OBJECTIVE:To assess the survival vulnerability of Oncomelania hupensis in Jiangxi Province under future climate scenarios, and to identify low-vulnerability areas for its survival in this province. METHODS:Village-level O. hupensis snail survey and O. hupensis snail control with chemical treatments in Jiangxi Province from 2016 to 2024 were captured from the Parasitic Disease Prevention and Control Information Management System of China Disease Prevention and Control Information System. Climatic data were primarily sourced from the Resource and Environmental Science Data Platform, Chinese Academy of Sciences (http://www.resdc.cn/), including annual average temperature, annual average precipitation, annual accumulated temperature above 10 °C, annual accumulated temperature above 0 °C, annual maximum temperature, annual minimum temperature, and annual average relative humidity, and nineteen bioclimatic variables were downloaded from the WorldClim website (https://www.worldclim.org/), including mean diurnal range, isothermality, temperature seasonality, and so on. Elevation and normalized difference vegetation index were catprued from the Resource and Environmental Science Data Platform, Chinese Academy of Sciences (http://www.resdc.cn/), and distance to rivers was downloaded from the WorldPop website (http://www.worldpop.org), and land use and land cover (LULC) data were downloaded from the Big Earth Data Center, Chinese Academy of Sciences (https://data.casearth.cn/), and nature reserve data were obtained from the China Nature Reserve Specimen Resource Sharing Platform (http://www.papc.cn/). Three Shared Socioeconomic Pathways (SSPs) from the Beijing Climate Center-Climate System Model version 2-Medium Resolution (BCC-CSM2-MR) global climate model were employed as future climate scenarios, including SSP126, SSP245, SSP585, and the biomod2 ensemble model in R package was used to simulate suitable habitats for O. hupensis snails in Jiangxi Province in 2050 and 2070 under these scenarios. A snail survival vulnerability index was constructed based on the area of suitable snail habitats, area covered by snail control through chemical treatment, area covered by nature reserves, and changes in snail habitat fragmentation, and a map of snail survival vulnerability distribution was plotted. RESULTS:The real area of snail habitats ranged from 78 486.76 to 85 309.47 hm2, and the area of snail control with chemical treatment ranged from 10 138.98 to 13 240.16 hm2 in Jiangxi Province from 2016 to 2024. There were 429 to 531 villages detected with snails during the nine-year period, and the number of actually snail-infested villages ranged from 645 to 686. A total of 818 snail-present points and 1 996 snail-absent points were obtained from snail survey records. The best performance of the biomod2 ensemble model was achieved if a weighted mean approach was used as the ensemble strategy, with a true skill statistic value of 0.799 and an area under the receiver operating characteristic curve of 0.957, and modeling identified annual average relative humidity and annual average precipitation as two most influencing climatic variables for snail distribution. Relative to the current areas of suitable snail habitats under present climate conditions, the area of suitable snail habitats was projected to expand by 24.49% to 46.28% in Jiangxi Province under future climate scenarios, and the proportion of nature reserves areas in the areas of suitable snail habitats was projected to decrease slightly from the current 2.77% to approximately 2.52%, while the proportion of areas of snail control through chemical treatment in areas of suitable snail habitats varied from 0.64% to 19.57%, and the percentage of changes in snail habitat fragmentation ranged from 3.86% to 12.23%. Based on these four indicators, the snail survival vulnerability index was estimated to range from -1.96 to 0.62 in Jiangxi Province. The arithmetic mean of the snail survival vulnerability index differed under three SSP scenarios (SSP126, SSP245 and SSP585), with the highest mean value (-0.69) in 2070 under SSP126, and the lowest mean value (-0.78) in 2070 under SSP585. CONCLUSIONS:The snail survival vulnerability index ranges from -1.96 to 0.62 in Jiangxi Province under future climate scenarios, and the suitable habitats for O. hupensis snails appear an overall tendency towards expansion. Low-vulnerability snail habitats are mainly distributed along the shores of Poyang Lake and the Yangtze River in Jiangxi Province, partially overlapping with nature reserves. Intensified surveillance of O. hupensis snails is recommended in these areas in the future.
OBJECTIVE:To establish a fluorescent recombinase-aided amplification (RAA) assay for detection of Strongyloides stercoralis nucleic acid and to preliminarily evaluate its performance. METHODS:Six sets of specific primers targeting S. stercoralis 18S ribosomal RNA (18S rRNA) gene and one fluorescent probe were designed and synthesized. The optimal primer-probe set was determined through systematic screening and optimization to establish the fluorescent RAA assay. The assay was evaluated using S. stercoralis genomic DNA at concentrations of 100, 10, and 1 pg/μL, and 100, 10, and 1 fg/μL, as well as recombinant pUC57 plasmids containing the target gene fragments at 1 × 105, 1 × 104, 1 × 103, 1 × 102, 1 × 101, 1 × 100 copies/reaction, to determine the analytical sensitivity. Genomic DNA from Ascaris lumbricoides, Ancylostoma duodenale, Enterobius vermicularis, Angiostrongylus cantonensis, Trichinella spiralis, Clonorchis sinensis, Schistosoma japonicum, and Taenia saginata was used to assess assay specificity. A total of 25 stool samples from patients suspected of S. stercoralis infection were tested by the modified Baermann funnel technique, PCR, and the established fluorescent RAA assay. The sensitivity, specificity, concordance rate and their 95% confidence intervals (CI) of these three techniques were estimated, and agreement between methods was evaluated using the Kappa coefficient. RESULTS:Exo-4 was identified as the optimal primer set screened from the six primer sets, and the best amplification performance was achieved when the final concentrations of the forward and reverse primers were 0.44 μmol/L and a probe concentration was 0.20 μmol/L. The limit of detection of the fluorescent RAA assay was 100 fg/μL for genomic DNA of S. stercoralis and 1 × 100 copies/reaction for recombinant plasmids. Specific fluorescence signals were detected within 5 min, with no cross-reactivity observed with A. lumbricoides, A. duodenale, E. vermicularis, A. cantonensis, T. spiralis, C. sinensis, S. japonicum, or T. saginata. Among the 25 clinical stool samples from patients suspected of S. stercoralis infections, the modified Baermann funnel technique and fluorescent RAA assay detected 19 positives and 6 negatives, whereas PCR detected 18 positives and 7 negatives. The fluorescent RAA assay showed a sensitivity of 100.00% [95% CI: (82.35%, 100.00%)], specificity of 100.00% [95% CI: (54.07%, 100.00%)], concordance rate of 100.00% [95% CI: (86.28%, 100.00%)], and a Kappa coefficient of 1.00 [95% CI: (1.00, 1.00)] (P < 0.001) relative to the modified Baermann funnel technique, and a sensitivity of 100.00% [95% CI: (81.47%, 100.00%)], specificity of 85.71% [95% CI: (42.13%, 99.64%)], concordance rate of 96.00% [95% CI: (79.65%, 99.90%)], and a Kappa coefficient of 0.90 [95% CI: (0.70, 1.00)] (P < 0.001). Positive amplification products emitted green fluorescence under a portable blue-light device, enabling visual interpretation of results. CONCLUSIONS:The fluorescent RAA assay established in this study is rapid, highly sensitive, and highly specific. It enables detection of S. stercoralis nucleic acid under isothermal conditions and allows visual interpretation of results, providing a novel tool for rapid clinical diagnosis and field screening of S. stercoralis infections.
