Table of Content

28 February 2021, Volume 39 Issue 1

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INVITED REVIEWS

Olfactory perception and sex determination of vector mosquitoes

LIU Tong, WU Yang, LIU Pei-wen, YANG Wen-qiang, JIN Bin-bin, GU Jin-bao, CHEN Xiao-guang

2021, 39(1):  1-7.  doi:10.12140/j.issn.1000-7423.2021.01.001

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Mosquitoe is a type of important vector organism. Female mosquitoes can transmit various infectious diseases such as malaria, dengue fever, and epidemic encephalitis B, through sucking blood. Mosquito olfactory perception and sex determination are essential for reproducing and transmitting pathogens and often critical for control of mosquito population density and mosquito-borne diseases. Herein, we review the basic functions, mechanisms, and research advances on olfactory perception and sex determination of vector mosquitoes, in order to provide reference for controlling mosquito population density and mosquito-borne diseases.

Prevalence of waterborne intestinal protozoosis and control strategies in China

SHEN Yu-juan, JIANG Yan-yan, CAO Jian-ping

2021, 39(1):  8-12.  doi:10.12140/j.issn.1000-7423.2021.01.002

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Intestinal protozoosis such as cryptosporidiosis, giardiasis, and cyclosporosis can be transmitted through water, and represents an important waterborne parasitic disease. Most intestinal parasites are characterized by the zoonotic nature and having multiple animal hosts, making it difficult to prevent and control. In addition, some of the intestinal protozoosis are emerging infectious diseases, with no available baseline data concerning human infection. This review focuses on the prevalence and detection techniques of the waterborne intestinal protozoosis in China, and discusses challenges for the disease prevention and control, in order to provide reference for establishment of an efficient disease surveillance network and an early-warning system, for carrying out risk assessments, and for proposing effective prevention and control measures.

ORIGINAL ARTICLES

Cloning, expression of the thioredoxin peroxidase gene of Paragonimus westermani and its immunodiagnostic potential

ZHOU Yan, CHEN Shao-hong, LI Hao, CHENG Na, HONG Jia-lin, XU Xue-nian

2021, 39(1):  20-26.  doi:10.12140/j.issn.1000-7423.2021.01.003

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Objective To immunologically screen the cDNA library of adult Paragonimus westermani for the gene encoding thioredoxin peroxidase (TPx), clone and express the gene, and evaluate the immunodiagnostic value of TPx recombinant protein. Methods The λ ZAP cDNA library was immunologically screened with the pooled serum of P. westermani patients. The obtained positive clones were sequenced and analyzed by multiple sequence alignment. The full length (rPwTPx) and N-terminal truncated (rPwTPx_1) sequences of PwTPX were subcloned into the prokaryotic plasmid pET28a (+), respectively, to construct the expression vectors rPwTPX and rPwTPX_1. The expression of the two constructed recombinant plasmids was induced by 1 mmol/L IPTG. Protein extraction reagents, lysozyme and nuclease were used to lyse and express the bacterial fluid. The recombinant proteins of rPwTPx and rPwTPx_1 were purified using the His-tagged affinity column (Ni-NTA). SDS-PAGE was used to analyzed the expression of the recombinant proteins. rPwTPx and rPwTPx_1 were used to test the sera of 36 paragonimiasis westermani patients, 15 patients with clonorchiasis sinensis, 15 schistosomiasis japonica patients, 15 fascioliasis gigantica patients, 15 cysticercosis patients, and 36 healthy donors, using the indirect ELISA method. Data were analyzed with the SAS 9.2 software. Results The TPx recombinant proteins rPwTPx and rPwTPx_1 were obtained through expression and purification, with relative molecular mass M_r of 25 000 and 22 000, respectively. The rPwTPx ELISA results showed that the A₄₅₀ values for the sera from patients of paragonimiasis westermani, healthy persons, clonorchiasis sinensis, schistosomiasis japonica, fascioliasis gigantic, and cysticercosis patients were 0.150 ± 0.092, 0.036 ± 0.014, 0.043 ± 0.019, 0.047 ± 0.013, 0.060 ± 0.022 and 0.048 ± 0.021, respectively, The positive rate in serum of paragonimiasis westermani patients was 58.3% (21/36). There was no cross-reaction with sera of healthy donors, clonorchiasis sinensis, schistosomiasis japonica and cysticercosis patients. The cross-reaction with sera of fascioliasis gigantic patients was 2 samples. The ELISA using rPwTPx_1 as the antigen presented the A₄₅₀ values to the above testing sera was 0.144 ± 0.092, 0.022 ± 0.009, 0.027 ± 0.015, 0.033 ± 0.022, 0.036 ± 0.015 and 0.032 ± 0.018, respectively. The positive rate of paragonimiasis westermani patients sera was 88.9% (32/36), while the sera of healthy donors showed no cross-reaction. Only 1 serum sample of 15 clonorchiasis sinensis patients had cross-reaction. The cross-reaction with sera of schistosomiasis japonica, fascioliasis gigantic and cysticercariasis patients were 3, 2 and 2 samples. The total diagnostic coincidence rate, sensitivity and specificity of ELLSA using rPwTPx and rPwTPx_1 as antigen were 87.1%, 58.3%, 97.9%, and 90.9%, 88.9%, 91.7%, respectively. The sensitivity of the rPwTPx_1 ELISA was significantly higher than that of the rPwTPx ELISA (P < 0.05). Crude antigen-ELISA showed that the A₄₅₀ value of serum samples from the 36 healthy donors was 0.012, and S was 0.006. The sensitivity, specificity and total diagnostic coincidence rate of crude antigen were 100%, 83.3% and 87.9%, which did not significantly differ from those of rPwTPx and rPwTPx_1 (P > 0.05). Conclusion The gene encoding TPx was screened and expressed, and two structural types of recombinant protein were obtained, including full length and truncated types, which recombinant protein shows proper sensitivity and high specificity for the serodiagnosis of P. westermani infection.

