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  • ZHENG Jun, ZHU Lin, LIU Chunting, ZHAO Mingwu, DONG Zeling, DONG Xia, SU Shaoxuan, LINGHU Caiyun, LI Zhongju, WEI Deqin, LONG Tao
    China Tropical Medicine.
    Accepted: 2026-03-05

     Objective To analyze the etiology, drug resistance and genome evolution of three cases of Meningococcal meningitis(MM) in 2024 in Zunyi City. Methods Three samples of cerebrospinal fluid from patients with suspected Nm infection were detected by macrogene sequencing and Real-time PCR, and 143 throat swabs from close contacts were detected by Real-time PCR. The isolates were isolated. Biochemical identification, serotyping, Etest and genome analysis were performed on the isolates. Results  The results of Real-time PCR showed that Nm was detected in 3 cases of cerebrospinal fluid and 18 samples of close contacts. No pathogen was isolated from the case samples, and 6 Nm strains were isolated from close contacts. Serotype distribution: cases 1, 2 and 15 were closely divided into group B, and case 3 was mixed infection of group B and group Y. Phenotypic resistance results showed that 6 strains were sensitive to ceftriaxone, meropenem, minocycline, chloramphenicol and rifampin, and all were intermediate resistant to ampicillin, 5 strains were resistant to penicillin and co-trimoxazole, and resistant to levofloxacin, ciprofloxacin and azithromycin, and 2 strains were resistant to cefotaxime. The 5 strains successfully isolated had farA, farB, macA, resistance genes.All strains carried virulence genes such as NmB0315, OpaA, and OpcA. Phylogenetic analysis showed that strains P171 and P173 clustered with strains 116953, 116959, 116962, and 116960, while strains P175 and P176 clustered with strains 116951, 87062, 131547, 131546, 131548, 116948, and 133566. These two clusters showed significant differences from P174. Conclusion  There is a risk of transmission of Neisseria meningitidis group B and Y in Zunyi City in 2024. The Nm strains exhibit multidrug resistance and carry multiple virulence genes, suggesting potential trans-temporal and trans-spatial transmission across the country.It is suggested to strengthen pathogen monitoring and drug sensitivity detection, guide clinical accurate drug use, and contain the spread of epidemic situation.

  • Qingwei Lin¹, Ye Zhou¹, Longping He¹, Lincui Zhong¹, Wei Zhang², Qing Song³, Jingchun Song¹
    China Tropical Medicine.
    Accepted: 2026-03-02

    Objective: To evaluate the clinical value of the Heatstroke Severity Score System (HSSS) in assessing disease severity and predicting prognosis in patients with heatstroke (HS). Methods: A retrospective analysis was conducted on the clinical data of 143 patients with heatstroke. Patients were stratified into mild (score 1-10, n=110), moderate (score 11-20, n=23), and severe (score ≥21, n=10) groups based on their HSSS scores. Demographic characteristics, Acute Physiology and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), and Glasgow Coma Scale (GCS) scores, as well as clinical indicators including blood counts, coagulation function, liver and kidney function, lactate levels, and mortality rates, were compared among groups. Spearmans rank correlation test was used to analyze the relationship between HSSS and SOFA/APACHE II scores. Receiver Operating Characteristic (ROC) curve analysis was performed to evaluate the predictive efficacy of HSSS for mortality, calculating the Area Under the Curve (AUC) and optimal cutoff value. Survival curves were generated using the Kaplan-Meier method, and a Cox proportional hazards model was employed to identify independent risk factors for mortality in heatstroke patients. Age, SOFA score, APACHE II score, and HSSS score were incorporated into the multivariate Cox regression model to calculate hazard ratios (HRs) and their 95% confidence intervals (CIs). Additionally, the distribution patterns of combined organ system injuries were characterized. Results: The mortality rate in the severe group was 90.0%, significantly higher than in the mild and moderate groups (both 0.0%, P < 0.001). Analysis of organ injury patterns revealed that three-system involvement was the most common (40 cases, 28.0%), with the combination of thermoregulatory dysfunction (hyperthermia), central nervous system (CNS) dysfunction, and renal impairment being the most frequent. This was followed by four-system involvement (36 cases, 25.2%), predominantly involving hyperthermia, CNS dysfunction, renal impairment, and hepatic injury. As HSSS scores increased, APACHE II scores, SOFA scores, and lactate levels significantly increased, while GCS scores significantly decreased; the severity of coagulation disorders and liver/kidney injury also markedly worsened (P < 0.05). Correlation analysis showed a strong positive correlation between HSSS and SOFA (r = 0.942, P < 0.001) and APACHE II scores (r = 0.816, P < 0.001). ROC analysis demonstrated that the AUC of HSSS... was 0.986... The AUC of HSSS was significantly higher than that of APACHE II (Z=2.384, P=0.017) and comparable to SOFA (P=0.093). at an optimal cutoff of 20 points, sensitivity was 100% and specificity was 93.4%. Survival analysis indicated that patients with HSSS ≥20 had a significantly increased mortality risk (HR = 2.06, 95% CI: 1.11-3.84, P = 0.02) and significantly lower cumulative survival compared to those with scores <20 (Log-rank P < 0.0001). Conclusion: The HSSS can accurately assess disease severity and reliably predict adverse outcomes in patients with heatstroke.