OBJECTIVE:To investigate the temporal changes in pathological damage and macrophage polarization in liver and spleen tissues of mice infected with Angiostrongylus cantonensis, and to preliminarily unravel the peripheral immune responses during the early stage of A. cantonensis infection. METHODS:Forty female BALB/c mice at ages of 6 to 8 weeks were randomly divided into four groups, including the control group and 7-, 14-, and 21-day infection groups, with 10 mice in each group. Each mouse in the infection groups was inoculated with 30 third-stage (L3) larvae of A. cantonensis by oral gavage, and five mice were randomly selected from each infection group on days 7, 14, and 21 post-infection, while mice in the control group were given the same volume of physiological saline and five mice were randomly selected from the control group on the day of oral gavage. Mouse liver and spleen tissues were sampled. The histopathological changes of mouse liver and spleen tissues were observed using hematoxylin and eosin (HE) staining, and the percentage of positive staining area and the co-localization positive rates of the macrophage surface antigens F4/80, CD86, and CD206 were quantified in mouse liver and spleen tissues using immunohistochemical and immunofluorescence staining. In addition, five mice were collected from each infection group on days 7, 14, and 21 post-infection, and five mice were collected from the control group on the day of oral gavage. Mouse liver and spleen tissues were sampled for detection of macrophage markers CD86 and CD206 and macrophage phenotyping using flow cytometry, and the expression of M1 macrophage markers, including inducible nitric oxide synthase (Nos2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and M2 markers, including arginase 1 (Arg1), mannose receptor C-type 1 (Mrc1) and chitinase-like protein 3 (Chil3) was quantified in mouse liver and spleen tissues using real-time quantitative PCR (RT-qPCR) assay. RESULTS:Proliferative lesions of the hepatocyte were observed in mouse liver tissues and the follicular structures of the mouse spleen white pulp were disrupted 21 days post-infection with A. cantonensis. Immunohistochemical staining showed that there were significant differences in the percentages of F4/80, CD86 and CD206 positive staining areas in the liver and spleen tissues among the four groups of mice (F = 242.40, 197.14, 183.19, 157.65, 242.35 and 146.24; all P values < 0.001), and the percentages of positive staining in the liver and spleen tissues of mice in the 14-day infection group [(4.45 ± 0.51)%, (3.74 ± 0.67)%, (8.32 ± 0.72)%, (16.56 ± 1.14)%, (11.62 ± 0.52)%, and (8.29 ± 0.72)%, respectively] and the 21-day infection group [(3.70 ± 0.11)%, (3.22 ± 0.43)%, (11.53 ± 1.03)%, (12.59 ± 1.05)%, (9.02 ± 0.83)%, and (11.67 ± 1.10)%, respectively] were higher than in the control group [(0.35 ± 0.16)%, (0.40 ± 0.02)%, (0.93 ± 0.05)%, (2.78 ± 0.26)%, (2.33 ± 0.20)%, and (1.85 ± 0.20)%, respectively] (all P values < 0.05). Immunofluorescence staining showed significant differences in the positive rates of F4/80 co-localization with CD86 and CD206 in mouse liver and spleen tissues among the four groups (F = 24.42, 25.28, 54.51 and 130.55; all P values < 0.001). Flow cytometry detected significant differences in the proportions of CD86+ and CD206+ macrophages in mouse liver and spleen tissues among the four groups (F = 67.98, 18.41, 29.77, 172.80; all P values < 0.001), and the proportions of CD206+ macrophages in the liver and spleen of the 21-day infection group were significantly higher than those in the control group [(9.25 ± 2.55)% vs (3.83 ± 0.72)%, and (4.22 ± 0.56)% vs (0.47 ± 0.18)%, respectively] (both P values < 0.05). In addition, RT-qPCR assay quantified significant differences in the relative mRNA expression of M1 macrophage markers (IL-1β, TNF-α and Nos2) and M2 macrophage markers (Arg1, Chil3 and Mrc1) in mouse liver and spleen tissues among the four groups (F = 41.30, 31.82, 199.33, 19.96, 62.01, 119.76, 23.67, 95.90, 72.27, 82.59, 123.41 and 29.75; all P values < 0.05). CONCLUSIONS:A. cantonensis infection may cause progressive pathological damage in mouse liver and spleen tissues, accompanied by dynamic temporal changes in macrophage polarization. M1 macrophage polarization predominates at the early stage of A. cantonensis infection and shifts towards M2 polarization at the later stages, suggesting that M2 polarization may participate in immune regulation at late stages of A. cantonensis infection by suppressing excessive inflammatory responses and promoting tissue repair.
Since the founding of the People's Republic of China, remarkable achievements have been gained in infectious disease prevention and control, and rich practical experiences have been accumulated. If these experiences are shared with developing countries, it will greatly contribute to global infectious disease control and global health security. Under the framework of Forum on China-Africa Cooperation, a series of China-Africa public health capacity training programs have been recently held in China, in order to help improve the capability of infectious disease control in African countries. This article summarized and refined good design concepts and practices from these programs, so as to provide insights into sustainable optimization of China-Africa public health capacity training and improvements of the training effectiveness.
As one of the most serious global public health concerns, malaria is highly prevalent in Africa and has severely hindered local social and economic developments. Anti-malaria aid underpinned by artemisinin has emerged as an iconic practice of China's engagement in global health governance in the context of evolving global health governance, which continuously exerts its distinctive impact. The Artemisinin Anti-Malaria Team at Guangzhou University of Chinese Medicine is dedicated to safeguarding global health, committed to transforming artemisinin, a precious gift of traditional Chinese medicine to the world, into tangible impetus for malaria elimination. At the convergence of the China-Africa Year of People-to-People Exchanges and World Malaria Day, a review of China-Africa health cooperation is of specific significance. Based on the practices of international anti-malaria projects led by the Artemisinin Anti-Malaria Team at Guangzhou University of Chinese Medicine, this paper systematically summarizes the theoretical innovations, practical values and humanistic core of China's anti-malaria approaches, and analyzes the core challenges in global malaria elimination programmes in the new era.
