Current Issue
28 February 2024
Volume 42 Issue 1
EDITORIAL
Epidemic status and key tasks for the control and elimination of key parasitic diseases in China
WANG Qiang, XU Jing, XIA Zhigui, HAN Shuai, ZHANG Yi, QIAN Menbao, LI Shizhu, ZHOU Xiaonong
2024, 42(1):  1-7.  doi:10.12140/j.issn.1000-7423.2024.01.001
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After more than 70 years of effective control programme, China has made remarkable achievements in the control of key parasitic diseases, and is moving towards the goal of control and elimination. This paper analyzes the epidemic status and challenges of schistosomiasis, malaria, echinococcosis, leishmaniasis, clonorchiasis and soil-transmitted helminthiasis in recent years, and puts forward the future directions and key tasks of those diseases, in order to provide reference for accelerating the control and elimination programmes on key parasitic diseases in China.

SPECIAL REPORTS
Progress of echinococcosis control in China, 2022
KUI Yan, XUE Chuizhao, WANG Xu, LIU Baixue, WANG Ying, WANG Liying, YANG Shijie, HAN Shuai, XU Xuenian
2024, 42(1):  8-16.  doi:10.12140/j.issn.1000-7423.2024.01.002
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To understand the work progress in nationwide control of echinococcosis, we summarize the experience and find the existing problems through descriptive analysis on the national control data in 2022. As of the end of 2022, there were 370 echinococcosis endemic counties (city, district, banner) covering 29 926 villages in China, having a total of 25 227 echinococcosis cases with an average prevalence of 58.35 per 100 000 (25 227/43 232 609), among them, 15 554 cases were of cystic echinococcosis, 8 169 cases alveolar echinococcosis, 255 mixed infection, and 1 249 cases pending; 1 270 cases were newly found, including 991 cases of cystic echinococcosis, 89 alveolar echinococcosis, 5 mixed infection, and 185 pending; revealing 102 cases were at age < 12, and 1 168 case were of age ≥ 12. In 2022, population screening by abdominal ultrasound scanning was performed in all endemic provinces (autonomous regions) for 3 576 121 person/times. Of them, 751 440 person/examinations were performed for the residents younger than 12, and 2 824 681 person/times were performed for residents older than 12. The serological examination was carried out for the suspected individuals for 17 404 person/times. According to data from 370 surveillance sites in 2022, the prevalence in residents younger than 12 was 0.02% (60/287 437) by ultrasound screening, with 40.00% (24/60) newly diagnosed cases. The prevalence in the residents older than 12 was 0.29% (772/270 407) in type Ⅰ and type Ⅱ endemic counties (city, district, banner). The newly diagnosed cases accounted for 8.29% (64/772) of the detected patients. In 2022, 18 354 patients received drug treatment, of which 16 625 patients received liver and kidney function tests or management against adverse reactions. A total of 1 418 patients received surgical treatment, including 69.82% (990/1 418) for cystic echinococcosis, and 26.52% (376/1 418) for alveolar echinococcosis. In 2022, the follow-up results showed that 999 cases were cured, 20 599 cases responded to the treatment, 2 546 cases failed in the treatment, 374 cases died (the causes of the deaths were not echinococcosis), 239 cases were excluded, 372 cases were lost in follow-up, 884 cases had not completed the follow-up, and 170 cases migrated to other places. In 2022, there were 2 478 608 dogs in the endemic townships (towns) nationwide, of which 2 250 694 were registered for management. Deworming work was conducted for dogs in 34 646 villages, with 24 289 457 deworming times. Wild canines were demormed by delivering 119 473 drug doses. A total of 394 851 fecal samples from domestic dogs were collected and detecteded, of which 1 756 were found positive for Echinococcus coproantigen, with a positive rate of 0.44% (1 756/394 851). Of the wild canines, 62 884 field fecal samples were collected and detected, among which 1 201 were found positive for Echinococcus coproantigen, with a positive rate of 1.91% (1 201/62 884). A total of 117 303 slaughtered livestock were randomly examined, among which 1 038 were diseased, with a prevalence of 0.88%. A total of 43 705 field rodents were examined, among which 403 were diseased, with a prevalence of 0.92%. Although the endemic of echinococcosis in China has been essentially controlled, there remain many difficulties and challenges in control work. It is imperative to continuously strengthen the prevention and control measures for echinococcosis, raise the disease prevention awareness, explore optimizing the control strategy, exert the role of regional joint prevention and control mechanisms and fully implement comprehensive measures to further control the prevalence of echinococcosis.

