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    30 April 2023, Volume 41 Issue 2
    EXPERT VIEWPOINT
    Research advances of the immune regulation of helminths and their derived molecules on mite-induced asthma
    LI Wenjie, FENG Meng, CHENG Xunjia
    2023, 41(2):  131-136.  doi:10.12140/j.issn.1000-7423.2023.02.001
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    With the improvement of living hygiene, the helminth infection rate has declined, and people have entered the post-parasite stage. But at the same time, the incidence rate of mite-induced asthma is increasing, which has caused a significant social and economic burden. Increasing evidence showed a correlation between helminth infection and allergy. This article reviews the regulation of helminth and their derived molecules on the occurrence and development of mite-induced asthma, including the direct regulation of antigen-presenting cells, humoral immunity, cellular immunity, release and action of cytokines, and the indirect regulation by regulating intestinal microflora, providing new ideas and directions for the treatment of mites-induced asthma.

    SPECIAL REPORTS
    Epidemiological characteristics of malaria in China, 2022
    ZHANG Li, YI Boyu, YIN Jianhai, XIA Zhigui
    2023, 41(2):  137-141.  doi:10.12140/j.issn.1000-7423.2023.02.002
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    Malaria epidemiological data in 31 provinces/municipalities/autonomous regions (excluding Taiwan region, Hong Kong SAR and Macao SAR) of China in 2022 were collected from the Information System for Parasitic Diseases Prevention and Control. The epidemiological characteristic of malaria cases was analyzed. In 2022, a total of 845 malaria cases were reported in China, which is increased by 5.8% compared to that in 2021 (799 cases). Of all these cases, 844 were imported cases and 1 was local recurrent case infected with Plasmodium malariae with along incubation period. In addition, 820 cases were of Chinese nationality (97.0%, 820/845) and 25 cases were of foreign nationality (3.0%, 25/845). Most of the cases were within the age range of 50-59 years (29.5%, 249/845), with a male-to-female ratio of 17.0:1. The reported cases included 494 cases of P. falciparum infection (58.8%, 494/845), 204 cases of P. vivax infection (24.1%, 204/845), 108 cases of P. ovale infection (12.8%, 108/845), 31 cases of P. malariae infection (3.7%, 31/845), and 8 cases of mixed-infection (0.9%, 8/845). The cases were reported from 26 provinces/municipalities/autonomous regions, with the top 5 provinces including Guangdong (182 cases), Yunnan (136 cases), Sichuan (72 cases), Zhejiang (64 cases) and Henan (59 cases), from which 513 cases (60.7%, 513/845) were reported. A total of 36 severe malaria cases (4.3%, 36/845) and 6 deaths (0.7%, 6/845) were reported. Although there has been no report of indigenous malaria cases in China for six consecutive years, there is still a risk of cluster outbreak of imported malaria and reemerging. After malaria elimination, malaria surveillance and response should be further strengthened, and malaria cases should be detected timely with accurate, diagnosis and standard treatment, so as to reduce the severe cases and deaths and finally prevent the reemerging of malaria transmission.

    Progress of echinococcosis control in China, 2021
    KUI Yan, XUE Chuizhao, WANG Xu, LIU Baixue, WANG Ying, WANG Liying, YANG Shijie, HAN Shuai, WU Weiping, XIAO Ning
    2023, 41(2):  142-148.  doi:10.12140/j.issn.1000-7423.2023.02.003
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    In order to understand the work progress in nationwide control of echinococcosis, data related to echinococcosis prevention and control in 2021 were collected and analyzed. As of the end of 2021, echinococcosis was found endemic in 370 counties (city, district, banner) covering 30 421 endemic villages in China. There were 47 584 117 permanent residents living in endemic townships. In 2021, 26 773 echinococcosis cases were documented in endemic counties (cities, districts, banners), with an average prevalence 0.06% (26 773/47 584 117), among them, 16 625 cases were of cystic, and 8 327 cases alveolar echinococcosis, 311 cases mixed infection, 1 510 cases unclassified. A total of 1 346 cases were newly diagnosed in 2021, including 1 075 cases of cystic echinococcosis, 86 cases of alveolar echinococcosis, 7 cases of mixed infection, and 178 cases of unclassified. In 2021, population screening by abdominal ultrasound scanning was performed in all endemic provinces (autonomous regions) for 4.471 7 million person/times, of them, 0.871 5 million person/examinations were for people under age of 12, 3.600 2 million person/times for permanent residents aged ≥ 12; serological examination was carried out for 11 358 person/times. Recorded from 370 surveillance sites in 2021, positive rate of ultrasound detection in people under age of 12 was 0.02% (72/336 959), of which 58.33% (42/72) were newly diagnosed. The positive rate of ultrasound imaging in permanent residents aged ≥ 12 was 0.26% (922/355 006) in type Ⅰ, Ⅱ endemic counties (city, district, banner), and the newly diagnosed patients accounted for 10.52% (97/922) of the detected patients. In 2021, 19 552 people received drug treatment, 14 440 people received liver and kidney function tests or treatment of adverse reactions. A total of 1 792 patients received surgical treatment, among them cystic echinococcosis accounted for 71.15% (1 275/1 792) and alveolar echinococcosis accounted for 23.66% (424/1 792). In 2021, the follow-up results showed that 3 063 cases were cured, 22 660 cases responded to the treatment, 2 356 cases failed in the treatment, 359 cases died (the cause of death was not echinococcosis), 285 cases were excluded, 301 cases were lost in follow-up, 312 cases had not completed the follow-up, and 146 cases migrated to other places. In 2021, there were 2 626 679 dogs in endemic townships (towns) nationwide, of which 2 389 828 were registered and documented. In 35 019 villages, deworming was conducted for dogs, with 25 844 226 deworming for domestic dogs and 131 315 deworming drug sites were distributed for wild canines. A total of 555 688 fecal samples from domestic dogs were collected and tested, of which 2 614 were found Echinococcus coproantigen positive, with a positive rate of 0.47% (2 614/555 688). Of wild canidae, 54 266 field fecal samples were collected and tested, among which, 422 were found Echinococcus coproantigent positive, with a positive rate of 0.78%. A total of 222 844 slaughtered livestock were randomly examined, among which 1 408 were positive, with a positive rate of 0.63% (1 408/222 844); and 56 124 field rodents were examined, of which 599 were found positive, with a positive rate of 1.07% (599/56 124). The epidemic state of echinococcosis has been basically controlled, but there are still many difficulties and challenges in the control and prevention. It is noted that there may be flaws in the control of the source of infection in some endemic areas, and it is likely that there might exist transmission chain in wild environment. It is imperative to continuously advance the comprehensive intervention areas as gripper to explore and optimize the control strategy, enhance the capacity of primary disease control institutions for control of echinococcosis, carry out pilot trial for controlling echinococcosis transmission in wild field, strengthen the surveillance-early warning system to further curb the epidemic of echinococcosis.