  • Yuqing Qiu, Longping He, Ye Zhou, Qinghua Huang, Qingwei Lin, Junjie Zeng, Qing Song, Jingchun Song
    China Tropical Medicine.
    Accepted: 2026-03-02

    Objective To construct a heat tolerance assessment scale and evaluate its reliability, validity, and application value systematically in quantifying heat tolerance levels and screening for individuals at high risk of heatstroke. Methods: Based on a systematic review of theories related to heat stress physiology and heat acclimatization, and with reference to exertional heat illness diagnosis and prevention guidelines of the U.S. and British military, a preliminary framework of a Heat Tolerance Assessment Scale was developed through literature analysis, item pool construction, and expert consultation. The scale consists of four dimensions—subjective perception, physiological sensation, physical performance, and training load—comprising a total of 13 items.The Delphi expert consultation method was used to conduct multiple rounds of evaluation and revision of the scale items to ensure their scientific validity and practical feasibility. Subsequently, a questionnaire survey was conducted among 383 military personnel from Fujian and Hebei provinces. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to examine the structural validity of the scale, and internal consistency indices were used to assess its reliability.On this basis, a further questionnaire survey was carried out among 1,451 military personnel from Hainan, Jiangxi, and Xinjiang. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the predictive validity of the scale.Results: The Kaiser-Meyer-Olkin value of the questionnaire was 0.792, and the Bartlett test χ⊃2;=2892.832 (P<0.001), EFA extracted 4 common factors with a cumulative variance contribution rate of 76.88%. The CFA fit indices were good (χ⊃2;/df=1.836, RMSEA=0.047, CFI=0.983, TLI=0.977). The overall Cronbachs α was 0.832, and the α value for each dimension was >0.75. ROC analysis demonstrated that the scale exhibited good discriminative validity for identifying the risk of exertional heat illness (AUC = 0.789) and excellent predictive validity for determining superior heat tolerance levels (AUC = 0.894), with corresponding cutoff values of 38.5 and 45.5, respectively. Conclusion: The heat tolerance assessment scale has good reliability and validity and can be used as an effective tool for assessing the heat tolerance levels of military personnel and screening for individuals at high risk of exertional heatstroke. 

  • YAO Hanli, LI Zhongqi, LIU Qiao, LU Peng
    China Tropical Medicine.