ORIGINAL ARTICLES
Effects of asymptomatic hookworm infection on intestinal microflora and metabolome in middle-aged and elderly people in rural area of Huangshan City
WANG Yebin, SHEN Xuhang, DENG Guoqiang, HU Saimin, WANG Fei, ZHANG Lingling, SHEN Jilong
2024, 42(1):  17-26.  doi:10.12140/j.issn.1000-7423.2024.01.003
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Objective To reveal the effect of mild asymptomatic hookworm infection on intestinal microflora and metabolome in middle-aged and the elderly people, to provide reference information for study on interaction of helminth-intestinal microflora. Methods In October to November 2022, from the parasite infection survey in residents at the surveillance site for soil-transmitted nematodes infection in Qimen County and Huangshan District of Huangshan City, Anhui Province, the hookworm egg positives detected by modified Kato-Katz thick smear method were assigned in infection group, and the hookworm egg negatives in control group. Fresh fecal samples from the examinees were collected for extraction of intestinal microflora DNA, of which 16S rRNA gene sequence was amplified by PCR and sequenced. The abundance-based coverage estimator (ACE), PD-wholetree, Chao index and Shannon index were calculated. The principal coordinate analysis (PCoA) and β diversity analysis of the unweighted pair group method with arithmetic mean (UPGMA) hierarchical clustering were used to compare the difference in the distribution of intestinal microflora between the infection group and the control group, to screen the indicator flora by indicator value analysis. The metabolites in the fecal samples were extracted with methanol-water extraction method for metabolome analysis by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) for non-targeted sequencing. Orthogonal partial least squares discriminant analysis (OPLS-DA) was used to establish a model for screening differential metabolites between the infection group and the control group, and generate the volcano plot. The differential metabolites were screened based on P-values, variable weight value, and difference multiple. The Kyoto Encyclopedia of Genes and Genomes (KEGG) database was used to search the metabolic pathways of related differential metabolites. Enrichment analysis of differential metabolites was performed, and the degree of linear correlation between two metabolites was analyzed by Pearson correlation analysis. Results A total of 22 subjects were studied, including 11 subjects of positive fecal eggs and 11 subjects of negative control. The average age of the infected group was 72.2 years old, and all of them presented mild asymptomatic hookworm infection. The average age of the control group was 53.1 years old. A total of 1 755 649 16S rRNA sequences were obtained and 1 245 amplicon sequence variants were clustered after quality control and assembly. A total of 389 species from 15 phyla, 22 classes, 58 orders, 94 families, and 191 genera were identified. The results of the diversity index analysis showed that the ACE, PD whole tree, Chao and Shannon indexes of intestinal flora diversity in the infection group were 188.768, 16.533, 192.667 and 5.195, respectively, whereas the control group were 167.829, 15.294, 157.371 and 4.898, respectively. No significant difference was seen between the two groups (t = 1.266, 0.952, 1.266, 0.962, P > 0.05). The PCoA analysis demonstrated that the intestinal microbiota of the infected group and the control group overlapped to varying degrees but could still be divided into two distinct taxa. Additionally, the UPGMA hierarchical clustering analysis exhibited that both the infection group and the control were clustered in the same group first, and then clustered with the other group, and only one case overlapped. Multivariate statistical analysis showed seven flora dominating in the infection group, including Prevotella, Feacalibacterium, Klebsiella variicola, Parasutteralla, Coprococcus, Clostridium UCG-014 and Enterobacterium; while in the control group, only B. vulgatus was abundant. The results of indicator value analysis revealed the bacteria with the largest indicator value that affect the intestinal environment in the infection group, including Prevotella, Klebsiella, Bacteroides, Dialister, Enterobacterium, Coprococcus, UCG-002 and Faecalibacterium in the infection group; while in the control group, Clade_Ⅰa, Clade_Ⅲ, Blautia, Alistipes, Lachnoclostridium, Bilophila, Turicibacter and Muribaculaceae were dominant. The OPLS-DA model could effectively distinguish the metabolites in fecal samples of the infection group and the control. A total of 400 different metabolites were identified in the two groups, of which 156 were significantly increased and 244 decreased. The KEGG enrichment analysis indicated that the differential fecal metabolites were mainly enriched in protein digestion and absorption (P = 0.000) and central carbon metabolism (P = 0.000). Positive correlations were noted in 15 pairs metabolites i.e. between delta2-THA and (22E)-3 beta-hydroxy-5 alpha-chola-7,22-dien-oic acid (r = 0.935, P < 0.01), and negative correlations were seen in 9 pairs metabolites i.e. between lysoPE and aminovaleric acid betaine (r = -0.500, P < 0.05). Conclusion Asymptomatic hookworm infection in middle-aged and elderly people in rural area of Huangshan City may affect the composition and metabolism of intestinal microflora, which may create a symbiotic and colonization environment for probiotics

Effect of Toxoplasma gondii infection on m6A methylation modification of transcripts in mice brain tissue
XIE Xiaoman, SUN Hang, DAI Lisha, ZHU Wenju, WANG Lilei, XIE Huanhuan, DONG Hongjie, ZHANG Junmei, WANG Qi, ZHOU Beibei, ZHAO Guihua, XU Chao, YIN Kun
2024, 42(1):  27-35.  doi:10.12140/j.issn.1000-7423.2024.01.004
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Objective To analyze the effect of Toxoplasma gondii infection on the level of N6-methyladenosine (m6A) methylation of brain transcripts in mice. Methods C57BL/6J female mice (n = 20) were randomly divided into TgCtwh6 infection group (n = 7), LHG infection group (n = 7) and control group (n = 3 for the control of TgCtwh6 infection and LHG infection group, respectively). The TgCtwh6 infection group and the LHG infection group were inoculated by gavage with 0.2 ml brain tissue suspension (20 cysts/mouse) from the mice infected with T. gondii Chinese Ⅰ genotype wh6 strain or Chinese Ⅲ genotype LHG strain, respectively. The control group was given with the same amount of normal saline. At 15, 30 and 45 days post-infection, one mouse was randomly selected by drawing lots from each infected group, which was sacrificed under anesthesia to collect brain tissue for microscopic examination and counting of the cyst number in the cerebral cortex, hippocampus and olfactory bulb. At 45 days post-infection, the whole brain tissues of 3 mice in each group were collected, the total RNA was extracted, the genome library was prepared, the transcriptome was sequenced, differential methylation loci (DML) were screened, and differential m6A methylation sites and transcripts of mRNA in infected group and control group were recorded. The transcripts with methylation sites were analyzed by gene ontology functional annotation (GO), Kyoto Encyclopedia of Gene and Genome (KEGG), and methylated differential transcripts by gene set enrichment analysis (GSEA). Three m6A methylation modification protein genes, methyltransferase like 3 (METTL3), fat mass and obesity-associated protein (FTO) and YTH domain family 3 (YTHDF3), were selected, and their relative transcription levels were detected by real-time fluorescence quantitative reverse transcription PCR (qRT-PCR) using the glyceraldehyde-3-phosphate dehydrogenase gene as an internal reference. Results All the mice in the infection group were infected successfully. On day 45 after infection, the cysts in cerebral cortex, hippocampus and olfactory bulb were (5 676 ± 10), (4 773 ± 9) and (243 ± 10), respectively. A total of 760 650 methylation sites were detected in the infection group and control group. Among them, the methylation levels of four m6A motifs, GGACA, GGACC and ACGAT, accounted for 16.8% (127 923/760 650), 4.6% (35 164/760 650), 3.8% (28 983/760 650) and 0.4% (3 122/760 650), respectively. A total of 127 016 transcripts with high methylation sites were detected, including 71 727, 27 754, 24 556 and 2 979 transcripts with GGACA, GGACC, GGACT and ACGAT, respectively. The total number of DML sites for four m6A motifs, including ACGAT, GGACA, GGACC and GGACT, in the transcriptome of the infected and control group mice brain tissue was 9 233, including 4 832 high methylation sites and 4 851 low methylation sites. The GO analysis showed that the transcripts where DML was located were significantly enriched in cellular processes of biological processes, cell of cellular components, and binding in molecular functions. The KEGG enrichment analysis of the transcripts where DML was located showed that the intermolecular interaction network was mainly enriched in signaling pathway such as lysosome, spliceosomes, dopamine synapses. The GO enrichment analysis of biological processes showed that in the transcripts where DML was located, some transcripts related to biological processes were mainly enriched in processes such as protein glycosylation, negative regulation of neuronal apoptosis and proteion import into nucleus. The GSEA analysis showed the differential methylation between the control group and the two infection groups was highly enriched in transcriptome subsets related to the negative regulation pathway of fibroblast proliferation and Hippo signaling pathway. Among them, four key transcripts, ENSMUST00000105393, ENSMUST00000006523, ENSMUST00000055261 and ENSMUST00000038658, were screened, which encode costimulatory factor ligand (ICOSL), cysteine-rich intestinal protein 1 (CRIP1), MOB kinase activator 1A201 (MOB1A201) and MOB1A202, respectively. Compared with the control group, the expression of these four genes in TgCtwh6 infection group and LHG infection group were all up-regulated. The results of qRT-PCR showed that the relative expression level of mettl3 mRNA in brain tissue of TgCtwh6 infection group and LHG infection group was 5.47 ± 1.09, 1.63 ± 0.06, respectively, which was significantly different from that of the control group (1.01 ± 0.11) (t = 4.05, 5.03; both P < 0.05). The relative expression level of ythdf3 mRNA in the control group was 3.57 ± 0.08 and 1.80 ± 0.25, respectively, which was significantly different from that in the control group (1.01 ± 0.11) (t = 18.95, 2.85; both P < 0.05). The relative expression level of fto mRNA was 0.41 ± 0.04, 0.60 ± 0.12, respectively, which was significantly different from the control group (1.00 ± 0.06) (t = 7.67, 2.99; both P < 0.05). The qRT-PCR results were consistent with the transcriptional trend obtained by transcriptional sequencing. Conclusion Chronic T. gondii infection may enhance the m6A methylation in mouse brain transcripts, leading to changes in the biological processes and signal pathways related to host mental behavioural through modifying and regulating key differential transcripts including icosl, crip1 and mob1a.