OBJECTIVE:To prepare the recombinant Echinococcus granulosus Polo-like kinase 2 (rEgPLK2) protein and evaluate its immunoprotective efficacy against cystic echinococcosis, so as to provide insights into research and development of novel vaccines against echinococcosis. METHODS:The Polo-like kinase (PLK) protein sequences were retrieved from 12 species in the NCBI protein database, including E. granulosus and E. multilocularis. Multiple sequence alignment was performed using the Clustal Omega program, and structural visualization and homology analysis were conducted using the ESPript 3.2 program. The recombinant plasmid pET-30a-EgPLK2 was transformed into BL21(DE3) competent cells. Protein expression was induced with isopropyl-β-D-thiogalactoside (IPTG), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize the expression and molecular weight of the rEgPLK2 protein. The purified rEgPLK2 protein was thoroughly emulsified with Freund's complete adjuvant at a 1 : 1 volume ratio. Two New Zealand white rabbits were immunized with multipoint subcutaneous injection on the back at a dose of 300 μg per rabbit for primary immunization. For booster immunizations, the protein was emulsified with Freund's incomplete adjuvant at a 1 : 1 volume ratio and administered on days 14, 28, and 42 after the primary immunization at a dose of 150 μg per rabbit. Serum was sampled from the rabbit ear vein on day 7 after the final immunization to yield anti-rEgPLK2 polyclonal antibodies. Antibody titer was determined by indirect enzyme-linked immunosorbent assay (ELISA), and antibody specificity was verified by Western blotting. The tissue localization of the EgPLK2 protein was detected in E. granulosus protoscoleces and adult worms using immunofluorescence assay (IFA). Eighteen 6- to 8-week-old female SPF-grade BALB/c mice were randomly divided into three groups, including the blank control group, rEgPLK2-ISA immunization group, and PBS-ISA adjuvant control group, of 6 mice each group. Mice in the rEgPLK2-ISA immunization group and PBSISA group received three primary immunizations via intramuscular injection, and animals in the rEgPLK2-ISA immunization group was inoculated with immunogens prepared by emulsifying rEgPLK2 protein with ISA 201 adjuvant at a 1 : 1 volume ratio (6 μg per mouse), while mice in the PBS-ISA adjuvant control group received an equal volume of PBS emulsified with ISA adjuvant at a 1 : 1 volume ratio. A fourth booster immunization was administered via intraperitoneal injection. Mice in the rEgPLK2-ISA immunization group received a booster immunization with 8 μg of rEgPLK2 protein per mouse, and animals in the PBS-ISA group received an equal volume of PBS, with immunizations given at 2-week intervals. Mice in the blank control group were given no treatment, and housed under standard conditions. Tail vein blood was collected from all mice 7 days after the final immunization, and levels of specific anti-rEgPLK2 IgG antibody and its subclasses (IgG1, IgG2a, IgG2b, IgG3) were measured by indirect ELISA. E. granulosus infection was modelled in mice through injection with 1 000 E. granulosus protoscoleces via intrahepatic portal vein in the rEgPLK2-ISA immunization group and PBS-ISA adjuvant control group 2 weeks after the last immunization. All mice were sacrificed and dissected. The number of cysts was counted in mouse livers, and the cyst reduction rate was calculated. Liver tissues were processed for paraffin sectioning and stained with hematoxylin and eosin (HE), and histopathological changes were examined under a light microscope. RESULTS:Sequence analysis revealed that EgPLK2 shared a high amino acid sequence homology with E. multilocularis PLK2 (EmPLK2) and contained the typical domains of the Polo-like kinase family, including the serine/threonine protein kinase catalytic domain (STKc) and Polo-box. The IPTG-induced rEgPLK2 protein was mainly expressed in the form of inclusion bodies, and the purified rEgPLK2 protein showed a relative molecular mass of approximately 70 kDa. The prepared rabbit anti-rEgPLK2 polyclonal antibody had a titer of 1 : 256 000, and Western blotting assay showed that this anti-body specifically recognized the rEgPLK2 protein with a relative molecular mass of approximately 70 kDa. Immunofluorescence assay showed that the EgPLK2 protein was localized in the excretory bladder and rostellum of E. granulosus protoscoleces, as well as the tegument, suckers, and inter-proglottid junctions of adult worms. Immunoprotective assay showed that the serum levels of specific anti-rEgPLK2 IgG, IgG1, IgG2a, and IgG2b antibodies were 2.92 ± 0.49, 0.33 ± 0.10, 0.31 (0.36), and 3.12 (1.73) in mice in the rEgPLK2-ISA immunization group, which were all significantly higher than those in the PBS-ISA adjuvant control group (0.14 ± 0.04, 0.07 ± 0.01, 0.12 ± 0.04, and 0.11 ± 0.04, respectively) (t = 19.28 and 8.46, Z = 3.75 and 4.15; all P values < 0.001); however, there was no significant difference in the serum anti-IgG3 antibody level between the rEgPLK2-ISA immunization group and the PBS-ISA adjuvant control group [0.07 (0.01) vs. 0.073 (0.07); Z = 0.69, P > 0.05)]. In the mouse model of E. granulosus infections, the area of hepatic lesions was reduced and the inflammatory infiltration was alleviated in the rEgPLK2-ISA immunization group than in the PBS-ISA adjuvant control group, and the number of hepatic cysts was higher in the PBS-ISA adjuvant control group than in the rEgPLK2-ISA immunization group [8.00 (2.00) vs. 1.00 (0.75); Z = -2.93, P < 0.01], with a cyst reduction rate of 80.40%. Indirect ELISA assay measured higher serum levels of specific anti-rEgPLK2 IgG (3.28 ± 0.48 vs. 0.11 ± 0.04; t = 15.86, P < 0.01), IgG1 (0.29 ± 0.02 vs. 0.09 ± 0.01; t = 15.67, P < 0.01), IgG2a [3.71 (1.09) vs. 0.08 (0.03); Z = 2.88, P < 0.01], and IgG2b antibodies [3.34 (1.01) vs. 0.08 (0.03); Z = 2.88, P < 0.01] in the rEgPLK2-ISA immunization group than in the PBS-ISA adjuvant control group, and there was no significant difference in the serum level of the specific anti-rEgPLK2 IgG3 antibody between the rEgPLK2-ISA immunization group and the PBS-ISA adjuvant control group (0.07 ± 0.01 vs. 0.07 ± 0.01; t = 1.29, P > 0.05). CONCLUSIONS:The prokaryotic expression system has been successfully constructed for the EgPLK2 gene and the anti-rEgPLK2 polyclonal antibody has been obtained. The rEgPLK2 protein exhibits a high immunogenicity, and is effective to protect against E. granulosus infection, and inhibits cyst development, which is a promising candidate vaccine target against cystic echinococcosis.
Malaria remains one of the most serious public health problems worldwide. After China achieved the target for malaria elimination, thousands of imported malaria cases are still reported annually. Timely and accurate diagnosis is critical to clinical treatment of cases and prevention of re-establishment of imported malaria. Detection of Plasmodium antigens is one of the criteria for definitive diagnosis of malaria. Malaria rapid diagnostic tests (RDTs) based on the immunochromatographic assay have become an important tool for clinical diagnosis of malaria due to convenient procedures and rapid detection. Nevertheless, there are still multiple misunderstandings pertaining to use of malaria RDTs among workers in medical and disease control and prevention institutions at all levels across China. To standardize technical guidelines and operational procedures for detection of Plasmodium spp., the National Disease Control and Prevention Administration has arranged the formulation of a recommended health industry standard Detection of Plasmodium spp. Immune-chromatographic test (WS/T 10029-2025), which has been officially iming immunochromatographic assays, including the testing principles, sample collection and detection procedures, and result interpretation, which provides the technical basis and operational specifications for detection of Plasmodium antigens in medical and disease control and prevention institutions at all levels. Based on analysis of the epidemiological characteristics of imported malaria in China, this article interprets the core content of this standard, aiming to promote its dissemination, implementation, and practical applications.
