Table of Content

28 August 2020, Volume 32 Issue 4

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A novel isothermal amplification assay improves the capability for the field rapid detection of parasitic diseases

2020, 32(4):  331. 

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With the rapid development of molecular biology, the isothermal amplification technique has been used for the nucleic acid detection of parasites and other pathogens due to its high efficiency and rapid and simple procedures, and has become an important tool to promote the field detection and control of parasitic diseases. Recombinase?aided isothermal amplification assay (RAA), a novel isothermal amplification technique, which is simple and easy to perform, rapid for field detection, no need for high?end equipment, and rapid field detection, may amplify the target gene fragments within 5 to 20 min under an isothermal condition (usually 37 to 42 ℃) and achieve a real?time observation of the amplification results. RAA has been successfully employed for the nucleic acid detection of a wide range of parasites and other pathogens to date, and has shown a high sensitivity and specificity. Notably, such an assay is suitable for the large?scale field detection in non?lab environments, and is therefore considered to have a potential value of application in rapid field detections.

Establishment of the gene detection method of Schistosoma mansoni based on the recombinase-aided isothermal amplification

ZHAO Song, LIU Yan-Hong, YE Yu-Ying, LI Wei, ZHANG Jian-Feng, GUO Li-Chuan, YING Qing-Jie, YANG Hai-Tao, YANG Kun

2020, 32(4):  335. 

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Objective　To establish a recombinase?aided isothermal amplification (RAA) assay for nucleic acid detection of Schistosoma mansoni. Methods　The 121 bp highly?repeated sequence of S. mansoni was selected as the target gene fragment to be detected. The primers and fluorescent probes were designed using the Amplfix software, and a fluorescent RAA assay was established and optimized. The fluorescent RAA assay was performed to detect gradient diluent recombinant plasmids containing target gene fragment and different concentrations of S. mansoni genomic DNA to determine the sensitivity, and this assay was applied to detect the genomic DNA of S. japonicum, S. haematobium, Ancylostoma duodenale and Clonorchis sinensis to evaluate the specificity. Results　A fluorescent RAA assay was successfully established, which was effective to amplify the specific gene fragments of S. mansoni within 20 min at 39 ℃. The minimum detectable limit of the fluorescent RAA assay was 10 copies/μL using recombinant plasmids as templates and 0.1 fg/μL using S. mansoni genomic DNA samples as templates. The fluorescent RAA assays were all negative for detecting the genomic DNA from S. japonicum, S. haematobium, A. duodenale and C. sinensis. Conclusion　A novel fluorescent RAA assay is successfully established, which is simple, rapid, sensitive and specific to detect genomic DNA of S. mansoni.

Establishment of a nucleic acid assay for detection of Echinococcus granulosus based on recombinase-aided isothermal amplification technique (RAA)

DING Xin, LIU Yan-Hong, NI Bi-Xian, WANG Xiao-Ting, XU Xiang-Zhen, YING Qing-Jie, Dai Yang, CAO Jun

2020, 32(4):  340. 

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Objective　To establish a nucleic acid assay for detection of Echinococcus granulosus based on recombinase?aided isothermal amplification technique (RAA). Methods　The 12S rRNA gene of E. granulosus was selected as the target gene, and the specific primers and fluorescent probes for RAA assay were designed, screened and synthesized to establish a fluorescent RAA assay for detection of E. granulosus. The sensitivity of the fluorescent RAA assay was evaluated using different copy numbers of target gene sequence?contained recombinant plasmids and various concentrations of E. granulosus genomic DNA as templates, and the specificity of the fluorescent RAA assay was evaluated using the genomic DNA from E. granulosus, E. multilocularis, Schistosoma japonicum, Schistosoma mansoni, Ancylostoma duodenale, Clonorchis sinensis, Taenia saginata, Spirometra mansoni and Taenia solium as templates. Results　A fluorescent RAA assay was successfully established for detection of E. granulosus, which achieved specific amplification of E. granulosus genomic DNA within 20 min at 39 ℃. The lowest detection limit of the fluorescent RAA assay was 10 copies/μL of recombinant plasmids and 0.1 ng/μL E. granulosus genomic DNA, which exhibited a high sensitivity, and the fluorescent RAA assay was all negative for the genomic DNA from E. multilocularis, S. japonicum, S. mansoni, A. duodenale, C. sinensis, T. saginata, Spirometra mansoni and T. solium, which exhibited a high specificity. In addition, this fluorescent RAA assay successfully detected genomic DNA from E. granulosus cysts. Conclusion　A rapid, sensitive and specific fluorescent RAA assay is successfully established for nucleic acid detection of E. granulosus.

Establishment and evaluation of a novel DNA detection method based on recombinase-aided isothermal amplification technique for Giardia lamblia

NI Bi-Xian, LIU Yan-Hong, XU Xiang-Zhen, WANG Xiao-Ting, WU Xiao-Min, YING Qing-Jie, CAO Jun, DAI Yang

2020, 32(4):  345. 

