan City. Results　A three⁃level schistosomiasis transmission risk assessment system was preliminarily constructed, which included a target layer, 5 criterion layers and 21 sub⁃criterion layers. Of all indicators in the criterion layer, transmission route had the highest weight (0.433), followed by source of Schistosoma japonicum infection (0.294); and among all indicators in the sub⁃criterion layer, S. japonicum infection in Oncomelania hupensis and sentinel mice had the highest combination weight (0.125), followed by prevalence of S. japonicum infection in humans (0.091) and bovines (0.053), snail control by chemical treatment (0.049), positive rate of inquiry examinations (0.048), allocation of schistosomiasis control professionals (0.045), and areas of submerged snail⁃infested settings (0.041). Of the 12 national schistosomiasis surveillance sites in Wuhan City, there were 5 sites with weights of > 0.8, 4 sites with weights of 0.6 to 0.8, and 3 sites with weights of < 0.6 in 2020. Conclusion　A schistosomiasis transmission risk assessment system has been constructed based on analytic hierarchy process in Wuhan City, which may provide a evidence⁃based basis for health resource allocation and decision⁃making for schistosomiasis control. 　

Surveillance on dengue vector Aedes albopictus in Ningbo City in 2021

HE Xin, MA Min, MA Xiao

2023, 35(4):  379-382,388. 

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Objective　To analyze the density, distribution and insecticide resistance of Aedes albopictus in Ningbo City in 2021, so as to provide insights into formulation of dengue fever control strategies. Methods　Four administrative villages were randomly selected from each county (district) in Ningbo City from April to November, 2021, to investigate the indoor population density of Aedes larvae, and the Breteau index (BI) was calculated. The population density of adult mosquitoes was investigated in residential areas, parks/bamboo forests, waste tire stacking sites/waste stations/construction sites in each county (district). On June 2021, larvae of the natural strain A. albopictus were collected from epidemic sites of dengue fever in Ningbo City in 2018, and raised in laboratory. Then, larvae and female mosquitoes without blood feeding were selected for insecticide resistance bioassays, while insecticide⁃sensitive strains of A. albopictus served as controls. The resistance of A. albopictus larvae to deltamethrin, beta⁃cypermethrin, propoxur, temephos and dichlorvos using the impregnation method, and the medium lethal concentration (LC50) and resistance ratio (RR) were calculated. The resistance of adult A. albopictus to beta⁃cypermethrin, permethrin, deltamethrin, propoxur and malathion was determined using the tube bioassay, and the mosquito mortality was calculated. Results　A total of 10 072 small water containers from 9 935 households were investigated in Ningbo City in 2021, and there were 1 276 containers with Aedes larvae detected, with an average BI of 12.89. Totally 1 422 mosquito nets were allocated and 954 female A. albopictus were captured, with an average net trapping index of 1.34 mosquitoes/(net·hour). Both larval and adult A. albopictus mosquitoes were found from April to November, and the density of larval A. albopictus peaked in September (BI = 21.21), while the density of adult A. albopictus peaked in August, with a net trapping index of 2.38 mosquitoes/(net ·hour). The LC50 values of deltamethrin, beta⁃cypermethrin, propoxur, temephos and dichlorvos were 0.017 4, 0.000 9, 0.364 1, 0.038 1 mg/L and 0.001 6 mg/L against larvae of natural strains of A. albopicchus, with RRs of 49.66, 25.53, 9.65, 2.24 and 6.06, and the mortality rates of adult mosquitoes were 66.00% (66/100), 69.39% (68/98), 25.00% (25/100), 98.97% (96/97) and 100.00% (98/98) 24 hours post⁃treatment with 0.08% beta⁃cypermethrin, 0.03% deltamethrin, 0.4% permethrin, 0.05% propoxur, and 0.5% malathion for 24 h, respectively. Conclusions　A. albopictus is widely distributed in Ningbo City, with a high population density and presents high⁃level resistance to common pyrethroid insecticides. The population density and insecticide resistance of A. albopictus requires to be reinforced.