OBJECTIVE:To investigate the palmitoyltransferase (PATs) activity during different developmental stages of Plasmodium falciparum and to explore the impact of PATs activity on intra-erythrocytic replication and gametocytogenesis, so as to provide insights into development of novel antimalarial targets. METHODS:The PATs activity was measured using the click chemistry method during different developmental stages of P. falciparum, including rings, trophozoites, schizonts, and gametocytes. P. falciparum-infected erythrocytes were divided into three groups, including a control group, a dimethyl sulfoxide (DMSO) group, and a 2-bromopalmitate (2-BP) group. Erythrocytes in the control group were incubated in normal culture media, and cells in DMSO and 2-BP groups were exposed to DMSO or 2-BP at a final concentration of 10 μmol/L to examine the inhibitory effect of 2BP on the PATs activity. The growth curve analysis and gametocyte production assay were employed to investigate changes in asexual proliferation and gametocyte production of P. falciparum following inhibition of the PATs activity with 2-BP, and transcriptomics sequencing was performed to examine the impact of inhibition of the PATs activity with 2-BP on transcriptional levels of P. falciparum and possible mechanisms. RESULTS:The green fluorescence intensity of PATs varied across developmental stages of P. falciparum (F = 38.120, P < 0.001), with a higher fluorescence intensity seen in trophozoites (35.680 ± 8.439), merozoites (33.380 ± 9.030) and gametocytes (21.540 ± 8.654), and a lower intensity in ring bodies (10.720 ± 3.183) (all P values < 0.05). The green fluorescence intensities were 8.738 ± 1.576, 8.633 ± 1.827 and 4.911 ± 0.318 in the control group, DMSO group, and 2-BP group 4 days post-culture (schizont stage), respectively (F = 91.490, P < 0.001), and the PATs activity was significantly inhibited post-treatment with 2-BP (P < 0.05). The areas under the time curve for the parasitemias were 25.700 ± 0.696, 28.630 ± 3.062 and 8.370 ± 1.751 in the control group, DMSO group, and 2-BP group following inhibition of the PATs activity during the asexual stage of P. falciparum (F = 83.440, P < 0.001), and the parasitemia was lower in the 2-BP group than in the control group and the DMSO group (both P values < 0.001). In addition, the asexual stage development was delayed in the 2BP group, with abnormal morphology seen. The numbers of merozoites were 18.050 ± 4.362, 18.200 ± 3.517 and 14.020 ± 4.320 in each schizont in the control group, DMSO group and 2-BP group, respectively (H = 39.100, P < 0.001), and the merozoite number was significantly lower in the 2-BP group than in the control group and the DMSO group (both Padjusted values < 0.001). The areas under the time curve for P. falciparum gametocyte production were 18.900 ± 0.384, 18.240 ± 0.177 and 7.507 ± 0.201 in the control group, the DMSO group, and the 2-BP group following inhibition of the PATs activity, respectively (F = 1 677.000, P < 0.001), and the proportion of gametocyte production was statistically lower in the 2-BP group than in the control group and DMSO group (both P values < 0.001). The formation and maturation of gametophytes were blocked in the 2-BP group, and most of them were arrested in the middle and late stages. Following 2-BP treatment, significantly down-regulated genes during the asexual stage of P. falciparum were significantly enriched in cell cycle regulation, mitosis, DNA damage/response and structural organization, and significantly down-regulated genes during the gametocyte stage were significantly enriched in biological processes of cell cycle (mitosis and G1/S transition), RNA regulation and metabolism (such as carbon catabolite repression 4-negative on TATA-less) and cell development and differentiation. CONCLUSIONS:The palmitoylation modification plays an important role in the asexual reproduction and gametocyte generation and development of P. falciparum.
OBJECTIVE:To analyze the spatiotemporal distribution characteristics of and trends in the disease burden of dengue fever in China from 2005 to 2024, so as to provide insights into formulation of dengue fever control strategies. METHODS:Data pertaining to dengue fever cases in China from 2005 to 2024 were retrieved from the Infectious Disease Reporting Information System of Chinese Center for Disease Control and Prevention, and city population, gross domestic product (GDP), GDP per capita, and consumer price index in China were captured from the China Statistical Yearbook, National Bureau of Statistics of China, the China City Statistical Yearbook, and bureaus of statistics in each city. The disability-adjusted life years (DALYs), years of life lost (YLLs), and years lived with disability (YLDs) due to dengue fever were calculated in China from 2005 to 2024. The direct and indirect economic burdens of dengue fever were estimated to calculate the total economic burden. The trends in the disease burden of dengue fever were estimated in China from 2005 to 2024 using a Joinpoint regression model with the software Joinpoint 4.9.0.0, and the average annual percent change (AAPC) and its 95% confidence interval (CI) were calculated. In addition, the DALYs rate and economic burden of dengue fever in China were subjected to global and local spatial autocorrelation analyses using the software ArcGIS 10.8. RESULTS:The gross DALYs due to dengue fever were 5 558 person-years in China from 2005 to 2024, and the DALYs of dengue fever increased from 36 person-years in 2005 to 899 person-years in 2024, with an increase of 23.97 folds. The average annual DALYs rate of dengue fever was 0.02 person-years/105 in China during the 20-year study period from 2005 to 2024, and the DALYs rate peaked in 2014 (0.13 person-years/105) and reduced during the COVID-19 pandemic from 2020 to 2022. YLDs were the main contributor of DALYs due to dengue fever in China from 2005 to 2024, with a total of 5 354 person-years, accounting for 96.33% (5 354 person-years/5 558 person-years) of the gross DALYs. The gross DALYs of dengue fever were 2 982 person-years among men (53.66%) and 2 575 person-years among women (46.34%) in China from 2005 to 2024, and high DALYs of dengue fever were measured among residents at ages of 15 to 30 years (1 639 person-years), 30 to 45 years (1 857 person-years), and 45 to 60 years (1 204 person-years), respectively, accounting for 84.56% (4 700 person-years/5 558 person-years) of total DALYs due to dengue fever in China. The total economic burden of dengue fever was estimated to be 612 million Yuan in China from 2005 to 2024, with an average annual economic burden of 30.584 million Yuan. The economic burden of dengue fever increased from 196 000 Yuan in 2005 to 121 million Yuan in 2024 in China, with an increase of 616.35 folds, and the per capita economic burden increased from 3 322.21 Yuan in 2005 to 4 940.01 Yuan in 2024, with an increase of 48.70%. Dengue fever cases were reported in 274 cities (counties) across 31 provinces (autonomous regions, municipalities) in China from 2005 to 2024, with relatively higher DALYs in Guangdong Province and Yunnan Province. Spatial autocorrelation analysis revealed that the disease burden of dengue fever appeared positive aggregation in Chinese cities (counties) from 2005 to 2024 (global Moran's I = 0.045, Z = 2.24, P < 0.05), with high-high clusters mainly concentrated in the Pearl River Delta region in Guangdong Province and Xishuangbanna Dai Autonomous Prefecture and Pu'er City in Yunnan Province, and the total economic burden (global Moran's I = 0.032, Z = 9.55, P < 0.001), per capita economic burden (global Moran's I = 0.208, Z = 27.34, P < 0.001), and the proportion of total economic burdens in GDP in 2024 (global Moran's I = 0.017, Z = 5.91, P < 0.001) all presented positive aggregation, with relatively higher total economic burdens mainly concentrated in Guangdong Province and Yunnan Province. Joinpoint regression analysis showed that the gross DALYs rates of dengue fever appeared an overall tendency towards a rise in China from 2005 to 2024 (AAPC = 16.24%, P = 0.029), and the DALYs rate presented an overall tendency towards a rise among both men (AAPC = 14.75%, P = 0.028) and women (AAPC = 14.93%, P = 0.037) during the study period. The per capita direct economic burden appeared an overall tendency towards a rise among dengue fever patients in China from 2005 to 2024 (AAPC = 2.16%, P = 0.012); however, there was no significant difference in the trends in the per capita indirect economic burden (AAPC = 0.46%, P = 0.470). In addition, the DALYs rate of dengue fever appeared a tendency towards a rise in 84.67% (232/274) of cities (counties) in China from 2005 to 2024, and the per capita economic burden appeared a tendency towards a rise in 85.40% (234/274) of cities (counties), while the DALYs rate and per capita economic burden of dengue fever appeared a tendency towards a rise in 77.01% (211/274) of cities (counties). CONCLUSIONS:The disease burden of dengue fever significantly increased in China from 2005 to 2024. It is recommended to reinforce integrated dengue fever control in high-risk areas and among high-risk populations, and to improve the surveillance of imported dengue fever cases and vector control.
