Current Issue
30 April 2022
Volume 40 Issue 2
EXPERT VIEWPOINT
Epidemiological characteristics of malaria in China, 2021
ZHANG Li, YI Bo-yu, XIA Zhi-gui, YIN Jian-hai
2022, 40(2):  135-139.  doi:10.12140/j.issn.1000-7423.2022.02.001
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Malaria epidemic data in 31 provinces/municipalities/autonomous regions (excluding Taiwan region, Hong Kong SAR and Macao SAR) of China in 2021 were collected from the Information System for Parasitic Disease Prevention and Control. The epidemiological characteristic of malaria cases was analyzed. In 2021, 799 malaria cases were reported in China, which was declined by 26.4% compared to that in 2020 (1 086). Of these cases, 798 imported cases and one long incubation case infected with Plasmodium malariae were identified, and no indigenous cases were reported. In addition, 783 cases were of Chinese nationality (98.0%, 783/799) and 16 cases were of foreign nationality (2.0%, 16/799). Most of the cases were within the age range of 30-49 years (55.7%, 445/799), with a male-to-female ratio of 14.4 ∶ 1. The reported cases included 390 cases of P. falciparum infection (48.8%, 390/799), 182 cases of P. vivax infection (22.8%, 182/799), 187 cases of P. ovale infection (23.4%, 187/799), 31 cases of P. malariae infection (3.9%, 31/799) and 9 cases with mixed-infection (1.1%, 9/799). The cases were reported from 31 provinces/municipalities/autonomous regions, with the top 5 provinces of Guangdong, Yunnan, Shanghai, Sichuan and Zhejiang, from which 480 cases (60.1%, 480/799) were reported. Totally 3 deaths were reported from Liaoning (1 case), Zhejiang (1 case) and Guangdong (1 case) provinces, which was decreased by 3 cases compared to 6 deaths in 2020. Noticeably, there have been no reported cases of of indigenous mosquito-borne malaria in China for consecutive five years. Nevertheless, it is imperative to continuously strengthen the surveillance on imported malaria and border malaria to prevent malaria re-introduction and consolidate the achievements of malaria elimination in China.

SPECIAL REPORTS
New strategies for malaria control: using mosquito symbiotic bacteria to block malaria transmission
JIANG Yong-mao, GAO Han, WANG Si-bao
2022, 40(2):  140-145.  doi:10.12140/j.issn.1000-7423.2022.02.002
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Malaria is a mosquito borne parasitic disease caused by Plasmodium infection. In the absence of highly effective vaccines, controlling malaria mainly relies on mosquito-controlling insecticides and antimalarial drugs. However, increased resistance to insecticides among mosquitoes and the emergence and spread of antimalarial drug-resistant parasites have become significant challenges in the fight against malaria. In recent years, global progress toward malaria prevention and control has remained stagnant, and new strategies to control malaria are urgently needed. Symbiotic control is a new strategy that uses mosquito gut symbiotic microorganisms to control vector mosquitoes or reduce vector competence. This strategy has made remarkable progress in recent years. Here, the advances in the development and research of this technology are reviewed, and the challenges in the application of symbiotic control of malaria are discussed.

Current status and challenges of visceral leishmaniasis in China
LUO Zhuo-wei, ZHOU Zheng-bin, GONG Yan-feng, FENG Jia-xin, LI Yuan-yuan, ZHANG Yi, LI Shi-zhu
2022, 40(2):  146-152.  doi:10.12140/j.issn.1000-7423.2022.02.003
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Visceral leishmaniasis once was one of the five parasitic diseases that were a serious public health problem in China. After decades of unremitting efforts, visceral leishmaniasis was eliminated in most endemic areas in the early 1980s. Since the 21st century, the disease has rebounded sharply, and the areas with endemic have been expanding steadily in western China. This review summarized the endemicity of visceral leishmaniasis and the tasks, strategies and measures for visceral leishmaniasis control in China. The challenges and potential approaches for future prevention and control of visceral leishmaniasis are also discussed.

ORIGINAL ARTICLES
Cloning and expression of yellow c gene from Aedes aegypti and its in vitro action of anti-coagulation
ZHANG Xia, YAN Feng, MU Xiao-hui, LIN Zi-min, NIE Ying, CHENG Jin-zhi, SHANG Zheng-ling, WU Jia-hong, , ,
2022, 40(2):  153-158.  doi:10.12140/j.issn.1000-7423.2022.02.004
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Objective To clone and express the Aedes aegypti yellow-c(Aael-yellow-c) gene and investigate the in vitro anticoagulation activity of recombinant Aael-yellow-c protein. Methods The Aael-yellow-c mature peptide gene was amplified by RT-PCR, and the purified target gene segment obtained was connected to the plasmid pEASY-E1, which was transformed into Escherichia coli DH5α competent cell. The clones were verified with PCR, double restriction enzymes and sequencing. After induction with 0.1 mol/L IPTG, the recombinant protein was purified by Ni-affinity chromatography and identified by SDS-PAGE and Western blotting. The effect of rAael-yellow-c protein on human platelet aggregation induced by adenosine diphosphate (ADP) was observed by turbidimetry. The affect of rAael-yellow-c at different concentrations on prothrombin time (PT), activated thromboplastin time (APTT) and thrombin time (TT) of human blood plasma was detected manually. Results A 1 200 bp fragment of Aael-yellow-c gene was obtained by RT-PCR, and an pEASY-E1-Aael-yellow-c plasmid was successfully constructed by PCR, double restriction enzymes and sequencing. The recombinant protein was expressed in the form of inclusion body confirmed by SDS-PAGE and Western blotting, the purified recombinant protein was obtained by Ni-NTA. The results of the platelet aggregation inhibition experiment showed that 2083.30, 416.66, 83.33, 16.67 and 3.33 nmol/L rAael-yellow-c protein could inhibit platelet aggregation induced by ADP, and the difference was statistically significant(t = 7.09, 10.39, 5.39, 10.54 and 8.93, P < 0.01). The strongest inhibition effect was at 3.33 nmol/L, and the inhibitory rate was (59.27 ± 11.90)%; The recombinant proteins of 0.67, 0.13 and 0.02 nmol/L had no effect on ADP induced platelet aggregation, and the results were not statistically different (t = 2.10, 1.33 and 0.00, P > 0.05); The results the of internal and external source coagulation test showed that compared with the negative control group, rAael-yellow-c (0.12, 1.20 and 12.00 μmol/L) treated human plasma had PT of 13.63-14.10 s, 13.32-14.38 s and 13.55-16.01 s. The difference was not statistically significant (t = 1.33, 0.63 and 1.00, P > 0.05). APTT was 32.76-38.46 s, 31.94-41.78 s and 33.34-39.29 s, the difference was not statistically significant (t = 0.47, 0.06 and 0.24, P > 0.05). TT was 19.12-21.20 s, 19.7-23.12 s, 21.85-25.3 s, the difference was not statistically significant (t = 0.47, 0.24 and 1.60, P > 0.05). Conclusion The recombinant Aael-yellow-c protein obtained may be aidful for mosquito in blood sucking through suppressing platelet aggregation induced by ADP.