    Accepted: 2026-01-28

    Objective To explore the association between the exposure of air pollutants sulfur dioxide (SO2), nitrogen dioxide (NO2), inhalable particles (PM10), fine particulate matter (PM2.5), carbon monoxide (CO) and ozone (O3) and the incidence risk of pulmonary tuberculosis (PTB) among students, so as to provide a scientific basis for the development of environmental risk prevention and control strategies for students tuberculosis. Methods We conducted a time-series analysis using weekly PTB cases and air pollutant concentrations (SO2, NO2, PM10, PM2.5, CO, and O3) from thirteen major cities in Jiangsu Province during 2014-2024. Generalized additive models (GAM) were employed to estimate the percentage change in PTB risk per standardized increase in pollutant concentrations at lag times of 0-25 weeks. Models were adjusted for time-varying confounders including meteorological factors (temperature and relative humidity), as well as socio-economic factors including GDP per capita and population density. Sensitivity analyses included dual-pollutant models and generalized additive mixed models (GAMM) with city as a random effect to account for heterogeneity. Restricted cubic spline functions were used to fit exposure-response curves to examine the linearity of dose-response relationships. Results Between 2014 and 2024, there were 11,084 newly diagnosed PTB cases among students reported in the 13 cities. Significant positive associations were observed between PTB risk and short-term NO2 (12.41%, 95% CI: 7.07-18.02% at lag 0), PM10 (9.19%, 95% CI: 4.32-14.29% at lag 6 weeks), O3 (10.04%, 95% CI: 4.27-16.12% at lag 5 weeks), and PM2.5 (9.83%, 95% CI: 5.07-14.81% at lag 5 weeks) per 10-μg/m⊃3; increase. These associations remained robust in dual-pollutant models and GAMM sensitivity analyses. Concentration-response curves indicated approximately linear relationships for NO2, O3, and PM2.5There is a generally positive correlation between PM10 and PTB incidence risk, but the curve remains relatively flat within the low concentration range, with more pronounced risk increases in the medium to high concentration range. Conclusions This study provides evidence that exposure to NO2, PM10, PM2.5, and O3 is associated with increased PTB risk among students in Jiangsu Province, with effects manifesting at different lag times. The findings highlight students as a vulnerable population to air pollution-related PTB. These findings suggest that integrating stringent air pollution control measures may contribute to PTB prevention strategies.

  • ZHOU Zhengbin¹, GONG Yanfeng², LI Yuanyuan¹, LI Zhongqiu¹, YANG Limin¹, LIU Qin¹, ZHANG Yi, CHEN Junhu, LI Shizhu
    China Tropical Medicine.
    Accepted: 2026-01-06
    Abstract: Visceral leishmaniasis (VL) was once one of the five major parasitic diseases posing a serious threat to public health in China. Through dedicated control efforts, the disease had been basically eliminated in most endemic areas by the early 1980s. However, since the 21st century, a rapid resurgence of mountain-type zoonotic visceral leishmaniasis has occurred in central and western China, with numerous historically endemic counties experiencing re-emergence and a continuous geographical expansion of the epidemic area, currently spanning seven provinces/municipalities: Gansu, Sichuan, Shaanxi, Shanxi, Henan, Hebei, and Beijing. This article systematically reviews the current epidemiological characteristics, spatiotemporal distribution, and monitoring status of vector sandflies and reservoir hosts (dogs). It analyzes the drivers of the resurgence under the combined effects of global climate change, ecological environmental shifts, and social factors. Existing control measures focusing on case management, reservoir host and vector control, along with their associated challenges, are summarized. To advance sustainable control and elimination, recommendations are proposed, including strengthening integrated research, promoting the translation of technologies into practice, and establishing a multi-sectoral collaborative governance network.
  • XUN Mengjun, LI Jinlan, ZHAO Peng, LIU Yining, HUANG Aiju
    China Tropical Medicine.
    Accepted: 2026-01-06
    Abstract: Objective To analyze the epidemiological characteristics and influencing factors of treatment outcomes of patients with pulmonary tuberculosis with diabetes mellitus (TB-DM) in Guizhou Province from 2017 to 2023, and to provide a reference for scientific formulation for the control and prevention strategies of co-morbidities. Methods The information data of pulmonary tuberculosis patients registered in Guizhou Province from 2017 to 2023 were collected from Tuberculosis Information Management System under National Health Insurance Disease Control Information System. The prevalence of TB-DM patients was analyzed using descriptive epidemiological methods, and the influencing factors of treatment outcomes were analyzed using binary logistic regression. Results From 2017 to 2023, a total of 7 892 TB-DM patients were registered in Guizhou Province, with an average registration rate of 2.94/100 000. The registration rate showed an increasing trend year by year, with an average annual increase of 28.84% (95%CI: 22.16%-35.87%, t=12.36, P<0.001); the proportion of TB-DM patients among pulmonary tuberculosis population was 3.14%, increasing from 1.24% in 2017 to 6.35% in 2023, showing an increasing trend (χ2trend=2 841.53, P<0.001). The proportion of males, 45-<65 years old, the proportion of farmers, positive etiological examinations, referrals for diagnosis, primary treatment patients, and secondary pulmonary tuberculosis in TB-DM patients were all higher than those in non-TB-DM patients, and the differences were statistically significant (P<0.05). The successful treatment rate of TB-DM patients in the province was 91.95%, and adverse outcome incidence was 8.05%. The adverse outcomes were mainly adverse reactions (3.34%) and treatment failure (2.49%). The results of multivariate logistic regression analysis showed that age≥65 years (OR=1.47, 95%CI: 1.17-1.85) and retreatment (OR=1.78, 95%CI: 1.14~2.78) were risk factors for adverse outcomes in TB-DM patients. Conclusion The number and proportion of registered TB-DM patients showed an upward trend in Guizhou Province from 2017 to 2023, and the incidence of adverse outcomes was high. We should focus on elderly people aged 65 and above, as well as patients with co-morbidities who have been retreated, and further do a good job in tuberculosis and diabetes mellitus bidirectional screening.