As one of major global public health challenges, malaria control is crucial to building a global community of health for all. The 2026 "China-Africa Year of People-to-People Exchanges" provides a new opportunity for China's participation in international cooperation for malaria control. This article introduces the strategic significance and practical path of China's participation in international cooperation on malaria control in the new era, and discusses policy recommendations for optimizing the cooperation model between China and African countries, aiming to provide insights into accelerating the progress towards global malaria elimination and facilitating the building of a China-Africa community of health for all.
Triatoma rubrofasciata is currently the most widely distributed species of Triatoma worldwide, and it is also widespread in southern China. T. rubrofasciata has been proven to transmit Trypanosoma cruzi, and is one of vectors transmitting Chagas disease, which poses a potential risk for transmission of imported Chagas disease in China. Findings from latest studies have shown that T. rubrofasciata naturally infects T. lewisi, T. conorhini, and T. rangeli, which undoubtedly increases significant risks of and challenges to trypanosomiasis control in China. This article briefly describes the species of T. rubrofasciata-transmitted trypanosomes, and summarizes the epidemiological characteristics of trypanosomiasis, so as to provide insights into T. rubrofasciata-transmitted trypanosomiasis surveillance and control, and prevention of trypanosomiasis development and transmission in China.
OBJECTIVE:To investigate the changes in the density of Aedes albopictus across different regions and different breeding habitats in Baoshan District, Shanghai Municipality from 2018 to 2024, so as to inform evidence-based control strategies for mosquito-borne infectious diseases in Shanghai Municipality. METHODS:Ae. albopictus surveillance sites were deployed in 12 subdistricts (towns) of Baoshan District, Shanghai Municipality from 2018 to 2024, and the surveillance on the density of Ae. albopictus was performed in each surveillance site once weekly during the peak activity period of Aedes mosquitoes from May to October each year from 2018 to 2024. Mosquito ovitraps were deployed in various breeding habitats in each surveillance site according to geographical locations, including residential areas, schools, government institutions, hospitals, recycling stations, and construction sites, and regularly collected, and the mosquito ovitrap index (MOI) was calculated. The changes in the Ae. albopictus density were analyzed based on MOI across years, regions, and breeding habitats. Additionally, from May to October each year between 2018 and 2024, monthly risk assessments of Aedes albopictus density were conducted in every subdistrict (town) of Baoshan District, Shanghai. RESULTS:The annual mean MOI values of Ae. albopictus were 5.88 ± 2.29, 8.19 ± 4.46, 7.43 ± 3.40, 5.44 ± 2.52, 3.97 ± 2.72, 3.82 ± 1.57, and 2.56 ± 1.11 in Baoshan District from 2018 to 2024, respectively (F = 75.886, P < 0.05), and the MOI appeared a rise followed by a reduction each year and peaked during the period between June and August. There was a significant difference in the 7-year mean MOI of Ae. albopictus across the 12 subdistricts/towns (F = 26.558, P < 0.05), and there were 6 subdistricts/towns with a 7-year mean MOI of over 5, including Songnan Town (8.44 ± 4.68), Dachang Town (7.71 ± 5.28), Gucun Town (7.13 ± 3.57), Yuepu Town (5.74 ± 1.69), Gaojing Town (5.51 ± 3.44), and Wusong Subdistrict (5.41 ± 2.04). There was a significant difference in the MOI of Ae. albopictus across breeding habitats (F = 3.843, P < 0.05), with the highest MOI seen in recycling stations (9.86 ± 4.61), which was significantly higher than in other habitats (P < 0.05), and the lowest seen in construction sites (4.90 ± 2.95), which was significantly lower than in other habitats (P < 0.05). The proportion of frequency with Ae. albopictus density transmission risk decreased from 54.17% in 2018 to 11.11% in 2024 in all subdistricts (towns) of Baoshan District, and the frequency of outbreak risks peaked in 2019 (18 instances) and declined substantially in 2021 (6 instances), with no records of outbreak or transmission risk documented across the district in 2024. CONCLUSIONS:There were substantial seasonal variations in the Ae. albopictus density in Baoshan District, Shanghai Municipality from 2018 to 2024. The Ae. albopictus density peaked during the period between June and August in Baoshan District each year from 2018 to 2024, with a relatively higher density in Songnan Town and Dachang Town, and in recycling stations. Precision control measures and intensified seasonal interventions are recommended in high-risk settings in Baoshan District to reduce the transmission risk of Aedes-borne infectious diseases.
This article reports the diagnosis and treatment of one patient with fascioliasis of the common bile duct, aiming to provide reference for the clinical diagnosis and treatment of this disease. The patient sought medical attention due to long-term symptoms such as abdominal pain, abdominal distension, nausea, and vomiting. Imaging examinations displayed dilatation of the common bile duct and intrahepatic bile ducts, and the patient was admitted to the hospital with a diagnosis of "common bile duct stone". Through endoscopic retrograde cholangiopancreatography and choledochoscopy, two worms were collected from the common bile duct, which were identified as Fasciola hepatica by high-throughput sequencing.