Establishment of multiplex PCR for malaria-transmitting vector surveillance
JIANG Li, ZHANG Yao-guang, LIU Hong-xia, WANG Zhen-yu, ZHU Min, WU Huan-yu
2022, 40(2):  159-167.  doi:10.12140/j.issn.1000-7423.2022.02.005
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Objective To establish an highly efficient multiplex PCR method for surveillance of mosquito vector in malaria post-elimination stage. Methods Four pairs of specific chimeric primers were designed for amplifying specific genes of Plasmodium, human blood, Anopheles sinensis and mosquitoes, which was connected with universal primer (5′-CGAGTCCTGCGGTCTCAAATT-3′) respectively. Routing PCR reaction was used to determine the best annealing temperature and concentration of primers, and the multiplex PCR condition was optimized for the mixed 4 primer pairs. The innovative design of simulated positive mosquito sample was introduced for establishing a sensitive multiplex PCR reaction system. The sensitivity was evaluated by detecting the parasite density using serially diluted samples from 4 Plasmodium species (P. falciparum, P. ovale, P. vivax and P. malariae) infected patient samples to check gene amplification. The specificity was evaluated by using a variety of other parasites’ DNA or samples infected with other parasites, including Entamoeba histolytica, Giardia lamblia, Cryptosporidium, Babesia microti, Leishmania donovani, Toxoplasma gondii, Schistosoma japonicum, Paragonimus westermani, Ascaris lumbricoides, Taenia saginata, T. solium. Field evaluation was performed using wild An. sinensis samples collected from animal farms. Results The optimized reaction system for each component content (volume ratio) was: 10% of DNA template, 10% of primer Mix, 30% of distilled water and 50% of Taq polymerase pre-mixed solution. The ratio of each primer in the mixture was 1 ∶ 1.75 ∶ 3 ∶ 5 for mosquitoes, An. sinensis, human blood and Plasmodium, respectively. The best circulation conditions for the system was as follows: 95 ℃ for 5 min, 94 ℃ for 15 s, 60 ℃ for 20 s, and 72 ℃ for 20 s, circulation 4 times; 94 ℃ for 15 s; 64 ℃ for 20 s, 72 ℃ for 20 s, circulation 9 times; 94 ℃ for 15 s, 68 ℃ for 20 s, 72 ℃ for 20 s, circulating 25 times. The length of the amplified products was 662-717 bp for Plasmodium, 519 bp for human blood, 432 bp for An. sinensis, 190-320 bp for mosquitoes, respectively. After optimization of multiplex PCR, the results showed that the assay has the highest sensitivity for P. vivax, with the detection limit of 10.7 parasite/μl blood. The assay had the lowest sensitivity for P. malariae with 133.3 parasite/μl blood detection limit. The detection limit for P. ovale and P. falciparum were 15.0 and 34.0 parasite/μl blood, respectively. The average detection limit was 48.25 parasite/μl blood. For An. sinensis mosquitos, simulated risk infection samples shows four bands (662-717, 519, 432, 190-320 bp), three bands (519, 432, 190-320 bp) in mosquitos which had human blood-meal, and two bands (432, 190-320 bp) in mosquitos which did not have blood-meal. Two bands (519, 190-320 bp) were shown in non-An. sinesis mosquito samples which had human blood-meal, only one band (190-320 bp) was shown from mosquitos which did not have blood-meal. For specificity, results from 11 other parasites samples are negative. Wild mosquito samples from An. sinensis around the corral and indoor human blood-fed samples showed good primer specificity for human blood. Conclusion The multiplex PCR method established in this study for malaria vector mosquito could provide multiple information on mosquito species identification, human blood index and malaria parasite infection simutanously in one assay, showing high sensitivity and specificity.

Study on the inhibitory effect of natural killer cells on liver fibrosis of schistosomiasis
GAO Yuan, ZHANG Xiao-cheng, HU Yuan, CAO Jian-ping
2022, 40(2):  168-174.  doi:10.12140/j.issn.1000-7423.2022.02.006
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Objective Using monoclonal antibodies to deplete or passively transfer natural killer (NK) cell, to explore the role of NK cells in schistosomiasis liver fibrosis. Methods The livers of 24 C57BL/6 healthy mice were collected to isolate NK cells, and the NK cells were activated with interleukin-15 (IL-15), IL-2 and IL-18. Forty C57BL/6 mice were randomly divided into five groups, namely monoclonal antibody group, IgG group, normal saline group, NK cell group and PBS group, with 8 mice in each group. Each mouse was infected with Schistosoma japonicum cercariae (20 ± 1) via an abdominal patch. The mice in the monoclonal antibody group, IgG group and normal saline group were injected with anti-NK1.1 monoclonal antibody (100 μg/mouse), IgG (100 μg/mouse), and normal saline through the tail vein at a dose of 200 μl/mouse each time, once a week, started one week before the infection. Four weeks after infection, the mice in the NK cell group and PBS group were transferred with activated NK cells (1 × 105/mouse) and PBS through the tail vein weekly at dose of 200 μl/mouse each time. At six and eight weeks after infection, flow cytometry was used to detect changes in the proportion of NK cells in the liver of the mice. Masson staining was used to observe liver tissue lesions, and Real-time PCR was used to detect indicators of liver fibrosis, including mRNA relative transcription levels of Ⅰ-collagen (Ⅰ-C), Ⅲ-C, Ⅳ-C, fibronectin (FN), and laminin (LN). Results The proportion of liver NK cells at six weeks after infection in the monoclonal antibody group was (2.56 ± 0.47)%, which was lower than that in the IgG group (4.75 ± 0.62)% and normal saline group (5.35 ± 0.40)% (F = 31.59, P < 0.01). At 8 weeks post-infection, the proportion of liver NK cells were (2.65 ± 0.23)%, (3.43 ± 0.46)%, and (3.56 ± 0.46)% for the monoclonal antibody group, the IgG group and the normal saline group, respectively, and the difference was not statistically significant (F = 4.48, P > 0.05). The proportion of liver NK cells in the NK cell group was (5.58 ± 0.30)% and (3.73 ± 0.42)% for 6 and 8 weeks after infection, respectively. There was no statistically significant difference between 6 weeks (5.51 ± 0.27)% and 8 weeks (2.32 ± 0.40)% after infection for the PBS group (t = 0.25, 2.64, P > 0.05). The area of liver fibrosis in the monoclonal antibody group was (8.42 ± 1.30) × 104 μm2 at 6 weeks after infection, which was larger than that in the IgG group (6.40 ± 1.40) × 104 μm2 and normal saline group (6.73 ± 1.61) × 104 μm2 (F = 13.63, P < 0.01). The area of liver fibrosis for the monoclonal antibody group was (9.55 ± 1.55) × 104 μm2 at 8 weeks after infection, which was larger than that in the IgG group (6.11 ± 1.10) × 104 μm2 and normal saline group (6.62 ± 1.60) × 104 μm2 (F = 30.33, P < 0.01). The area of liver fibrosis in the NK cell group was (5.97 ± 0.96) × 104 μm2 at 6 weeks after infection, which was smaller than that in the PBS group (8.27 ± 1.62) × 104 μm2 (t = 4.85, P < 0.01). However, at 8 weeks after infection, the area of liver fibrosis for the NK cell group and the PBS group were (6.33 ± 0.98) × 104 μm2 and (6.97 ± 1.11) × 104 μm2, respectively. The difference was not statistically significant (t = 1.80, P > 0.05). The relative transcription levels of Ⅳ-C, FN, and LN mRNA in the monoclonal antibody group were 1.81 ± 0.47, 1.63 ± 0.38 and 1.41 ± 0.16, which are higher than that in the IgG group (1.00 ± 0.35, 0.81 ± 0.29, 0.79 ± 0.16) and the normal saline group (1.00 ± 0.12, 1.00 ± 0.10, 1.00 ± 0.14) (F = 8.30, 8.25, 14.40, P < 0.01). At 8 weeks after infection, the relative transcription level of Ⅳ-C mRNA in the monoclonal antibody group was 1.66 ± 0.21, which is higher than that in the IgG group (0.94 ± 0.26) and the saline group (1.00 ± 0.09) (F = 15.95, P < 0.01). At 6 weeks after infection, the relative transcription levels for Ⅰ-C, Ⅲ-C and LN mRNA in the NK cell group were 0.66 ± 0.12, 0.61 ± 0.06, 0.64 ± 0.09, respectively. The relative transcription levels were much higher compared with the PBS group (1.01% ± 0.14, 1.01 ± 0.14, 1.01 ± 0.16) (t = 3.36, 4.41, 3.59, P < 0.05). No statistical significant differences were observed at 8 weeks after infection for the NK cell group (0.82 ± 0.40, 0.93 ± 0.37, 0.73 ± 0.30) and the PBS group (1.04 ± 0.38, 1.02 ± 0.25, 1.06 ± 0.49) (t = 0.55, 0.27, 0.81, P > 0.05). Conclusion It was shown that after being infected with S. japonicum, NK cells from mouse liver might inhibit liver fibrosis in the early stage of its formation.