Diversity and genotype analysis of tick-borne pathogens in grasslands in the central and western part of Inner Mongolia

Wulantuya, YIN Xu-hong, CUI Yun-hong, LIU Dan, WANG Ting-fu, MIAO Yu-run, , CAO Min-zhi, ZHAO Zhi-wei, XING Fang-chao, LU Jian-ying, GAO Wa

2021, 39(1):  27-35.  doi:10.12140/j.issn.1000-7423.2021.01.004

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Objective To investigate the structure of tick populations, the diversity of pathogens they carry, and the genotypes of tick-borne Rickettsia-related pathogens in central and western part of Inner Mongolia of China. Methods Tick samples were collected from body surface of animals in the grasslands in central and western Inner Mongolia in spring and summer between 2016 and 2019. The tick species was identified. The salivary glands of ticks were dissected and genomic DNA was extracted. PCR was performed to amplify citrate synthase A (gltA) in spotted fever Rickettsia, flagellin gene B (flaB) in Borrelia, outer membrane protein 1 (omp1) in Ehrlichia, and major surface protein 2 (msp2) in Anaplasma. The samples positive for Rickettsia gltA were classified by restriction fragment length polymorphism (RFLP), and then 20 to 30 representative samples were selected for each type for each species and region for gene sequencing of gltA and Rickettsia outer membrane protein A (rOmpA). Homology analysis was performed by BLAST, Clustal W and MEGA 7.0 softwares, and the phylogenetic tree was constructed using the adjoining method. Results A total of 3 822 ticks were collected, 3 genera of 2 species were identified by morphological observation and genotyping of the specific 18S rRNA, which were Dermacentor nuttalli, Hyalomma asiaticum and H. marginalis, of which D. nuttalli (55.7%, 2 129/3 822) and H. asiaticum (30.0%, 1 147/3 822) constituted the predominant species. PCR results showed that 1 899 ticks were positive for Rickettsia gltA, with positive rate of 49.7% (1 899/3 822). The gltA-positive samples were divided into two groups according to the RFLP results. The gltA sequence was 581 bp in both groups, and was 100% homologous to R. raoultii (DQ365804) or R. aeschlimanni (KT873466). The rOmpA length of the two groups was 367 bp, which was 100% homologous to R. Raoultii (AH015610) or R. aeschlimanni (U83466), consistent with the results of gltA. The positive rates of R. raoultii and R. aeschlimanni in the 3 822 ticks were 37.2% (1 422/3 822) and 12.5% (477/3 822), respectively; 58.5% (1 245/2 129) and 11.1% (477/2 129) in D. nuttalli, respectively; 15.4% (177/1 147) and 0 in H. asiaticum; and 0 and 44.0% (240/546) in H. marginalis, respectively. A total of 28 ticks (0.7%, 28/3 822) were positive for Borrelia flaB, with positive rate of 0.8% (16/2 129) in D. nuttalli and of 1.0% (12/1 147) in H. asiaticum. A total of 10 sequences of Borrelia flaB were obtained, with 90.6%-100% and 95.6%-100% homology to B. garinii (AB035602) and B. afzelii PKO (NC008277), the main pathogens of Lyme disease. The positive rates of B. garinii and B. afzelii were 0.9% (10/1 147) and 0.2% (2/1 147) in H. asiaticum, respectively, and were both 0.4% (8/2 129) in D. nuttalli. Of the 3 822 ticks examined, 1 tick was positive for Ehrlichia omp1. After TA cloning, 8 clones with the same amino acid sequence and 3 with different amino acid sequences were obtained. The amino acid sequences of the 11 clones had the highest homology with E. muris, although the homology was only 65%-69%. No Anaplasma microbiome was detected in the 3 822 ticks. The phylogenetic tree analysis showed that the Rickettsia that infected the three tick species clustered with R. raoultii and R. aeschlimanni. Among the 10 Borrelia flaB sequences obtained, one sequence from D. nuttalli and H. asiaticum clustered with B. garinii, another sequence from D. nuttalli also clustered with B. afzelii, and the remaining 8 sequences were in different branches from the flaB sequences of B. garinii and B. afzelii. The Ehrlichia infected by D. nuttalli was also far from the known Ehrlichia, forming a separate cluster. Conclusion D. nuttalli, H. asiaticum and H. marginalis are found in grasslands in the central and western part of Inner Mongolia. Infection of spotted fever Rickettsia and Lyme disease spirochete are widespread in the ticks, creating potential natural foci of R. raoultii, R. aeschlimanni, B. garinii, B. afzelii and Ehrlichia infection. It is necessary to strengthen the prevention and control of tick-borne infectious diseases in these areas.