OBJECTIVE:To investigate the distribution characteristics of Oncomelania hupensis snails in Yunnan Province fol-lowing interruption of schistosomiasis transmission, so as to provide the evidence for assessing the risk of schistosomiasis transmission and scientifically formulating the schistosomiasis surveillance program. METHODS:According to the requirements of the National Schistosomiasis Surveillance Scheme (2020 Edition), O. hupensis snail surveillance data were collected from 18 schistosomiasis-endemic counties (cities, districts) in Yunnan Province from 2020 to 2024, including area of snail survey, area of snail habitats, area of re-emerging snail habitats, number of frames surveyed, number of frames with O. hupensis snails, number of O. hupensis snails captured, and number of living snails, and the occurrence of frames with snails and mean density of living snails were calculated. Changes in snail status over the 5-year period from 2020 to 2024 and the differences in snail distributions specified by epidemic intensity, environmental type, and vegetation type were analyzed. RESULTS:The areas of snail survey increased from 1 727.96 hm2 in 2020 to 3 894.45 hm2 in 2024 (peak) across 18 schistosomiasis-endemic counties (cities, districts) in Yunnan Province during the period from 2020 through 2024. The areas of snail habitats increased from 70.36 hm2 in 2020 to a peak in 2023 (172.04 hm2), followed by a reduction to 132.36 hm2 in 2024, and the areas of re-emerging snail habitats increased from 42.71 hm2 in 2020 to a peak in 2022 (78.43 hm2), followed by a reduction to 40.21 hm2 in 2024. The occurrence of frames with snails and mean density of living snails increased from 1.24% (3 025/244 404) and (0.033 2 ± 0.038 7) snails/0.1 m2 in 2020 to peaks at 2.03% (6 231/307 563) and (0.066 9 ± 0.068 4) snails/0.1 m2 in 2023, followed by reductions to 1.04% (5 829/559 941) and (0.032 6 ± 0.057 7) snails/0.1 m2 in 2024, respectively. There was a significant difference in the occurrence of frames with snails over the 5-year study period (χ2 = 1 962.95, P < 0.05), and the occurrence of frames with snails reduced by 48.71% in 2024 relative to in 2023 (χ2 = 1 411.05, P < 0.005); however, there was no significant difference in the mean density of living snails over the 5 years (H = 5.310, P > 0.05). There were significant differences in the occurrence of frames with snails (χ2 = 481.27, P < 0.05) and mean density of living snails (H = 6.872, P < 0.05) in schistosomiasis-endemic areas with different epidemic intensities. The occurrence of frames with snails (χ2 = 25.32 and 38.70, both P values < 0.017) and mean density of living snails (Z = 28.55 and 49.96, both P values < 0.017) were higher in schistosomiasis transmission-interrupted and eliminated areas with snails than in schistosomiasis-eliminated areas without snails, and the occurrence of frames with snails (χ2 = 453.54, P < 0.017) and mean density of living snails (Z = -56.97, P < 0.017) were higher in schistosomiasis-eliminated areas with snails than in schistosomiasis transmission-interrupted areas with snails. O. hupensis snails were mainly distributed in paddy fields, dry farmlands and ditches; however, the occurrence of frames with snails (13.40%, 424/3 164) and mean density of living snails [(0.252 8 ± 0.158 7) snails/0.1 m2] were higher in ponds/weirs than in other types of environments (both P values < 0.05). Rice, dry farmland crops and weeds were main vegetations in which O. hupensis snails were distributed, and the occurrence of frames with snails (2.29%, 7 111/310 140) and mean density of living snails [(0.072 3 ± 0.018 9) snails/0.1 m2] were higher in weeds than in other types of environments (both P values < 0.05). CONCLUSIONS:O. hupensis snails have been effectively controlled in Yunnan Province following implementation of integrated schistosomiasis control measures; however, there are still risk factors for schistosomiasis transmission, including reduced attention to schistosomiasis control and snail re-emergence. Improved control efforts and surveillance system construction and timely identification of risk factors of snail status and timely management are recommended to ensure the achievement of the target of schistosomiasis elimination as scheduled.
OBJECTIVE:To examine the association between epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) and meteorological factors in Shenzhen City during the period from 2012 to 2019. METHODS:Average atmospheric pressure, average air temperature, average relative humidity, precipitation, wind speed, and sunshine duration were captured from Meteorological Bureau of Shenzhen City each month from 2012 to 2019. The average monthly rodent densities in Shenzhen City from 2012 to 2019 were acquired from the Vector Surveillance Management System of Guangdong Provincial Center for Disease Control and Prevention, and the monthly HFRS incidence was retrieved from Shenzhen Municipal Disease Surveillance System from 2012 to 2019. The correlation between meteorological factors and the monthly incidence of HFRS was examined us ing Spearman's rank correlation in Shenzhen City, and the temporal trends in monthly HFRS incidence and the degrees of freedom for the rodent density were determined in Shenzhen City with a generalized additive model. The optimal lag time was identified using excess risk (ER) and its 95% confidence interval (CI), and univariate and multivariate models were fitted to evaluate the impact of meteorological factors on HFRS incidence in Shenzhen City. RESULTS:The median number of incident HFRS cases was 3.00 (interquartile range, 3.25) in Shenzhen City from 2012 to 2019, with an average air temperature of (23.44 ± 4.91) °C, average relative humidity of (76.05 ± 7.61)%, median precipitation of 4.10 (interquartile range, 6.83) mm, average wind speed of (1.97 ± 0.26) m/s, average sunshine duration of (5.17 ± 1.64) h, and median monthly rodent density of 1.74% (interquartile range, 2.52%). Spearman's rank correlation analysis showed that the average air temperature positively correlated with average relative humidity (rs = 0.420, P < 0.05), precipitation (rs = 0.658, P < 0.05) and sunshine duration (rs = 0.633, P < 0.05), and the atmospheric pressure negatively correlated with average air temperature (rs = -0.925, P < 0.05), relative humidity (rs = -0.614, P < 0.05), precipitation (rs = -0.789, P < 0.05) and sunshine duration (rs = -0.437, P < 0.05), while the average relative humidity correlated positively with precipitation (rs = 0.724, P < 0.05) and negatively with sunshine duration (rs = -0.218, P < 0.05). Univariate modeling analysis showed that the ERs and their 95% CI were 0.639% (0.540%, 0.737%) for average atmospheric pressure, -7.157% (-8.113%, -6.190%) for average air temperature, -3.603% (-4.219%, -2.985%) for average relative humidity, -5.889% (-7.085%, -4.669%) for precipitation, 21.881% (-5.149%, 56.612%) for average wind speed, and -13.877% (-16.641%, -11.022%) for sunshine duation (all P values < 0.05). Multivariate modeling analysis showed that in the ensemble model combining average atmospheric pressure and precipitation, the highest ER (6.686%) was caused by increased average atmospheric pressure, and the highest absolute ER values for average air temperature (6.615%), average relative humidity (3.107%) and precipitation (5.386%) were seen after adjustment only for sunshine duration (all P values < 0.05), while the highest absolute ER for sunshine duration (11.875%) was found after adjustment for precipitation (P < 0.05). CONCLUSIONS:An increase in average air temperature, relative humidity, precipitation and sunshine duration resulted in a reduced incidence rate of HFRS in Shenzhen City from 2012 to 2019, and an increase in average atmospheric pressure increased the incidence of HFRS. Meteorological factors are important determinants affecting HFRS incidence in Shenzhen City.