    ORIGINAL ARTICLES
    Prevalence of visceral leishmaniasis in China in 2021
    ZHOU Zhengbin, PAN Gaiqin, LI Yuanyuan, LIU Qin, YANG Limin, LI Zhongqiu, MA Zhitao, ZHANG Yi, LI Shizhu
    2023, 41(2):  149-155.  doi:10.12140/j.issn.1000-7423.2023.02.004
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    Objective To analyze the epidemic situation of visceral leishmaniasis in China in 2021 and to provide the scientific basis for formulating the prevention and control strategies. Methods Data on visceral leishmaniasis in 2021 was collected from the web-based National Diseases Reporting Information System. After excluding suspected cases, duplicates and cutaneous leishmaniasis cases, a database was established, based on which the distribution of visceral leishmaniasis was analyzed using descriptive epidemiological method with Microsoft Excel version 2016. Results A total of 230 cases of visceral leishmaniasis were reported in 14 provinces (autonomous regions and municipalities) in 2021, among them 180 cases were reported from mountain-type zoonotic visceral leishmaniasis endemic areas, 4 cases from desert-type zoonotic visceral leishmaniasis endemic areas, 1 case from anthroponotic visceral leishmaniasis endemic areas, and 45 cases were imported from non-endemic areas. These cases were mainly distributed in Shanxi (127 cases), Shaanxi (35 cases) and Gansu (20 cases), the total reported accounting for 79.1%(182/230) of the overall total in China. A total of 185 local transmitted cases were reported from 44 endemic counties; other 37 counties were of non-endemic areas, reporting 45 imported cases. The Pingding County, outer suburbs of Yangquan City, mining district of Yangquan City, Hancheng City, and Xiangfen County were the major endemic counties, with 33, 29, 18, 11 and 10 cases reported, respectively, the total accounting for 43.9% (101/230) of the overall total cases in China. In 2021, recurrence endemic counties of visceral leishmaniasis were mainly concentrated in Gansu Province (Qinzhou District, Xihe County), Shanxi Province (Yaodu District, Heshun County, Lingchuan County, Qin County, Tunliu District, Xiyang County) and Henan Province (Xin’an County, Xinmi City), with a total of 10 local cases reported. Yumen City in Gansu Province was the newly emerging endemic county with 1 local case reported. The peak incidence occurred in April. The ratio of male to female cases was 1:0.4. The number of reported cases in peasants and infants accounted for 47.4% (109/230) and 24.8% (57/230) of the total cases, respectively. The reported cases at age of ≥ 15 accounted for 73.5% (169/230). Conclusion Visceral leishmaniasis presents a low prevalence in China, whereas, the range of endemic area is gradually expanding. Thus, surveillance and control activities should be strengthened.
    Effect of intraperitoneal inoculation with Echinococcus microcysts on the infection and pathogenicity of E. multilocularis in mouse liver
    GUO Gang, REN Yuan, JIAO Hongjie, WU Juan, GUO Baoping, QI Wenjing, LI Jun, ZHANG Wenbao
    2023, 41(2):  156-162.  doi:10.12140/j.issn.1000-7423.2023.02.005
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    Objective To investigate the effect of intraperitoneal inoculation of Echinococcus granulosus (Eg) or E. multilocularis (Em) micorcysts on hepatic infection and pathogenesis of Em in mice liver. Methods The protoscoleces (PSCs) of Eg and Em were collected and cultured in vitro for 6 and 8 weeks to encyst, respectively. Sixty C57 female mice were randomly assigned to 4 groups, which were Em/Em infection, Em/Eg infection, pure Em infection and sham surgery groups, with 15 mice in each group. The mice of designated infection groups were intraperitoneally injected with 50 Em microcysts (diluted in 1 ml 1 × PBS), the mice in the Eg/Em infection group were intraperitoneally inoculated with 50 Eg microcysts, and 1 ml of normal saline, respectively. After 1 month, the mice in all three groups underwent laparotomy and were injected with 2 000 Em PSCs (200 µl) through hepatic portal vein (HPV). The mice in the sham operation group were injected with the same amount of normal saline into HPV in abdominal cavity. Mice blood was collected from the tail vein before intraperitoneal inoculation and at 1, 3 and 6 months after inoculation. In the collected blood samples, serum antibodies against hydatid cyst fluid antigen were detected by ELISA. At 1, 3 and 6 months after HPV infection, 5 mice in each group were dissected to inspect the liver lesions of infection with naked eyes and conduct quantitative scoring. The big lobe of liver was collected from mice to prepare paraffin section, and stain with HE to observe the changes in liver lesion tissue. SPSS 21.0 was used for statistical analysis, and an independent sample t-test was used to compare the mean between the two groups. Results The diameter of Eg microcysts cultured for 6 weeks in vitro is about 300 to 500 µm, and the diameter of Em microcysts cultured for 8 weeks is about 150 to 300 µm. ELISA results showed that after 1, 3, and 6 months of intraperitoneal infection with echinococcus microcapsules, the levels of anti-cyst fluid protein antibodies (A405 values) in the serum of mice infected with Em/Em and Eg/Em elevated and maintained at high level. One month after intraperitoneal inoculation of microcysts, the serum anti cyst fluid protein antibody levels (A405 values) in mice infected with Em/Em and Eg/Em groups were 2.77 ± 0.62 and 2.35 ± 0.23, respectively, which were more than 10 times higher than 0.15 ± 0.02 in the sham operation group. After 1, 3, and 6 months of HPV infection, the autopsy was performed. Eg cysts were seen in the abdominal cavity of the Eg/Em infected group, while no cysts were seen in the Em/Em group, the Em liver infected group and the sham group. Liver infection at different stages was the most severe in the Em liver infection group, where the liver surface was mostly covered with punctate or vesicular lesions of varying sizes. In the Eg/Em infection group, the infected lesions were weak or normal, and there were 1-3 small lesions on the liver surface that tend to become normal as the infection cycle extends. No infectious lesions were found in the Em/Em group and the sham group at different stages. The results of the lesion severity score showed that the scores of each stage in the group with Em liver infection (4.8 ± 1.3, 5.0 ± 1.5, 4.5 ± 1.4) were higher than those in the group with Eg/Em infection (1.6 ± 0.9, 1.2 ± 1.1, 1.6 ± 0.9) (t = 4.92, 4.81, 5.24, all P < 0.01). The results of HE staining showed that 1 month after HPV infection with Em PSCs, there was a large number of inflammatory cells infiltrating the lesions in the Em liver infection group, mainly eosinophils; In the Eg/Em infected group, there was less infiltration of inflammatory cells in the lesion. At 3 months after infection, the inflammatory cells in the focus of the simple Em liver infection group decreased relative to the prophase, with neutrophils predominating, and a collagen fibre layer formed around the focus; In the Eg/Em infection group, the focus was mainly collagen fibre layer; At 6 months after infection, the lesions in both the Em liver infection group and the Eg/Em infection group showed a trend of recovery, mainly with connective tissue hyperplasia. Conclusion Em microcysts infection via abdominal cavity can completely block Em reinfection in mice liver, and Eg infection via abdominal cavity can suppress Em infection in mice liver to a greater extent.
    Comparative study on DNA barcoding of house oribatid mites based on the 18S and 28S ribosomal DNA gene
    CHEN Huilin, ZHU Yonghang, FAN Haiye, ZHAO Wei, LIU Luyao, CAO Yuxiang, YE Changjiang, SUN Entao
    2023, 41(2):  163-169.  doi:10.12140/j.issn.1000-7423.2023.02.006
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    Objective To compare the validity and applicability of 18S and 28S rDNA genes in species identification of house oribatid mites. Methods Oribatid mite were isolated from the dust samples collected from residential houses, farmhouses and warehouses in 9 citiess of Anhui Province (Bozhou, Fuyang, Huainan, Chuzhou, Hefei, Wuhu, Tongling, Anqing, Huangshan) from February 2021 to October 2021, and the mite species were identified morphologically. The genomic DNA was extracted from each individual oribatid mite, and the 18S rDNA, 28S rDNA D3 and D8 genes were obtained by PCR, and sequenced. The sequences of house oribatid mites genes were downloaded from GenBank. The sequence feature analysis and genetic distance calculation were carried out based on MEGA X software, and the DNA barcoding gap analysis was performed through ABGD website. The phylogenetic tree was created using neighbor joining method. Results A total of 53 mites were collected and morphologically identified of species, which belongs to three families, five genera and five species, particularly for Scheloribates laevigatus (15), Oribatula sakamorii (9), Oppiella nova (10), Ramusella clavipectinata (10), Neoamerioppia interrogate (9). The 18S rDNA, 28S rDNA D3 and D8 gene haplotypes were obtained from these five mite species with 7, 5 and 11 haplotypes, respectively. A total of 42 sequences of house oribatid mites were downloaded from GenBank. Sequence analysis showed that the lengths of 18S rDNA, 28S rDNA D3 and D8 genes were 442-590, 247-331 and 270-283 bp, respectively, with GC contents of 45.6%, 52.2% and 57.5%, and variation rates of 17.6%, 21.4% and 21.7%, respectively. The mean intraspecies genetic distances of 18S rDNA, 28S rDNA D3 and D8 gene were 0.001, 0.001 and 0.005, respectively. The mean interspecies genetic distances were 0.064, 0.115 and 0.109, respectively, with the mean interspecies genetic distances greater than the mean intra-species genetic distances (more than 10-fold). The results of DNA barcode gap analysis showed that there were overlapping regions between the intraspecific and interspecific genetic distances of 18S rDNA and 28S rDNA D3 gene sequences, and there was an significant DNA barcode gap in 28S rDNA D8 gene sequences. The phylogenetic tree showed that the taxonomic order clustering of house oribatid mite family are consistent with the morphological clustering results, but Hypochthonius luteus and H. rufulus showed clustering together in the 18S rDNA gene systematic evolution tree and could not be separated. The 28S rDNA D3 gene systematic evolution tree showed cross-class clustering. Conclusion 18S rDNA and 28S rDNA D3 and D8 genes can be effectively used for species identification of house oribatid mites, of them, 28S rDNA D8 gene is suitable for the species identification of low-classification taxa, while 18S rDNA and 28S rDNA D3 genes are suitable for the species of high-classification taxa.