  • LAI Lin, LI Jiaying, HUANG Qifeng, WANG Chongcai
    China Tropical Medicine.
    Accepted: 2026-01-06
    Abstract:Objective Investigate the detection rate of hyperuricemia (HUA) among the personnel stationed on Xisha Islands, analyze the correlation as well as influencing factors between HUA and various biochemical indicators, so as to provide a scientific basis for the prevention and treatment of HUA. Methods A cross-sectional study method was adopted using the laboratory data from the physical examination (n=2 100) of the personnel stationed on the islands at the People's Hospital of Sansha City in Xisha Islands. Statistical analysis was carried out on biochemical test indicators. The differences in biochemical test indicators between the HUA group (n=724) and the control group (n=1 376) were compared. Pearson correlation analysis and logistic regression model were used to analyze the independent risk factors for HUA. Results The total detection rate of HUA was 34.48%. The uric acid (UA) level in the HUA group was significantly higher than that in the control group, and the difference was statistically significant (P<0.05). The levels of CR, BUN, ALT, AST, TBIL, ALB, TC, TG, and LDL-C in the HUA group were all higher than those in the control group (P<0.05), and the HDL-C level in the HUA group was lower than that in the control group, with a statistically significant difference (P<0.05). Pearson correlation analysis showed that the uric acid (UA) level was positively correlated with CR, BUN, ALT, AST, TBIL, ALB, TC, TG, and LDL-C, while HDL-C was negatively correlated with the UA level. Logistic regression model analysis showed that CR, ALT, AST, TBIL, ALB, TC, TG, and LDL-C were independent risk factors for the occurrence of HUA, while HDL-C was a protective factor for the occurrence of HUA. Binary logistic regression analysis showed that abnormal renal function, abnormal transaminase, and hyperlipidemia were risk factors for the occurrence of HUA. Conclusion The detection rate of HUA among the personnel stationed on Xisha Islands is relatively high. There is a significant correlation between abnormal renal function indicators, abnormal transaminase indicators, hyperlipidemia, and HUA. It is recommended to establish a regular monitoring mechanism for this group, and implement lifestyle intervention and drug prevention strategies for those with abnormal metabolic indicators.
  • LIU Jingyi, GU Yingpei, LIN Chen, LU Xinchen, HU Chenxi, LIU Jun, YUAN Yongting, GU Ruohua, LU Qi, GE Ge, LI Huihui, LIU Hanzhao,
    China Tropical Medicine.
    Accepted: 2026-01-06
    Abstract: Objective To investigate the composition of fly populations and the characteristics of enteric pathogen spectrum carried by flies in a large urban village in Pudong New Area, Shanghai, and to assess the potential role of flies in the transmission of intestinal infectious diseases, to provide a reference for formulating targeted control and prevention measures.  Methods From June to October 2024, 18 sampling sites were set up in Taiping Village, Kangqiao Town, Pudong New Area. Flies were collected outdoors using trap cages and indoors using sticky traps. Captured flies were morphologically identified, and real-time fluorescent quantitative RT-PCR was used to detect 31 enteric pathogens (including viruses, bacteria, and parasites). The incidence of diarrhea among residents and related factors were collected through questionnaires. Data were processed using descriptive statistics, chi-square test, and Pearson correlation analysis. Results A total of 214 flies were captured, with Sarcophagidae (60.75%), Anthomyiidae (17.29%), and Lucilia sericata (13.55%) being the dominant species. Thirteen enteric pathogens were detected in flies, including 8 bacteria, 3 viruses, and 2 parasites, with Cryptosporidium having the highest detection rate (51.68%). Green belts and residential outdoor environments were the primary habitats where pathogens were detected in flies. Sarcophagidae carried the highest variety of pathogens, while Chrysomyia megacephala only carried two parasites: Cryptosporidium and Blastocystis hominis. The incidence of diarrhea among the population was 6.86% (58/845), and the detection rate was significantly positively correlated with the diarrhea rate (P<0.05). Conclusions The fly populations are highly diverse in the urban village environment of Pudong New Area, and can carry multiple enteric pathogens, posing a relatively high transmission risk for Cryptosporidium, Sapovirus, and diarrheagenic E. coli. The temporal trend is relatively consistent with the detection rate of fly-borne pathogens in July and August. The results of correlation analysis show that the detection rates of sapovirus, Blastocystis hominis, EPEC and O157 increased. It is recommended to enhance environmental management in urban villages, implement integrated fly control measures, and strengthen health education among residents to reduce the risk of intestinal infectious diseases.