Impact of COVID⁃19 pandemic on the management of imported malaria in China

LIU Ying, WANG Dan, HE Zhiquan, ZHANG Tao, YAN Hui, LIN Wen, ZHANG Xuan, LU Shenning, LIU Yuting, WANG Duoquan, LI Jun, RUAN Wei, LI Shizhu, ZHANG Hongwei

2023, 35(4):  383-388. 

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Objective　To examine the impact of COVID⁃19 pandemic on the epidemic status of imported malaria and national malaria control program in China, so as to provide insights into post⁃elimination malaria surveillance. Methods　All data pertaining to imported malaria cases were collected from Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 through December 31, 2021. The number of malaria cases, species of malaria parasites, country where malaria parasite were infected, diagnosis and treatment after returning to China, and response were compared before (from January 1, 2018 to January 22, 2020) and after the COVID⁃19 pandemic (from January 23, 2020 to December 31, 2021). Results　A total of 2 054 imported malaria cases were reported in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 to December 31, 2021, and there were 1 722 cases and 332 cases reported before and after the COVID⁃19 pandemic, respectively. All cases were reported within one day after definitive diagnosis. The annual mean number of reported malaria cases reduced by 79.30% in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region after the COVID⁃19 pandemic (171 cases) than before the pandemic (826 cases), and the number of monthly reported malaria cases significantly reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region since February 2020. There was a significant difference in the constituent ratio of species of malaria parasites among the imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID⁃19 pandemic ([χ2] = 146.70, P < 0.05), and P. falciparum malaria was predominant before the COVID⁃19 pandemic (72.30%), while P. ovale malaria (44.28%) was predominant after the COVID⁃19 pandemic, followed by P. falciparum malaria (37.65%). There was a significant difference in the constituent ratio of country where malaria parasites were infected among imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID⁃19 pandemic ([χ2] = 13.83, P < 0.05), and the proportion of malaria cases that acquired Plasmodium infections in western Africa reduced after the COVID⁃19 pandemic that before the pandemic (44.13% vs. 37.95%; [χ2] = 4.34, P < 0.05), while the proportion of malaria cases that acquired Plasmodium infections in eastern Africa increased after the COVID⁃19 pandemic that before the pandemic (9.58% vs. 15.36%; [χ2] = 9.88, P = 0.02). The proportion of completing case investigation within 3 days was significantly lower after the COVID⁃19 pandemic than before the pandemic (96.69% vs. 98.32%; [χ2] = 3.87, P < 0.05), while the proportion of finishing foci investigation and response within 7 days was significantly higher after the COVID⁃19 pandemic than before the pandemic (100.00% vs. 98.43%; [χ2] = 3.95, P < 0.05). Conclusions　The number of imported malaria cases remarkably reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region of China during the COVID⁃19 pandemic, with a decreased proportion of completing case investigations within 3 days. The sensitivity of the malaria surveillance⁃response system requires to be improved to prevent the risk of secondary transmission of malaria due to the sharp increase in the number of imported malaria cases following the change of the COVID⁃19 containment policy.

Molecular detection and phylogenetic analysis of Wolbachia infection in common mosquito species in Henan Province

LIU Yuting, WANG Dan, HE Zhiquan, QIAN Dan, LIU Ying, YANG Chengyun, LU Deling, ZHANG Hongwei

2023, 35(4):  389-397. 