Fasciola spp. infection and molecular identification in cattle and sheep in Wushen Banner, Inner Mongolia
LI Na, ZANG Dare, WURI Lige, ALATENG Burigude, HAI Ying, HASI Surong
2024, 42(1):  36-41.  doi:10.12140/j.issn.1000-7423.2024.01.005
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Objective To investigate the endemic status of Fasciola spp. infection in cattle and sheep in Wushen Banner of Inner Mongolia. Methods From August 2022 to March 2023, blood and fecal samples from cattle and sheep were collected from Galutu, Sulide Sumu, Wulantaolegai, Wushenzhao and Tuke towns in Wushen Banner to detect serum Fasciola hepatica antibodies by using indirect ELISA. Cattle and sheep feces samples corresponding to some serum antibody detection samples were randomly selected, in which the parasite eggs were qualitatively examined by egg sedimentation method. The consistency test was performed for the findings from serum and fecal examination. In April 2023, Fasciola spp. adult worms and eggs were collected from the carcasses livers and bile of cattle and sheep that died of Fasciola spp. infection in Galutu, Sulidesumu and Tuke towns. The DNA of the worms and eggs was extracted to amplify ribosomal transcriptional spacer sequence 2 (ITS2) by PCR and sequenced. Sequence alignment was then performed by BLAST with NCBI database. The phylogenetic tree was constructed by the neighbour-joining method. SPSS 25.0 software was used for statistical analysis, and the chi-square test was used to compare the positive rates in different regions. Results A total of 825 serum samples were collected from cattle and sheep, in which 295 samples were positive for serological antibodies, with a total sero-positive rate of 35.8% (295/835), of which the sero-positive rates of sheep and cattle were 34.7% (227/655) and 40.0% (68/170), respectively. The sero-positive rate of sheep was the highest at 81.8% (45/55) in Sulide Sumu, and the lowest at 22.0% (27/123) in Wushenzhao. There was a significant difference in the sero-positive rate of antibodies in different regions (χ2 = 73.93, P < 0.05). The sero-positive in bovine was the highest at 65.1% (28/43) in Garutu and lowest at 19.2% (5/26) in Tuke. There was a significant difference in the sero-positive rate of antibodies in different regions (χ2 = 21.50, P < 0.05). A total of 88 fecal samples (59 sheep fecal samples and 29 bovine fecal samples) were detected, among which 1 sheep and 5 bovine fecal samples were positive for F. hepatica eggs, and 4 bovine fecal samples were positive for Paramphistomum eggs. Among the 88 samples, the positive rate of anti-F. hepatica antibody was 29.5% (26/88), and the positive rate of F. hepatica eggs was 6.8% (6/88). The kappa value was 0.086, indicating weak consistency between the two methods. Adult worms and eggs were collected from 2 dead cattle and adult worms from 2 dead sheep. The DNA were extracted from 5 adult worms and 2 eggs samples. A total of 7 bands of approximately 550 bp were obtained by PCR amplification for sequencing. BLAST alignment analysis showed that the identities of 4 obtained sequences were 92.97%, 96.62%, 95.74% and 95.91% with the ITS2 sequences (GenBank: HQ700438) of F. gigantica from China, respectively, and identified as F. gigantica. The identities of the other three obtained sequences were 95.69%, 99.80% and 99.23% with the ITS2 sequences (GenBank: JF496717) of F. hepatica from China, respectively, and identified as F. hepatica. The phylogenetic tree showed that the F. hepatica identified in this study clustered on the same branch with the F. hepatica from China (GenBank: JF496717), Kenya (GenBank: MZ396926) and Egypt (GenBank: MW620063). The F. gigantica identified in this study clustered in the same branch with the F. gigantica from China (GenBank: HQ700438) and India (GenBank: OL691113). Conclusion F. hepatica and F. gigantica infections are present in both cattle and sheep in Wushenqi area of Inner Mongolia, and the infection rate of Fasciola spp. was relatively high.