  • LI Shizhen, ZHANG Lijuan, GUO Suying, LI Yinlong, CAO Cunli, XU Jing
    China Tropical Medicine.
    Accepted: 2025-12-31
    Abstract:  Objective To analyze the epidemiological characteristics and challenges in the control and prevention of imported schistosomiasis cases in China, providing scientific evidence for schistosomiasis control and prevention during the transition from transmission interruption to elimination. Methods Data were obtained from the China Disease Control and Prevention Information System (National Notifiable Disease Reporting System). All imported schistosomiasis cases reported nationwide between January 1, 2015, and December 31, 2024 were included. Variables such as source country, reporting province, Schistosoma species, and demographic characteristics were analyzed descriptively. Results From 2015 to 2024, a total of 32 imported schistosomiasis cases were reported in China, with 2-6 cases annually, the proportion of reported in spring was 46.9% (15/32). The mean age was (36.66±10.41) years, and males accounted for 93.8% of all cases. The occupations were mainly laborers (31.3%) and students (25.0%). Cases originated from 16 countries, of which 27 cases (84.4%) were from sub-Saharan Africa; the major source countries were Nigeria (n=5), Angola (n=4), Zimbabwe (n=3), Equatorial Guinea (n=3), and Sudan (n=3). Most cases were reported in endemic provinces (24 cases, 75.0%), mainly in Zhejiang and Jiangsu. By species, infections were predominantly by Schistosoma haematobium (56.3%) and S. mansoni (18.8%); two cases were caused by S. intercalatum. Nine cases had follow-up data, and all were cured after praziquantel treatment. Conclusion Imported schistosomiasis in China shows concentrated sources of infection abroad, distinct occupational patterns, and partial overlap between domestic reporting locations and endemic areas. Although the number of cases remains sporadically reported, potential risk of re-transmission exists. Strengthened health management for cross-border populations, enhanced clinical recognition and laboratory capacity, and improved surveillance are essential to consolidate achievements in transmission interruption and prevent re-emergence.
  • WU Ping , ZHUANG Li, ZHENG Ju, KE Qian
    China Tropical Medicine.
    Accepted: 2025-12-31

    Abstract: Objective    To analyze the epidemic characteristics and hemagglutinin (HA) gene variations of influenza B virus (IBV) in Guizhou Province from 2022 to 2024, aiming to provide a basis for optimizing the local influenza prevention and control strategies. Methods    A total of 76 976 samples were collected from patients with influenza-like illness (ILI) at 13 sentinel hospitals for influenza surveillance in Guizhou Province from January 2022 to December 2024. Influenza B virus nucleic acid was confirmed by real-time fluorescence quantitative polymerase chain reaction (qPCR), and virus isolation was performed using MDCK cells. Fifty-two isolates of influenza B virus were selected for sequencing. Phylogenetic trees were constructed using bioinformatics software, and their molecular evolutionary characteristics were analyzed. Result    A total of 2 893 cases of influenza B were detected, with a detection rate of 3.76% (2 893/76 976), all of which belonged to the Victoria subtype. The detection rate varied significantly by year (P≤0.001), peaking in 2022 (6.75%), and also by age group and season (P≤0.001 for both). There was no significant difference between genders (P=0.222). The highest detection rates were observed in the 15–<60 age group (5.38%) and during winter (10.21%), followed by spring (4.51%). Phylogenetic analysis showed that the HA gene sequences of all 52 isolates were highly homologous and clustered within the V1A.3 subclade, alongside the B/Austria/1359417/2021 vaccine strain. Eight amino acid mutations occurred in the key antigenic epitope regions (120-loop, 150-loop, 190-helix) of the HA protein. Forty-nine of the isolates shared 10 conserved potential N-glycosylation sites with the vaccine strain. Conclusion    Influenza B in Guizhou Province shows a winter-spring epidemic pattern, with young and middle-aged adults as the key population for prevention and control. The V1A.3 clade of the B/Victoria subtype is the predominant strain. While the HA gene of circulating viruses showed good homology to the contemporary vaccine strain, the presence of site mutations in key antigenic determinant regions highlights the need for dynamic monitoring and timely update of vaccine components.