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Objective　To establish a novel nucleic acid assay for detection of Giardia lamblia based on the recombinase?aided isothermal amplification technique (RAA), and evaluate its sensitivity and specificity for detection of G. lamblia. Methods　The specific primer sequences and florescent probes were designed and synthesized based on the G. lamblia β?giardin gene as the target gene, and a fluorescent RAA assay was established. The recombinant plasmids at various copies (containing the β?giardin gene target sequence) and the genomic DNA of G. lamblia at various concentrations were used as templates for the fluorescent RAA assay to assess the sensitivity, and the genomic DNA from G. lamblia, Schistosoma japonicum, Clonorchis sinensis, Cryptosporidium parvum, Ascaris lumbricoides, Salmonella and Shigella was used as templates to assess the specificity of the fluorescent RAA assay. Results　A novel fluorescent RAA assay was successfully established for detection of G. lamblia, which allowed the rapid and specific amplification of the target gene fragments at 39 ℃ within 20 min. The sensitivities of the fluorescent RAA assay were 102 copies/μL and 1 pg/μL for detection of the recombinant plasmid and G. lamblia genomic DNA, respectively, and the fluorescent RAA assay was negative for detection of the genomic DNA from S. japonicum, C. sinensis, C. parvum, A. lumbricoides, Salmonella and Shigella, which showed a high specificity. Conclusion　A fluorescent RAA assay, which is simple, sensitive and specific, is successfully established for nucleic acid detection of G. lamblia.

Establishment of a recombinase-aided isothermal amplification technique (RAA) for nucleic acid detection of Angiostrongylus cantonensis

ZHANG Qiang, DING Xin, LIU Yan-Hong, LIU Jian-Feng, XU Xiang-Zhen, YING Qing-Jie, DAI Yang, CAO Jun

2020, 32(4):  350. 

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Objective　To establish a recombinase?aided isothermal amplification technique (RAA) for the nucleic acid detection of Angiostrongylus cantonensis. Methods　The internal transcribed spacer?1 (ITS1) gene sequence of A. cantonensis was used as the detection target sequence, and the specific primers and probes were designed and synthesized, followed by screening of the primers and probes with the highest specificity, to establish the basic and fluorescent RAA assay for nucleic acid detection of A. cantonensis. The sensitivity of the fluorescent RAA assay was evaluated by using the target gene fragment sequence?contained recombinant plasmids at various copy numbers and the genomic DNA from A. cantonensis as the template DNA samples, and the specificity of the fluorescent RAA assay was evaluated by using the genomic DNA from A. cantonensis, Schistosoma mansoni, Ascaris lumbricoides, Clonorchis sinensis, Echinococcus granulosus and Ancylostoma duodenale, as well as Pomacea canaliculata and Biomphalaria straminea snail tissues as the template DNA samples. Results　A fluorescent RAA assay was successfully established for nucleic acid detection of A. cantonensis, which achieved real?time amplification of the specific DNA fragment of A. cantonensis within 20 min at 37 ℃. By using the target gene fragment sequence?contained recombinant plasmids at various copy numbers and the genomic DNA from A. cantonensis as the DNA templates, the lowest detection limits of the fluorescent RAA assay were 10 copies/μL of recombinant plasmids and 100 pg/μL of genomic DNA, respectively. The fluorescent RAA assay was negative for detection of the genomic DNA from A. cantonensis, S. mansoni, A. lumbricoides, C. sinensis, E. granulosus, A. duodenale, and P. canaliculata and B. straminea snail tissues. Conclusion　A simple, rapid fluorescent RAA assay has been successfully established, which has a high sensitivity and specificity for the nucleic acid detection of A. cantonensis.

Expression, purification and polyclonal antibody preparation of the Schistosoma japonicum SjGrpE protein

XIAO Fei, HU Zhi, TAN Xiao, HUANG Ze-Zhi

2020, 32(4):  355. 

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Objective　To investigate the biological properties of Schistosoma japonicum SjGrpE protein, and to express and purify the recombinant SjGrpE protein and test its immunogenicity. Methods　The amino acid composition, molecular weight, hydrophilicity and hydrophobicity, transmembrane region, signal peptide, localization, phosphorylation site, ubiquitination site, glycosylation site, secondary and tertiary structures and B cell epitopes of the SjGrpE protein were predicted using bioinformatics analyses. The SjGrpE gene was amplified using PCR assay using S. japonicum cDNA as a template, double enzyme?digested and linked to the pET28a vector to yield the recombinant plasmid pET28a?SjGrpE. The recombinant plasmid pET28a?SjGrpE was transformed into Escherichia coli BL21, and then IPTG was employed to induce the expression of the target protein, which was purified by nickel ion affinity chromatography. After mice were immunized with the recombinant SjGrpE protein, mouse sera were collected, and the polyclonal antibody against the SjGrpE protein was characterized. Results　SjGrpE protein, which was identified as a hydrophilic protein, was predicted to have a molecular weight of approximately 24.3 kDa without transmembrane regions or signal peptides, and locate in the mitochondrion. SjGrpE protein contained 18 phosphorylation sites and 2 ubiquitination sites, but had no glycosylation sites. In addition, SjGrpE protein contained 5 B?cell epitopes. The full length of SjGrpE gene was approximately 660 bp. The recombinant pET28a?SjGrpE plasmid was successfully generated, and the recombinant SjGrpE protein was obtained following the affinity chromatography, which stimulated mice to secrete high?titer antibodies. Conclusion 　The recombinant SjGrpE protein has been successfully prepared and this recombinant protein has a high immunogenicity, which provides a basis for evaluating its value as a vaccine candidate for S. japonicum infections.

Protective effect of recombinant adult serine protease inhibitor from Trichinella spiralis on sepsis-associated acute kidney injury in mice

YANG Hui-Juan, LI Hui-Hui, PANG Xue-Rui, GAO Shi-Fang, LIANG Jin-Bao, ZHENG Xin, LI Ding-Ru, WANG Yu-Hang, YU Xue-Qin, QIAN Xue-Qian, YANG Xiao-Di, CHEN Wei-Dong

2020, 32(4):  361. 