    Current status of the primary surveillance and response system during the post malaria elimination phase in Fujian Province
    CHEN Zhuyun, OUYANG Rong, XIAO Lizhen, LIN Yaoying, XIE Hanguo, ZHANG Shanying
    2023, 41(2):  170-175.  doi:10.12140/j.issn.1000-7423.2023.02.007
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    Objective To analyze the current status of primary surveillance and response system in Fujian Province after malaria elimination, and to provide the scientific basis for the formulation of malaria control and prevention measures. Methods In October 2020, a retrospective survey was carried out on the malaria control and prevention capability in 85 counties (cities and districts) during 2016—2020 in Fujian Province. The survey content included the funding for control, number of technical personnel, medicine back store, detection equipments, designated hospitals, clinical cases monitoring, transmission vector surveillance, and personnel training, combining with the annual malaria control reports in in post-elimination years, to analyze the current status of primary surveillance response system during the malaria post-elimination phase in the province based on the risk ranking of imported cases vs retransmission. SPSS 17.0 software was used for statistical analysis. The measurement data were analyzed using t-test or Wilcoxon rank sum test based on the homogeneity of variance, and the counting data were analyzed using chi-square test. Results A total of 92 280 blood samples were tested in the province from 2016 to 2020, among 505 were positive (0.55%), defined as imported cases. The reported cases first visited primary medical institutions accounted for 23.37%(118/505), which increased year by year, with statistical significance (χ2 = 16.49, P < 0.05). But the initial diagnosis rate was 27.97% (33/118), which did not increase with the number of patients (χ2 = 2.50, P > 0.05). A total of 94.12% (80/85) of primary centers for Disease Control and Prevention had funding for malaria control and elimination in the previous three years (2018—2020), with an average of 9 700 yuan per county per year. The average annual funding in counties with higher risk of re-establishment of transmission by Plasmodium vivax was higher (13 500 yuan) than the counties with the potential risk (8 800 yuan). The difference was statistically significant (t = 2.16, P < 0.05). There were 20 primary CDCs (23.53%) without the capacity to detect malaria, which were due to the lack of microscopes or professionals, and 80% of them (16/20) had imported malaria cases in their service areas during the past three years. The percentage of CDCs with antimalarial drugs and rapid diagnostic test (RDT) in primary CDCs were 4.71% (4/85) and 8.24% (7/85), respectively. The percentage of CDCs with RDT in storage in counties with the risk of re-establishment of P. vivax transmission (4/17) were higher than those in counties with potential risk (4.41%, 3/68). The difference was statistically significant (χ2 = 4.29, P < 0.05). From 2016 to 2020, a total of 12 040 people were trained in 85 counties of the province. The number of trainings for control and prevention personnel and laboratory personnel showed a downward trend (from 1 509 and 656 in 2016 to 819 and 348 in 2020), while the number of training for clinicians showed an increase trend (from 404 in 2016 to 887 in 2020). From 2018 to 2020, at least one training was organized by 85.88% (73/85) of the counties, but training for village and individual doctors was only organized by 3.53% (3/85) and 2.35% (2/85) of the counties. In three years, the Anopheles mosquito population and density monitoring which were carried out by 29 primary CDCs (34.12%) and 20 CDCs (23.53%). And a total of 8 148 Anopheles were captured, all of which were An. sinensis, but no An. anthropophagus or An. minimus. During the population monitoring by lamp trap, 1.57 An. sinensis per lamp per night were captured in counties with the risk of re-establishment of transmission by P. vivax, which was lower than that in counties with potential risk (2.16 per lamp per night) (χ2 = 5.72, P < 0.05). Conclusion After the elimination of malaria in Fujian Province, the capacity of malaria diagnosis and surveillance of primary medical settings is weakening. It is imperative to optimize the surveillance scheme based on the risk ranking, provide stable funding and personnel training to enhance the primary surveillance-response capacity for consolidating the accomplishments of malaria elimination.
    Immunoproteomic analysis on the soluble antigens of Trichinella spiralis newborn larvae
    HAO Huinan, CHENG Yongkang, ZHANG Ru, HAN Lulu, SONG Yanyan, LONG Shaorong, LIU Ruodan, ZHANG Xi, WANG Zhongquan, CUI Jing
    2023, 41(2):  176-182.  doi:10.12140/j.issn.1000-7423.2023.02.008
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    Objective To identify the soluble antigens of Trichinella spiralis newborn larvae recognizable by the serum of mice infected with T. spiralis for screening candidate antigens of anti-newborn larvae vaccines. Methods The adult worms were collected from the intestine of T. spiralis-infected BALB/c mice and cultured to collect the newborn larvae, of which the soluble antigens were extracted for screening out the antigen band recognized by sera from T. spiralis-infected mice using Western blotting. The recognized antigen on the blotting band was identified by liquid chromatograph tandem mass spectrometer (LC-MS/MS), and aligned with data of T. spiralis in the Uniprot database. The physicochemical properties of identified proteins were analyzed using the bioinformatics online website. The InterProscan software was used to perform proteins sequences searches against InterPro member databases to identify signatures, and the matched terms were further subjected to gene ontology (GO) categorizing using WEGO online software. The worms at different developmental stages including muscle larvae, infectious intestinal larvae (6 h post-infection), adult worms (2 d post-infection) and newborn larvae were collected to extract total RNA,which was then reversely transcribed into cDNA. The relactive transcription levels of the C-type lectin (CTL), calreticulin (CRT), zinc finger protein (ZFP) and pyruvate kinase (PK) at four developmental stages were analyzed by qPCR using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene as the internal reference and compared with their transcription level at muscle larval stage using one-way ANOVA. Results Western blotting showed that among the 11 protein bands of the soluble antigens of newborn larvae, 4 bands [the relative molecular mass (Mr) were 99 700, 79 600, 68 900 and 46 000] were recognized by T. spiralis-infected mice sera. A total of 353 T. spiralis proteins were identified by LC-MS/MS, of which 166 proteins (47.0%) had Mr 40 000-70 000, 182 proteins (51.8%) had isoelectric point of 5-6, 31 proteins had signal peptides and 58 proteins had transmembrane domains. Out of the 353 proteins, 285 proteins had the GO annotations, of which 177 proteins (62.1%) had catalytic activity, 192 proteins (67.4%) had binding activity, 158 proteins (55.4%) were involved in the metabolic process and 149 proteins (52.3%) were involved in the cellular process. The qPCR results showed that compared to those at the muscle larvae stage, the relative transcript level of CTL at infectious intestinal larvae, adult worm and newborn larvae stages were 140.99%, 90.99% and 65.71%, respectively (F = 1 875.105, P ˂ 0.01); the CRT were 79.33%, 41.59% and 58.58%, respectively (F = 2 192.665, P ˂ 0.01); the ZFP were 64.93%, 105.36% and 126.74%, respectively (F = 475.836, P ˂ 0.01); the PK were 73.93%, 98.09% and 43.19%, respectively (F = 1 373.743, P ˂ 0.01). Conclusion A total of 353 soluble proteins of T. spiralis newborn larvae recognized by T. spiralis-infected mice sera were identified, and these proteins may involve in the processes of growth and development, immune evasion, and invasion of the host etc, and might be the candidate target molecules for anti-newborn larvae vaccines.
    A case-control study on the influencing factors of echinococcosis in Qinghai Province
    MA Bingcun, LIU Yuying, ZHANG Tiantian, LEI Wen, MA Xiao, LIU Shou
    2023, 41(2):  183-191.  doi:10.12140/j.issn.1000-7423.2023.02.009
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    Objective To study the main influencing factors to echinococcosis in Qinghai Province, to provide scientific basis for interventions. Methods A case-control study was conducted on the infection factors of adult echinococcosis cases in the significant endemic areas (Guoluo, Haibei, Hainan, Haixi, Huangnan and Yushu) and in the nonsignificant endemic areas (Haidong and Xining) of Qinghai Province. The study was carried out by setting the matching factors of age, sex and ethnicity, with the maching control ratio of patients against heathy people 1:2, defining whether or not the disease case as the dependent variable for univariate analysis using a logistic regression model constructed to analyze the factors influencing residents contracting echinococcosis. Statistical analysis was conducted using SPSS 22.0 statistical software. Results A total of 1 447 cases met the inclusion criteria was enrolled as the case group in this study, with a mean age of (38.7 ± 13.3) years, 58.3% male (844/1 447), 41.7% female (603/1 447), 65.2% Tibetan (944/1 447), 22.9% Han Chinese (332/1 447), 6.6% Hui (95/1 447); the control group consisted of 2 894 individuals with a mean age of (38.5 ± 13.0) years, 58.3% male (1 688/2 894), 41.7% female (1 206/2 894), 60.5% Tibetan (1 751/2 894), 26.4% Han (763/2 894), and 6.0% Hui (175/2 894). The results of univariate analysis showed that 25 factors, such as canine ownership, canine breeding method, canine use, frequent contact with drinking water, no disposal of canine feces, frequent contact with canine, and domestic animal ownership, were statistically significant between the case and control groups (χ2 = 143.53, 46.88, 40.26, 80.63, 38.77, 107.16, 117.27; P < 0.01). Multivariate logistic regression analysis showed that the type of canine ownership (OR = 1.37, 95%CI: 1.03-1.82), use of canines (OR = 1.59, 95% CI: 1.01-2.51), canine contacted with drinking water (OR = 1.63, 95% CI: 1.19-2.24), disposal of canine feces (OR = 2.51, 95% CI: 1.95-3.26), slaughter of livestock at home in the last year (OR = 1.44, 95% CI: 1.09-1.91), slaughterhouse or butcher shop around home (OR = 1.67, 95% CI: 1.21-2.26), canine fed with raw livestock organs (OR = 1.53, 95% CI: 1.18-2.03), drinking unboiled water (OR = 1.42, 95% CI: 1.05-1.91), living with wild animals around home (OR = 1.53, 95% CI: 1.19-1.95), drinking water storage method (OR = 1.88, 95% CI: 1.37-2.59), as well as prevention knowledge (OR = 1.75, 95% CI: 1.36-2.28) were the main risk factors for echinococcosis prevalence in adults. Conclusion This study indicates that the factors of dog-related behavior, hygienic habits, lifestyle and the wareness on knowledge of disease prevention and control are highly associated with echinococcosis in adults in Qinghai Province and are the key behavioural factors in echinococcosis intervention in Qinghai endemic areas.