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Objective　To investigate the infection and genotypes of Wolbachia in common mosquito species in Henan Province, so as to provide insights into management of mosquito⁃borne diseases. Methods　Aedes, Culex and Anopheles samples were collected from cowsheds, sheepfolds and human houses in Puyang, Nanyang City and Xuchang cities of Henan Province from July to September, 2022, and the infection of Wolbachia was detected. The 16S rDNA and wsp genes of Wolbachia were amplified and sequenced. Sequence alignment was performed using the BLAST software, and the obtained 16S rDNA gene sequence was compared with the sequence of the 16S rDNA gene in GenBank database. In addition, the phylogenetic trees were created based on 16S rDNA and wsp gene sequences using the software MEGA 11.0. Results　A total 506 female adult mosquitoes were collected from three sampling sites in Nanyang, Xuchang City and Puyang cities from July to September, 2022. The overall detection of Wolbachia was 45.1% (228/506) in mosquitoes, with a higher detection rate in A. albopictus than in Cx. pipiens pallens [97.9% (143/146) vs. 50.6% (85/168); [χ2] = 88.064, P < 0.01]. The detection of Wolbachia in Cx. pipiens pallens was higher in Xuchang City (96.8%, 62/64) than in Nanyang (15.6%, 7/45) and Puyang cities (27.1%, 16/59) ([χ2] = 89.950, P < 0.01). The homologies of obtained Wolbachia 16S rDNA and wsp gene sequences were 95.3% to 100.0% and 81.7% to 99.8%. Phylogenetic analysis based on wsp gene sequences showed Wolbachia supergroups A and B in mosquito samples, with wAlbA and wMors strains in supergroup A and wPip and wAlbB strains in supergroup B. Wolbachia strain wAlbB infection was detected in A. albopictus in Puyang and Nanyang Cities, while Wolbachia strain wPip infection was identified in A. albopictus in Xuchang City. Wolbachia strain wAlbA infection was detected in Cx. pipiens pallens sampled from three cities, and one Cx. pipiens pallens was found to be infected with Wolbachia strain wMors in Nanyang City. Conclusions Wolbachia infection is commonly prevalent in Ae. albopictus and Cx. pipiens pallens from Henan Province, and Wolbachia strains wAlbB and wAlbA are predominant in Ae. albopictus, while wPip strain is predominant in Cx. pipiens pallens. This is the first report to present Wolbachia wMors strain infection in Cx. pipiens pallens in Henan Province.

Experimental study on the molluscicidal activity of surfactin against Oncomelania hupensis

YANG Cheng, TANG Xingli, PAN Zhongwu

2023, 35(4):  394-397. 

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Objective　To evaluate the molluscicidal activity of surfactin against Oncomelania hupensis, so as to provide the experimental basis for use of Bacillus for killing O. hupensis. Methods　O. hupensis snails were collected from schistosomiasis⁃endemic foci of Wuhu City on September 2022, and Schistosoma japonicum⁃infected snails were removed. Then, 60 snails were immersed in surfactin at concentrations of 2, 1, 0.5, 0.25, 0.125 mg/mL and 0.062 5 mg/mL for 24, 48, 72 hours at 26 ℃, while ultrapure water⁃treated snails served as controls. The median lethal concentration (LC50) of surfactin against O. hupensis snails was estimated. O. hupensis snails were immersed in surfactin at a concentration of 24 h LC50 and ultrapure water, and then stained with propidium iodide (PI). The PI uptake in haemocyte was observed in O. hupensis snails using fluorescence microscopy. Results　The mortality of O. hupensis was 5.0% following immersion in surfactin at a concentration of 0.062 5 mg/mL for 24 h, and the mortality was 100.0% following immersion in surfactin at a concentration of 2 mg/mL for 72 h, while no snail mortality was observed in the control group. There were significant differences in the mortality of O. hupensis in each surfactin treatment groups at 24 ([χ]2 = 180.150, P < 0.05), 48 h ([χ]2 = 176.786, P < 0.05) and 72 h ([χ]2 = 216.487, P < 0.05), respectively. The average mortality rates of O. hupensis were 38.9% (140/360), 62.2% (224/360) and 83.3% (300/360) 24, 48 h and 72 h post⁃immersion in surfactin, respectively ([χ]2 = 150.264, P < 0.05), and the 24, 48 h and 72 h LC50 values of surfactin were 0.591, 0.191 mg/mL and 0.054 mg/mL against O. hupensis snails. Fluorescence microscopy showed more numbers of haemocytes with PI uptake in 0.5 mg/mL surfactin⁃treated O. hupensis snails than in ultrapure water⁃treated snails for 24 h, and there was a significant difference in the proportion of PI uptake in haemocytes between surfactin⁃and ultrapure water⁃treated snails ([χ]2 = 6.690, P < 0.05). Conclusion　Surfactin is active against O. hupensis snails, which may be associated with the alteration in the integrity of haemocyte membrane.