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Objective　To investigate the protective effect of recombinant adult serine protease inhibitor from Trichinella spiralis (TsadSPI) on sepsis?associated acute kidney injury in mice. Methods　A total of 18 male BALB/c mice were randomly divided into the sham?operation group, the model group, and the TsadSPI treatment group, of 6 mice in each group. Sepsis?associated acute kidney injury was modeled in the model group and TsadSPI treatment group by cecal ligation puncture (CLP), while mice in the sham?operation group were only given exploratory laparotomy without ligation or perforation of the cecum. After 30 min of CLP, mice in the sham?operation group and the model group were intraperitoneally injected with PBS (100 μL), and mice in the TsadSPI treatment group were intraperitoneally injected with PBS (100 μL) containing TsadSPI (2 μg). At 12 h following modeling, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr) and urea nitrogen (BUN) were measured to assess the liver and kidney functions, and the changes of the mouse kidney structure were observed using HE staining. In addition, the serum levels of tumor necrosis factor (TNF)?α, interleukin (IL)?6, IL?10 and transforming growth factor (TGF)?β were measured using an enzyme?linked immunosorbent assay (ELISA), and the myeloid differentiation factor 88 (MyD88) and nuclear factor kappa?B (NF?κB) p65 expression was determined in kidney tissues using immunohistochemical staining. Results　At 12 h following CLP, there were significant differences in the serum levels of ALT (F = 41.031, P < 0.001), AST (F = 54.757, P < 0.001), Cr (F = 24.142, P < 0.001) and BUN (F = 214.849, P < 0.001) among the three groups, and higher levels of ALT, AST, Cr and BUN were measured in model group than in the sham?operation group (P < 0.001), while lower ALT, AST, Cr and BUN levels were found in the TsadSPI treatment group than in the model group (P < 0.001). HE staining showed severe mouse kidney injuries following CLP, and TsadSPI treatment resulted in remarkable alleviation of the injury. ELISA measured significant differences in the TNF?α (F = 47.502, P < 0.001) and IL?6 levels (F = 222.061, P < 0.001) among the three groups, and showed a remarkable reduction in the TNF?α and IL?6 levels in the TsadSPI treatment group as compared to those in the model group (P < 0.001). In addition, there were significant differences in serum IL?10 (F = 16.227, P < 0.001) and TGF?β levels (F = 52.092, P < 0.001) among the three groups, and higher IL?10 and TGF?β levels were seen in the TsadSPI treatment group than in the model group (P < 0.001). Immunohistochemical staining showed greater MyD88 expression and a higher nuclear positive rate of NF?κB p65 in kidney tissues in the model group than in the TsadSPI treatment group. Conclusion　TsadSPI may reduce the MyD88 expression and nuclear positive rate of NF?κB p65 in mouse kidney tissues to up?regulate the expression of immunomodulatory factors and down?regulate the expression of pro?inflammatory cytokines, thereby protecting sepsis?associated acute kidney injury.

Polarization of human acute monocytic leukemia THP-1 cells-derived macrophages induced by Nippostrongylus brasiliensis proteins in vitro

WU Xiao-Min, ZHANG Qiang, DING Xin, MAO Fan-Zhen, WANG Xiao-Ting, DAI Yang, WANG Jun-Hong, CAO Jun

2020, 32(4):  367. 

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Objective　To investigate the polarization of human acute monocytic leukemia THP?1 cells?derived macrophages induced by Nippostrongylus brasiliensis proteins in vitro, so as to provide insights into the elucidation of the mechanisms underlying host immune responses to hookworm infections. Methods　The in?vitro culture of N. brasiliensis was established and maintained in the laboratory, and the third? (L3) and fifth?stage larvae (L5) were collected under a sterile condition for preparation of L3 and L5 proteins. The in?vitro culture of THP?1 cells was established, stimulated with 500 ng/mL PMA to yield M0 macrophages that were adherent to the plate wall. The LPS + IFN?γ group, IL?4 + IL?13 group, L3 protein group and L5 protein group were given stimulation with 500 ng/mL LPS plus 100 ng/mL IFN?γ, IL?4 and IL?13 (both 100 ng/mL), L3 protein (5 mg/mL) and L5 protein (5 mg/mL), respectively, while the negative control group was given no stimulation. The cell morphology was observed using microscopy, the mRNA expression of M1/M2 macrophages?specific genes was quantified using a quantitative real?time PCR (qPCR) assay, and the surface markers of M1/M2 macrophages were detected using flow cytometry, while the levels of cytokines secreted by M1/M2 macrophages were measured using enzyme?linked immunosorbent assay (ELISA) following stimulations, so as to examine the polarization of THP?1?derived macrophages induced by N. brasiliensis proteins in vitro. Results　Following stimulation with PMA, THP?1 cells appeared wall?adherent M0 macrophages, and polarized to typical M1 macrophages following stimulation with LPS + IFN?γ, and typical M2 macrophages following stimulation with IL?4 + IL?13, IL?3 protein or L5 protein. There was a significant difference in the proportion of M1 macrophages among the negative control group, the LPS + IFN?γ group, the IL?4 + IL?13 group, the L3 protein group and the L5 protein group ([χ2] = 3 721.00, P < 0.001), with the highest proportion detected in the LPS + IFN?γ group, and there was also a significant difference in the proportion of M2 macrophages among groups ([χ2] = 105.43, P < 0.001). There were significant differences among groups in terms of the mRNA expression of CCL2 (F = 191.95, P < 0.001), TNF?α (F = 129.95, P < 0.001), IL?12b (F = 82.89, P < 0.001), PPARγ (F = 11.30, P < 0.001), IL?10 (F = 9.51, P < 0.001) and Mrc1 genes (F = 12.35, P < 0.001). In addition, there were significant differences in the proportion of positive CD86 and CD206 expression among groups ([χ2] = 24 004.33 and 832.50, P < 0.001). Higher IL?1β and TNF?α levels were measured in the LPS + IFN?γ group than in the IL?4 + IL?13 group, the L3 protein group and the L5 protein group (P < 0.001), and greater TGF?β1 and IL?10 levels were seen in the IL?4 + IL?13 group, the L3 protein group and the L5 protein group than in the negative control group and the LPS + IFN?γ group (P < 0.05). Conclusion　Both L3 and L5 proteins of N. brasiliensis may induce the polarization of THP?1?derived macrophages to M2 type in vitro.