OBJECTIVE:To investigate the antibacterial activity of the antifungal peptide Mt6-21DLeu derived from Musca domestica against Acinetobacter baumannii (AB) and unravel its underlying mechanisms, so as to provide insights into development of novel agents against AB. METHODS:The minimum inhibitory concentrations (MICs) of Mt6-21DLeu, M. domestica-derived antifungal peptide-1 (MAF-1A), and polymyxin B were determined against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and AB using the broth microdilution assay, and the antibacterial activity of Mt6-21DLeu and polymyxin B was dynamically assessed against AB over 24 hours with time-kill curves. The inhibitory effects of Mt6-21DLeu and polymyxin B on biofilm formation in AB at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, and the eradication effects of Mt6-21DLeu and polymyxin B on mature biofilms in AB at concentrations of MIC, 2 × MIC, and 4 × MIC were evaluated using crystal violet staining. Structural changes in the cell membrane of AB were observed 3 hours post-exposure to Mt6-21DLeu at concentrations of MIC and 2 × MIC using scanning electron microscopy, and alterations in the cell membrane permeability of AB were analyzed 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC by means of fluorescence microscopy and propidium iodide (PI) staining. Intracellular reactive oxygen species (ROS) levels in AB were measured 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC using flow cytometry. The survival of Caenorhabditis elegans exposed to Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC was monitored for 7 consecutive days, and survival curves were plotted to evaluate the in vivo toxicity of Mt6-21DLeu. In addition, C. elegans infected with AB and treated with Mt6-21DLeu at a concentration of 4 × MIC served as the treatment group, and uninfected C. elegans served as the control group, while infected but untreated C. elegans served as the infection group. The in vivo antibacterial efficacy of Mt6-21DLeu at a concentration of 4 × MIC was evaluated by comparing the survival curves and bacterial load among the three groups. RESULTS:The MICs of MAF-1A were all >128 μg/mL against S. aureus, B. subtilis, E. coli, K. pneumoniae, P. aeruginosa, and AB. In contrast, the MICs of Mt6-21DLeu were >128, 32, 8, 8, 16, and 4 μg/mL against these strains, respectively, and the MIC of Mt6-21DLeu against AB was close to that of polymyxin B (2 μg/mL). Time-kill curve analysis showed that both Mt6-21DLeu at concentrations of MIC and 2 × MIC and polymyxin B at a concentration of MIC inhibited AB growth over the 24-hour study period. The biofilm biomass in AB was (52.38 ± 6.92)%, (40.88 ± 9.17)% and (14.77 ± 6.00)% post-exposure with Mt6-21DLeu at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, (61.58 ± 7.35)%, (47.42 ± 5.51)% and (20.85 ± 10.48)% post-treatment with polymyxin B at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, and (100.00 ± 15.92)% in the control group (only bacterial suspension), respectively (F = 68.38, P < 0.001), and pairwise comparisons indicated that Mt6-21DLeu and polymyxin B at all concentrations significantly inhibited biofilm formation as compared to the control group (all P values < 0.001). The mature biofilm biomass in AB was (73.44 ± 11.41)%, (72.56 ± 13.08)% and (49.65 ± 9.23)% post-exposure to Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC, (84.38 ± 8.60)%, (72.31 ± 9.63)% and (58.85 ± 4.96)% post-treatment with polymyxin B at concentrations of MIC, 2 × MIC, and 4 × MIC, and (100.00 ± 6.36)% in the control group (F = 35.63, P < 0.001), and pairwise comparisons revealed that Mt6-21DLeu at all concentrations significantly eradicated biofilm biomass (all P values < 0.05); however, polymyxin B showed no clear-cut eradication effect at a concentration of MIC (P > 0.05). Scanning electron microscopy revealed pore formation and content leakage in the cell membrane of AB 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC. Fluorescence microscopy showed that the proportions of PI-stained AB were (24.79 ± 11.51)% and (68.44 ± 15.80)% post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC, and (0.96 ± 0.94)% in the phosphate-buffered saline (PBS) treatment group (F = 105.90, P < 0.001), with the highest proportion of PI-stained AB seen post-treatment with Mt6-21DLeu at a concentration of 2 × MIC (P < 0.05). Flow cytometry revealed that the relative intracellular ROS levels in AB were (652.00 ± 141.90), (694.33 ± 14.19), and (974.33 ± 160.02) 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC, 2 × MIC and 4 × MIC, and (403.67 ± 86.56) in the PBS treatment group, respectively (F = 12.27, P < 0.05), with the highest intracellular ROS level measured following treatment with Mt6-21DLeu at a concentration of 4 × MIC (P < 0.05). Survival curve analysis revealed that Mt6-21DLeu posed no impact on C. elegans survival at concentrations of MIC (χ2 = 0.02, P > 0.05), 2 × MIC (χ2 = 0.06, P > 0.05) or 4 × MIC (χ2 = 0.16, P > 0.05), and there was a significant difference in the survival period of C. elegans among the control group, the infection group, and the treatment group (χ2 = 82.66, P < 0.05), with a significantly longer survival period in the treatment group than in the infection group (χ2 = 45.00, P < 0.05). In addition, the log-transformed bacterial colony counts in C. elegans were (0.00 ± 0.00), (5.46 ± 0.03), and (3.91 ± 0.47) CFU/mL in the control group, the infection group, and the treatment group, respectively (F = 324.80, P < 0.001), and the log-transformed bacterial colony counts in C. elegans were significantly lower in the treatment group than in the infection group (P < 0.05). CONCLUSIONS:Mt6-21DLeu exerts potent antibacterial effects through disrupting the cell membrane integrity of AB and promoting intracellular ROS accumulation in AB, and exhibits promising potential for treatment of AB infections both in vivo and in vitro, which may serve as a candidate drug molecule against multidrug-resistant AB infections.
OBJECTIVE:To investigate the epidemiological characteristics of cross-county imported dengue fever cases within Yunnan province in 2023, so as to provide insights into formulation of preventive and control measures for intra-provincial spread of dengue fever. METHODS:All data pertaining cross-county imported dengue fever cases within Yunnan Province in 2023 were collected, and the temporal, regional and population distributions of the cases were descriptively analyzed. RESULTS:A total of 1 664 intra-provincial cross-county imported dengue fever cases were reported in 95 counties (cities, districts) cross 16 profectures (cities) in Yunnan Province in 2023, accounting for 12.34% of total cases in the province. Cross-county imported dengue fever cases were predominantly reported during the period between August and October (1 516 cases, 91.11% of total cases), and peaked in September (659 cases), with a single-day peak on October 8 (36 cases). During the period from September 4 to 10, five counties (cities) with local dengue fever epidemics, including Jinghong City of Xishuangbanna Dai Autonomous Prefecture, Gengma Dai and Wa Autonomous County of Lincang City, Ruili City of Dehong Dai and Jingpo Autonomous Prefecture, Mengla Coun ty of Xishuangbanna Dai Autonomous Prefecture, and Zhenkang County of Lincang City, exported 165 cross-county imported dengue fever cases to the rest of the province. Among the 1 644 intra-provincial cross-county imported dengue fever cases, the male to female ratio was 1.40∶1.00, and 1 329 cases were at ages of 15 to 55 years (79.87%), with farmers as the predominant occupation (886 cases, 53.25%). The top 5 counties (cities/districts) reporting the highest number of intra-provincial cross-county imported dengue fever cases included Simao District (266 cases) and Lancang Lahu Autonomous County (118 cases) of Pu'er City, Mengla County (91 cases) and Menghai County (91 cases) of Xishuangbanna Dai Autonomous Prefecture, and Mangshi City (73 cases) of Dehong Dai and Jingpo Autonomous Prefecture, which accounting for 38.40% of total imported cases. These intra-provincial cross-county imported dengue fever cases originated from 7 counties (cities/districts) in 4 prefectures (cities), including 1 261 cases (76.70%) from Jinghong City of Xishuangbanna Dai Autonomous Prefecture, 224 cases (13.63%) from Ruili City of Dehong Dai and Jingpo Autonomous Prefecture, 103 cases (6.27%) from Gengma Dai and Wa Autonomous County of Lincang City, 31 cases (1.89%) from Mengla County of Xishuangbanna Dai Autonomous Prefecture, 30 cases (1.82%) from Zhenkang County of Lincang City, 10 cases (0.61%) from Cangyuan Wa Autonomous County of Lincang City, and 5 cases (0.30%) from Mohan-Boten Economic Cooperation Zone of Kunming City. In addition, local dengue fever epidemics following intra-provincial cross-county importation of dengue fevers cases in Simao District, Jinggu Dai and Yi Autonomous County, Mangshi City, Longchuan County, and Cangyuan Wa Autonomous County. CONCLUSIONS:Farmers and students are high-risk populations for intra-provincial cross-county imported dengue fever cases in Yunnan Province, and health education pertaining personal protection against dengue fever should be strengthened among these high-risk populations by governments at all levels. There is a high risk of local out-break of dengue fever following continuous introduction of intra-provincial cross-county imported cases. Standardized management of intra-provincial cross-county imported dengue fever cases should be reinforced to reduce the risk of local epidemics.