Preliminary study on autophagy of lung tissue cells in rats infected with Paragonimus proliferus

MA Zhi-qiang, WANG Lin, LI Sheng-hao, XU Jing-jing, LI Cai-xin, LIU Yuan, ZHANG Yan-ling, SHU Qiu-hong, ZHUANG Shan-shan, HE Shu Mei-qi, WANG Wen-lin, WANG Wei-qun

2021, 39(1):  35-42.  doi:10.12140/j.issn.1000-7423.2021.01.005

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Objective To explore whether Paragonimus proliferus infection in rats can cause autophagy in lung tissue cells, by detecting the expression of factors related to the protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. Methods Forty SD rats were randomly divided into 4 groups (n = 10 in each group). The rats in all groups (except the control group) were intraperitoneally injected with 6 P. proliferus metacercaria, and were sacrificed on days 3, 7 and 14 after injection, respectively. Serum samples collected from the rats were used to detect the levels of IL-1 and IL-6 by ELISA. The lung tissues were examined for autophagosome formation by transmission electron microscopy (TEM), pathological changes by HE staining, and protein expression of Akt, mTOR, Beclin 1 and LC3Ⅱ by Western blotting and immunohistochemistry. Statistical analysis was performed with the SPSS 19.0 software. Results The ELISA results showed that the expression levels of IL-1 on days 3, 7 and 14 after infection was (1 558.0 ± 123.6), (1 511.0 ± 213.1) and (1 448.0 ± 176.8) pg/ml, respectively, all significantly higher than the normal group (1 222.0 ± 112.8) pg/ml (P < 0.05); the expression levels of IL-6 on days 3 and 7 after infection was (1 481.0 ± 197.9) and (1 423.0 ± 210.0) pg/ml, respectively, both higher than the control group (1 221.0 ± 138.9) pg/ml (P < 0.05). TEM revealed autophagy in mitochondria at different stages of infection. HE staining results showed that the cells in each infection group were arranged disorderly and the alveolar structure showed varied degrees of impairment. There was no significant difference in the protein level of Akt in the infection groups, compared to the control group (P > 0.05); the protein levels of p-Aktser ⁴⁷³ on days 3 and 7 after infection were (1.288 ± 0.109) and (1.619 ± 0.132), respectively, both higher than that of the normal group (0.733 ± 0.135) (P < 0.01). The protein levels of p-mTORser ²⁴⁴⁸ in the infection groups were (1.574 ± 0.278), (2.384 ± 0.125) and (1.808 ± 0.121), all higher than the normal group (1.260 ± 0.087) (P < 0.05). The protein levels of mTOR and Beclin 1 on day 3 after infection were (1.714 ± 0.217) and (2.736 ± 0.333), respectively, both higher than (1.345 ± 0.067) and (1.974 ± 0.225) in the normal group (P < 0.01). The LC3Ⅱ protein level on day 14 after infection was (1.938 ± 0.191), higher than that of the normal group (1.401 ± 0.200) (P < 0.01). The results of IHC showed that the lung tissue cells of the negative control group were blue, while the positive staining was in brown yellow; the proteins stained positive were all located in the cell membrane and cytoplasm. Compared with the control group, Akt and mTOR in each infection group showed no obvious brown color in the lung tissue cells, and there was no significant difference in the optical density of Akt and mTOR between the infection groups and the control group (P > 0.05). The staining for p-Aktser ⁴⁷³, p-mTORser ²⁴⁴⁸ and Beclin 1 in the groups 3 d, 7 d, and 14 d after infection showed denser brown yellow signals compared with the control group, and the optical densities were (0.104 ± 0.010), (0.143 ± 0.022), (0.088 ± 0.013); (0.100 ± 0.007), (0.151 ± 0.006), (0.120 ± 0.012); and (0.129 ± 0.005), (0.047 ± 0.004), (0.050 ± 0.005), which were higher than those in the normal group brown yellow signals[(0.032 ± 0.001), (0.065 ± 0.002) and (0.031 ± 0.001)] (P < 0.05). The LC3Ⅱ showed significantly darker brown yellow signals than the control group on days 3 and 14 after infection, and the optical densities were (0.056 ± 0.006) and (0.120 ± 0.007), which were higher than that of the normal group (0.042 ± 0.004) (P < 0.05). Conclusion P. proliferus infection in rats causes lung injury and inflammatory response, which may induce autophagy of liver cells. The autophagy event could be detected by assessing the expression of factors related to the Akt/mTOR signaling pathway.

Epidemiological characteristics of imported malaria in Henan Province in 2019

YANG Cheng-yun, QIAN Dan, LU De-ling, LIU Ying, ZHOU Rui-min, LI Su-hua, GUAN Zhou, ZHAO Yu-ling, ZHANG Hong-wei, ZHAO Dong-yang, GUO Wan-shen