Diagnosis of imported malaria cases in Henan Province from 2015 to 2019

ZHANG Qun-Qun, LIU Ying, ZHOU Rui-Min, YANG Cheng-Yun, QIAN Dan, LI Su-Hua, ZHANG Hong-Wei

2020, 32(4):  374. 

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Objective　To analyze the diagnosis of imported malaria cases in Henan Province from 2015 to 2019, so as to provide the evidence for malaria surveillance during the post?elimination stage. Methods　The data pertaining to malaria cases in Henan Province from 2015 to 2019 were extracted via the web?based Chinese Information System for Infectious Diseases Control and Prevention and the Parasitic Diseases Information Reporting Management System (PDIRMS) of Chinese Center for Disease Control and Prevention, and the diagnostic methods, diagnostic institutions and diagnostic time of imported malaria cases were analyzed. Results　A total of 952 imported malaria cases were reported in Henan Province during the period from 2015 through 2019, and all cases were laboratory?confirmed. The positive rate of malaria rapid diagnostic tests (RDTs) was 98.61% (779/790), which was significantly greater than that (94.22%, 897/952) of microscopic examinations ([χ2] = 22.773, P < 0.05). The proportion of imported malaria cases diagnosed in medical institutions increased from 65.22% (120/184) in 2015 to 81.50% (185/227) in 2019. Among the 238 imported malaria cases diagnosed in centers for disease control and prevention (CDC), 71.01% (169/238) were diagnosed in county?level CDC, and among the 704 cases diagnosed in medical institutions, only 8.38% (59/704) were diagnosed at county?level medical institutions. The median time from onset to definitive diagnosis of malaria was 3 days, and the median duration between onset and initial diagnosis of malaria was 1 day. The duration between initial diagnosis and definitive diagnosis of malaria varied significantly among years ([χ2] = 24.956, P < 0.05), and the interquartile range from initial diagnosis to definitive diagnosis reduced from 4 days in 2016 to 2 days in 2019. In addition, the median time from initial diagnosis to definitive diagnosis was significantly longer in severe falciparum malaria cases than in non?severe falciparum malaria cases (2 days vs. 1 day; Z = 7.557, P < 0.05). Conclusions　Medical institutions play a more and more important role in the identification and surveillance of malaria cases; however, the diagnostic capability of malaria remains low in county?level medical institutions. The diagnostic awareness and capability of county?level medical institutions requires to be improved, in order to play their roles as sentinel hospitals in the malaria surveillance during the post?elimination stage.

Genetic analysis of mitochondrial pcox1 and ribosomal 18S rRNA genes in Eurytrema pancreaticum isolates from goat in Huaihua City, Hunan Province

HOU Qiang-Hong, ZHOU Xiao-Huai, YAO Guo-Min, LI Zhong-Bo, SHU Ming, WANG Xiang, LUO Wei

2020, 32(4):  380. 

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Objective　To investigate the genetic variation of Eurytrema pancreaticum isolated from goats in Huaihua City, Hunan Province. Methods　The partial sequence of mitochondrial cytochrome I (pcox1) and ribosomal 18S rRNA genes were amplified using a PCR assay in E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and the PCR amplification products were sequenced. Then, the gene sequences were subjected to genetic variation and phylogenetic analyses. Results　The sequences of the pcox1 and 18S rRNA genes were 430 bp and 1 857 bp in length in 18 E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and there were 14 and 35 variation sites in pcox1 and 18S rRNA gene sequences, with intra?species genetic variations of 0 to 1.4% and 0 to 0.8%, respectively. The sequences of pcox1 and 18S rRNA genes had 99.0% to 99.8% and 99.5% to 99.8% homologies with those from E. pancreaticum Chinese strain recorded in the GenBank database. Consistent phylogenetic analysis results were found based on pcox1 and 18S rRNA genes. The 18 E. pancreaticum isolates from goats in Huaihua City were clustered into a clade with the known E. pancreaticum isolates registered in GenBank, and the clade with these 18 E. pancreaticum isolates was close to the clades with Eurytrema species and far from the clades with other trematodes. Conclusions The E. pancreaticum isolates from goats have a low genetic variation in Huaihua City, Hunan Province. Mitochondrial pcox1 and ribosomal 18S rRNA genes may serve as molecular markers for the studies on the genetic variation in goat?derived E. pancreaticum.

Comprehensive benefits of agroforestry snail control forests in Eryuan County, Yunnan Province

GUO Yu-Hong, XU De-Bing, JIANG Qi-Chuan, SHI Ying, ZHOU Feng-Lin, YUAN Qi-Qiong

2020, 32(4):  384. 