Traditional Chinese medicine for treatment of echinococcosis: a review

CHEN Qing, LIU Chuanchuan, LI Caixia, ZHANG Boen, FAN Haining

2023, 35(4):  398-406,412. 

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Echinococcosis is a zoonotic parasitic disease caused by infection with Echinococcus species. As the drug of first choice for treatment of echinococcosis, albendazole suffers from problems of large doses and remarkable adverse reactions in clinical therapy. Development of novel drugs against echinococcosis is of urgent need. Recently, great advances have been achieved in the research on traditional Chinese medicine for treatment of echinococcosis. This review summarizes the progress of researches on traditional Chinese medicine for treatment of echinococcosis, aiming to provide insights into development of anti⁃echinococcosis drugs.

Progress of researches on the role and mechanisms of non⁃coding RNA in Angiostrongylus cantonensis infection

CHENG Donghui, LI Zhongqiu, ZENG Wenbo, JIANG Tiange, GUO Yunhai, ZHANG Yi

2023, 35(4):  407-412. 

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Angiostrongylus cantonensis is a food⁃borne zoonotic parasite, and human infection may cause eosinophilic meningitis. Non⁃coding RNAs (ncRNAs) may regulate physiological and pathological processes at multiple biological levels; however, there are few studies pertaining to the regulatory role of ncRNAs in A. cantonensis infection. Based on publications retrieved from PubMed, Wanfang Data and CNKI, the regulatory role of ncRNAs in A. cantonensis infections mainly includes immune responses, cell apoptosis and signaling transduction, and ncRNAs may serve as biomarkers for diagnosis of angiostrongyliasis. This review summarizes the main roles of ncRNAs in A. cantonensis infections and the underlying mechanisms, so as to provide insights into diagnosis and treatment of angiostrongyliasis.

Progress of researches on Blastocystis hominis infection among patients with inflammatory bowel disease and irritable bowel syndrome

LI Lin, CAI Yuchun, YU Chenghang, CHEN Muxin, TIAN Liguang

2023, 35(4):  413-420,426. 

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Blastocystis is a common unicellular intestinal protozoa in humans and animals, and the most common clinical manifestations of infections include abdominal pain and diarrhea. Based on the sequence of the small⁃subunit ribosomal RNA (SSU rRNA) gene, 28 subtypes of B. hominis (ST1 to ST17, ST21 and ST23 to ST32) have been characterized. Previous studies have demonstrated that B. hominis infection is strongly associated with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and other intestinal diseases, which threatens the health and quality of life among patients with B. hominis infection and is considered as an important public health problem. This review summarizes the progress of researches on B. hominis infection among IBD and IBS patients during the past 20 years, so as to provide insights into management of blastocystosis in China.

A close contact of coronavirus disease 2019 with severe imported malaria: a case report

OUYANG Shi, ZHAI Yanping, FENG Ruihai, XIONG Yasha, YU Lina, LIU Chongwen

2023, 35(4):  421-423. 

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This article presents a severe cerebral malaria patient in shock with a close contact of COVID⁃19 that was successfully cured in a negative pressure ward during the global pandemic of COVID⁃19. The patient experienced a sudden onset of high fever and coma in a designated isolation hotel after returning from Africa, and was transferred to a designated hospital. Following antimalarial therapy, blood pressure elevation, increase of blood volume, bedside hemodialysis, mechanical ventilation, plasma and platelet transfusions, the case gradual recovered.

The first imported case of visceral leishmaniasis in Shenzhen City

HUANG Yanfei, GAO Shitong, LI Yuan

2023, 35(4):  424-426. 

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A patient with fever, chills, and pancytopenia as major clinical manifestations was presented. To investigate the cause, the patient’s peripheral blood was collected for pathogen screening using metagenomic next⁃generation sequencing (mNGS). The DNA sequence of Leishmania donovani was detected, and Leishmania amastigotes were found in bone marrow smears using microscopy. The case was therefore definitively diagnosed as visceral leishmaniasis, and was cured and discharged from hospital following treatment with liposomal amphotericin B for 14 days. This is the first imported case of visceral leishmaniasis since the founding of Shenzhen City in 1979.