OBJECTIVE:To investigate the prevalence of Schistosoma japonicum infections in wild rodents in schistosomiasis-endemic areas of China, so as to provide insights into formulation of technical guidelines for monitoring of and the precise control strategy for S. japonicum infections in wild rodents during the elimination phase. METHODS:Two administrative villages where schistosomiasis was historically highly prevalent were selected each from Dongzhi County, Anhui Province, and Duchang County, Jiangxi Province as study villages. Wild rodents were captured from study villages with baited traps or cages at night in June and September, 2021. The number of rodents captured was recorded, and the rodent species was characterized based on morphologi-cal characteristics. Liver tissues were sampled from captured rodents for macroscopical observation of the presence of egg granulomas, and S. japonicum infection was detected simultaneously using liver tissue homogenate microscopy, examinations of mesenteric tissues for parasites, and modified Kato-Katz thick smear technique (Kato-Katz technique). A positive S. japonicum infection was defined as detection of S. japonicum eggs or adult worms by any of these methods. The rate of wild rodent capture and prevalence of S. japonicum infections in wild rodents were compared in different study villages and at different time periods, and the detection of S. japonicum infections in wild rodents was compared by different assays. RESULTS:The overall rate of wild rodent capture was 8.28% (237/2 861) in Dongzhi County, and the wild rodent capture rates were 9.24% (133/1 439) and 7.31% (104/1 422) in two study villages (χ2 = 3.503, P = 0.061), and were 8.59% (121/1 409) and 7.99% (116/1 452) in June and September, 2021, respectively (χ2 = 0.337, P = 0.561). The overall rate of wild rodent capture was 3.72% (77/2 072) in Duchang County, and the wild rodent capture rates were 6.91% (67/970) and 0.91% (10/1 102) in two study villages (χ2 = 51.901, P < 0.001), and were 4.13% (39/945) and 3.37% (38/1 127) in June and September, 2021, respectively (χ2 = 0.815, P = 0.365). Rattus norvegicus was the predominant rodent species captured in both counties, accounting for 70.04% (166/237) of all captured wild rodents in Dongzhi County and 88.31% (68/77) in Duchang County. No S. japonicum infection was detected in wild rodents captured in Duchang County. Nevertheless, the overall prevalence of S. japonicum infections was 51.05% (121/237) in wild rodents captured in Dongzhi County, with prevalence rates of 50.38% (67/133) and 51.92% (54/104) in two study villages (χ2 = 0.098, P = 0.755), and 54.31% (63/116) and 47.93% (58/121) in September and June, 2021, respectively (χ2 = 0.964, P = 0.326). Of 237 wild rodents captured in Dongzhi County, there were 140 (59.07%) rodents with visible hepatic egg granulomas, 117 (49.47%) tested positive for S. japonicum eggs by liver tissue homogenate microscopy, 34 (14.35%) tested positive for S. japonicum eggs with Kato-Katz technique; however, no adult S. japonicum worms were detected in mesenteric tissues. In addition, hepatic egg granulomas were found in all wild rodents tested positive for S. japonicum eggs with liver tissue homogenate microscopy. CONCLUSIONS:The rate of wild rodent capture and prevalence of S. japonicum infection in wild rodents vary greatly in schistosomiasis-endemic areas of China, and the prevalence of S. japonicum infection is slightly higher in wild rodents captured in autumn than in summer. Liver tissue is recommended as the preferred sample for surveillance of S. japonicum infection in wild rodents, and a combination of macroscopical observation of hepatic egg granulomas and liver tissue homogenate microscopy may be a standard method for surveillance of S. japonicum infection in wild rodents.
OBJECTIVE:To investigate the epidemiological characteristics and control measures of dengue fever in Zhongshan City in 2024, so as to provide insights into optimization of dengue fever control strategies in the city. METHODS:Data pertaining to dengue fever cases in Zhongshan City in 2024 were collected from the Infectious Disease Reporting System of China Disease Prevention and Control Information System, and the epidemiological characteristics of the cases were analyzed using a descriptive statistical method. The density of Aedes albopictus mosquito was monitored across all 23 townships (subdistricts) using Breteau index (BI) and mosquito ovitrap index (MOI) at midmonth each month from March to December 2024. In addition, the climatic characteristics, case reporting patterns, and corresponding control measures were analyzed during different phases of dengue fever epidemics in Zhongshan in 2024. Furthermore, real-time quantitative reverse transcription PCR (RT-qPCR) assay was employed to serotype the dengue virus among local dengue fever cases with unknown sources of infections. The dengue virus envelope (E) gene was sequenced using Sanger sequencing among dengue fever cases without apparent epidemiological links. A phylogenetic tree was constructed using the neighbor-joining method to infer major transmission chains during the dengue fever epi demics. RESULTS:A total of 952 dengue fever cases were reported in Zhongshan City in 2024, including 879 local cases, 57 domestically imported cases from other regions, and 16 overseas imported cases, representing the largest outbreak in nearly two decades. The first local dengue fever case was reported on July 5, and the last one was detected on December 19, with all townships and subdistricts affected. Mosquito monitoring data indicated that both MOI and BI rose rapidly from March to May, and then remained at high levels with fluctuations, and began to decline in October. The dengue fever epidemic was categorized into five distinct phases in Zhongshan, including non-epidemic, pre-epidemic, early-epidemic, peak, and receding stages. During the pre-epidemic and early-epidemic phases, key measures included enhancing sensitivity of case detection, implementing isolation and treatment of hospitalized cases, and carrying out standardized vector control measures in affected communities. In the peak phase, the strategy shifted towards targeted mosquito control in key communities and clinical rescue and treatment emphasized on "preventing severe cases and deaths". Among 481 local cases with unknown sources of infections, RT-qPCR assay revealed that 68.8% (331/481) were infected with dengue virus type I and 31.2% (150/481) with type II among local dengue fever cases in Zhongshan City in 2024. Phylogenetic analysis revealed two major transmission chains: one originating from imported cases within Guangdong Province around Zhongshan City, and another from cases imported from Malaysia. Late detection of local dengue fever cases contributed to widespread community outbreaks. CONCLUSIONS:The 2024 dengue fever epidemic in Zhongshan City was of considerable scale, which was primarily driven by imported cases from overseas and surrounding regions, leading to local community outbreaks. The epidemic began in early July, increased rapidly during August and September, peaked in October, and subsequently declined, with a trend consistent with the average pattern observed in previous high-incidence years. By implementing differentiated control measures tailored to each phase of the epidemic, the local transmission of dengue fever was successfully contained in Zhongshan City in 2024.
Flood disasters frequently occur in schistosomiasis-endemic regions of China during the flood season, which causes a high risk of schistosomiasis transmission. Therefore, it is particularly crucial to control schistosomiasis transmission during the flood season. Based on field schistosomiasis control needs, this article proposes scientifical and operational countermeasures during three phases of pre-flood preparation, response to flood disasters, and post-flood management, and emphasizes multi-faceted interventions as responses to the risk of Oncomelania hupensis spread and schistosomiasis transmission caused by flood disasters, including information collection, risk assessment, material reserve, health education, Oncomelania hupensis control, cercariae elimination, personal protection, and preventive treatment, so as to provide insights into schistosomiasis prevention and control during the flood season.