Cloning, expression, immunogenicity and bioinformatics analysis of Dermatophagoides pteronyssinus allergen Der p 4
LI Qisong, YANG Li, TENG Feixiang, MA Guifang
2024, 42(1):  42-47.  doi:10.12140/j.issn.1000-7423.2024.01.006
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Objective To clone the Der p 4 gene of the Dermatophagoides pteronyssinus allergen, express recombinant protein, ascertain the protein immunogenicity and analyze biological information. Methods The PCR primers were designed according to the known Der p 4 gene sequence. The total RNA of D. pteonyssinus was extracted to produce cDNA by reverse transcription PCR (RT-PCR) and amplify Der p 4 gene. The sequenced gene fragment was cloned into the pET-28a (+) vector. The plasmid was extracted for sequence identification, and the recombinant plasmid was transformed into Rosetta2 (DE3) pLysS competent cells to express recombinant protein by induction with 1 mmol/L IPTG. The recombinant protein was analyzed by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and purified by affinity chromatography. The immunogenicity of the recombinant protein was analyzed by Western blotting with serum from patients with D. pteronyssinus allergy as the primary antibody. The antigen specificity was assessed by indirect ELISA with the purified recombinant protein as the coating antigen for detecting, serum IgE in 30 dust mite allergy patient samples. ProtParam tools, SignalP5.0, NetPhos3.1, CD-search, Alphafold, Immune Epitope Database and Analysis Resource (IEDB) and bioinformatics prediction antigen peptide (BPAP) system were used to analyze the physicochemical properties, signal peptide sequence, phosphorylation sites, the secondary and tertiary structures and antigen epitopes of B cell were analyzed by bioinformatics approaches. Results A target gene band with a length of 1 090 bp was amplified by RT-PCR. The sequencing results of the recombinant plasmid showed that the inserted fragment was Der p 4 gene with 1 090 bp length. The SDS-PAGE analysis results showed that the Der p 4 recombinant protein was an inclusion body protein with a relative molecular weight (Mr) of approximately 60 000. The purity of the purified recombinant protein was > 90%. Western blotting analysis showed that IgE from the serum of patients with dust mite allergy specifically binds to the Der p 4 recombinant protein with a distinct band at Mr 60 000. The results of indirect ELISA showed that the recombinant protein Der p 4 was specifically bound to the serum of 14 (46.67%) dust mite allergy patients. Bioinformatics analysis showed that Der p 4 protein was highly stable, and the secondary and tertiary structures were dominated by α-helix and random coiling. The IEDB and BPAP systems predicted the presence of 15 B-cell epitope peptide sequences in Der p 4. Conclusion Purified Der p 4 recombinant protein shows reactivity and specifie binding to IgE antibodies in the serum of D. pteronyssinus allergy patients.

Imvolvement of placental neutrophils and IL-17 in adverse pregnancy outcome caused by Toxoplasma gondii infection in pregnant mice
ZHENG Guangfu, LIU Xianbing, JIANG Yuzhu, LI Xinyu, HU Xuemei, ZHANG Haixia
2024, 42(1):  48-54.  doi:10.12140/j.issn.1000-7423.2024.01.007
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Objective To explore the mechanism of placental neutrophils and IL-17 in adverse pregnancy outcomes of pregnant mice infected with Toxoplasma gondii. Methods C57BL/6 pregnant mice were randomly divided into uninfected group and infected group. Each mouse in the infected group was intraperitoneally injected with 0.2 ml suspension of T. gondii RH strain (about 400 tachyzoites per mouse) on day 8 of gestation. The mice in the uninfected group were intraperitoneally injected with the same amount of sterilized PBS on day 8 of gestation. On day 14 of gestation, the two groups of mice were euthanized by cervical vertebra dislocation to inspect by dissection and record the pregnancy outcome. The placental tissue were sampled to prepare paraffin sections for observing histological changes and infiltration of polymorphonuclear grannulocyes by hematein-eosin (HE) staining to calculate the infiltration index. Additional placental tissues were collected to prepare single-cell suspension, with which the percentages of neutrophils in the placental immune cells were detected by flow cytometry. Immunohistochemical staining was used to detect the distribution and localization of T. gondii and IL-17 expression level (gray value). Spearman correlation analysis was used to analyze the relationship between the IL-17 expression and neutrophil infiltration index. Data between two groups were compared using independent sample Student’s t-test. Results Compared with the uninfected group, the infected group showed significant bleeding and congestion in fetal mice and placenta, fetal dysplasia. The abortion rate in the infected group was 82.35% (42/51), which was higher than that in the uninfected group 4.08% (2/49) (t = 7.683, P < 0.01). HE staining showed that the placental tissue of pregnant mice infected with T. gondii had enhanced hepatocellular contour and was accompanied by a large number of polymorphonuclear granulocytic infiltration. The infiltration index was 14.500 ± 0.965, which was significantly higher than that of the uninfected group (3.917 ± 0.633) (t = 9.168, P < 0.01). Flow cytometryanalysis showed that the percentage of neutrophils in placental cells in the infected group was (13.700 ± 1.790)%, which was significantly higher than that in the uninfected group (4.783 ± 0.723)% (t = 5.107, P < 0.01). Immunohistochemical staining analysis showed that a large number of T. gondii could be detected in the placental tissue and mainly concentrated in neutrophils. The IL-17 intensity in the placenta tissue of the infected pregnant mice (17.510 ± 1.372) was significantly higher than that of uninfected pregnant mice (8.178 ± 1.293) (t = 4.951, P < 0.05). Correlation analysis showed that the expression level of IL-17 in the placenta was positively correlated with the degree of neutrophil infiltration (R2 = 0.652, P < 0.01). Conclusion T. gondii infection can lead to a significant infiltration of large number of neutrophils and a high level of IL-17 expression in the placenta tisseus of pregnant mice. The elevated expression level of IL-17 may relate to the recruitment of neutrophils at the maternal-fetal interface.