  • YANG Zaogai , SONG Jing , , ZHANG Yuanyuan , NING Siqi , SHI Xinping , CHEN Chunqiong, , SHEN Meifen, , WANG Hongqiong, , DU Chunhong, , LI Shizhu , HAO Yuwan , DONG Yi,
    China Tropical Medicine.
    Accepted: 2025-12-31
    Abstract: Objective    This study aimed to optimize the laboratory rearing method for Oncomelania hupensis robertsoni (the Dianchuan subspecies snail) artificially infected with Schistosoma japonicum, thereby providing a theoretical foundation for establishing a standardized laboratory system for rearing S. japonicum-infected snails. Methods    A total of 240 uninfected snails, screened via the cercarial shedding method, were individually infected with S. japonicum miracidia at a miracidium-to-snail ratio of 5:1. Under identical environmental conditions, four rearing methods were applied in parallel: the mud pot method, the sponge and straw paper method, the enamel tray with straw paper and coarse soil method, and the enamel tray with straw paper and fine soil method. Dead snails were removed and recorded weekly to calculate the mortality rate in each group. After 60 days post-infection, infected snails were identified using the cercarial shedding method, which was conducted weekly for nine consecutive weeks. Snails that did not shed cercariae were dissected and examined microscopically at 120 days post-infection; if cercariae were present, these snails were classified as infected and included in the infection rate analysis. Identified infected snails were maintained using their original rearing methods, and cercarial shedding was performed every 10 days for a total of five shedding events. Results    After 120 days of rearing, the cumulative mortality rates for the mud pot method, sponge and straw paper method, enamel tray with straw paper and coarse soil method, and enamel tray with straw paper and fine soil method were 40.00%, 41.67%, 25.00%, and 36.67%, respectively. The corresponding cumulative infection rates were 31.67%, 30.00%, 41.70%, and 43.33%, respectively. The average numbers of shed S. japonicum cercariae were 1 169, 615, 412, and 1 022, respectively. The time required for one person to prepare and replace one set of rearing materials was approximately 25 minutes for the mud pot method, 12 minutes for the sponge and straw paper method, 10 minutes for the enamel tray with straw paper and coarse soil method, and 12 minutes for the enamel tray with straw paper and fine soil method. Statistical analysis revealed no significant differences in snail mortality rate (χ⊃2;=4.442, P>0.05) or infection rate (χ⊃2;=3.589, P>0.05) among the methods. However, significant differences were observed in the average number of shed cercariae (F=6.875, P<0.05) and the workload required (F=117.195, P<0.05). Conclusion    Considering the snail mortality rate, average number of shed cercariae, and rearing workload comprehensively, the enamel tray with straw paper and fine soil method is the most suitable approach for laboratory rearing of artificially infected Oncomelania hupensis robertsoni
  • LI Jingwen , LIU Zhiyun , DUAN Like , ZHANG Lin , HOU Xuexia , LI Juan , HAO Qin
    China Tropical Medicine.