Study on the polarization of MDSC stimulated by Echinococcus granulosus protoscolex-derived exosomes in vitro
SUN Ye-ting, JIANG Nan, JIANG Yan-yan, LI Teng, JIANG Xiao-feng, CAO Jian-ping, SHEN Yu-juan
2022, 40(2):  175-180.  doi:10.12140/j.issn.1000-7423.2022.02.007
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Objective To investigate the dynamic changes of the polarization of myeloid-derived suppressor cells (MDSC) to M2 macrophages stimulated by Echinococcus granulosus protoscolex-derived exosomes, and to explore the biological significance of their synergistic immunosuppressive effect. Methods The exosomes were collected by ultracentrifugation of supernatant of E. granulosus protoscoleces in vitro culture. The morphology of exosomes was observed by transmission electron microscope, and the expression of exosomal protein CD9 and enolase were detected by Western blotting. Subsequently, MDSC stimulated from myeloid cells of 3 healthy BALB/c mice femoral bone marrow were added at 1 × 106 MDSC per well of a 6-well plate, and divided into experimental group, positive control group and negative control group. 20 μl exosomes (5 μg), 20 μl IL-4 (40 ng) and 20 μl RPMI 1640 medium were added respectively for co-culture. The proportions of monocytic DMSC (M-MDSC) and the expression of M2 macrophages molecular markers F480 and CD206 in co-cultured cells at 24 h, 48 h, and 72 h, were analyzed by Flow cytometry, respectively. Statistical analysis was performed by statistical software GraphPad Prism 8.0.2. Results E. granulosus protoscolex-derived exosomes are of circular membrane structure with a diameter of 60-90 nm by transmission electron microscopy. The expression of specific protein CD9 and enolase in exosomes was detected by Western blotting. The proportions of M-MDSC in MDSC in the negative control, experimental and positive control group were (78.13 ± 0.81)%, (77.14 ± 0.78)%, and (75.74 ± 0.50)%, respectively after 24 h of stimulation by exosomes. The differences were not significant (P > 0.05). The proportions of M-MDSC in the negative control, experimental and positive control group were (80.47 ± 0.85)%, (78.27 ± 0.69)%, and (68.01 ± 1.33)%, respectively, after 48 h of stimulation, showed no significant difference between experimental group and negative control group (P > 0.05), however significant difference was observed between the positive control and the negative control group (P < 0.01). After 72 h, the proportions of M-MDSC in the experimental and positive control groups in MDSC were (50.03 ± 0.59)% and (46.14 ± 0.87)%, which are lower than negative control group (74.94 ± 1.53)%, and the differences were statistically significant (P < 0.001). After stimulation with exosomes for 24 h, 48 h, and 72 h, the proportions of M-MDSC expressing M2 macrophages molecular markers in experimental and positive control group were (11.83 ± 0.06)%, (12.48 ± 0.12)%; (15.11 ± 0.21)%, (15.42 ± 0.27)%; and (29.12 ± 1.34)%, (31.83 ± 1.27)%, respectively, which were higher than those in the negative control group(8.52 ± 1.11)%, (8.79 ± 0.35)%, and (15.49 ± 0.26)%, and all differences were statistically significant (P < 0.05 or P < 0.01). Conclusion E. granulosus protoscolex-derived exosomes could regulate the polarization of M-MDSC to M2 macrophages, and the polarization continued to advance with the stimulation time.

Characteristics of alveolar echinococcosis cases and genetic polymorphism of the parasite from Xinyuan County, Xinjiang
CAI Ren, REN Yuan, MI Rong-sheng, GUO Gang, QI Wen-jing, ZHANG Zhuang-zhi, GUO Bao-ping
2022, 40(2):  181-186.  doi:10.12140/j.issn.1000-7423.2022.02.008
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Objective To understand the characteristics of alveolar echinococcosis (AE) cases and the genetic polymorphism of the parasites in Xinyuan County, Xinjiang, to provide reference information for formulating developing prevention and control strategies for AE. Methods During 2016—2020, information on AE patients and some surgically resected liver lesion samples from Xinyuan County in the biological sample bank of the First Affiliated Hospital of Xinjiang Medical University were collected. Genomic DNA of the liver lesion samples was extracted, and the mitochondrial NADH dehydrogenase 2 (nad2) gene was amplified by PCR and sequenced. The PCR products were sequenced and spliced for Blast comparison. Mega10.0 software was used to construct a phylogenetic tree by the neighbor-joining method, DnaSPv5 software was used to analyze the genotype of amplified sequence, and Network10.0 software was used to make nad2 genotype network map. Results A total of 28 AE cases were collected, including 7 in rural areas and 21 in Kunes River Basin, among which 60.71% (17/28) were male, and 39.29% (11/28) were female (χ2 = 0.704, P < 0.05). Ethnic distribution was mainly Han (42.86%, 12/28) and Kazak (39.29%, 11/28), and the highest infection rate among Mongolians was 11.17%. There was a significant difference in the infection rate among different ethnic groups (χ2 = 61.08, P < 0.01). Farmers and herdsmen were the dominant occupations, accounting for 92.86% (26/28), while only 7.14% (2/28) were of other occupations. There was no significant difference in infection rate among different age groups (χ2 = 0.418, P > 0.05). A expected, 25 samples were amplified by PCR with a fragment size of 1 031 bp. Sequence alignment results showed that there were four genotypes: H1, H2, H3 and H4, among which H1 was the main genotype and the sequence consistency was 100% with Kazakhstan (GenBank accession no. AB461406). Phylogenetic tree results showed that the four genotypes in Xinyuan county isolates were in the same branch as the Poland (GenBank accession no. KY205700) and Kazakhstan (GenBank accession no. AB461406), but more distantly related to France (GenBank Accession no. AB461404), Austria (GenBank accession no. AB461403), Canada (GenBank accession no. JF751036), Alaska (GenBank accession no MT429275), Indiana, USA (GenBank accession no. AB461409) and Inner Mongolia, China (GenBank accession no. AB461411). According to the results of centering on the H1, the genotype network diagram showed H2, H3, H4, Sichuan of China, Poland, Canada and Japan were scattered distributed which indicated that the isolates with H1 has a very close relationship, but it is not in the same clade with France, Austria, Canada, Alaska, USA isolates, and had a distant relationship. Conclusion The majority of AE patients were Han and Kazakian farmers and herdsmen, and the Mongolians had the highest infection rate. There were 4 genotypes in AE patients, among which H1 was the main genotype in Xinyuan County.