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Objective　To investigate the efficiency of various agroforestry systems for snail control in plateau hilly schistosomiasis?endemic areas of Yunnan Province, so as to provide insights into the construction of agroforestry schistosomiasis control projects in plateau hilly regions. Methods　The pilot areas of snail control forests with various agroforestry systems were built in snail?breeding farmlands in Eryuan County, Yunnan Province in 2010, and the economic benefits and snail control effect were investigated in 2018. In addition, a fuzzy comprehensive evaluation model was created to screen the agroforestry system with high comprehensive benefits. Results　A total of 14 types of pilot areas of snail control forests with various agroforestry systems were built. Economic benefit analysis showed that the “walnut + garlic” pattern had the best economic benefit, with annual economic benefits of 270 000 Yuan/hm2, followed by the “walnut + chili” pattern (annual economic benefits of 120 000 Yuan/hm2) and the “walnut + vegetables” pattern (annual economic benefits of 105 000 Yuan/hm2). No snails were detected in 8 types of the agroforestry systems, including the “walnut + chili” pattern, the “walnut + tobacco” pattern and the “walnut + garlic” pattern; however, there were snail found with various densities in other types of systems. Fuzzy comprehensive evaluation showed that the “walnut + garlic” pattern had the best comprehensive control effect, followed by the “walnut + chili” pattern and the “walnut + tobacco” pattern, while the pure grassland pattern showed no effect on snail control. Conclusion　The agroforestry system is a preferential approach of forestry schistosomiasis control in plateau hilly schistosomiasis?endemic areas, which not only achieves snail control effects, but also promotes economic development and ecological construction in poor hilly areas.

Surveillance of malaria vectors in Anhui Province from 2016 to 2018

JIANG Jing-Jing, ZHANG Tao, XU Xian, Lü Xiao-Feng, WANG Shu-Qi, TIAN Cui-Cui, LI Wei-Dong

2020, 32(4):  389. 

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Objective　To understand the population distribution, density, seasonal fluctuation and nocturnal activity of malaria vectors in Anhui Province from 2016 to 2018, so as to provide a data support for formulating the control strategy for imported malaria during the malaria post?elimination stage. Methods　The malaria vectors were monitored in 105 counties (cities or districts) of Anhui Province from 2016 to 2018, and the population density, seasonal fluctuation and nocturnal activity of the mosquitoes were observed using the lamp trapping and human bait trapping methods. The density of Anopheles mosquitoes was compared among different years, regions and mosquito?capturing sites. Results　Anopheles mosquitoes were captured in 103 counties (cities or districts) of Anhui Province during the period from 2016 to 2018, and a total of 32 494 mosquitoes were captured using the lamp trapping method and 36 228 captured using the human bait trapping method. All captured mosquitoes were morphologically identified as Anopheles sinensis, and no An. anthropophagus was found. The density of An. sinensis peaked from June to August, and the peak nocturnal activity was found during the period between 19∶00 and 23∶00. Among all mosquito?capturing sites, the highest mosquito density was seen in the livestock and poultry sheds (H = 18.835, P < 0.05). The density of An. sinensis varied significantly in regions in 2016 and 2017 (H = 16.655 and 11.566, P < 0.01), and a low density was found in north of the Huai River. Conclusions　An. sinensis is widely distributed in Anhui Province, which is the currently predominant malaria vector in the province. During the malaria post?elimination stage, the malaria vector monitoring should be intensified and vector control interventions should be timely adopted in epidemic foci of Anhui Province to prevent the local re?transmission of overseas imported malaria.

Investigation on Schistosoma japonicum infection in goats in Dantu District, Zhenjiang City from 2004 to 2019

SHEN Xue-Hui, LI Ye-Fang, WANG Lin, YANG Wei-Hua

2020, 32(4):  393. 

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Objective　To investigate the prevalence and changing patterns of Schistosoma japonicum infections in goats in Dantu District of Zhenjiang City, so as to provide the scientific data for the management of in livestock. Methods　The S. japonicum infections were detected using a miracidial hatching test (one test for one stool specimen) in goats grazed in settings with snail habitats in Dantu District of Zhenjiang City at spring and autumn of each year from 2004 to 2019, and the prevalence and intensity of S. japonicum infections were estimated. Results　A total of 21 836 goat stool samples were detected from 2004 to 2019, and 86 were positive for S. japonicum (0.39% prevalence). The highest prevalence of S. japonicum infections in goats was seen in 2004 (1.25%) and no infections were detected in goats since 2013. S. japonicum?infected goats were identified in marshland?type endemic areas and plain regions with waterway networks, and there was a significant difference in the prevalence of S. japonicum infections in goats between these two types of endemic areas (0.50% vs. 0.15%; χ2 = 11.566, P < 0.05). The prevalence of S. japonicum infections was significantly greater in goats at ages of more than 10 months (0.51%) and over 10 months (0.44%) than in other goats (χ2 = 13.088, P < 0.05), and higher prevalence was found in autumn than in spring (0.54% vs. 0.27%; χ2 = 9.597, P < 0.05). In addition, there were 76.74% of S. japonicum?infected goats with intensity of “+++” and “++++”. Conclusion　Although the high prevalence of S. japonicum infections has been effectively controlled in goats in Dantu District, goat remains to be an important source of S. japonicum infections that should be given a high priority for control to consolidate the schistosomiasis control achievements.

Epidemic situation of human echinococcosis in Inner Mongolia Autonomous Region: a sampling survey from 2012 to 2017

JIANG Xiao-Feng, HAO Hui-Xia, FENG Ke-Min, SONG Jian, GUO Wei-Dong

2020, 32(4):  397. 