    Surveillance of soil-transmitted nematode infections in Sichuan Province from 2016 to 2021
    LUO Jingwen, TIAN Hongchun, TIE Lei, ZHANG Liping, XIE Hong, GONG Xi, WU Xiaohong, DENG Xiu
    2023, 41(2):  192-197.  doi:10.12140/j.issn.1000-7423.2023.02.010
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    Objective To understand the current situation and trend of soil-transmitted nematode infection in Sichuan Province from 2016 to 2021, and to provide scientific basis for formulating the control strategies of soil-transmitted nematode disease. Methods From 2016 to 2021, 4 fixed and 136 mobile were set up in 140 counties (cities, districts) in Sichuan Province. The surveillance sites were assigned to five areas according to geographical location of east, west, south, north and central. One administrative village (community) of one township (town, street) was randomly selected from each geographical area, and no less than 200 permanent residents over age 3 in the survey year was cluster sampled from each administrative village. The fecal samples of participants were collected, and examined for intestinal nematode eggs using modified Kato thick smear method (two slide-reading each sample). χ2 test was used to compare the infection rate between groups. Results A total of 165 551 people were surveyed, and the overall infection rate was 7.02% (11 614/165 551). The infection rate in each year was 8.19% (2 946/35 985), 7.75% (2 675/34 520), 8.14% (1 654/20 316), 8.05% (2 518/31 292), 3.57% (937/26 264), 5.15% (884/17 174), respectively (χ2 = 415.370, P < 0.05). The infection rate of hookworm, ascaris and trichuris was 5.63% (9326/165 551), 1.04% (1730/165 551) and 0.60% (993/165 551), respectively. Among the five types of landform in Sichuan Province, the infection rate of soil-transmitted nematodes among people in hilly areas was the highest, being 9.42% (7 648/81 168); the infection rate in northwest Sichuan plateau is the lowest, which was 1.8% (205/11 406) (χ2=1 771.185, P < 0.05). The infection rates of soil-transmitted nematodes in males and females was 6.84% (5 389/78 777) and 7.17% (62 225/86 774), respectively (χ2 = 7.018, P < 0.05). Among different age groups, the infection rate of soil-transmitted nematodes in the 70-79 age group was the highest, which was 11.85% (2 319/19 569) (χ2=2 056.363, P < 0.05). Among people with different education levels, the infection rate of soil-transmitted nematodes in illiterate people was the highest at 10.04% (2 133/21 244)(χ2 = 994.429, P < 0.05). Among different occupational groups, the infection rate of soil nematode was the highest, which was 7.93%(9 921/125 079) in farmers(herdsmen and fishermen) (χ2 = 734.068, P < 0.05). Among different ethnic groups,the infection rate of soil-transmitted nematodes in the Yi ethnic group was the highest, which was 19.48% (890/4 569) (χ2 =1 638.694, P < 0.05). Conclusion From 2016 to 2021, the infection rate of soil-transmitted nematodes in Sichuan Province showed a downward trend, mainly hookworm infection. Hilly areas and mountainous areas in southwestern Sichuan had higher infection rate and are key areas to prevention and control. Women, older people, people with lower education level and Yi ethnic group had higher infection rate, and are the key groups to prevention and control populations.
    Excystment conditions and excysted metacercaria morphological observation of Fasciola hepatica
    FANG Wen, YANG Jing, WANG Haiying, CHEN Shaorong, LIU Yuhua, LI Tianmei
    2023, 41(2):  198-201.  doi:10.12140/j.issn.1000-7423.2023.02.011
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    Objective To observe the required conditions of excystment and morphology of metacercariae of Fasciola hepatica. Methods Eggs of F. hepatica from cattle were collected and placed in 28 ℃ water bath for 10 or 11 days to hatch miracidia, which were used to infect Galba pervia for 35-40 days for collection of metacercariae. The metacercariae were assigned to 3 groups with 30 in each group. The metacercariae were placed in bovine bile at 50%, 75% and 100% dilution, respectively. Each group of metacercariae was futher divided into 3 groups and placed in water baths at 37 ℃ and 39 ℃ to observe emerging excysted worms every 30 min for ascertaining the optimal excystment temperature. In addition, 15 experimental groups of metacercariae were set up with 10 in each group to examine the excyst condition. After treatment with artificial gastric juice for 10 min, 30 min, 1 h, 1.5 h and 2 h, the cysts were transferred into 50%, 75% and 100% bovine bile, respectively, and incubated at the optimal temperature for 6 h to observe the exeyt process by inspection every 30 min. The morphology of excysted worms were examined microscopically. For control group, distilled water, normal saline, artificial gastric juice and 50%, 75% and 100% bovine bile were used alone, respectively. For those metacercarae that has not excysted, incubation will be continued in water bath for 24 h upon observation. Results After incubation at 37 ℃ and 39 ℃ separately for 24 h, highest yield of excysted worms was seen at 39 ℃, with 9, 12 and 4 excysted cercariae observed in 50%, 75% and 100% bile, respectively. It was indicated that the optimal incubation temperature for excystment in bile was 39 ℃. The excysted cercariae were earliest seen after incubation in artificial gastric juice for 2 h coupling with 100% bile for 1 h. The highest number of excysted cercariae was found in artificial gastric juice incubation for 1 h coupling with 100% bile 6 h, yieling 8 excysted cercariae. No excyst was observed in the 6 control groups during the observation period, but dead excysted worms were seen after 24 h in different concentrations of bile. Under microscope, the excysted cercariae were shaped in long oval, similar to the cercariae body in morphology, which become the juvenile form of adult worm. The size of excysted cercariae was (228.0-361.0) μm × (114.0-209.0) μm, with an average of 291.0 μm × 163.9 μm, having clearly visible oral and ventral suckers; the intestinal duct is yellowish brown in color, extending from the oral sucker, pharynx and esophagus to two branches in coiled overlapping, being full of both sides of worm body through to the tail. Conclusion F. hepatica metacercariae are unable to excyst spontaneously, which requires gastrointestinal digestive fluid factors to co-activate. The body morphology and size of excysted worms are similar to those of cercariae.
    Molecular identification and genetic characterization of Cryptosporidium spp. in patients with diarrhea in Ningbo City
    QIN Yuan, LIU Hua, JIANG Yanyan, CAO Jianping, SHEN Yujuan
    2023, 41(2):  202-208.  doi:10.12140/j.issn.1000-7423.2023.02.012
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    Objective To analyze the Cryptosporidium infection and genetic characterization of outpatients with diarrhea in a sentinel hospital in Ningbo, to provide new ideas for clinical investigation on etiology of diarrhea. Methods A total of 650 fecal samples were collected from clinical diarrhea patients in NingBo City from November 2019 to July 2021. The genomic DNA from these samples was extracted, and the small subunit ribosomal ribonucleic acid gene (SSU rRNA) of Cryptosporidium was amplified by nested PCR. The products were analyzed by 1.5% agarose gel electrophoresis. The DNA from above positive sample was used as the template to amplify the 60-kDa glycoprotein (gp60) gene by nested PCR, of which the product was analyzed by 1.5% agarose gel electrophoresis. PCR amplification products of similar size to the target bands were sequenced in both directions, and blasted to identify the species or genotype according to the GenBank public database resources using Clustalx 2.1 software. Use Mega 11.0 software to draw the phylogenetic tree by the neighbour-joining (N-J) method. Results Among the fecal samples collected, 369 (56.8%) were from male diarrhea cases, and 281 (43.2%) female cases; of them the ages ranged from 1 to 99 years. After amplifying of the SSU rRNA gene, only one DNA sample showed specific bands at around 830 bp in electrophoresis, indicating Cryptosporidium spp. positive. The patient was a 53-year-old male, farmer with watery stool. According to the analysis of DNA sequence, it was identified as C. meleagridis, which has 100% homology with those of a human-derived isolate from Shanghai, a dairy-derived isolate from Heilongjiang Province, a chicken-derived isolate from Yunnan Province. The phylogenetic tree showed that these isolates locate in the same branch. The product of gp60 gene amplification displayed a specific band at around 955 bp, which was identified as the Ⅲb subtype family, with the highest homology (99.8%) to the human derived ⅢbA24G1R1 subtype, sequence alignment indicate it is a new subtype ⅢbA26G1 of C. meleagridis (GenBank accession No. OQ032548). Conclusion Zoonotic C. meleagridis was identified from a clinical diarrhea case in Ningbo area, suggesting that surveillance on Cryptosporidium infection in people with diarrhea and epidemiological tracing for infection source should be strengthened.
    REVIEWS
    The biological significance of malarial hemozoin’s formation
    SUN Jun
    2023, 41(2):  209-212.  doi:10.12140/j.issn.1000-7423.2023.02.013
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    The formation of the Plasmodium hemozoin and its biological significance has been controversial. Given that it is closely related to the growth, reproduction and pathogenicity of Plasmodium, the biological function of malarial hemozoin needs to be further elucidated. This article preliminarily discussed the morphology of hemozoin, the formation of hemozoin, the biological function of hemozoin, its relationship with the host macrophages, and its pathogenicity to reveal the role of the formation of hemozoin in the use of heme and iron, the unique function of hemozoin in the evolution, growth, and reproduction of malaria parasites, which helps to clarify the limitations of the traditional understanding of the Plasmodium hemozoin formation. It provides ideas for further understanding the pathogenic mechanism of Plasmodium and developing new antimalarial drugs.