Differential expression and action mechanism of lncRNA102796 in the brain of mice with chronic infection of Toxoplasma gondii
WANG Zhen-xun, XIONG Si-si, SUN Xia-hui, WANG Yong-liang, PAN Ge, HE Shen-yi, CONG Hua
2022, 40(2):  187-193.  doi:10.12140/j.issn.1000-7423.2022.02.009
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Objective To investigate the differential expression and mechanism of long non-coding RNA102796 (lncRNA102796) in the brain of mice with chronic Toxoplasma gondii infection. Methods The model for chronic T. gondii infection was established using specific-pathogen-free female BALB/c mice. Two months after infection, the brains of infected mice (n = 10) and healthy mice (n = 10) were collected two months after infection. The expression of lncRNA102796 in mice chronically infected with T. gondii was detected by qRT-PCR, using the total RNA extracted from the brains of infected mice. The location of lncRNA102796 was determined by qRT-PCR using RNA which is extracted from the nucleus and cytoplasm of mice brains. The target gene of lncRNA102796 was predicted as opioid receptor delta 1 (oprd1) gene by bioinformatics analysis. The expression of oprd1 was further determined by qRT-PCR using the total RNA from the brains of infected mice and healthy mice. The expression of OPRD1 was further determined by Western blotting, using the brains of the infected mice. The interference and overexpression plasmids of lncRNA102796, the uninterfered lncRNA102796 plasmid pGPU6/GFP/Neo and non-overexpressed lncRNA102796 pcDNA3.1+ plasmid were used as control. The plasmids were transfected into BV-2 cells. The regulation of lncRNA102796 expression on oprd1 was investigated by qRT-PCR, using the RNA extracted from BV-2 cells. The regulation of lncRNA102796 expression on OPRD1 was investigated by western blotting, using protein extracted from BV-2 cells. The regulation of lncRNA102796 expression on cell proliferation was investigated by cell counting kit-8 assay, using BV-2 cells transfected with constructed plasmids. Constructed overexpression plasmids of anti-sense lncRNA102796 and sense lncRNA102796. The protein binding to lncRNA102796 was determined by RNA pull down and Western blotting, using the RNA and protein extracted from the overexpression BV-2 cells. Results qRT-PCR results confirmed that the expression of lncRNA102796 in the brain of mice infected chronically with T. gondii was 0.303 ± 0.054, which was down-regulated by (69.7 ± 6.7)% (t = 18.12, P < 0.05) compared to uninfected mice. The expression of lncRNA102796 was higher in the nucleus (85.04 ± 9.41)% than that in the cytoplasm (14.95 ± 9.41)% of BV-2 cells (t = 7.45, P < 0.05). The results from qRT-PCR suggested that the expression of oprd1 mRNA was 0.170 ± 0.040 in the infected mice brain, which was down-regulated (83.0 ± 5.3)% (t = 27.17, P < 0.05) compared to that of the normal mouse brain. Results from Western blotting suggested the expression of OPRD1 protein was down-regulated in the infected mice brain compared to that of normal mouse brain; Upon interfering lncRNA102796, the expression of lncRNA102796 was 0.311 ± 0.054, which was down-regulated by (68.9 ± 6.6)% compared to the control group (t = 18.00, P < 0.05); the expression of oprd1 was 0.175 ± 0.04, which was down-regulated by (82.5 ± 5.1)% compared to the control group (t = 28.08, P < 0.05); the expression of oprd1 protein also reduced. Upon overexpressing lncRNA102796, the expression of lncRNA102796 was 8.220 ± 1.192, which was up-regulated by (722.0 ± 146.0)% compared to the control group (t = 8.56, P < 0.05); the expression of oprd1 was 2.533 ± 0.365, which was up-regulated by (153.3 ± 44.7)% compared to the control group (t = 5.95, P < 0.05); the expression of oprd1 protein also increased. Results from CCK-8 assay revealed that interfered lncRNA102796 inhibited the proliferation of microglia. After 48 and 72 hours, the A450 of BV-2 cells were 0.272 ± 0.021, 0.508 ± 0.014, respectively, which are lower than the A450 of the control group 0.473 ± 0.024, 0.816 ± 0.014 (t = 6.35, 46.77, P < 0.05). Overexpression of lncRNA102796 can accelerate the proliferation of microglia. After 48, 72 h, the A450 of BV-2 cells were 0.621 ± 0.038 and 1.026 ± 0.114, which were higher than the A450 of control group 0.365 ± 0.010 and 0.530 ± 0.147 (t=10.55, P < 0.05). Results from Western blotting showed that RNA pull down confirmed that sense lncRNA102796 binds to OPRD1. Conclusion In the brain of mice chronically infected with T. gondii, lncRNA102796 suppresses microglial cell proliferation, affecting the cell cycle through binding to the target gene oprd1, thereby, causing neurological cell impairment.

Sequencing and analysis of the mitochondrial genome of Hoplopleura edentula
SUN Jia-ning, CHEN Ting, DONG Wen-ge
2022, 40(2):  194-203.  doi:10.12140/j.issn.1000-7423.2022.02.010
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Objective To conduct sequencing and analysis the mitochondrial (mt) genome of Hoplopleura edentula to understand the structure and variation of the mt genome of Hoplopleura. Methods We used stratified random sampling to capture the Eothenomys miletus in Mount Cangshan Geopark Dali, and collected all sucking lice on the surface of E. miletus by complete catching method and identified the species of the sucking lice. The DNA of each H. edentula was extracted using the Dneasy Tissue Kit. Universal primers were used to amplify the short fragment of small ribosomal submit RNA (rrnS) and large ribosomal submit RNA (rrnL) genes of H. edentula. Subsequently, the specific primers in the conserved regions of the short fragment were designed to amplify long fragment sequences of rrnS and rrnL genes, and the specific primers in the minichromosomes conserved region were designed to amplify all the coding regions of the minichromosomes. The successfully amplified PCR products were purified and sequenced by Illumina HiSeq X Ten platform high-throughput sequencing method. The structure and variation of the mt genome were analyzed by bioinformatics tools such as Geneious, tRNAscan, CodonW, BLAST, etc. Results A tatol of 6 812 606 bp sequence reads were obtained from the H. edentula mt genome and 24 mt genes (7 protein-coding genes, 15 tRNA genes and 2 rRNA genes) of common genes in arthropod mt genomes were identified after assembly. The mt genome of H. edentula fragmented into 8 minichromosomes (GenBank accession number: MW835203-MW835210). These genes were unevenly distributed on minichromosomes. The coding region of each minichromosome contains 1-4 genes, at least one protein-coding gene or rRNA gene. AT content of the coding region is 61.0%. All start codon of protein-coding genes were ATN, except for cox2, which start codon was TTG. All protein-coding genes use TAA and TAG as stop codons. The codon AUU is the most frequently used (RSCU: 1.53). The secondary structure of 15 tRNA genes is a typical clover like structure. There are 31 mismatches in tRNA genes, mainly G-U mismatch. The rrnS and M-L1(tag)-rrnL-V minichromosomes have all the non-coding regions, and there are 2 types of tandem repetitive sequences, and they were 88.0%-90.0% identical. An AT-rich motif (50 bp, 64.0% A&T) is present in the non-coding region upstream of the 5′-end of the coding region, whereas a GC-rich motif (42 bp, 85.7% G&C) is present downstream of the 3′-end of the coding region. We also sequenced parts of the non-coding regions upstream and downstream of the coding regions of the other 6 H. edentula minichromosomes, and the identity reached to 86.5%-88.5%. Comparing the mt genomes of H. edentula, H. akanezumiand H. kitti showed that the mt genomes of all three species were fragmented. There were four minichromosomes that have the same gene composition and sequence: E-cob-S1(tct)-S2(tga), I-cox1, K-nad4 and rrnS. The H-nad5-F-T minichromosome of H. edentula was not found in the other two Hoplopleura species. trnT gene translocated frequently and distributed in the different minichromosomes of three Hoplopleura species. trnS1(tct) of H. edentula has a typical clover-leaf structure, while trnS1(tct) of the other two Hoplopleura species lacks D-arm. Conclusion H. edentula has 24 genes distributed unevenly on eight minichromosomes, each of them contains a coding region and a non-coding region, and is of AT rich. The number of base mismatches of tRNA is considerably high. The trnS1(tct) of H. edentulais shows a typical clover like structure. The structure of Hoplopleura mt genome varies, and its particularity may be related to the genome cracking.