Expression of Cryptosporidium parvum GP900829-1099 protein and its immunomodulatory effects on mouse macrophages cells
YANG Ling, WANG Long, WANG Jiayang, ZHOU Kunzheng, YAN Baolong, ZHAO Wei, HUANG Huicong
2024, 42(1):  55-62.  doi:10.12140/j.issn.1000-7423.2024.01.008
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Objective To probe the immunomodulatory effects of Cryptosporidium parvum micronemal glycoprotein 900 (GP900) 829-1 099aa fragments (GP900829-1099) on mouse macrophages (RAW264.7 cells) through the nuclear factor kappa-B (NF-κB)/mitogen-activated protein kinase (MAPK) signalling pathways. Methods The amino acid sequence of GP900829-1099 was obtained from the NCBI database for bioinformatics analysis. Sequence fregment of gp900829-1099 was amplified with PCR using cDNA from C. parvum oocysts as a template. After gel extraction, gp900829-1099 were inserted into the pET-32a-gp900829-1099 vector and transformed into BL21 competent cells for induced expression. The recombinant proteins were purified and filtered, concentrated by ultrafiltration and further cleaned by removing endotoxin. The GP900829-1099 recombinant protein at concentration of 0.16, 0.80, 4.00, 20.00, 100.00 and 500.00 μg/ml was applied to stimulate RAW264.7 for 24 h, subsequently, its regulatory effect on the cell viability was detected by CCK-8 assay. Using PBS as the control group and lipopolysaccharide(1 μg/ml)as the positive control group, the recombinant protein at the concentration of 0.16, 0.80 and 4.00 μg/ml was applied to stimulate the RAW264.7 cells for 24 h to detect CD86 expression by flow cytometry. qPCR was used to detect the relative transcription levels of IL-6 and TNF-ɑ mRNA in RAW264.7 cells. ELISA was used to detect the expression levels of IL-6 and TNF-ɑ in the supernatant of RAW264.7 cell culture. The phosphorylation levels of P65 protein and extracellular regulated protein kinase (ERK) in NF-κB and MAPK signaling pathways were detected by Western blotting assay. Results In the secondary structure of GP900829-1070 proteins β corners account for 9.23%, irregular curls account for 64.58%, and contain abundant T and B cell antigenic epitopes. The molecular mass of the expressed recombinant protein GP900829-1099 was consistent with the theoretical value. The CCK8 results showed no toxic effect on the cells, and the subsequent working concentrations were selected as 0.16, 0.80 and 4.00 μg/ml. Flow cytometry results showed that the positive expression rate of CD86+ was (13.500 ± 0.815)%, (18.670 ± 0.657)% and (20.470 ± 1.271)%, respectively, and the latter two were higher than that of the blank control group (14.500 ± 0.872)% (t = 3.818, 3.872; both P < 0.05). qPCR results showed that the relative transcription levels of IL-6 mRNA in macrophages in 0.16, 0.80 and 4.00 μg/ml groups were 1.409 ± 0.050, 2.052 ± 0.098 and 3.284 ± 0.097, respectively, which were higher than those in the blank control group (1.010 ± 0.097) (t = 3.700, 7.595, 16.700; all P < 0.05). The TNF-ɑ mRNA relative transcription levels in macrophages of the three concentration gradient groups were 1.077 ± 0.034, 1.440 ± 0.021 and 2.378 ± 0.037, respectively, with the latter two being higher than that of the blank control group (1.000 ± 0.025) (t = 13.380, 30.850; both P < 0.01). ELISA results showed that the expression levels of IL-6 cytokines in macrophage culture supernatants were (535.400 ± 17.230), (572.800 ± 8.286) and (555.600 ± 23.940) mg/L in the 0.16, 0.80 and 4.00 μg/ml groups, respectively, which was higher than that in the blank control group [(454.400 ± 18.630) mg/L] (t = 3.193, 5.809, 3.339; all P < 0.05); the expression levels of TNF-ɑ cytokine were (351.800 ± 12.270), (386.400 ± 10.250) and (489.800 ± 10.540) mg/L, respectively, and the latter two were higher than that of the blank control group [(324.200 ± 11.070) mg/L] (t = 4.125, 10.830; both P < 0.01). Western blotting results showed that the relative expression levels of p-P65 protein and p-ERK protein in macrophages in 0.16, 0.80 and 4.00 μg/ml groups were 2.294 ± 0.254, 1.714 ± 0.205, 1.877 ± 0.309 and 1.522 ± 0.054, 1.760 ± 0.066, 1.582 ± 0.027, all were higher than that of the blank control group (1.0 ± 0.0) (t = 5.100, 3.489, 2.836 and 9.737, 11.450, 21.900; all P < 0.05). Conclusion GP900829-1070 recombinant protein stimulated macrophages at different concentrations, which activates NF-κB and MAPK signalling pathways to induce activation of macroopages and promote the transcription of TNF-α and IL-6 mRNA, thereby, participating in macrophage immunomodulation.

Infection and molecular characterization of Enterocytozoon bieneusi and Cyclospora cayetanensis in pet dogs and cats in Shanghai
QIN Yuan, LIU Hua, WANG Yaxue, ZHANG Jing, SU Yaxin, CAO Jianping, SHEN Yujuan
2024, 42(1):  63-68.  doi:10.12140/j.issn.1000-7423.2024.01.009
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Objective To investigate the infection and molecular characteristics of Enterocytozoon bieneusi and Cyclospora cayetanensis in pet dogs and cats in Shanghai and assess the zoonotic potential. Methods Fresh fecal samples were collected from dogs and cats at a pet hospital in Shanghai from November 2021 to June 2022. Genomic DNA was extracted from the fecal samples, and nested PCR was used to amplify the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) of E. bieneusi and the small subunit ribosomal RNA (SSU rRNA) sequence of C. cayetanensis. The positive products were subjected to bidirectional sequencing and sequence alignment by BLAST in the GenBank database. The phylogenetic tree was constructed using MEGA 11.0 software based on the neighbor-joining method. Results A total of 145 fecal samples were collected (99 from dogs and 46 from cats). The positive rates of E. bieneusi and C. cayetanensis were 4.1% (6/145) and 4.8% (7/145), respectively. The positive rates of E. bieneusi and C. cayetanensis in dogs were 3.0% (3/99) and 6.1% (6/99), respectively, while those in cats were 6.5% (3/46) and 2.2% (1/46), respectively. The ITS sequences of 6 E. bieneusi were 100% identical to human genotype A (GenBank accession number: MK982500), and the SSU rRNA sequences of 7 C. cayetanensis were 100% identical to human C. cayetanensis (GenBank accession number: KJ569533). The results of the phylogenetic tree analysis showed that all the E. bieneusi isolates belonged to the same branch as the reported human E. bieneusi genotype A isolates and fell into group 1. All the C. cayetanensis isolates belonged to the same branch as the reported human C. cayetanensis isolates. Conclusion E. bieneusi and C. cayetanensis infections were detected in pet dogs and cats in Shanghai, all of which were caused by zoonotic parasite strains.