    Research progress on molecular markers and epidemiology of Echinococcus ortleppi
    SUN Hui, LI Li, YAN Hongbin, LI Xiurong, FU Baoquan, JIA Wanzhong
    2023, 41(2):  213-218.  doi:10.12140/j.issn.1000-7423.2023.02.014
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    Echinococcosis is an important zoonotic parasitic disease caused by the metacestode stage larval of the genus Echinococcus. In China, it is mainly endemic in the western region. E. ortleppi is a unique specie of Echinococcus, due to its morphological and developmental characteristics, which are significantly different from that of E. granulosus. Its suitable intermediate host is cattle. Humans, pigs, camels, sheep, goats, lemurs and deers can be infected with E. ortleppi. In this review, the morphology, genetic variation, molecular genetic markers and epidemiology of E. ortleppi were summarized to provide a reference for epidemiological investigation, prevention and control and monitoring of echinococcosis.

    Research advances on the role and mechanism of neutrophil extracellular traps in parasitic infection
    LI Chang, DU Xinyue, YAN Min, WANG Zhaojun
    2023, 41(2):  219-222.  doi:10.12140/j.issn.1000-7423.2023.02.015
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    Neutrophil extracellular traps (NETs) are neutrophil-derived extracellular net-like structures that are composed of chromatin and granule proteins. Initial reports demonstrated that the infection of parasites like protozoa and helminths could induce NETs formation, which plays important roles in the immune defence against parasites and immunopathology caused by infection. This review described the mechanisms of NETs formation and the role of NETs in protozoan and helminth infection, which provides new ideas for the prevention and treatment of parasitic diseases.