Clinical outcome and change of antibody level in cerebral sparganosis mansoni patients after treatment: a multicenter study
XIE Hui-qun, XU Yun, GONG Zhi-hong, HU Fei, WAN Hui, XU Chun-hua, WU Jie, LIU Jun-pu, HONG Dao-jun
2022, 40(2):  204-210.  doi:10.12140/j.issn.1000-7423.2022.02.011
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Objective To analyze the clinical outcomes and changes in serum IgG antibody titers against Sparganum mansoni after treatment, for further exploring the indicators in assessing the therapeutic effects for cerebral sparganosis. Methods Cases of cerebral sparganosis patients followed-up on continuous inpatient or outpatient treatment were collected from Jiangxi Provincial Institute of Parasitic Diseases, the First Affiliated Hospital of Nanchang University and Guangdong 999 Brain Hospital during 2013 to 2018. The patients were administrated with praziquantel 50 mg/(kg·d) for 10 days per cource, continuing for three cources at a 60-day interval. The surgical treatment includes craniotomy and CT-guided stereotactic aspiration. Twelve months after the treatment with praziquantel and surgery, the clinical manifestations of patients were followed-up, imaging examination (including brain MRI flat and enhanced scan) rechecked, and the serum IgG titer assayed. Statistical analysis was performed using SPSS 18.0 software. Results Eighty-seven cases of cerebral sparganosis were collected, of which 62 patients received praziquantel treatment (10 patients were treated with praziquantel prior to surgery), and 35 patients underwent surgical therapy. After 12 months of treatment, among the 71 patients with good outcomes, 57.7% (41/71) were asymptomatic, 42.3% (30/71) had clinical symptoms, among them 26.8% (19/71) with seizure, 14.1% (10/71) with paresis, and 1.4% (1/71) with diplopia. Radiography showed that 85.9% (61/71) of active enhanced foci were resolving, while 14.1% (10/71) foci remained, of them 12.7% (9/71) were single small nodular lesions. Serology examination revealed that 64.28% (52/71) cases were negative for IgG against Sparganum mansoni (antibody titer < 1 ∶ 100), 23.80% (12/71) had an antibody titer of 1 ∶ 100, and 11.90% (7/71) had the titer of 1 ∶ 200. After treatment for 12 months, 16 patients were of poor outcomes, showing 1/16 was free of symptom, and 15 had clinical symptoms, of them 12/16 patients with seizure, 3/16 with paresis, while headache, aggravating illness, no significant improvement and emerging new symptoms were found of 1 case each. Radiography indicated that among the cases, 6/16 showed no changes in lesion images, 1/16 had enlarged foci, 7/16 changes in lesion location, and 2/16 newly enhanced lesions. Serology examination on the patients showed 4/16 had an antibody titer of 1 ∶ 400, 8/16 had the titer of 1 ∶ 800 and 4/16 had the titer of 1 ∶ 1 600. Conclusion Most of the cerebral sparganosis cases had a good prognosis after praziquantel and surgery treatment. Serological tests could be used for assessment of recent therapeutic effect in 12 months, redeeming the limitations in appraisal by symptoms and imaging.

Surveillance and trends of soil-transmitted helminth infections in Liaoning Province, 2016—2020
YU Wei-jun, WANG Zi-jiang, WANG Bo, MAO Ling-ling, WU Qi-jun, YAO Wen-qing, SUN Ying-wei
2022, 40(2):  211-215.  doi:10.12140/j.issn.1000-7423.2022.02.012
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Objective To investigate the prevalence and transmission of soil-transmitted helminth (STH) in Liaoning Province, in order to provide scientific evidence for development of control plans, strategies and measures aagainst these diseases in Liaoning Province. Methods The surveillance was performed during 2016—2020 in Liaoning Province according to the National Surveillance Program and Implementation Guideline for Chlonorchiasis and Soil-transmitted Helminthiasis. One county (city or district) per provincial city was selected annually as a surveillance site. Each surveillance site was further divided 5 regions as geographical east, west, south, north and centre. One village was chosen from each region to conduct surveillance, and 200 permanent residents over 3 years old were randomly enrolled from each village. Fecal samples ( > 30 g) from enrolled residents were collected and were examined for STH eggs (two slide-reading for each sample) using the modified Kato-Katz thick smear method to estimate infection rate and intensity. The samples that are positive for hookworm eggs were further examined by test-tube filter paper incubation for the larva to identify the species. Cellophane anal swab method was used to detect Enterobius vermicularis eggs in children aged 3-9 years. The contamination of Ascaris eggs and hookworm larvae was also monitored in soil samples collected from 5 households in each village. Chi-square test was used to compare the infection rates. Results Total 69 909 people were recruited from 70 surveillance sites in Liaoning Province during 2016—2020, including 4 659 children aged 3-9, and the overall infection rate of STH infection was 0.26% (184/69 909), and the infection rate of A. lumbricoides and Trichuris trichiura were 0.25% (178/69 909) and 0.01% (6/69 909), respectively. Hookworm and E. vermicularis were not detected. The STH infection rate in the residents from 2016—2020 respectively were 0.59% (89/15 097), 0.19% (28/14 554), 0.27% (33/12 044)), 0.13%(19/14 103), and 0.11%(15/14 111) (χ2 = 59.44, P < 0.01). The top three cities with the highest infection rate of STH include Dandong (1.77%, 89/5 042), Dalian (0.56%, 28/5 004) and Benxi (0.42%, 23/5 451). The STH infection rate in females was 0.27% (94/35 057) and in males was 0.26% (90/34 852). The difference was not statistically significant (χ2 = 0.07, P > 0.05). The infection rate in the 60-69 age group was the highest (0.36%, 50/13 803), followed by the 40-49 age group (0.32%, 34/10 788) and the age group over 70 years old (0.31%, 23/7 396). The differences were statistically significant among the different age groups (χ2 = 18.30, P < 0.01). The infection rate in Man ethnicity (0.55%, 97/17 643) was statistical-significantly higher than that in Han ethnicity (0.17%, 87/51 154) (χ2 = 75.04, P < 0.01). The STH infection rate among medical personnel, farmers and workers were 0.67% (2/298), 0.31% (158/50 631) and 0.28% (7/2 542), respectively. The differences were statistically significant (χ2 = 26.90, P < 0.01). The infection rate among participants with primary school, education, middle school education and college education or higher were 0.32% (76/24 019), 0.26% (93/36 406) and 0.28% (5/1 815), respectively. The difference was not statistically significant (χ2 = 10.12, P > 0.05). Among 69 909 people surveyed, only 232 people (0.33%) had taken deworming medications within 3 months prior to the examination. A total of 1 757 soil samples were examined in Liaoning Province during 2016—2020, and the result indicated the positive rate of A. lumbricoides eggs of 2.22% (39/1 757), while hookworm larvae not found. Conclusion The STH infection rate showed a declining trend and remained at a low level in Liaoning Province during 2016—2020, with mainly Ascaris infection. Attention should be paid to the 60-69 age group, farmers, people with primary school education, Man ethnicity, and the residents in southern Liaoning Province in the control practice.