2021, 39(1):  43-48.  doi:10.12140/j.issn.1000-7423.2021.01.006

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Objective To analyze the epidemiological characteristics of malaria in Henan Province in 2019, in order to provide a basis for formulating effective strategies and measures for surveillance after malaria elimination in Henan Province. Methods Data of malaria cases in Henan Province in 2019 were collected. The epidemiological information of malaria was analyzed with the descriptive epidemiological method. Results A total of 228 cases of malaria were reported in 2019, including 176 cases (77.2%) of falciparum malaria, 12 cases of vivax malaria, 33 cases of oval malaria and 7 cases of quartan malaria; having 222 male(97.4%) and 6 female cases. The majority of the cases was aged between 30 to 59 years (82.9%, 189/228) and were migrant workers (78.9%, 180/228). All of the malaria cases were imported cases and 96.1% (219/228) of them were from Africa. The top five cities having highest reports of cases were Zhengzhou (77 cases), Luoyang (22), Puyang (20), Anyang (19) and Xuchang cities (15), which accounted for 67.1% of total cases in Henan Province. The cases were reported throughout the year, particularly higher in January and December. The average time from onset to first visit to a doctor was 1.6 d and 202 (88.6%) cases went to visit a doctor within 3 days after onset. The average time from the first visit to confirmed diagnosis was 1.7 d, and 188 (82.5%) cases were diagnosed as malaria within 3 days. All of the cases (100%) were reported within 24 h, of them, 225 cases (98.7%) were underwent epidemiological investigation within 3 days, while 213 (93.4%) epidemic sites were surveyed within 7 days. Conclusion All the cases reported from Henan Province in 2019 were imported from abroad. It is suggested that the local health sections should strengthen the surveillance of imported cases from abroad to prevent the occurrence of secondary cases.

Investigation of differentially expressed genes in liver tissues of patients with alveolar echinococcosis

ZHU Ji-hai, CAO De-ping, ZHAO Jun, LIU Jun, SHI Hu-xiang, LIU Yan

2021, 39(1):  48-54.  doi:10.12140/j.issn.1000-7423.2021.01.007

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Objective To investigate the expression profile of differentially expressed genes in liver lesions of alveolar echinococcosis patients, based on the findings that these genes were indentified in mice infected with alveolar metacestode. Methods The gene chip dataset (No. GSE24376) in the high-throughput gene expression database was selected from the gene expression omnibus (GEO), to compare the genes with differential expression between infected and uninfected mice. The differentially expressed genes underwent gene ontology (GO) analysis. Lesion tissues and adjacent tissues 2 cm from the lesion were collected from 6 patients with E. multilocularis cyst infection. Fluorescence quantitative PCR was performed to detect the relative mRNA levels of two highly expressed differential genes. Forty-five paraffin-embedded liver tissue samples from patients with multilocular hydatid infection (29 samples with severe inflammatory response and liver fibrosis, and 16 with relatively normal liver tissue with less inflammatory cell infiltration and liver fibrosis) underwent immunohistochemistry to analyze the expression of the two highly expressed differential genes. Statistical analysis was performed on the data with SPSS 21.0 statistical software. Results As compared to the normal mice, 21 differentially expressed genes were found, including 9 overexpressed genes and 12 downregulated genes in liver tissues of infected mice. The results of GO analysis showed that the differentially expressed genes were expressed in vesicle lumen, cytoplasmic vesicle lumen and extracellular matrix, participated in biological processes of neutrophil degranulation and activation, and possessed CC chemokine receptor binding activity and chemokine activity. The fluorescence quantitative PCR results showed that the mRNA expression levels of CHI3L3 (CHI3L1 in humans) and CCL8, which had higher differential expression, were higher in the liver lesion tissues than in the surrounding tissues of the 6 patients with multilocular hydatid infection (P < 0.01), reaching an utmost 7 and 9 folds, respectively. The results of immunohistochemistry showed that among the 29 lesion samples with severe inflammatory reaction and liver fibrosis, 20 samples (69%) showed high expression of CHI3L1 protein, with staining mainly located in the cytoplasm, and 22 samples showed high levels of CCL8 protein (76%). Of the 16 relatively normal liver tissue samples, only 2 (13%) were positive for CHI3L1 protein, and only 4 were positive for CCL8 protein (33%). In the lesions with severe inflammatory response and liver fibrosis, the positive expression rate of CHI3L1 and CCL8 proteins reached 96% and 97%, respectively, which were higher than 3% and 8% in normal liver tissues (P < 0.01). Conclusion The expression of CHI3L1 and CCL8 was upregulated in the liver tissues of patients with E. multilocularis, suggesting that they play a role in the immune response to parasites.

Prevalence and genotype analysis of Blastocystis hominis among HIV/AIDS patients in Nanchang City

QIAN Ke, HU Zhu-hua, WU Xiu-ping, PENG Guo-hua, YU Ying-fang, CHU Yan-hong, ZHOU Xian-feng, XU Dan, TENG Xue-jiao, LI Hui, TIAN Li-guang

2021, 39(1):  55-60.  doi:10.12140/j.issn.1000-7423.2021.01.008

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Objective To determine the prevalence and genotype of Blastocystis hominis among HIV-positive individuals in Nanchang City. Methods A cross-sectional questionnaire survey was made among registered HIV-positive individuals in Nanchang City during May and September in 2016. Blood and fecal samples were collected. The level of CD4 ⁺ T cells in blood was detected. DNA genome was extracted from the fecal samples to amplify the small subunit ribosomal ribonucleic acid (SSU rDNA) of B. hominis. The positive products were sequenced and aligned to confirm the diagnosis, and phylogenic tree was constructed for genotyping. Results A total of 505 subjects were surveyed, and 505 fecal samples and 475 blood samples were collected. The infection rate of B. hominis was 4.16% (21/505) in the HIV/AIDS individuals, 4.22% (18/427) in the males and 3.85% (3/78) in the females, with no significant difference between males and females (P > 0.05). The infection rates in the HIV/AIDS populations from Methadone outpatient clinics of the Center for Disease Control, municipal infectious disease hospitals, and prison hospitals were 3.74% (4/107), 1.62% (5/308) and 13.33% (12/90), respectively. The infection rate in those from prison hospitals was significantly higher than the other two (P < 0.05). The infection rates in the HIV/AIDS populations with CD4 ⁺ T cell count > 400/μl and ≤ 400/μl were 3.29% (5/152) and 4.64% (15/323), respectively (P > 0.05). Sequencing results revealed prevalence of subtypes ST1 (4.76%, 1/21), ST3 (90.48%, 19/21), and ST7 (4.76%, 1/21) in Nanchang City. Conclusion There is high prevalence of B. hominis in HIV/AIDS cases from prison hospitals in Nanchang, and ST3 is the predominant subtype.