    Accepted: 2025-12-31
    Abstract: Objective    To investigate the bacterial diversity and prevalence of common tick-borne pathogens in ticks parasitizing water buffaloes in Anfu County, Jian City, Jiangxi Province, China. Methods    A total of 104 ticks were collected from water buffaloes in Xiatanyuan Village, Yangmen Township, Anfu County, Jiangxi Province. Species identification was performed using morphological and molecular biological methods. DNA from 46 randomly selected ticks was subjected to high-throughput sequencing of the 16S rDNA V3-V4 region to analyze bacterial diversity, and species composition was calculated and analyzed for each sample. Additionally, polymerase chain reaction (PCR) was used to screen all 104 ticks for six major tick-borne pathogens: Borrelia burgdorferi, Borrelia miyamotoi, Coxiella burnetii, Anaplasma phagocytophilum, Ehrlichia chaffeensis, and spotted fever group rickettsiae (SFGR). Positive amplicons were sequenced and phylogenetic trees were constructed. Results    All 104 engorged female ticks were identified as Rhipicephalus microplus. High-throughput sequencing of the 16S rDNA V3-V4 region revealed that the dominant bacterial phyla were Bacillota (mean relative abundance:61.30%) and Pseudomonadota (38.37%), with Aeromonas hydrophila (31.66%) being the predominant species. Several pathogenic bacteria were detected: Coxiella burnetii (positive rate 23.91%), Anaplasma phagocytophilum (17.39%), Klebsiella pneumoniae (15.22%), Acinetobacter lwoffii (10.87%), and Rickettsia conorii (2.17%). PCR results showed that 14 ticks carried tick-borne pathogens: Borrelia theileri (6.73%), SFGR (2.88%), Borrelia burgdorferi (0.96%), Borrelia miyamotoi (0.96%), Coxiella burnetii (0.96%), and Anaplasma phagocytophilum (0.96%). Both methods indicated co-infections with multiple pathogenic bacteria in the ticks. Conclusions    Rhipicephalus microplus parasitizing water buffaloes in Anfu County, Jiangxi Province, harbors a highly diverse bacterial community, including multiple pathogenic and opportunistic bacteria, indicating potential public health risks. Systematic investigation and monitoring of tick-borne diseases in this region should be strengthened to provide a scientific basis for targeted prevention and control.
  • FAN Yubing , HUANG Quanfeng , ZENG Weidan , ZHANG Bei,
    China Tropical Medicine.
    Accepted: 2025-12-31
    Abstract:   Objective    To investigate the reparative effects and underlying mechanisms of vanillic acid on myocardial hypertrophy-induced injury in C57BL/6J mice and HL-1 cardiomyocytes induced by angiotensin II (Ang II). Methods     C57BL/6J mice and HL-1 mouse cardiomyocyte cell line were randomly assigned to four experimental groups: control, Ang II, vanillic acid, and vanillic acid+Ang Ⅱ , with appropriate interventions administered accordingly. In the in vivo study, cardiac hypertrophy was evaluated by heart weight-to-body weight ratio (HW/BW) and heart weight-to-tibia length ratio (HW/TL); cardiac hemodynamic function were assessed via echocardiography; the degree of myocardial tissue and cell hypertrophy and fibrosis, were analyzed using hematoxylin-eosin (HE) staining, Masson's trichrome staining, and wheat germ agglutinin (WGA) staining; immunohistochemical analysis was performed to determine the expression levels of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and NADPH oxidase 4 (NOX4) in myocardial tissues of each group. In the in vitro study, the optimal non-cytotoxic concentration of vanillic acid for HL-1 cells was determined using the cell counting kit-8 (CCK-8) assay; cellular morphology and size were assessed by phalloidin staining; protein expression levels of Keap1, Nrf2, and NOX4 were quantified by Western blot analysis.  Results    In vivo findings demonstrated that, compared with the control and vanillic acid groups, the Ang II group exhibited significant myocardial hypertrophy, interstitial fibrosis, and cardiomyocyte enlargement (P<0.05), increased interventricular septal thickness at end-systole (P<0.05), reduced left ventricular ejection fraction (P<0.05), and upregulated expression of Keap1, Nrf2, and NOX4 (P<0.05). These pathological changes were significantly attenuated following vanillic acid treatment (P<0.05). In vitro results showed that, compared with the control and vanillic acid groups, AngⅡ treatment led to a marked increase in cardiomyocyte cross-sectional area (P<0.05), and elevated expression of Nrf2, Keap1 and NOX4 (P<0.05), both of which were reversed by vanillic acid co-treatment. Conclusion     Vanillic acid ameliorates cardiac dysfunction and suppresses myocardial hypertrophy, through modulation of the Keap1/Nrf2 signaling pathway.
  • LI Lingzhi, HUANG Zheng, YAO Dong, OU Xinhua, DUAN Chenglin, XIAO Shan
    China Tropical Medicine.