Analysis on genetic variation and differentiation of Tyrophagus putrescentiae in different geographic populations
QIAO Tingting, TAO Xianglin, YE Changjiang, LI Zheng, ZHOU Xiaoyan, SUN Entao
2024, 42(1):  69-77.  doi:10.12140/j.issn.1000-7423.2024.01.010
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Objective To analyze the genetic diversity and differentiation of different geographic populations of Tyrophagus putrescentiae. Methods From June to July 2018, mite specimens were collected from flour and rice mills in Wuhu City (WH) and Fuyang City (FY) in Anhui Province, Shijiazhuang City (SJZ) and Zhangjiakou City (ZJK) in Hebei Province, to screen for copra mites identified by morphology and cytochrome C oxidase subunit 1 (cox1) gene sequence. Mitochondrial cytochrome b (Cytb) and ribosomal DNA internal transcriptional spacer (ITS) of the copra mites were amplified by PCR and sequenced. Using Chromas 2 and DNAStar 1.00 software were used to proofread and concatenate gene sequences. DnaSP 5.10.00 software to calculate haplotype diversity (Hd) and nucleotide polymorphism (Pi) of various mite populations, MEGA 10.2 software package to analyze population genetic variation and differentiation index (Fst) and gene flow (Nm), Arlequin 3.1 software to calculate Tajima’s D value, neutral tests to estimate Fu’s FS value, and analysis of molecular variance to assess genetic variation. To construct haplotype network diagram, Network 10.2 program was used based on the median-joining method. Haplotype phylogenetic tree was constructed using maximum likelihood method (ML). Results The T. putrescentiae mite was elliptical in shape, with soft skin, milky white or yellow-brown colour, and highly variable or degraded mouthparts. The consistency between the cox1 sequence obtained in this study and the cox1 sequence in GenBank (login number: LC190838.1) was greater than 98%. The length of the Cytb gene in the sample of T. putrescentiae was 372 bp. Among the 16 haplotypes (H1-H16), only H4 was a shared haplotype (shared by 9 individuals from the WH and FY populations), while the rest were exclusive haplotypes. The Hd of the four geographical populations was relatively high, with an overall value of 0.895 (> 0.5), with the WH population having the highest Hd (0.867) and the SJZ population having the lowest Hd (0.464). Based on Cytb sequence analysis, it was found that the genetic diversity of the four geographical populations of T. putrescentiae was relatively high (Pi > 0.005). Molecular analysis of variance showed that the Fst of the four geographical populations of T. putrescentiae was > 0.15 (P < 0.05). The neutral test results showed that the Tajima’s D value and the Fu’s FS value were -0.737 22 and 2.336 33, respectively (both P > 0.05). The haplotype network diagram was consistent with the results of the phylogenetic tree, where individuals from the four geographic populations were interwoven and distributed, with only a few individuals from the ZJK population clustered into another branch. The length of the ITS gene sequence was 1259-1405 bp, and all 32 haplotypes (G1-G2) were exclusive haplotypes. The Hd of the four geographical populations was relatively high, with an overall value of 1.000 (> 0.5) compared to the respective values. Based on ITS sequence analysis, it was also found that the genetic diversity of the four geographical populations of T. putrescentiae was high (Pi > 0.005), with Fst > 0.25 (P < 0.05). The Tajima’s D value and Fu’s FS value were 2.030 29 and 3.044 54, respectively (both P > 0.05). The haplotype network diagram was consistent with the results of the phylogenetic tree. The haplotypes of WH, FY and SJZ populations were clustered into one branch, while the haplotypes of ZJK were clustered into a single branch. Conclusion 4 geographic populations of T. putrescentiae are highly polymorphic, showing significant genetic differentiation. FY population might expanded to WH population historically, and there have been high level of partial gene exchange between different geographic populations of copra mites, but no obvious geographical distribution pattern was found.

Distribution of the neurotransmitter 5-hydroxytryptamine in Clonorchis sinensis
LIU Liu, ZHANG Jing, LI Jianke, ZHANG Hao, ZHANG Fengyu
2024, 42(1):  78-82.  doi:10.12140/j.issn.1000-7423.2024.01.011
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Objective To understand the distribution pattern of the neurotransmitter 5-hydroxytryptamine (5-HT) in Clonorchis sinensis. Methods The metacercariae of C. sinensis were isolated from infected Pseudorasbora parva fish by digestion, and used to infect Kunming mice (40-50 metacercariae/mouse) by gavage. Mice were euthanized 10, 20 and 30 days after infection, and the parasites were collected from the liver portal vein. The development status of worm organs at different stages were observed after staining with acetic carmine under optical microscope, at the same time, 5-HT immunofluorescence staining was performed to observe the distribution of 5-HT using laser scanning confocal fuorescence microscope. Results Under the optical microscope, the acetic acid magenta staining showed that in the C. sinensis d10 larva, the digestive and excretory organs were basically mature, the reproductive organs were not fully mature, and scattered eggs could be seen in the uterus. In the d20 larva, the reproductive organs in the worm were matured, the number of eggs in the uterus increased, and the testis branches increased. In the d30 adult worm, the digestive, excretory and reproductive systems were all mature, the eggs were more closely arranged in the uterus than the larvae, and the testis were enlarged and branched obviously. Under laser scanning confocal microscopy, the 5-HT immunofluorescence staining showed that in the d10 larva, the fluorescence staining was strong in the central parts of the body through the system segment, nerve union and oral sucker and was distributed in a dotted pattern within the internal organs in the body. In the d20 larva, a small number of nerve cells were observed in the nerve union near the ventricle sucker. Besides the central nervous system, 5-HT fluorescence staining appeared in the excretory sac, excretory pore and reproductive organs of the body. In the d30 adult worm, 5-HT was found in the digestive, excretory and reproductive organs of the worm, and the fluorescence staining of the testis was stronger than that of intestinal branches and oral sucker, and there were more nerve cells in the worm. Conclusion 5-HT is widely distributed in the body of C. sinensis, mainly in the organs and viscera rich in muscle tissue. There were differences in the distribution of 5-HT in different organs at the same developmental stage, and differences were also seen in the same type of organs at different developmental stages.

Current situation of capacity building for key parasitic diseases control in CDCs of China
HAO Yuwan, TIAN Tian, ZHU Zelin, CHEN Yijun, ZHU Huihui, WANG Qiang, LI Shizhu, ZHOU Xiaonong
2024, 42(1):  83-90.  doi:10.12140/j.issn.1000-7423.2024.01.012
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Objective To understand the current situation of capacitity building in team development and technical needs and to propose pertinent improvement suggestion for key parasitic disease control in the centers for disease control and prevention (CDC) at all levels in China. Methods An on-line questionnaire survey was performed to collect information on the professional staff structure, technique training, laboratory testing capability, and technology needs for parasitic disease control in the CDCs and schistosomioasis control institutions at all levels. The data was analyzed using SPSS 26.0 software. Results A total of 1 855 (provincial, municipal and county) CDCs participated in the survey. Among 122 282 technicians on duty, 7.31% (8 493/122 282) were responsible for parasitic disease control. A total of 4 745 are full-time, accounting for 53.06% (4 745/8 943) of all staff working on parasite disease control. There were significant differences in the distribution of professional titles and educational levels among employees working in CDCs. Higher proportions of senior professional titles and postgraduate degrees were found in the eastern region (19.92%, 13.52%) than in the central (17.02%, 8.29%) and western region (13.88%, 8.25%) (χ2 = 1 063.60, 2 892.89;both P < 0.01). The proportion of senior professional titles and postgraduate education among the personnel involved in parasitic disease prevention and control were also higher in the eastern region (21.20%, 12.51%) compared to the central region (15.63%, 7.30%) and western region (11.62%, 6.57%) (χ2 = 142.19, 314.93; both P < 0.01). The daily tasks of disease control agency staff at all levels have varying emphases. During the past year, 2 207 technical trainings were given to subordinate CDCs. On average, each individual at provincial CDCs has taken 2.7 training courses, each individual at city-level CDCs has taken 1.4 training courses, and each individual at county-level CDCs has taken 1.1 training courses. There were 12.50% (4/32) of province-level CDCs, 34.02% (83/244) of city-level CDCs and 49.02% (774/1 579) of county-level CDCs without specific laboratories for parasitic diseases. 55.90% (398/712), 40.22% (218/542) and 14.55% (117/804) of CDCs performed the ability for diagnosis of schistosomiasis, echinococcosis and visceral leishmaniasis in provinces where the disease is endemic, and the proportions were higher than those in non-endemic provinces (29.83%, 7.77%, 6.95%)(χ2 = 124.36, 283.05, 28.67; all P < 0.01). In addition, the requirements of CDCs mainly focused on personnel training (34.61%, 642/1 855), diagnosing and testing technology (12.40%, 230/1 855), and financial and equipment inputs (5.44%, 101/1 855). Conclusion The CDCs at all levels in the country show capability imbalance in parasitic disease control. Therefore, it is imperative to continuously optimize personnel structure, strengthen professional training and capacity building for laboratory testing, ensuring adequate personnel support for the control and elimination of parasitic diseases.