Analysis of clinical features of echinococcosis cases

ZHU Ling-hong, ZHU Lu-min, WANG Bo, YANG Zhi-yong, ZHANG Jing-ni, JI Li, CAI Qi-gang, HAN Xiu-min

2021, 39(1):  61-68.  doi:10.12140/j.issn.1000-7423.2021.01.009

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Objective To analyze the clinical features and treatment of echinococcosis inpatients in Qinghai Province, in order to provide scientific basis for improvement of diagnosis and treatment of echinococcosis. Methods Demographic and clinical information of 949 echinococcosis inpatients in Qinghai Provincial People’s Hospital during January 2016 and June 2019 were collected and entered in database in duplicates by using the EpiData software 3.02. Univariate analysis was performed for the two types of echinococcosis, using hydatid disease as the dependent variable. Logistic regression model was constructed based on the univariate analysis results, in order to analyze factors influencing the treatment outcome of echinococcosis. Data were analyzed with the SPSS 17.0 software. Results Clinical information of 949 echinococcosis cases was collected, including 756 cystic echinococcosis (CE) cases comprising 350 males and 406 females, and 193 alveolar echinococcosis (AE) cases comprising 90 males and 103 females. There were 524 Tibetan CE cases and 141 Tibetan AE cases. The cases were mainly distributed in farmers and herdsmen, including 604 CE cases and 157 AE cases. Most of the cases were illiterate, including 596 CE cases and 147 AE cases. CE cases were mainly distributed in Yushu Prefecture (209 cases) and AE mainly in Guoluo Prefecture (93 cases). In addition, 548 CE cases and 141 AE cases had clinical symptoms of abdominal discomfort, while 663 CE cases and 142 AE cases had Child-Pugh stage A of liver functions. Ultrasound imaging classification revealed 227 cases of the CE2 type and 302 cases of the CE4 type, and the predominance of AE1 type among the AE cases. Moreover, 19.8% CE cases and 19.2% AE cases had complications; 409 CE cases and 83 AE cases received surgery. The univariate analysis of CE showed that gender, age, cyst size, ultrasonic image classification, the occurrence of complications and prognosis of surgery (P < 0.01) were different between groups. The univariate analysis of AE showed that the Child-Pugh score (P < 0.05) and prognosis of surgery (P < 0.01) were different between groups. Logistic regression results showed that the main factors influencing the cure of CE were gender (P < 0.05), cyst size (P < 0.05) and whether or not receiving surgery (P < 0.01), while surgery (P < 0.01) was the main factor influencing the cure of AE. Conclusion The clinical data of the two types of echinococosis in Qinghai Province suggest that surgery is an effective way to improve the cure rate of AE and CE.

Infection status of clonorchiasis sinensis and the knowledge, attitudes and practices towards the disease among human population in Xinfeng County of Jiangxi Province in 2016 and 2018

CHEN Zhe, YUAN Chang-hong, JIANG Wei-sheng, YANG Yu-hua, LAN Ming-xing, LIU Ke-xing, ZENG Xiao-jun, ZHU Hui-hui

2021, 39(1):  69-75.  doi:10.12140/j.issn.1000-7423.2021.01.010

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Objective To evaluate assess changes in knowledge, attitude, practice (KAP) towards clonorchiasis and the status of human infection three years after the establishment of a demonstration area for clonorchiasis control in Xinfeng County. Methods In 2016 and 2018, 150 permanent residents aged 3 years or above were cluster sampled in each of the 26 administrative villages in the demonstration area, for fecal examination and questionnaire survey. The questionnaires survey was applied to understand the changes of knowledge, behavior and attitude toward clonorchiasis control among participants. The fecal examination was conducted using the modified Kato-Katz thick smear method (two slide-reading/one sample) to assess the status of Clonorchis siensis infection. The participants in the two-year suvey were included in the analysis, and the comparisons between groups were made with the Chi-square test. Results A total of 1 108 residents participated in the two surveys in 2016 and 2018. The infection rate of Clonorchis sinensis dropped from 22.5% (249/1 108) in 2016 to 9.7% (107/1 108) in 2018 (P < 0.01). The infection rate in males (31.9%, 171/536; 13.6%, 73/536) was higher than that in females (13.6%, 78/572; 5.9%, 34/572) in the two years (P < 0.01). The questionnaire analysis revealed that the awareness rate on the knowledge of clonorchiasis control increased significantly from 4.3% (48/1 108) in 2016 to 25.0% (277/1 108)in 2018 (P < 0.01). The infection rate was higher in the awareness group (35.4%, 17/48; 10.1%, 28/277) than that in the unawareness group (21.9%, 232/1 060; 9.5%,79/831) in both years (P₂₀₁₆ < 0.01, P₂₀₁₈ > 0.05). In 2018, 77.9% (141/181) of raw-fish consumers would refuse to eat raw fish again, and 99.7% (1 105/1 108) would be willing to receive treatment after infection, which was higher than 28.9% (68/235) and 95.6% (1 059/1 108) in 2016 respectively (P < 0.01). The proportion of residents eating raw fish decreased from 21.2% (235/1 108) in 2016 to 16.3% (181/1 108) in 2018 (P < 0.01), and the infection rate in those eating raw fish (61.3%, 144/235; 43.1%, 78/181) was significantly higher than that in those not eating raw fish in both years(12.0%, 105/873; 3.1%, 29/927)(P < 0.01). The deworming coverage increased from 69.9% (174/249) in 2016 to 89.7% (96/107) in 2018 (P < 0.01). The percentage of residents who were unaware of clonorchiasis in both years was 73.2% (811/1 108), and the proportion of residents eating raw fish in both years was 10.3% (114/1 108). Conclusion With the implementation of control measures in the demonstration area, there has been a decrease in the Clonorchis infection rate and increases in the awareness rate of knowledge on clonorchiasis control, as well as the proportions of people showing willingness to give up eating raw fish and to receive treatment after being infected. The proportion of behavior of eating raw fish and the average infection rate were significantly decreased. These findings suggest remarkable achievements in clonorchiasis control.