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Objective　To investigate the epidemiological characteristics of human echinococcosis in Inner Mongolia Autonomous Region, so as to provide evidence for the development of the precision control strategy of human echinococcosis in the region. Methods　A sampling survey of human echinococcosis was conducted in 28 banners (counties, districts) of Inner Mongolia Autonomous Region from 2012 to 2017, and the epidemiological characteristics were descriptively analyzed. Results　A total of 90 058 residents were examined for echinococcosis in 28 banners (counties, districts) of Inner Mongolia Autonomous Region from 2012 to 2017, and 71 patients were detected with echinococcosis, with a detection rate of 0.08%. No echinococcosis cases were identified in 8 banners (counties), and there were 6 banners (counties) with echinococcosis prevalence of 0.1% to 1%, and 14 with prevalence of 0 to 0.1%. The echinococcosis prevalence was significantly greater in women (0.11%) than in men (0.05%) ([χ2] = 10.09, P = 0.001), and the highest prevalence was detected in patients at ages of over 50 years (38 cases, 53.52%). In addition, the highest echinococcosis prevalence was detected in herdsmen (0.14%), or in primary school children (0.13%). Conclusions　Human echinococcosis is widely, but lowly prevalent in Inner Mongolia Region, with a diverse density of infections. Echinococcosis has remarkable characteristics of regional and population clusters in Inner Mongolia Region, and the management of echinococcosis requires to be reinforced in key regions and populations.

Epidemiological characteristics of imported malaria cases in Fujian Province from 2014 to 2018

XIAO Li-Zhen, OUYANG Rong, XIE Han-Guo, CHEN Zhu-Yun, LIN Yao-Ying, ZHANG Shan-Ying

2020, 32(4):  401. 

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Objective　To analyze the epidemiological characteristics of imported malaria cases in Fujian Province from 2014 to 2018, so as to provide scientific basis for the development of the control strategy for imported malaria. Methods　The epidemiological data of malaria cases in Fujian Province from 2014 to 2018 were retrieved from the Notifiable Disease Reporting System and Parasitic Disease Information Reporting System of Chinese Center for Disease Control and Prevention, and the classification, origin of infections, temporal distribution, spatial distribution, population distribution, reporting institutions and diagnosis were analyzed. Results　A total of 540 overseas imported malaria cases were reported in Fujian Province from 2014 to 2018, and all cases were laboratory?confirmed, including 398 cases with falciparum malaria, 88 cases with vivax malaria, 38 cases with ovale malaria, 14 cases with malariae malaria and 2 cases with mixed infections. There were 90.56% (489/540) of the imported malaria cases with infections in 27 African countries, 5.92% (32/540) with infections in 5 Asian countries and 3.52% (19/540) with infections in one Oceania country. There was no significant seasonal distribution of the cases, and the imported malaria cases were predominantly detected in Fuzhou City (80.00%, 432/540) and at ages of 20 to 49 years (81.48%, 440/540). Initial diagnosis was predominantly at the city?level medical institutions, and 77.96% (421/540) were diagnosed as malaria at the initial diagnosis institutions. The median duration from onset to initial diagnosis was 2 days and 70.19% (379/540) were diagnosed within 3 days of onset. The interval between initial diagnosis and definitive diagnosis was 0 day, with 85.37% (461/540) definitively diagnosed within 3 days of initial diagnosis. Conclusions　Overseas imported malaria is a continuous problem challenging the malaria elimination programme of Fujian Province. Improving the healthcare?seeking awareness and the diagnostic capability of healthcare workers, and intensifying the monitoring and management of malaria among overseas labors are strongly recommended.

Value of shear-wave elastography of the liver and spleen for predicting the risk of esophageal-gastric varices and bleeding in patients with advanced schistosomiasis

DING Yan, LI Shao-Lei, ZHOU Feng-Sheng, WU Peng-Xi, ZHU Qiao-Ying

2020, 32(4):  405. 

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Objective　To assess the value of shear?wave elastography (SWE) of the liver and spleen for predicting the risk of esophageal?gastric varices (EGV) and the bleeding from EGV (EGVB) in patients with advanced schistosomiasis. Methods　The medical records of 90 patients with definitive diagnosis of advanced schistosomiasis in Wuxi People’s Hospital Affiliated to Nanjing Medical University from January 2017 through January 2020 were retrospectively reviewed. The severity of EGV was graded in the 90 patients with advanced schistosomiasis using gastroscopic findings as a golden standard. Then, the subjects were assigned to the non?EGV and EGV groups, and the low? and high?risk EGVB groups according to the grading. The SWE elastic moduli of the liver and spleen were measured and compared between groups. In addition, the receiver operating characteristic (ROC) curve was plotted, and the area under the ROC curve (AUC) was estimated to evaluate the diagnostic efficiency of the SWE elastic moduli of the liver and spleen for predicting the high risk of EGV and EGVB. Results　The 90 patients with advanced schistosomiasis included 61 men and 29 women, and had a mean age of (74.3 ± 8.6) years (range, 62 to 83 years). If gastroscopic findings were employed as a golden standard, there were 32 cases with grade 0 (35.5%), 17 cases with grade 1 (18.9%), 15 cases with grade 2 (16.7%) and 26 cases with grade 3 EGV (28.9%). There were 32 cases in the non?EGV group (35.6%) and 58 cases in the EGV group (64.4%), and 41 cases in the high?risk EGV group (45.6%) and 49 cases in the low?risk EGV group (54.4%), respectively. The SWE elastic moduli of the liver and spleen were both significantly greater in the EGV group than in the non?EGV group (t = 5.73 and 7.26, both P values < 0.05). The SWE elastic moduli of the liver and spleen had AUCs of 0.70 and 0.75, optimal cut?off of 16.1 kPa and 22.6 kPa, sensitivities of 80.6% and 83.9% and specificities of 71.4% and 78.6% for the prediction of EGV, respectively. In addition, the SWE elastic moduli of the liver and spleen were significantly greater in the high?risk EGVB groups than in the low?risk EGVB group (t = 7.35 and 9.61, both P values < 0.05), and the SWE elastic moduli of the liver and spleen had AUCs of 0.68 and 0.71, optimal cut?off of 22.7 kPa and 33.8 kPa, sensitivities of 70.4% and 73.6% and specificities of 89.3% and 93.1% for the prediction of high?risk EGV, respectively. Conclusion　SWE is useful to predict the risk of EGV and EGVB in patients with advanced schistosomiasis.