Current prevalence and sub-genotype analysis of Blastocystis in residents of Luoyang City
CHEN Hui-hui, LI Yun-xia, NING Chao-qun, DENG Yan, ZHANG Hong-wei, WEI Xue-fang, SUO Hui-fang, ZHANG Ting, LIU Qin, CHEN Jun-hu, TIAN Li-guang
2022, 40(2):  216-222.  doi:10.12140/j.issn.1000-7423.2022.02.013
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Objective To understand the infection status and distribution of sub-genotype of Blastocystis hominis in Luoyang City, Henan Province. Methods From September 13-20, 2020, a cross-sectional study with cluster random sampling was conducted in Luoning County, which was selected from the Luoyang City soil-transmitted nematode surveillance sites as the survey site. In the study, we selected no less than 200 permanent residents aged 3 and above from five administrative villages of Cheng jia zhuang, Xijie, Zhong gao, Nanpo and Mogou. A questionnaire was performed to collect the basic information of name, gender, age, ethnicity, occupation, education level, village and whether they had taken deworming medication in the three months prior to the survey. For those infected with Blastocystis information on living hygiene conditions and clinical signs were investigated. Faecal DNA was extracted and the small subunit RNA (SSU-rRNA) gene was amplified by PCR, sequenced and BLAST in the GenBank database to identify the genetic subtype. A phylogenetic tree based on the SSU-rRNA gene was constructed using the Mega 7.0, and allstatistical analysis was performed using SPSS 25.0 software; Results A total of 890 people were investigated and 20 people were found positive for Blastocystis infection. The Blastocystis infection rate was 2.2% (20/890). Among them, the male infection rate was 2.0% (8/399), and the female infection rate was 2.4% (12/491), and the difference was not statistically significant(χ2 = 0.193, P > 0.05). The 11-20 years age group had the highest infection rate, which was 5.1% (3/59), and the difference in infection rate among different age groups was statistically significant(Fisher =11.895, P < 0.05). Farmers had the highest infection rate at 2.6%, and there was no significant difference in infection rates among different occupations(Fisher = 1.535, P > 0.05). The infection rate among junior high school educated participants was the highest (2.7%), and there was no significant difference in infection rate among different education levels(Fisher = 1.283, P > 0.05). We found the Blastocystis infection rate in Zhonggao Village was the highest at 4.3% (7/164), and differences among 5 administrative villages were statistically significant (Fisher = 10.929, P < 0.05). As for PCR amplification, results showed that 20 samples amplified the SSU-rRNA gene fragment of Blastocystis, about 1 100 bp in size. Sequencing results showed that ST3 subtypes accounted for 90.0% (18/20), and ST1 subtypes accounted for 10.0% (2/20), which was consistent with the phylogenetic tree results. Within the infectious of Blastocystis, Mogou and Zhonggao villages included both ST3 subtypes and ST1 subtypes, and Nanpo and Xijie villages were both ST3 subtypes. Then, the phylogenetic tree results showed that 18 of the 20 positive faecal samples were in the same evolutionary branch as the Austrian isolate (GenBank accession no. MN914073.1), the German isolate (GenBank accession no. MK801403.1) and the Singaporean isolate (GenBank accession no. KX618192.1), all of which were ST3 subtypes. Two copies were in the same evolutionary branch as the German isolate (GenBank accession no. MK801408.1) and the Austrian isolate (GenBank accession no. MN914072.1), both ST1 subtypes of Blastocystis. As for hygienic conditions and clinical manifestations in 20 infected patients, 65.0% (13/20) used dry toilets or cesspools, 35.0% (7/20) used flushing toilets, and 45.0% (9/20) kept pets or livestock at home. 15.0% (3/20) showed symptoms of abdominal pain, diarrhea and abdominal distension, including one ST1 subtype and two ST3 subtypes; 20% (3/20) showed symptoms of dry stools, including one ST1 subtype and three ST3 subtypes. Conclusion The overall infection rate of B. hominis in the population of Luoyang City is relatively low, with the main sub-genotype ST3.

REVIEWS
Research progress on signal pathways related to host T cell immune response in helminth infection
HE Wei, ZHOU Bi-ying
2022, 40(2):  223-227.  doi:10.12140/j.issn.1000-7423.2022.02.014
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Helminthiasis is highly prevalent in Asia, Africa and South America, seriously affecting human health and economic development. Helminths infection can initiate host T cell immune response, thereby affecting T cell proliferation and differentiation. Some data indicate that in helminth infection, signalling pathways including transforming growth factor-β/Smad(TGF-β/Smad), inducible costimulator-inducible costimulator ligands (ICOS-ICOSL), programmed cell death protein-1/programmed death protein-1 ligand (PD-1/PD-L1), toll-like receptors/myeloid differentiation factor 88 (TLRs/MyD88). can participate in host T cell immune response, the interaction between signalling molecules can induce T cell proliferation and differentiation, then affect the host T cells to play an role in anti-worm infection effect. This article has reviewed the research advances on T cell immune response-related signalling pathways in worm infection.

Research progress on acquired toxoplasmosis in immunocompetent individuals
ZHAO Zi-qi, LV Fang-li
2022, 40(2):  228-235.  doi:10.12140/j.issn.1000-7423.2022.02.015
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Although Toxoplasma gondii infection is usually asymptomatic in immunocompetent individuals, a small part of T. gondii-infected immunocompetent individuals may have mild or even severe clinical symptoms. Using the keywords “immunocompetent” “T. gondii” “toxoplasmosis” “diagnosis” and “treatment” in the PubMed and China National Knowledge Infrastructure (CNKI) search engines, the authors systematically searched the cases of acquired toxoplasmosis in immunocompetent individuals reported from 1984 to 2021. This review summarizes the clinical manifestation, pathogenesis, diagnosis, and treatment of acquired toxoplasmosis in immunocompetent individuals, to provide a reference for clinical differential diagnosis and treatment of toxoplasmosis.

SHORT COMMUNICATIONS
Affect of Trichomonas vaginalis excretory secretory protein on sperm quality of mice
LUO Cheng-yang, HAO Li-xia, GUO Li-hua, WANG Bing-li, JI Si-fan, LIAN An-na, ZHU Xiao-hui, MEI Xue-fang, TIAN Xiao-wei, WANG Shuai, ZHANG Zhen-chao
2022, 40(2):  236-241.  doi:10.12140/j.issn.1000-7423.2022.02.016
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Trichomonas vaginalis excretory secretory protein (TvESP) was collected for determining the concentration using Bradford method kit and further analyzed of TvESP by thesodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Mouse sperm were collected from the epididymis of Kunming mice, and the sperm density was adjusted to 1 × 107/ml. Sperm were divided into 6 groups and co-cultured with TvESP at final concentrations of 0, 5, 10, 20, 40 and 80 ng/μl, respectively. After co-culturing with TvESP for 1 h, sperm motility was observed using an inverted microscope, and sperm apoptosis was detected by flow cytometry. After co-culturing for 0.5, 1 and 2 h, the sperm viability was analyzed by trypan blue staining. After sperm were incubated with TvESP at final concentrations of 0 and 40 ng/μl for 1 h, sperm were stained with a fluorescent dye and the acrosome was observed under a fluorescence microscope. One-way ANOVA was used for comparing between groups. The results showed that the percentage of active sperm in the 5, 10, 20, 40 and 80 ng/μl groups were (31.90 ± 4.10)%, (23.00 ± 4.90)%, (18.80 ± 3.50)%, (13.60 ± 1.20)% and (8.60 ± 1.20)%, respectively, which were significantly lower than that of the 0 ng/μl concentration group (44.50 ± 3.20)% (F = 30.76, P < 0.01). The apoptosis rates of sperm in the 5, 10, 20, 40 and 80 ng/μl groups were (17.99 ± 1.73)%, (22.43 ± 1.53)%, (26.76 ± 2.20)%, (32.05 ± 1.68)% and (41.37 ± 2.28)%, respectively, which were significantly higher than that of the 0 ng/μl group (15.42 ± 1.10)% (F = 256.79, P < 0.01). After treatment with TvESP for 0.5 h, the mortality rates of sperm treated with 10 ng/μl (11.90 ± 1.70)%, 20 ng/μl (14.10 ± 1.40)%, 40 ng/μl (16.30 ± 1.20)%, 80 ng/μl (17.90 ± 1.30)% of TvESP were significantly higher than that of the 0 ng/μl group (7.80 ± 1.10)% (F = 15.72, P < 0.05). The sperm mortality rate in the 5 ng/μl group (10.10 ± 1.40)% was not statistically different from that of the 0 ng/μl group. After treatment with TvESP for 1 h, the sperm mortality rates in the 5, 10, 20, 40 and 80 ng/μl groups were (12.90 ± 0.90)%, (14.60 ± 0.90)%, (16.20 ± 1.30)%, (18.10 ± 1.10)%, (20.00 ± 1.40)%, which were significantly higher than that of the 0 ng/μl group (9.90 ± 1.90)% (F = 15.76, P < 0.01). After 2 h treatment, the mortality rates in the 10, 20, 40 and 80 ng/μl groups were (17.00 ± 1.20)%, (18.30 ± 1.20)%, (20.50 ± 1.20)% and (22.80 ± 1.50)%, respectively, which were significantly higher than that of the 0 ng/μl group (12.90 ± 0.50)% (F = 22.22, P < 0.01), and the mortality rate in the 5 ng/μl group (15.00 ± 0.40)% was not statistically different from that of the 0 ng/μl group. After co-culturing the sperm with TvESP at a final concentration of 40 ng/μl for 1 h, the integrity of acrosome was destroyed. All results suggested that TvESP can reduce sperm quality.