Consensus on Chinese terminology in the clinical field of echinococcosis

TUERHONGJIANG Tuxun, SHAO Ying-mei, TUERGANAILI Aji, WEN Hao

2021, 39(1):  76-84.  doi:10.12140/j.issn.1000-7423.2021.01.011

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The research field of echinococcosis involves nearly disciplines, and thus it is of vital importance to use standard terminology in different specialist fields. To standardize the related terminology, the World Association of Echinococcosis has launched a Formal Consensus process on terminology to ensure both language refinement and scientific rigorousness. The international consensus on terminology to be used in the field of echinococcosis was finally published in Parasite in 2020. International experts from different countries and regions in various fields of echinococcosis participated in the drafting of the consensus. As a reference center of the World Health Organization Echinococcosis Prevention and Management in China and host institution of Chinese Medical Doctor Association Surgery Branch Specialized Committee for Echinococcosis, we participated in the drafting process of the international consensus, and herein share the related Chinese terminology in clinical practice of echinococcosis with domestic experts. The related terminology covers all aspects of clinical practice for echinococcosis and represents the first successful attempt for standardization of science and medical terminology for parasitic diseases, especially for echinococcosis.

Applications of Qinghai provincial information management platform for echinococcosis control and monitoring

MA Jun-ying, WANGN Hu, ZHANG Xue-fei, DING Hai-yuan, LEI Wen, MA Xiao, CAI Hui-xia, WANGN Wei, ZHANG Qing, ZHANG Xiong-ying, LIU Jia, ZHAN Pei-zhen, ZHANG Jing-xiao, LIU Yu-fang, LIU Na, ZHAO Cun-zhe, SHI Ke-mei, LIU Pei-yun, GUO Shuai, SI Xiao-mei

2021, 39(1):  85-88.  doi:10.12140/j.issn.1000-7423.2021.01.012

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There are many links in the prevention and treatment of echinococcosis, establishment of province-based information management platform for control of echinococcosis is an important issue in recent years of high prevalence areas to provide effective data support, changing the lagged situation through offline practice, and achieving precise control. In this article, we introduce the main structure, major functions and characteristics of Qinghai provincial information management platform for echinococcosis control. The systemic development of Qinghai provincial platform has enabled achieving information-based and process-manageable control, which facilitates the integrated management, analysis, display and utilization of various multi-source heterogeneous data related to echinococcosis, and provides an effective decision-making basis for the prevention and treatment of echinococcosis in Qinghai Province.

The design and interpretation of sampling for the national survey on important parasitic diseases in 2014—2015 in China

QIAN Men-bao, CHEN Ying-dan, ZHU Hui-hui, LIU Heng-hui, ZHOU Chang-hai, ZHU Ting-jun, XU Long-qi, LI Shi-zhu, ZHOU Xiao-nong

2021, 39(1):  88-92.  doi:10.12140/j.issn.1000-7423.2021.01.013

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A national survey on important parasitic diseases was implemented in China between 2014 and 2015. This survey covered all the 31 provinces (autonomous regions, municipalities) in the mainland of China, using the multiple-stage stratified cluster sampling strategy. This survey was carried out in two types of area, the rural and the urban areas. The sampling in rural areas was based on the prevalence of soil-transmitted nematodiasis, using stratifying factors of province, ecological region and economy. The sampling in urban areas was based on the prevalence of clonorchiasis, which lead to categorize into five types of region at the national level, among them, four highly endemic provinces applied the sampling according to the local clonorchiasis prevalence. The sampling design in this national survey fully took into account the differences in parasitic diseases and populations to maximize the representation of samples.