    Research progress on the cellular signal pathways associated in alveolar echinococcosis
    MA Hui, CHONG Shigui, CHEN Gen, ZHANG Linghui, QIN Junmei, ZHAO Yumin
    2023, 41(2):  223-227.  doi:10.12140/j.issn.1000-7423.2023.02.016
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    Alveolar echinococcosis (AE) is a highly harmful zoonotic parasitic disease, which is prevalent in the high latitudes of the northern hemisphere. AE usually occurs in liver tissue and Echinococcus grows infiltratively in patients. It can cause serious damage to the morphology and physiological function of the involved organs. In this process, the cellular signaling pathway is closely related to the course of AE. Cell signaling pathways, such as the mitogen-activated protein kinases (MAPK) pathway, insulin (Ins) pathway, programmed cell death protein 1 (PD-1) pathway and transforming growth factor β (TGF-β) pathway, are closely related to proliferation of Echinococcus, body immune response and differentiation of immune cells. This article has reviewed the role of related cellular signaling pathways in the immune regulation of alveolar echinococcosis and host in the process of AE infection.

    SHORT COMMUNICATIONS
    Epidemiological characteristics of visceral leishmaniasis in Yangquan City, Shanxi Province from 2006 to 2021
    WANG Fenfen, ZHANG Peijun, REN Mengzhi, LI Daohao
    2023, 41(2):  228-232.  doi:10.12140/j.issn.1000-7423.2023.02.017
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    Data of visceral leishmaniasis in Yangquan City from 2006 to 2021 was collected based on the current address and final audit date from the China Infectious Disease Information Reporting Management System. WPS office 2019 was used to establish the database for descriptive epidemiological analysis of visceral leishmaniasis. SPSS 20.0 was used for statistical analysis to compare the difference of rates between different groups. The analysis results showed that a total of 258 cases of visceral leishmaniasis were reported in Yangquan City from 2006 to 2021, with an average annual incidence rate of 1.18/100 000. The annual incidence increased over the years, from 0.08/100 000 in 2006 to 7.36/100 000 in 2021, and the difference was statistically significant among different years (χ2 = 441.984, P < 0.05). Visceral leishmaniasis cases were reported in five counties (districts) of Yangquan City, and the average annual incidence ranged from 0.50/100 000 to 4.05/100 000, with statistically significant differences among counties (districts) (χ2 = 70.770, P < 0.05). The age of visceral leishmaniasis cases ranged from 7 months to 85.81 years old, with a median age of 48.57 years old. The lowest incidence was in the 10-19 years old group (0.15/100 000), and the highest incidence was in the 0-9 years old group (2.96/100 000), with statistically significant differences among all age groups (χ2 = 20.564, P < 0.05). There were more males cases (180 cases) than females cases (78 cases), and the ratio of males to females was 2.31:1. Farmers and children had accounted for 64.73%(167/258)of all reported cases. There was no significant seasonal difference in the cases.

    Epidemiological analysis on malaria cases reported in Kunming during 2006—2021
    CHEN Zhihui, HONG Jing, ZHANG Rongbing, YANG Qian, YE Qing, LI Jianrong, TIAN Rong
    2023, 41(2):  233-237.  doi:10.12140/j.issn.1000-7423.2023.02.018
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    To analyze the epidemiological characteristics of malaria in Kunming before (2006—2010) and after the malaria elimination plan (2011—2021), which had started in 2010 to provide scientific strategies for the prevention of malaria re-transmission. Data of malaria cases in Kunming from 2006 to 2021 were collected from the Infectious Disease Network Direct Reporting System of the Chinese Center for Disease Control and Prevention. The data were grouped as pre- or post-eradication campaign, which were introduced in 2011. IBM SPSS statistics v26 statistical software was used for descriptive statistical analysis for the three spatial distributions of the cases, the place of infection, the awareness of the patients and the diagnostic capacity. The results showed that a total of 551 malaria cases were reported in Kunming from 2006 to 2021, 274 and 277 cases were reported in 2006—2010 and 2011—2021 respectively, including 5 indigenous cases (2 cases in 2006 and 2008 and 1 case in 2010) and 546 imported cases. The number of reported cases decreased over the year. The distribution of cases was concentrated, and indigenous cases were sporadically distributed in the rural regions from 2006 to 2010. The imported cases were mainly distributed in Guandu District before and after the elimination plan started, accounting for 55.8% (153/274) and 82.7% (229/277), respectively. Malaria cases were distributed in all months from 2006 to 2021, and more cases reported in July (41 cases) and June (48 cases) before and after the plan of action. In 2006—2010 and 2011—2021, the age distribution was mainly young adults aged 20-49 years (83.5%, 460/551), accounting for 82.1% (225/274) and 84.8% (235/277) respectively. The occupational distribution was mainly farmers and workers (57.4%, 316/551), accounting for 56.6% (155/274) and 58.1% (161/277) respectively. From 2006 to 2010, the cases were mainly imported from Southeast Asia (73.0%, 200/274). Of all cases, Plasmodium vivax infection accounted for 39.1% (107/274), P. falciparum infection accounted for 19.0% (52/274) and unclassified accounted for 42.0% (115/274). From 2011 to 2021, most of cases were imported from Africa (57.4%). Of all cases, P. vivax infection accounted for 41.2% (114/277), P. falciparum infection accounted for 52.4% (145/277), mixed infection accounted for 0.2% (5/277), unclassified accounted for 4.0% (11/277). Only one case of P. malariae and one case of P. ovale was reported. Before and after the initiation of the action plan, the time interval between onset of symptoms and visiting a doctor was 2 days, and the difference was not statistically significant (H = 0.568, P > 0.05). The interval between attending a health facility and diagnosis was 4 days and 3 days respectively, and the difference was statistically significant (H = 6.423, P < 0.05). The analysis showed that no indigenous cases were reported in Kunming after the action plan, and the goal of eliminating malaria has achieved as scheduled.