Analysis on implementation and effectiveness of imported malaria surveillance-response system post-elimination in Shanghai
ZHU Min, ZHANG Hao, WU Liming, ZHANG Chengang, ZHANG Yaoguang, WANG Zhenyu, CHEN Jian, WU Huanyu, CHEN Xin
2024, 42(1):  91-97.  doi:10.12140/j.issn.1000-7423.2024.01.013
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Objective To analyze the implementation and effectiveness of imported malaria surveillance-response system in Shanghai after malaria elimination, and to provide scientific basis for maintaining malaria post-elimination status and consolidating the achievements of malaria elimination. Methods The activity plan and records related to malaria surveillance-response in Shanghai were systematically collected and sorted. The data of individual malaria case in 2017—2022 from web-based National Information System for Infectious Disease surveillance and National Information System for Parasitic Diseases Control and Prevention were analyzed using SPSS 25.0. Results From 2017 to 2022, a total of 281 malaria cases were reported in Shanghai, including Shanghai nationality (16.7%, 47/281), other province nationality (76.5%, 215/281) and foreign nationality (6.8%, 19/281), all of them have the malaria-endemic areas traveling experiences. All reported cases were imported from abroad, the mainly infection sources were African countries, such as Guinea (17.4%, 49/281), Nigeria (14.2%, 40/281) and the Democratic Republic of the Congo (12.1%, 34/281). The reported cases were mainly falciparum malaria (83.3%, 234/281) and mainly reported from Jinshan District (15.7%, 44/281), Pudong New Area (14.9%, 42/281) and Minhang District (11.7%, 33/281). A total of 106 361 blood tests were performed in Shanghai from 2017 to 2022, with a positive rate of 3.3‰ (353/106 361). The positive rates of passive case detection, proactive case detection and reactive case detection were 3.6‰ (350/97 917), 0.4‰ (3/7 828) and 0 (0/616), respectively. Malaria reported cases were mainly detected by passive monitoring (98.9%, 278/281). All cases were reported in 24 hours after diagnosis and checked in 1 day after reporting, the rate of individual cases epidemiological investigation within 2 days was 90.0% (253/281), all foci were investigated and disposed within 3 days, and all cases were assessed in one month without transmission risks. The median time from the illness onset to confirmed diagnosis was 2 d (P25, P75: 1 d, 4 d). A total of 2 126 Anopheles were captured, all of which were Anopheles sinensis. The mainly distribution areas were suburban districts such as Jiading District (31.6%, 672/2 126) and Chongming District (24.9%, 529/2 126). Conclusion The surveillance-response system of imported malaria was operated well in Shanghai after malaria elimination and the epidemic handling was standardized and timely.

REVIEWS
Research advances on the taxonomy of Spirometra tapeworms
ZHANG Xi, RU Sisi, LONG Shaorong, LIU Ruodan, JIANG Peng, CUI Jing, WANG Zhongquan
2024, 42(1):  98-104.  doi:10.12140/j.issn.1000-7423.2024.01.014
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The genus Spirometra is a group of medical tapeworms that have been neglected for a long time. Its plerocercoid larvae can parasitize different tissues and organs in humans, causing a food/water-borne parasitic zoonosis known as sparganosis. The classification system of Spirometra was controversial for a extended period of time, causing confusion for related scientific research and teaching. In this paper, we provided a systematic review of systematic changes and taxonomic research progress of Spirometra tapeworms, to find appropriate answers to relevant questions and lay foundation for the study of related species.

Advances in anti-Trichomonas vaginalis target and drug research
ZHUO Xin, HUANG Cuilan
2024, 42(1):  105-110.  doi:10.12140/j.issn.1000-7423.2024.01.015
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Trichomonas vaginalis mainly invades the human genitourinary system and is a common non-viral sexually transmitted pathogen in clinics. Oral metronidazole is a widely used treatment, but the resistance of T. vaginalis to metronidazole has been spreading due to monotherapies in the past, so it is urgent to find alternative means. In this paper, the relavent research on anti-T. vaginalis targets and treatments in recent years were summarized and analyzed. The new advances were specifically introduced to provide a reference for future research and applications.

Research progress on Plasmodium membrane protein complexes
HAN Zhuxi, ZHU Xiaotong
2024, 42(1):  111-116.  doi:10.12140/j.issn.1000-7423.2024.01.016
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Malaria is one of the world’s three most serious infectious diseases which caused by Plasmodium spp. The Plasmodium merozoite, ookinete, and sporozoite all have characteristic endomembrane complexes (IMCs). IMC is localized under the plasma membrane and is closely linked to the subpellicular protein network on the cytoplasmic side of the membrane. IMC is involved in the parasite development and invasion of the host cells by providing a support backbone during cell division, maintaining cell morphology and stability. In-depth studies of the structure, function and transcriptional regulation mechanism of IMC protein are of great significance for the development of corresponding inhibitors or blockers to block malaria transmission. In this paper, we reviewed the research progress of IMC protein structure and transcriptional regulation mechanisms in recent years.