Assessment and analysis of malaria diagnostic capacity by microscopy at primary health institutions in Chongqing

LUO Fei, TAN Yan, ZHOU Shuang, YUAN Yi, LI Shan-shan, XU Jing-ru, ZHOU Yang

2021, 39(1):  93-99.  doi:10.12140/j.issn.1000-7423.2021.01.014

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To evaluate the diagnostic capacity of malaria by microscopy at primary medical and health institutions in Chongqing, four technicians for malaria diagnosis by microscopy were randomly selected from each of the 39 districts (counties) in Chongqing from March 2014 to December 2017 for assessment of their diagnostic capability. The test results underwent descriptive statistical analysis, correlation analysis, spatial autocorrelation analysis and ROC curve analysis. The average score of the 156 microscopy technicians was 4.33 ± 0.47, and among them the number of technicians who made one slide error on species determination was found the highest (75, 48.1%). The microscopic sensitivity was highest in qualitative diagnosis (98.9%), and lowest (15.9%) for Plasmodium ovale; the specificity was highest in the diagnosis of P. ovale (96.2%), and lowest for P. vivax (77.2%). The Youden index of different species was highest for P. falciparum (0.682 6), and lowest for P. ovale (0.121 4). The assessment score was positively correlated with the level of institutions technicians worked in (R = 0.21, P < 0.01), and negatively correlated with age (R = -0.31, P < 0.01). The average score was highest in Shapingba District and Wuxi County (4.88 points for each). The scores of the districts and counties showed a pattern of spatial aggregation (P < 0.01). The score was highest in the main urban area (4.51), and lowest in the central part of Yuzhong (4.08). There was a statistically significant difference in the score among geographical areas (P < 0.05). The areas under the ROC curve for species determination for P. falciparum, P. vivax and P. ovale was 0.97, 0.84, 0.78 and 0.56, respectively. The comparison of ROC curves showed that the efficiency of microscopic diagnosis of P. falciparum was significantly higher than those of other species (P < 0.01), and the efficiency of diagnosis of P. ovale was significantly lower than those of other species (P < 0.01). The results suggested that the technicians of microscopy at primary health institutions in Chongqing Municipality had good performance in qualitative diagnosis, but did not do well in Plasmodium species identification. The malaria diagnostic capacity of microscopy at town-level health institutions in the central areas of Chongqing was weaker than those in other areas.

REVIEWS

Application of spatial epidemiology in research on the transmission risk of parasitic diseases

GONG Yan-feng, ZHENG Jin-xin, HU Xiao-kang, XIA Shang, LI Shi-zhu

2021, 39(1):  101-106.  doi:10.12140/j.issn.1000-7423.2021.01.015

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Spatial epidemiology is a discipline that studies the spatial distribution of diseases in human population and the influencing factors, including disease mapping, clustering analysis and related factor analysis. With the development of modern spatial technology, spatial epidemiology has been widely used in the visual analysis, hotspot analysis, identification of risk factors and prediction of transmission risk of parasitic diseases. This paper mainly introduces the spatial distribution pattern, spatial interpolation and spatial modeling algorithms used in the research of transmission risk of parasitic diseases.

Research progress on host cell immunity in Fasciola hepatica infection

ZHANG Bao-yue, SONG Zheng-yi

2021, 39(1):  107-112.  doi:10.12140/j.issn.1000-7423.2021.01.016

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Fascioliasis hepatica is a devastating zoonotic disease. Fasciola hepatica mainly infects ruminants and mammals including humans. Fascioliasis hepatica has become a public health problem that poses severe threats to human health and economic development. Currently, the treatment of fascioliasis hepatica is challenged by limited medication choice and unsatisfactory curative effect. Extensive studies have shown that F. hepatica infection is regulated by the immune response of the host. In this review, we summarize the pathogenesis of fascioliasis hepatica, several cellular immune responses induced by F. hepatica and related research progress, in order to provide information for the clinical treatment of fascioliasis hepatica.

Research progress on immune regulation of medical protozoa-related proteins

LIU Bing, WANG Qi, HE Yong-jun, HE Ping

2021, 39(1):  112-119.  doi:10.12140/j.issn.1000-7423.2021.01.017

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Protozoan, a type of single-celled eukaryotes with simple structure, is widely distributed in natural world. Medical protozoa can parasitize humans in body fluid, tissues and cells, and regulate host immune response, escaping from attack of the host immune system, and enabling survival and proliferation in the host and causing the occurrence of disease. In this paper, we summarize the immunomodulatory effects of proteins associated with Plasmodium, Toxoplasma gondii, Leishmania donovani and Giardia lamblia, in order to provide information for the prevention and treatment of medical protozoa-related parasitic diseases.

SHORT COMMUNICATIONS

Proteome-based identification and bioinformatics analysis of protein phosphatases of Toxoplasma gondii