    Investigation of Anisakis spp. infection in marine fish in Fujian Province, 2019—2021
    ZHENG Dan, LIN Chenxin, CAI Wuwei, XIE Hangguo
    2023, 41(2):  238-240.  doi:10.12140/j.issn.1000-7423.2023.02.019
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    To investigate the infection of Anisakis spp. larvae of marine fish in Fujian Province. From 2019—2021, two coastal cities were randomly selected in each of the three fisheries in the eastern, the central and the southern Fujian Province as survey points. The samples of marine fish were randomly collected from ports, docks, seafood markets and farmers’ markets. After dissection, the contents of the abdominal cavity were collected and the larvae of nematodes were picked out under the stereomicroscope and identified to calculate the infection rate and infectivity of Anisakis spp. A total of 515 fishes of 32 species of marine fishes were examined, of which 183 fishes of 20 species were found to be infected with Anisakis spp. larvae, and the infection rate of fingerling was 62.5%, the overall infection rate of Anisakis spp. larvae was 35.5%. The higher infection rates were found in Ilisha elongata (5/5), Michthys miiuy (5/5), Engraulis japonicus (5/5), Trichiurus lepturus 74.7% (19/23), Scomberomorus niphouius 66.7% (32/48), Girella punctata (4/6), Nibea abiflora (3/7), Pennahia argentata 36.4% (8/22), Plectorhynchus cinctus 37.5% (9/24), and Ditrema temmincki 34.7% (33/95). The difference of infection rate of Anisakis spp. larvae in different fish species and areas was statistically significant (χ2 = 192.70, P < 0.05). The infection rates of Anisakis spp. in the three fishing grounds of the eastern, the central, and the southern Fujian were 43.1% (72/167), 28.3% (66/233), and 39.1% (45/115) (χ2 = 10.12, P < 0.05). A total of 2 767 larvae of Anisakis spp. were obtained, and the average infectivity was 15.1 larvae/fish. Among them, Engraulis japonicus 137.0 larvae/fish, Trichiurus lepturus 23.7 larvae/fish, Ilisha elongata 9.2 larvae/fish, Scomberomorus niphouius 7.4 larvae/fish are highly infectivity. The Oncorhynchus sp, Pneumatophorus jqponicus et al 64 fishes of 12 species were not infected with Anisakis spp. These findings indicated the infection rate of Anisakis spp. larvae of marine fish in Fujian Province is higher, so the prevention and control should be strengthened.

    Epidemiological investigation on the recurrence of visceral leishmaniasis in Shijiazhuang City
    GUO Zhanjing, ZHANG Shiyong, LIU Li
    2023, 41(2):  241-244.  doi:10.12140/j.issn.1000-7423.2023.02.020
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    Case investigation data of visceral leishmaniasis reported in Shijiazhuang City from 2019 to 2021 was collected from the national infectious disease reporting and information management system. Blood samples were collected from all dogs in the villages where the patients reside. Meantime, venous blood samples were collected from the patient’s family members and neighbours within an area of 100 meters radius centered on the patient’s residence. The rk39 immunochromatographic test strip was used to detect serum anti-Leishmania antibodies. From May to September, sandflies were captured using light traps in the courtyards where the patients reside. A total of 8 visceral leishmaniasis cases were reported in Shijiazhuang City from 2019 to 2021 (1 case in 2019, 7 cases in 2021), 6 cases in Jingxing County, 1 case in Gaocheng District and 1 case in Luquan District respectively. There were 4 males and 4 females. Their age ranged from 1 year old to 71 years old, among which there was 2 cases aged ≤ 2 years, 1 case aged 30-49 years, 5 cases aged ≥ 50 years. There were 2 young children, 5 farmers and 1 cadre. Seven cases were infected in local counties and 1 case was imported from another province (Shanxi Province). A total of 400 dogs were tested, and the positive rate of anti-Leishmania antibody was 11.0% (44/400). The positive rates of anti-Leishmania antibody in dogs from 6 villages of Jingxing County ranged from 6.4% to 8/20 (χ2 = 14.76, P < 0.05), and were 1.2% (2/172) and 0 (0/31) in dogs from Shijing Village of Luquan District and Xixinzhuang Village of Gaocheng District, respectively, with statistically significant differences between Jingxing County and Luquan District or Gaocheng District (χ2 = 32.55, 8.10; P < 0.05). The 309 and 4 blood samples collected from the key personnel in Jingxing County and Gaocheng District respectively were negative for anti-Leishmania antibody, 118 blood samples collected from key personnel in Luquan District, among which 1 blood sample was positive, and the positive rate is 0.9% (1/118). Four Phlebotomus chinensis were captured in Jingxing County, while no sandflies was captured in Luquan District and Gaocheng District. There was a high risk of the spread of visceral leishmaniasis in Jingxing County. Active prevention and control measures were needed to prevent further spread.

    Investigation of Blastocystis spp. infection in stray dogs and cats and the parasite genotyping in Zhangzhou, Fujian
    LI Yongxia, LI Mengrui, LI Shiyi, HUANG Xiaohang, WU Wei, HUANG Zhijian, YIN Guangwen
    2023, 41(2):  245-248.  doi:10.12140/j.issn.1000-7423.2023.02.021
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    To investigate the prevalence of Blastocystis infections among dogs and cats at stray animal shelters in Zhangzhou City, Fujian Province, fecal samples were collected from rescued dogs and cats in Zhangzhou City, and DNA was extracted. Blastocystis ribosomal small subunit RNA (SSU rRNA) was used as a primer for PCR amplification. The positive samples were sent for Sanger sequencing, followed by BLAST sequence alignment analysis using the GenBank public database resources. A phylogenetic tree was constructed using MEGA 7.0 software. A total of 121 cat fecal samples and 119 dog fecal samples were collected. PCR test showed that the Blastocystis positivity rate of 5.04% (6/119) in dogs and 0.82% (1/121) in cats. The difference between dogs and cats was statistically significant (χ2 = 4.153, P < 0.05). Only one fecal sample from a dog was successfully sequenced by PCR amplification of the SSU rRNA gene, yielding the YN-145 sequence. Sequence alignment using BLAST showed a high similarity of 95%-97% with zoonotic Blastocystis ST3 subtype sequences (GenBank accession numbers MW404497.1, MW242639.1, and MW767066.1). Phylogenetic analysis revealed that the YN-145 sequence formed a separate cluster within the ST3 subtype.

    Surveillance on imported malaria in Linyi City of Shandong Province from 2015 to 2021
    LIU Jiancheng, XU Yan, WANG Longjiang, KONG Xiangli, WANG Yongbin, LI Yuejin
    2023, 41(2):  249-252.  doi:10.12140/j.issn.1000-7423.2023.02.022
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    The information on imported malaria cases and pidemiological case investigation in Linyi City, Shandong Province, from 2015—2021 were collected and analyzed. A total of 78 imported malaria cases were reported, including 65 cases of Plasmodium falciparum infection (83.3%), 11 cases of P. ovale infection (14.1%), 1 case of P. vivax infection (1.3%), and 1 case of P. malariae infection (1.3%). Among the reported cases, 1 case was imported from Myanmar (1.3%), and the remaining 77 cases were imported from African countries (98.7%). There was no obvious seasonal variation in the time of case reporting, but there were peaks in April, August, October and January; the main areas of case reporting were Hedong District (43 cases) and Lanshan District (16 cases) in Linyi City. The reported cases were all young and middle-aged males, with an average age of (41.03 ± 9.18) years old, and most cases were among the returned workers (68 cases). Among the reported cases, 38 were seen on the same day from the onset of symptoms, and the longest symptom-to-diagnosis interval was 30 days. All the reported cases had a history of overseas residence from 1 month to 3 years before the onset of the symptoms. The primary diagnosis and treatment units were mainly to medical units at the county level or below, accounting for 65.4% (51/78); the misdiagnosis rate of the initial diagnosis was 37.2% (29/78). 8 cases (10.3%) presented with complications. It is recommended to focus on providing health education on malaria prevention and control knowledge for labor exporting personnel, strengthen monitoring of mobile populations, and timely conduct pathogen screening and verification for personnel traveling to high malaria prevalence areas.