SHORT COMMUNICATIONS
Investigation of Anisakis larvae infection in marine fishes from Shanghai market
ZHANG Rui, WANG Zi, WANG Jiahui, LI Fengqin, XIE Qingchao, ZHAO Yong
2024, 42(1):  117-120.  doi:10.12140/j.issn.1000-7423.2024.01.017
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To understand the Anisakis larvae infection status in marine fishes sold in Shanghai, the fresh marine fishes caught in the East China Sea area were collected from Farmers’ markets, supermarkets and seafood markets in Shanghai in 2022. The suspected Anisakis larvae were searched in the offal and muscles after dissection and observed under optical microscope and scanning electron microscope, respectively. A total of 338 marine fish of 16 species were collected, and 1 065 Anisakis larvae were found from 116 fish of 6 species, with a total infection rate of 34.3% (116/338) and average infection intensity of 9.2 larvae/fish. The highest infection rate was 11/12 in Lophiiformes, and the highest average infection intensity was 13.0 larvae/fish in Larimichthys polyactis. The Anisakis larvae infection rates increased gradually from spring to winter. The infection rate and average infection intensity in winter were 51.1% (46/90) and 12.3 larvae/fish, respectively, which were the highest seasons of the year. The predominant sites of Anisakis larvae parasitise in marine fishes were the intestines and abdominal cavity, with infection rates of 54.6% (582/1 065) and 40.7% (433/1 065), respectively. The result showed that Anisakis larvae infections were present in marine fish sold in Shanghai and the infection rates of commonly consumed marine fishes such as Lophiiformes and L. polyactis were high.

Establishment of loop-mediated isothermal amplification detection for Paragonimus westermani
ZHOU Shuimao, JIA Xishuai, YANG Yan, ZHANG Juan
2024, 42(1):  121-124.  doi:10.12140/j.issn.1000-7423.2024.01.018
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In 2022, a total of 34 and 27 brook crabs were collected from Xingshan and Baokang Counties, respectively, in Hubei Province, a region where Paragonimus westermani is endemic. The DNA was extracted by NaOH digestion method after crushing from crab. Based on the 5.8S ribosomal RNA sequence of P. westermani, Primer Explorer V5 software was used to design specific primers for loop-mediated isothermal amplification (LAMP) of P. westermani, and a LAMP detection method for P. westermani was established. The specificity, sensitivity, amplification efficiency, and field application effect of the method were evaluated, and compared with precipitation microscopy. The results indicated that the LAMP method displayed a detection limit of a single P. westermani metacercaria without any cross-reactivity with five non-target species, including Schistosoma japonicum, Clonorchis sinensis, Fasciola hepatica, Capillaria hepatica, and hookworm. The assay’s performance was quantified using the average turbidity time (Tt value) of 29.0 min and the peak turbidity rate (Df) of 0.237 min for four metacercariae samples. The LAMP method revealed 24 and 0 positive stream crabs infceted with P. westermani in Xingshan County and Baokang County, with positive rates of 70.6% (24/34) and 0 (0/27), respectively; the precipitation microscopy method revealed 23 and 0 positive stream crabsin Xingshan County and Baokang County, with positive rates of 67.6% (23/34) and 0 (0/27), respectively. There is no statistically significant difference in the results between the two detection methods (χ2 = 0.2, P > 0.05). Conclusively, the LAMP method developed in this study is a straightforward, specific, and highly sensitive diagnostic tool for the detection of P. westermani in freshwater crabs. Its proven efficacy suggests that it is well-suited for in-field surveys or as a screening mechanism in endemic regions.

Investigation on host-feeding habits of Anopheles minimus in Yingjiang County at the China-Myanmar border
ZOU Wenjian, WU Linbo, XU Xiang, TANG Yerong, SUN Xiaodong, ZENG Xucan
2024, 42(1):  125-128.  doi:10.12140/j.issn.1000-7423.2024.01.019
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To understand the host-feeding habits of Anopheles minimus, the main malaria vector at China-Myanmar border areas, mosquitoes were captured from May to July 2021 in Nabang Town, Yingjiang County, Yunnan Province by the ultraviolet mosquito trap method. The captured mosquitoes were identified by morphology. The blood-sucking status of female mosquitoes was recorded: the female mosquitos with scarlet abdomens were regarded as blood-filled mosquitos. The genomic DNA of the mosquitoes identified as An. minimus were extracted, and the cytochrome C oxidase subunit 1 gene (cox1) were amplified by PCR. The sequence comparison of the positive products was performed to determine the mosquito species. Subspecies identification was based on multiplex PCR amplification of the second internal transcribed spacer (ITS2) sequence of ribosomal DNA. The blood sources identification of blood-filled female mosquitos was based on multiplex PCR amplification of cytochrome b (cytb) of mitochondrial DNA. A total of 3 419 mosquitoes were captured and 303 An. minimus were identified by morphology initially. A total of 245 mosquitoes were cox1 positive by PCR, and the sequences were over 99% identical to An. minimus (GenBank accession number: GQ259177.1). ITS2 multiplex PCR amplification results showed that all 245 An. minimus mosquitos were type A. Cytb multiplex PCR amplification results of 20 blood-filled female mosquitos showed that the blood sources of 4 mosquitos were from humans, 14 were from pigs and 2 were from cows. The human, pig, and cow blood index were 0.2 (4/20), 0.7 (14/20) and 0.1 (2/20), respectively. This study showed that the dominant Anopheles population in Yingjiang County, Yunnan Province were An. minimus, whose subspecies types were all type A. Their preferred host includes both animals and humans. The risk of malaria transmission was high.

Analysis of imported malaria epidemic in Zigong City of Sichuan Province from 2011 to 2023
LI Chunyan, ZHANG Fuyan, SHI Peng, TIAN Fengyuan
2024, 42(1):  129-133.  doi:10.12140/j.issn.1000-7423.2024.01.020
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This study aimed to reveal the epidemiological characteristics of imported malaria cases pre- and post-malaria elimination in Zigong by collecting and analyzing the imported malaria cases information and epidemiological data from January 2011 to July 2023. A total of 26 imported malaria cases were reported from 2011 to 2023, of which 61.5% (16/26) were falciparum malaria, 30.8% (8/26) were vivax malaria and 7.7% (2/26) were mixed infection of P. falciparum and P. ovale. All reported cases were imported with the residence time abroad of 62 days to 6 years. Most reported cases were returned from Africa (76.9%, 20/26), which showed peak epidemics in summer and winter and were distributed mainly in Fushun and Rongxian. The majority of imported malaria cases were male (92.3%, 24/26), of which 69.2% (18/26) were migrant workers whose ages were predominantly between 20 and 50. The median time interval between the return to China and the onset of symptoms was 7 days, with 88.0% (22/25) developing illness within 14 days after returning. The median time interval between the onset and the first visit was 1 day, with 80.8% (21/26) first visiting a doctor within 3 days after the onset of symptoms. A total of 84.6% (22/26) of the imported malaria cases were first visited by county-level medical units or above, with 69.2% (18/26) being diagnosed with malaria. It is suggested that early malaria diagnosis is yet to improve in the health service centres in Zigong. Improving the diagnostic ability of malaria, strengthening the health education on malaria prevention and control knowledge for labour exporting personnel, and monitoring the population who turned from high malaria prevalence areas are required to prevent the reemergence of malaria in Zigong.