Association between blood test parameters and intensity of Plasmodium falciparum infections in imported falciparum malaria cases in Tianjin City from 2015 to 2019

ZHANG Yong-Mei, LI Na, Lü Jie

2020, 32(4):  409. 

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Objective　To evaluate the association between blood test parameters and intensity of Plasmodium falciparum infections among imported falciparum malaria cases in Tianjin City from 2015 to 2019, so as to provide insights into the early diagnosis of imported P. falciparum malaria. Methods　The epidemiological data of 37 imported cases with confirmed diagnosis of P. falciparum malaria in Tianjin City from 2015 to 2019 were collected, and the epidemiological features and clinical manifestations were retrospectively analyzed. In addition, the association between blood test parameters and intensity of P. falciparum infections was evaluated among the imported P. falciparum malaria cases. Results　Among the 31 imported P. falciparum malaria cases, there were 31 cases (83.8%) with a reduction in platelet (PLT) counts, 16 cases (43.2%) with a reduction in red blood cell (RBC) counts, 16 cases (43.2%) with a reduction in hemoglobin (Hb) concentrations, 23 cases (62.2%) with a rise in neutrophil percentage (NEUT%), 32 cases (86.5%) with a rise in total bilirubin (TBIL) concentrations, 29 cases (78.4%) with a rise in alanine aminotransferase (ALT) concentrations, 28 cases (75.7%) with a rise in aspartate transaminase (AST) concentrations, and 23 cases (62.2%) with a rise in gamma?glutamyl transpetidase (GGT) concentrations. The PLT count and Hb concentration correlated negatively with the intensity of P. falciparum infections (Goodman?Kruskal γ = –0.568 and –0.521, both P values < 0.05) and the TBIL concentration and NEUT% correlated positively with the intensity of P. falciparum infections (Goodman?Kruskal γ = 0.496 and 0.610, both P values < 0.05) among imported falciparum malaria cases; however, there were no associations of ALT, AST, GGT levels or RBC count with the intensity of P. falciparum infections among the imported falciparum malaria cases (Goodman?Kruskal γ = 0.370, 0.497, 0.314 and –0.434, all P values > 0.05). Conclusion　PLT, Hb, TBIL and NEUT% may serve as markers for early auxiliary diagnosis of imported P. falciparum malaria, and PLT and TBIL may provide valuable information for the diagnosis of severe imported P. falciparum malaria.

SWOT analysis of schistosomiasis elimination in Laos

SHAN Xiang-Xiang, HUANG Lu-Lu, DING Wei, LI Chun-Yang, CUI Xiao-Yu, QIAN Ying-Jun, GUAN Ya-Yi

2020, 32(4):  414. 

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Objective　To analyze the advantages, disadvantages, opportunities and challenges for schistosomiasis elimination in Laos, so as to propose the corresponding healthy policies and suggestions. Methods　A SWOT analysis was performed to analyze the strength, weakness, opportunity and threat for the schistosomiasis elimination program in Laos, and the corresponding policy suggestions were proposed. Results　The national schistosomiasis elimination program of Laos receives governmental emphases and great supports. A strategy based on mass drug administration was proposed and a sentinel site?bases surveillance system has been built for schistosomiasis elimination in Laos; however, there are several challenges for the national schistosomiasis elimination program in Laos, including insufficient financial supports, inadequate professional capability, weak schistosomiasis control awareness in community populations and difficulty in vector control. Conclusion　Persistent governmental leadership, increasing financial supports, strengthening professional team building and improving schistosomiasis control awareness in community populations are required to facilitate the progress towards schistosomiasis elimination in Laos.

Healthy China Strategy and schistosomiasis control

YANG Jin-Ru, XU Ming-Xing, TAN Xiao-Dong

2020, 32(4):  419. 

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This paper summarizes the changes in the policy associated with schistosmiasis control in the new era, analyzes the background of Health China Strategy and its association with the current schistosomiasis control program in China, describes several schistosomiasis control models and proposes some suggestions responding to the challenges in current schistosomiasis control program of China, so as to provide insights into the development of the effective control strategy for schistosomiasis.

Correlation between Toxoplasma gondii infection and spontaneous abortion in pregnant women: a case-control study

SUN Xiao-Jing, GUO Chuan-Jia, SHI Hong

2020, 32(4):  423. 

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Objective　To examine the correlation between Toxoplasma gondii infection and spontaneous abortion among pregnant women, so as to provide the evidence for the development of preventive measures for spontaneous abortion. Methods　A total of 228 serum samples collected from women with spontaneous abortion for the first time from January 2018 to December 2019 were selected as the case group, while 228 serum samples collected from pregnant women with a normal delivery and without a history of abortion during the same period were selected as the control group. The serum IgG and IgM antibodies against T. gondii were detected and compared in both groups, and the correlation between T. gondii infection and spontaneous abortion was evaluated. Results　There were no significant differences between the case and control groups in terms of age, education levels, occupation, residency and proportion of keeping cats (all P values > 0.05). The positive rate of anti-T. gondii IgM antibody was significantly higher in the case group than in the control group (adjusted [χ2] = 4.08, P < 0.05; OR = 8.25), while no significant difference was seen between the case and control groups ([χ2] = 0.42, P > 0.05). Conclusions　Acute maternal T. gondii infection may remarkably increase the chance of spontaneous abortion. Progestational health education regarding toxoplasmosis prevention and control knowledge and detection of T. gondii infection during pregnancy should be strengthened.