    CASE REPORTS
    A child case of pulmonary cystic echinococcosis
    LU Weimin, YANG Xiaotao, ZHU Ying, ZHANG Hong, LI Jiwei, WANG Yanchun
    2023, 41(2):  253-256.  doi:10.12140/j.issn.1000-7423.2023.02.023
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    The patient was a 12-year-old boy of Han ethnic group who lived in Xiangyun County, Dali. The patient complained of wet cough on August 2, 2020, and took amoxicillin capsules for 3 days, without relief. Then he was brought to the local clinic and received amoxicilin/Clavulanate potassium, potassium sodium dehydroandroan drographolide succinate for injection and bromhexine hydrochloride for 3 days. The patient was subsequently referred to the Department of Pediatrics of the Xiangyun County People’s Hospital due to fever, shortness of breath and cyanosis on August 11, 2020. The blood routine test showed elevated white blood cells and eosinophils. The chest CT scan showed a large cystic mass with a thick wall in the left lobe of the lung. The patient was misdiagnosis as lung abscess and severe pneumonia, received intravenous vancomycin for 3 days, but also in fever. The patient was admitted to Kunming Children’s Hospital with diagnosed as pneumonia and lung abscess on August 14, 2020. The patient, who was an inhabitant of a rural area, had a history of prolonged exposed to domestic dogs and goats. Laboratory investigations showed marked eosinophilia and positive Echinococcus IgG antibody. The chest CT scan showed infiltration in the lung and a large cystic mass in the left upper lobe of the lung with curvilinear septa within the lesion. The Water-Lily sign was reported. The patient was therefore diagnosed with pulmonary cystic echinococcosis. Removal of cyst in the left upper lobe of the patient’s left lung. The pathological biopsy identified E. granulosus parasite in the lung tissue. The total DNA was extracted from the paraffin-embedded samples of the hydatid cyst, and the molecular analysis was performed. The amplified PCR products were purified and subjected to direct sequencing. The results showed 99.2% sequence identity to the cox2 gene of mitochondrial of E. granulosus. The patient was administrated with albendazole at oral dose of 10 mg/(kg•d), twice a day for 3 months. The body temperature of the patient returned to normal and without cough. A postoperative chest CT scan showed the cavity in the left upper lobe of the lung was significantly reduced and sufficient expansion of the lung in the sixth mouth. Recurrence was not observed for more than 18 months of follow-up.

    A case of visceral leishmaniasis misdiagnosed as a hematological disorder
    JIA Zhenzhen, LIU Hongying, JIANG Qi, WANG Lingling, LIU Xiangjun
    2023, 41(2):  257-259.  doi:10.12140/j.issn.1000-7423.2023.02.024
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    A 65-year-old male patient, who was a farmer from Hebei, went to the local hospital for “intermittent fever of unknown origin” on August 12, 2021, and his blood test showed pancytopenia, which was misdiagnosed as a blood system disease, after antibiotic treatment, ferrous succinate supplementation for restoring hematopoietic deficiencies. The symptoms were improved temporarily, but his condition recurred, and the patient was hospitalised for more than 6 months. On February 19, 2022, he developed a fever again, with a body temperature of up to 39 °C, and was admitted to Hebei Provincial People’s Hospital for further diagnosis and treatment. The patient has a history of previous contact with street dogs. The history of blood-sucking sandfly bites exposure is unknown. The admission examination showed anemia appearance, soft abdomen, liver and spleen slightly hard. Blood count showed that the white blood cell count was 0.72 × 109/L, the neutrophils count was 0.34 × 109/L, the lymphocytes count was 0.30 × 109/L, the red blood cell count was 3.03 × 1012/L, the hemoglobin level was 72 g/L, the platelet count was 46.00 × 109/L. Immunological tests showed that immunoglobulin G level was 32.9 g/L, complement C3 was 0.53 g/L, complement C4 was 0.095 g/L, complement C1q was 144.6 mg/L, direct anti-human globulin was positive for IgG and positive for antinuclear antibodies. Relevant pathogens were tested. The fungus D-dextran was 814.0 pg/ml, human herpesvirus type 4 (HHV-4) PCR was below 500 copies/ml. The chest and abdominal CT and ultrasound showed splenomegaly and flaky low-density shadows could be seen in the spleen, with unclear boundaries. Bone marrow aspiration smear showed Leishmania donovalii in and around some macrophages without flagellates. The whole blood samples were sent to Jiangsu Simcere Medical Diagnostics Co., Ltd. for metagenomic second-generation sequencing. A total of 266 335 Leishmania DNA sequences were detected, including 145 767 L. infantiles, 66 243 L. donovalii, 53 461 L. dononii and 28 HHV-4 lesions. Combined with clinical symptoms and laboratory findings, L. donovalii infection diagnosis was made. Intravenous amphotericin B was administrated, starting from 5 mg to 100 mg and gradually ramping up the treatment, the patient’s body temperature decreased after 3 days of treatment, and the body temperature was normal after 1 week. The patient was and then transferred to a specialist hospital for 20 days of continuous treatment before discharged. After about 3 months of follow-up, the patient reported no discomfort and no leishmania on the bone marrow aspiration smear.

    Investigation on the first imported visceral leishmaniasis case in Ningxia in the past 44 years
    GU Yan, YU Jin, XU Cehua
    2023, 41(2):  260-262.  doi:10.12140/j.issn.1000-7423.2023.02.025
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    The patient, a 46-year-old male, was a farmer from Zhongning County, Zhongwei City, Ningxia. The patient worked as a Gogie berry farmer and picker in Sidaogou Village, Yumen City, Jiuquan City, Gansu Province during 2013—2021 March to October. The patient showed fever, sweating and joint pain with no obvious causes on February 18, 2022. The highest body temperature exceeded 40 ℃ and the patient was diagnosed with a“lung infection” at a local clinic. Penicillin and cephalosporin were administrated but unsuccessful. On March 6, the patient was treated at the General Hospital of Ningxia Medical University. The patient’s physical examination upon admission showed clear consciousness, a flat and soft abdomen, no palpable abdominal mass, and no palpable subcostal liver. Blood routine showed: white blood cell count was 2.61 × 109/L, hemoglobin level was 122.0 g/L, platelet count was 114.0 × 109/L. On March 17, abdominal ultrasound showed liver enlargement, reduced and uniform echo in the paren-chyma, and unclear vascular imaging. Spleen enlargement without obvious lesions. On March 21, blood samples were sent to Yugok Biotechnology Co. Ltd. for the second-generation sequencing of the macro genome. The results showed 420 sequences of the Leishmania genus, including 418 sequences of L. donovani. Based on the clinical symptoms and laboratory examination results, it was diagnosed as visceral leishmaniasis. Amphotericin B (5 mg) was administered intravenously for 8 consecutive days, and the condition improved. The body temperature dropped to 36.2 ℃. On day 9, she was discharged after 1 day of intravenous drip with antimony sodium gluconate (6 ml). After discharge, the patient was given an intramuscular injection of antimony sodium gluconate (6 ml/d, suspended for 2 weeks after continuous injection for 6 days, and continued for 9 days), and other symptoms were treated accordingly. After one month of discharge, there was a phone follow-up, and the body felt light and weak; two months after discharge, the telephone follow-up showed good recovery.