Surveillance of echinococcosis in Ningxia in 2020
WU Xiang-lin, YAN Fang, DUAN Hong-ju, QI Rong-ting, GAO Jian-wei
2022, 40(2):  242-246.  doi:10.12140/j.issn.1000-7423.2022.02.017
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In order to understand the surveillance results and epidemic characteristics of echinococcosis in Ningxia, the prevalence of echinococcosis among the residents over 3 years old in 3 type Ⅰ epidemic areas, 9 type Ⅱ epidemic areas and 7 type Ⅲ epidemic areas in Ningxia was examined by ultrasound imaging method in 2020. Echinococcus infection in dogs was detected by ELISA. The infection of hydatid cyst in the liver, lung and abdominal cavity of cattle, sheep and mice was observed by autopsy and physical examination. A total of 30 700 persons were examined, with a detection rate of 0.09% (28/30 700). The detection rates of type Ⅰ, Ⅱand Ⅲ were 0.39% (12/3 046), 0 (0/9 938) and 0.09% (16/17 716), respectively. Echinococcosis was detected only in Xiji County and Zhongning County in type Ⅰ epidemic areas, with a detection rate of 0.79% (8/1 013) and 0.39% (4/1 033), respectively. Echinococcosis patients were detected only in Jinfeng District, Haiyuan County and Pingluo County in type Ⅲ epidemic areas, with a detection rate of 0.25% (5/2 038), 0.20% (10/5 101) and 0.02% (1/4 358), respectively. The majority of cases were male and 50-59 age group, accounting for 64.29% (18/28) and 42.86% (12/28), respectively. A total of 19 727 children were screened in 57 primary schools in 19 endemic areas. No children with echinococcosis were detected. A total of 13 549 feces samples were tested in 19 counties, with an infection rate of 0.89% (121/13 549). The infection rate of domestic dogs in different areas was significantly different (χ2 =62.59, P < 0.05). A total of 670 feces from street dogs were tested in the 3 type Ⅰ epidemic areas, and the infection rate was 2.69% (18/670), which was higher than that of domestic dogs (0.89%, 121/13 549) (χ2 = 21.21, P < 0.05). A total of 6 017 sheep were monitored and the infection rate was 0.83% (50/6 017). The infection rate among cattle was 0.08% (3/3 915). The infection rate among sheep was higher than that of cattle (χ2 = 25.43, P < 0.05). No echinococcus multilocularis were detected in 1 507 rodent samples. It is suggested that the echinococcosis epidemic areas in Ningxia should be redefined according to the criteria of the National Echinococcosis Surveillance Program (2020 Edition). Increase population screening in key areas, strengthen sheep monitoring, and carry out monitoring, deworming and management of ownerless dogs.

Retrospective analysis of paragonimiasis cases in Jiangxi Province from 2011 to 2020
GONG Zhi-hong, GONG Hong-ka, XU Yun, LIU Jun-pu, TU Yong-hong, XIE Hui-qun
2022, 40(2):  247-251.  doi:10.12140/j.issn.1000-7423.2022.02.018
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To analyze the epidemiology and clinical characteristics of paragonimiasis in Jiangxi Province in recent ten years. The epidemiological and clinical data of patients with paragonimiasis who were diagnosed and treated at Jiangxi Institute of Parasitic Diseases from May 2011 to December 2020 were collected and analyzed retrospectively. A total of 41 patients’ data were collected. The average age of the 41 patients was (29.69 ± 19.94) years. Patients aged between 18-59 accounted for 51.2% (21/41). Out of all the patients, 29 cases were males, and 12 were females. The course of the disease lasts 10 days to 5 years. The patients were from 8 districts and cities in Jiangxi Province, of which Yichun had the most cases, accounting for 43.9% (18/41). Before the onset of the disease, 48.8%(20/41) of the patients drank stream water, 31.7% (13/41) ate raw/half raw shrimps and crabs, 9.7%(4/41) caught or played with crabs, 9.7% (4/41) had no clear history of eating raw or semi-raw food. The positive rate of serum anti-Paragonimus antibodies was 100%. The mixed type accounted for 39.0% (16/41), thoracopulmonary type accounted for 26.8% (11/41), subcutaneous type for 14.6% (6/41), abdominal and hepatic type for 12.1% (5/41), cerebral type for 7.3%(3/41). The eosinophils count was increased in 41 patients, the highest was 17.74 × 109/L, and the highest percentage of eosinophils was 76.34%; 21 patients (51.2%) had significantly increased peripheral blood leukocyte count, the highest was 44.10 × 109/L. The paragonimiasis serum IgG antibodies of the patients were all positive and had cross-reaction with various parasites, among which the positive crossover rate with serum schistosomiasis antibody was 58.5%(24/41). Computed tomography (CT) results showed that 22 cases of chest bilateral or unilateral pleural effusion of varying degrees, 5 cases of local encapsulated effusion, and 3 cases of pericardial effusion; chest CT scan results showed that 9 cases of intrapulmonary scattered patchy and nodular increased density shadows, 10 cases of tunnel sign, and 1 patient had atelectasis. Magnetic resonance imaging (MRI) showed that 6 patients with cerebral paragonimiasis had hemorrhagic foci, circular, quasi- circular cystic, multiple nodules, with aggregation, migration-like lesions and tunnel-like changes. Susceptibility-weighted imaging (SWI) showed multiple short-track-like low-intensity shadows and round-like low-intensity shadows in the brain. Three patients underwent fine-needle aspiration cytology examination of subcutaneous mass. Lymphocytes, eosinophils and fusiform bamboo leaf-shaped Charcot-Ryden crystals were found under wright staining microscopy. Eggs or parasites of Paragonimus were not found in all 41 patients by pathogenic examination. 41 patients were all cured after more than one course of treatment. The prevalence of paragonimiasis in Jiangxi Province was sporadic. Paragonimiasis should be diagnosed with a comprehensive analysis of the epidemiological history, serum antibody testing, imaging examination, eosinophilia, etc. A good prognosis is expected after praziquantel treatment.

Blastocystis infection and its effect on blood parameters in laboratory mice
QIAO Hai-xia, CAO Meng-juan, HUANG Jing, MA Lei
2022, 40(2):  252-255.  doi:10.12140/j.issn.1000-7423.2022.02.019
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To analyze the infection of Blastocystis and its effect on blood parameters in laboratory mice. Fecal samples of clean-grade BALB/c mice raised in 6 different laboratories in Shijiazhuang City were collected from 2020 to 2021. The fecal DNA was extracted, and then the 18S-specific fragments of Blastocystis were amplified, sequenced and BLAST in the GenBank database. The subtypes of Blastocystis were analyzed, and the phylogenetic tree based on the 18S sequence was constructed by the maximum likelihood method. Five mice infected with Blastocystis and five uninfected mice raised in the same conditions were selected to collect blood samples for the routine blood test. The results were analyzed by t-test to compare the differences between the two groups. A total of 238 fecal samples were collected, and 47 were Blastocystis positive with an infection rate of 19.8% (47/238). The sequence of the 47 positive samples displayed 80.31%-82.79%, 97.84%-99.13% and 98.79% identity to MK782501.1 (ST1), MN338076.1 (ST2) and MK861934.1 (ST7), respectively. The phylogenetic tree showed that the sequences of positive samples were clustered into a branch with the sequences of ST1, ST2 and ST7 subtypes, respectively. The results of the blood test showed that the average hemoglobin content in mice infected with Blastocystis was (21.17 ± 0.45) pg, which was lower than that in the uninfected mice (23.90 ± 0.60) pg(t = 6.308, P < 0.01). The average hemoglobin concentration was (480.00 ± 23.64) g/L, which was lower than that in the uninfected mice (544.33 ± 15.70) g/L(t = 3.927, P < 0.05), while there was no significant difference in other indicators (P > 0.05). The results of this study suggest that the subtypes of Blastocystis which the mice infected were ST1, ST2 and ST7. The infection of Blastocystis will result in abnormal blood parameters in the mice.