    Accepted: 2025-12-31
    Abstract: Objective To investigate the epidemiological characteristics of two local cases of severe fever with thrombocytopenia syndrome (SFTS) in Changsha, analyze the molecular genetic characteristics of Dabie bandavirus (DBV), and we provide a scientific basis for local epidemic surveillance and prevention and control. Methods Blood samples from two
    SFTS cases and their close contacts, as well as serum samples from animals and tick specimens collected from the surrounding living environment of the cases, were collected. DBV nucleic acid was detected using quantitative reverse transcription polymerase chain reaction (RT-PCR). Positive samples were subjected to whole-genome sequencing using the Illumina platform, and sequence assembly was performed using CLC Genomics Workbench 25.0 software. Sequences with high similarity to those in this study were downloaded from the GenBank database. Bioinformatics software such as DNA STAR and MEGA7 were used to analyze gene sequence homology, amino acid variations, and construction of phylogenetic trees. Results The DBV nucleic acids of the two Changsha cases were both positive. The nucleotide homology of their L, M, and S gene fragments exceeded 99.8%. The homology with the reference sequences in the GenBank database was 95.9%-99.6% (L gene), 93.7%-99.8% (M gene), and 95.6%-99.8% (S gene) respectively. Among these, the homology with the Shandong strain QD04 was the highest (99.6%-99.8%). Phylogenetic analysis indicated that the L, M, and S genes of the two case samples all belonged to genotype B. Amino acid analysis identified specific mutation sites in the GPs protein (GPs-501T, 662P, 962S), which might be associated with viral pathogenicity. Conclusion Two local epidemic DBV strains in Changsha are highly homologous to the Shandong strain, but have unique amino acid variations, which may affect the transmission characteristics of the virus. It is necessary to strengthen surveillance of tick vectors and animal hosts as well as research on multi-route transmission mechanisms.
  • MA Binzhong, WEI Yujia, JIANG Mingxia, LI Yongsheng, LI Erchen, QI Xiaoyun
    China Tropical Medicine.
    Accepted: 2025-11-18
    Abstract: Objective This study aimed to examine the patient delay status and associated factors among Tibetan pulmonary tuberculosis (PTB) patients in Qinghai Province, China, to provide a basis for optimizing tuberculosis prevention and control strategies for this population. Methods Data were obtained from the Tuberculosis Management Information System, a subsystem of Chinese Center for Disease Control and Prevention Information System, for all Tibetan PTB cases registered in Qinghai between 2013 and 2023. Compare differences in patient-delay rates across subgroups, and multivariate logistic regression was applied to identify factors influencing patient delay. Results A total of 23 868 Tibetan PTB cases were included in this study, among which 11 492 cases experienced patient delay, with a delay rate of 48.15% (11 492/23 868). The median delay duration was 14(4, 35) days. From 2013 to 2023, the patient-delay rate has shown a significant downward (χ2 trend=395.226, P<0.001). This downward trend was consistent in both male (χ2 trend=223.946, P<0.001) and female patients (χ2 trend=174.259, P<0.001). Multivariate analysis identified that older age≥21 years (OR=1.194, 95%CI:1.101-1.294), ≥41 years (OR=1.212, 95% CI: 1.107-1.328), ≥61 years (OR=1.195, 95%CI: 1.070-1.333), occupation as farmer (OR=1.218, 95% CI: 1.103-1.345), herdsman (OR=1.265, 95%CI: 1.157-1.383), or other occupations (OR=1.203, 95%CI: 1.085-1.347), case source being referral (OR=1.629, 95%CI: 1.223-2.171) or other sources (OR=2.055, 95%CI: 1.459-2.893), and retreatment classification (OR=1.165, 95%CI: 1.033-1.315) were risk factors for patient delay. Bacteriologically positive (OR=0.736, 95%CI: 0.664-0.816) and negative results (OR=0.642, 95%CI: 0.582-0.708) were protective factors against patient delay. Conclusions Although the patient-delay rate among Tibetan PTB patients in Qinghai has decreased in recent years. However, enhanced interventions, such as health education and social support for middle-aged and elderly populations, farmers, and herdsmen are still needed. Strengthening the capacity of designated TB hospitals at the primary level is also essential to encourage early seeking of care and further reduce patient delay.