HE Cheng, PAN Shuai, XU Mei-zhen, YUAN Fei, HE Jing-mei, LIU Zhuan-zhuan

2021, 39(1):  120-124.  doi:10.12140/j.issn.1000-7423.2021.01.018

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The proteomic amino acids of Toxoplasma gondii strains GT1, ME49 and VEG, Plasmodium, and 44 other eukaryote species were downloaded from related databases. The amino acid sequences of various T. gondii strains and other species were searched using the HMMER3 software to identify the phosphatases of. T. gondii and other species. Cluster analysis was performed for all of the identified phosphatases to extract the conserved amino acid sequences of phosphatases, and phylogenetic trees were constructed with the neighbor-joining method and maximum likelihood method, respectively. Meanwhile, the catalytic domains of these identified phosphatases were annotated using the Pfam online tool, and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. Gene array data were used to analyze and compare the transcription levels of protein phosphatases in different strains and at different developmental stages of ME49 strain. Results showed that 64 phosphatases were identified, which were classified into 5 subfamilies: phosphoprotein phosphatase (PPP) family (11 proteins), protein tyrosine phosphatase-like A (PTPLA) family (1 protein), ASP-dependent tyrosine phosphatase (APP) family (8 proteins), dual-specificity phosphatase (DSP) family (9 proteins) and Mg ²⁺ or Mn ²⁺-dependent protein phosphatase (PPM) family (35 proteins). The bioinformatics analysis revealed that the identified phosphatases mainly possessed phosphatase activity, hydrolase activity and catalytic activity, and participated in the regulation of dephosphorylation. The phylogenetic analysis suggested that the phosphatases were conserved among the T. gondii strains. In addition, similar protein phosphatase expression profiles were found at the tachyzoite stage of different T. gondii strains. The most significant difference was found in TG_312200 among different stains. Its expression in ME49 was 4 times as that in the GT1 strain and VEG strains. However, the transcription levels of some phosphatases varied significantly among various developmental stages of the ME49 strain. For example, TG_318660 transcription was at a low level in unsporulated oocysts while TG_304955 transcription was at a high level in both tachyzoites and bradyzoites. These results suggested that these differentially expressed phosphatases may play essential roles in the development of T. gondii.

Investigation and analysis on the prevalence of Clonorchis sinensis infection in Guizhou Province in 2015

LI An-mei, HUANG Yu-ting, YAO Dan-cheng, ZHU Ai-ya, LI Yang, SHI Wei-fang, DAI Jia-rui, GENG Yan, SHE Dan-ya, ZHANG Nian-heng

2021, 39(1):  125-128.  doi:10.12140/j.issn.1000-7423.2021.01.019

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To investigate the status of Clonorchis sinensis infection in Guizhou Province, a survey was carried out according to the National Survey Program for Human Key Parasitic Diseases. A total of 30 villages and 5 towns were selected as the survey sites from 16 counties (cities and districts) in the Province using the stratified cluster random sampling method, with no less than 250 people in each site being examined. The fecal samples were examined by the modified Kato-Kats method (two-slide reading/one sample). The eggs of C. sinensis and other important parasites in the fecal samples were examined and counted under microscopy. General information of the participants was collected. A total of 8 838 people were investigated, of them 37 were found with C. sinensis infection, showing a infection rate of 0.42% (37/8 838), and all of them had mild infection. The infection rate in males and females was 0.50% (22/4 375) and 0.34% (15/4 463), respectively. Thirty-six cases were distributed in the Qiandongnan prefecture, and one case in the Liupanshui City, with a significant regional difference (P < 0.01). The infection rate was 0.04% (3/7 572) among 7 572 people in rural areas, and 2.69% (34/1 266) among 1 266 people in urban areas, indicating a significant difference between them (P < 0.01). In the Qiandongnan prefecture, the infection rate in Rongjiang County (township) was 11.90% (30/252), which was significantly higher than that of Kaili City (urban area) (1.60%, 4/250) (P < 0.01). Only one out of 37 cases of C. sinensis infection also had Ascaris lumbricoides infection. The age group of 11-20 years had the highest infection rate (0.97%) among age groups, the education group of high school and college level had the highest infection rate (3.14%) among education groups, and the occupation group of workers and officials had the highest infection rate (2.36%) among occupation groups (P < 0.01). Qiandongnan prefecture is still the key epidemic area of C. sinensis infection in Guizhou Province. It is necessary to expand the survey sites in towns to further understand the prevalence of C. sinensis infection.

Analysis on laboratory diagnosis efficacy and reexamination of the results for imported malaria cases in Tai’an City of Shandong Province during 2015—2019

ZHANG Xin-feng, LIU Yun-qiang, ZHANG Zhi-jun, XU Yan, LI Jin, ZHANG Ben-guang

2021, 39(1):  129-132.  doi:10.12140/j.issn.1000-7423.2021.01.020

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The imported malaria cases in Tai’an City, Shandong Province, during 2015—2019 were diagnosed and the results rechecked at Province-, city-, and county-based laboratories using microscopy, nested-PCR, and colloidal gold methods, respectively. A total of 122 imported malaria cases were diagnosed and the results rechecked by the city laboratory. Rechecking the results, the provincial malaria diagnosis reference laboratory confirmed 122 cases positive, among them, the coincidence rate by microscopy, colloidal gold and PCR methods was 94.3% (115/122), 95.9% (117/122), and 100%, respectively; 7 cases of microscopy negative were falciparum malaria; while of 5 cases of colloidal gold method negative, 2 cases were falciparum, and 3 non-falciparum. There was a significant difference in the coincidence rate among the three examination methods (P < 0.05). In addition, there was a significant difference in the coincidence rate of laboratory diagnosis for four plasmodium species (P < 0.01), among them, the diagnosis coincidence rate for Plasmodium falciparum and P. vivax was highest (100%), whereas the lowest coincidence was seen in P. ovale (12/18). The pass rate of diagnosis at the first visit in medical institutions was 94.3% (115/122), and the pass rate of rechecking at city-level and county-level centers for disease control (CDC) were 97.5% (119/122) and 95.1% (116/122), respectively (P > 0.05). It is necessary to further strengthen skill training for laboratory microscopy examiners and actively carry out malaria nucleic acid testing, in order to improve the performance level of diagnosis in medical institutions and CDCs.