Epidemiological characteristics of echinococcosis in Yili Prefecture of Xinjiang from 2005 to 2020
WANG Shuo, ZHAI Xiao-hu, ZHANG Hai-ting, SHI Guang-zhong, YANG Han-qi, CHEN Xia, MAIMAITIJIANG Wumaier, ZHAO Jiang-shan
2022, 40(2):  256-260.  doi:10.12140/j.issn.1000-7423.2022.02.020
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In order to understand the epidemiologic characteristics and status of echinococcosis in Yili Prefecture of Xinjiang Uygur Autonomous Region from 2005 to 2020. Data from Echinococcus cases in Yili Prefecture of Xinjiang during 2005 and 2020 were collected from National Infectious Disease Reporting Information Management System and analyzed using descriptive epidemiology approaches. The results showed that 4 612 echinococcosis cases were reported in Yili Prefecture from 2005 to 2020. The average annual incidence rate was 9.92/100 000. The number of reported cases peaked in 2017, followed by a decline annually, with no significant seasonal patterns. Cases were reported in all 11 counties (cities) of Yili Prefecture. Chabuchaerxibo Autonomous Country (20.96/100 000), Zhaosu County (19.94/100 000) and Nileke County (16.61/100 000) had the highest incidence rate. Of all the reported cases, 2 488 cases were male, with an average annual incidence of 10.46/100 000; 2 124 cases were female, with an average annual incidence of 9.27/100 000. There was no significant difference in annual incidence between males and females (χ2 = 1.063, P > 0.05). The average age of the reported echinococcosis patients was 39 years, while the majority of the cases were aged between 20 and 59, accounting for 75.1% (3 462 cases) of the total cases. The occupation was mainly farmers and herdsmen, accounting for 63.1% (2 909 cases) of the cases. It is suggested that the prevalence of echinococcosis in Yili Prefecture of Xinjiang is high, affecting a large number of people suggesting the need for developing science-based and effective prevention approaches that are suitable for controlling the transmission of echinococcosis.

Investigation of imported malaria cases at a COVID-19 isolation point in Qingdao
LIU Su-zhen, JI Feng-ying, SHI Li-mei
2022, 40(2):  261-265.  doi:10.12140/j.issn.1000-7423.2022.02.021
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The epidemiological data were collected from travellers who returned from Guinea on the 23rd of September, 2020 and were diagnosed with malaria at a COVID-19 quarantine site in Qingdao, Shandong Province. The epidemiological characteristics, diagnosis and treatment of the cases and the epidemiology investigation and the rapid test screening results for other travellers on from the same flight and the interventions in reaction to the imported malaria cases were analyzed. The results showed that 4 out of 231 Guinean returned travellers had developed malaria symptoms, including chills and fever, during the isolation period. Rapid diagnostic test (RDT) indicated Plasmodium falciparum infection. Considering the patients’ travel history, clinical manifestations, and laboratory RDT test results, a confirmed diagnosis of imported P. falciparum malaria was made. The four malaria cases, who are male workers aged 29 to 55, were transferred to Jiaozhou People’s Hospital for treatment. All four patients were administrated of artemether tablets upon diagnosis. One of the cases experienced severe malaria complications and were administrated with 12 doses (60 mg/dose) of artesunate intravenously for five days. The other three patients were treated with dihydroartemisinin and piperaquine phosphate tablets for one course of 8 tablets in 2 days (40 mg dihydroartemisinin and 320 mg piperaquine phosphate), respectively. Among the 231 returned travellers, 111(48.1%) had a history of malaria overseas. There were 23 positive cases detected by RDT, including the four symptomatic cases. The other 19 cases were asymptomatic. One of the asymptomatic cases became symptomatic three months later and was diagnosed as an imported P. malariae infection. Laboratory blood smear microscopic tests at the Jiaozhou City and Qingdao Municipal Center For Disease Control and Prevention showed negative results for the four malaria cases and the 19 RDT positive case. The samples from the four malaria cases were rechecked by the provincial reference laboratory of Shandong Institute of parasitic Disease. The results were negative for malaria infection by microscopic examination but positive for P. falciparum infection by nucleic acid test. It is suggested that during the routine control of COVID-19, the awareness of COVID-19 and malaria should be established among the returned travellers from high malaria-endemic areas. The health education “gate” should be moved forward to improve the treatment compliance for malaria cases and reduce the relapse or recrudescence caused by sub-optimal treatment.

CASE REPORTS
Relapse of visceral leishmaniasis in a cured case after 64 years
ZHANG Ai-ping, LIANG Man-man, ZHU Ling-ling, SHENG Hao-yu, YANG Jiang-hua
2022, 40(2):  266-268.  doi:10.12140/j.issn.1000-7423.2022.02.022
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A 74-year-old patient from Juxian County, Rizhao, Shandong Province was diagnosed with visceral leishmaniasis and treated with pentavalent antimony for 6 d in the local hospital of Juxian in 1957. In 1964, the patient migrated to Ma’anshan City, Anhui Province. In October 2014, He travelled back to Juxian County for two weeks before returning to Ma’anshan City. In July 2020, he migrated to Bozhou City, Anhui Province. The patient denied any history of being bitten by sandfly, living with a dog at home during this period. The patient had no contact history of visceral leishmaniasis patients or Leishmannia infected dogs. The patient presented unexplained emaciation and fatigue from July 2020, and dizziness from April 2021. The patient had a sudden high fever without obvious inducement and aggravated fatigue and dizziness in June 2021. Bone marrow smear examination revealed Leishmania parasite flagellate body. The metagenomic analysis of the bone marrow pathogenic microorganisms revealed 30 366 sequences of the Leishmania genus, including 128 sequences of Leishmania donovani. Serum rk39 immunochromatographic strip showed a positive result. Combining the epidemiological history and labortory test results, a recurrent visceral leishmaniasis diagnosis was made. The patient was discharged after treatment with pentavalent antimony (0.6 g/d, intramuscular injection, 6 g, one course of 10 days). The patient was followed up by telephone after discharge, and showed no fever but did not go to the hospital for review.

An imported case of severe falciparum malaria
SHE Dan-ya, LU Li-dan, LAN Zi-yao, HUANG Yu-ting, LIANG Wen-qin
2022, 40(2):  269-271.  doi:10.12140/j.issn.1000-7423.2022.02.023
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In October 2019, Guizhou Center for Disease Control and Prevention received a report of one imported case of malaria. The patient worked in the outdoor advertising business in Coate d’Ivoire from April 2018 to October 2019. No other anti-mosquito measures were taken except for mosquito coil incense. During this period, the patient was infected with malaria twice. On admission, the patient was in coma with jaundice, shortness of breath and brain damage, ARDS, shock, severe anemia, acidosis, and other complications. Plasmodium antigen tests were positive. Ring forms, trophozoites, merozoites and gametocytes were found in blood smears. Nested PCR showed positive for Plasmodium falciparum bands. P. falciparum malaria diagnosis was made based on the epidemiological history and laboratory test results. Standard antimalarial treatment was given to the patient, and the parasitemia was monitored. Administration of the anti-malarial drugs was effective. The patient did not report any symptoms over the follow-up period.