Investigation of Anisakis infections in market-available marine fish in Dongtai City

ZHANG Xue-Yan, YU Min, ZHAO Qing-Qing, WANG Ying, SUN Bo-Chao

2020, 32(4):  426. 

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Objective　To understand the situation of Anisakis infection of in market?available marine fish in Dongtai City, so as to provide the evidence for the assessment of the risk of human Anisakis infections. Methods　Raw and fresh marine fish caught in the sea of Dongtai City for sale were collected in 2018. The fish were weighted and dissected for the identification of Anisakis, and the prevalence and intensity of Anisakis infections were calculated. In addition, the correlation between the weight of Anisakis?infected marine fish and the infection intensity of Anisakis was examined. Results　There were four species of marine fish infected with Anisakis, including Trichiurus haumela, Scomberomorus niphonius, Pneumatophorus japonicus and Larimichthys polyactis. Among the 149 fish samples, there were 78 with Anisakis infections, with a prevalence rate of 52.35%. The prevalence of Anisakis infection was 100.00% (28/28), 30.00% (9/30), 0 (0/30), 53.33% (16/30) and 80.65% (25/31) in T. haumela, S. niphonius, cuttle fish, P. japonicus and L. polyactis, respectively. A total of 1 049 Anisakis worms were collected, and the overall intensity of infection was 13.45 worms per fish. Spearman correlation analysis showed a positive correlation between the weight of T. haumela and the intensity of Anisakis infection (rs = 0.38, P = 0.047), and no correlation was found in other fish species. Conclusions　There is a high rate of Anisakis infection in marine fish along the offshore areas of Dongtai City. Intensification of health education is required and healthy and safe dietary habits are encouranged.

Investigation on Demodex infections among university students in Kunming City

WANG Li-Ming, WANG Wei-Qun, SHEN Li-Jie, JIA Xue-Mei, YANG Zhao-Qing, LI Cui-Ying, WANG Hong

2020, 32(4):  428. 

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Objective　To investigate the prevalence of Demodex infection among students in Kunming Medical University, and identify the factors affecting Demodex infections, so as to provide the evidence for the development of the strategy for the prevention of Demodex infections. Methods　A total of 1 463 students from Grade 2014 who studied Medical Parasitology in Kunming Medical University were included in the survey. Demodex was examined in students’ facial skin using the cellophane tape method, and the species was identified using microscopy. The students’ gender, ethnicity, place of origin and skin type were captured using a questionnaire survey. Results　The overall prevalence of Demodex infections was 19.07% (279/1 463) on the facial skin among the university students, and a higher prevalence was seen in girls (21.16%, 183/865) than in boys (16.05%, 96/598)([χ2] = 5.965, P < 0.05). The prevalence of Demodex infections was 18.33% (66/360) among minor ethnic students, and no ethnicity?specific prevalence was seen (P > 0.05). Demodex folliculorum was the predominant species, with a prevalence of 50.54% (141/279), and mild infections were predominant among all infections (96.77%, 270/279), without severe infections seen. Multivariate non?conditional logistic regression analysis revealed that gender and roommates with Demodex infections were risk factors of Demodex infections, and the infection was not associated with ethnicity, place of origin or skin type. There were only 2.53% (37/1 463) of the subjects understanding the knowledge pertaining to the prevention and control of Demodex infection. Conclusions　A relatively low prevalence of Demodex infection is detected in the facial skin of students from Kunming Medical University, and Demodex infection is associated with gender and roommates with Demodex infections. Health education pertaining to the prevention of Demodex infections is suggested to be intensified among university students.

The role of macrophage polarization in parasitic infections: a review

CAI Juan, HUANG Lin, WANG Ling-Jun, ZHENG Ming-Hui, LIU Hui

2020, 32(4):  432. 

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Macrophages are important members of innate immunity and play an extremely important role in the host defense against pathogenic infections, tumors, and allergic diseases. Macrophages have a high degree of plasticity, and may be polarized into classical activated macrophages (M1 macrophages) and alternative activated macrophages (M2 macrophages) under the stimulation of different environments. M1 macrophages are found to promote inflammatory responses, which facilitates the clearance of pathogens, while M2 macrophages may inhibit inflammatory responses, which facilitates the survival and reproduction of pathogens. This review summarizes the role of macrophage polarization in parasitic infections, so as to provide insights into the prevention and treatment of parasitic diseases.

Main non-state actors and progress of actions in global malaria elimination programme: a review

WANG Zhe-Bin, XIE Zheng, YAN Shu-Rui, CAO Jun

2020, 32(4):  436. 

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With the joint efforts of countries and global non?state actors, great achievements have been made in the global malaria control programme; however, malaria remains a serious threat to human health. As the global leader for combating malaria, WHO formulated The Global Technical Strategy for Malaria 2016–2030, and the Global Malaria Programme, under the leadership of WHO, is responsible for implementing 5 key projects to achieve the goal proposed in The Global Technical Strategy for Malaria 2016–2030. In addition, the Global Fund, the U.S. President’s Malaria Initiative and Bill & Melinda Gates Foundation also play an important role in global malaria elimination programme. This review describes the currently main non?state actors participating in the global malaria elimination programme, and calls for the enhanced inter?actor coordination and close collaboration with state governments to achieve the great goal of malaria elimination in the world.