Objective To analyze the species composition, density distribution, seasonal fluctuation, and insecticide resistance of flies, particularly Musca domestica, in Shandong Province, China, thereby providing a scientific basis for the prevention and control of flies. Methods The cage trapping method was used for fly ecological surveillance, and the topical application method was employed to determine the insecticide resistance of M. domestica. Excel 2010 and SPSS 20.0 software were used to analyze the surveillance data statistically. The chi-square test was used to compare the composition of fly species. Fly densities were compared by the one-way ANOVA or the Kruskal-Wallis H test. The Probit regression model was used to calculate the median lethal dose (LD₅₀), 95% confidence interval (CI), and virulence regression equation. Results From 2019 to 2023, a total of 10 371 fly traps were deployed in Shandong Province, capturing 68 668 flies, with an overall average density of 6.62 flies/cage. The dominant species were M. domestica, Sarcophagidae, M. sorbens, and Lucilia sericata, accounting for 57.31%, 10.35%, 8.26%, and 7.57% of the total catch, respectively. Among the four types of habitats, the density of flies in farmers' markets was highest, reaching 9.59 flies/cage, followed by green belts, catering surroundings, and residential areas, showing significant differences in fly density among different habitats (H=11.777, P<0.01). Fly density showed a unimodal pattern, with peak periods occurring from June to August. All habitats also displayed a unimodal pattern, with peaks occurring from June to July. M. domestica showed resistance to beta-cypermethrin, lambda-cyhalothrin, deltamethrin, permethrin, propoxur, temephos, but remained sensitive to tetramethrin, dichlorvos, malathion, and imidacloprid. Conclusions Shandong Province exhibits a diverse fly population, with dominant species, such as Musca domestica and Sarcophagidae, requiring targeted control efforts. Fly density peaks from June to August, and farmers' markets are key places for targeted fly control. Therefore, it is recommended that integrated control measures be implemented in key locations prior to peak fly activity periods to reduce fly density. M. domestica has developed varying levels of resistance to certain insecticides. Future control efforts should involve the scientific and rational use of insecticides to delay the emergence of resistance.

Objective To study on ecological niches of sandflies, and classify their species in Hainan Island, provide a scientific basis for risk assessment of sandfly-borne diseases and the development of targeted prevention and control strategies in tropical regions of China. Methods In response to the diverse geographical environment of Hainan Island, a sandfly investigation were conducted across 11 towns in 7 counties in Hainan Island from 2023 to 2024. Light trap method was used to catch sandfly samples, with environmental observations. The morphological characteristics of cibarium, pharyngeal armature, spermatheca, and male external genitalia of sandfly specimens were observed and recorded under a microscope to identify species. Results The sampling sites were located between 109°-110° E longitude and 19°-20° N latitude in Hainan Island, spanning mountainous regions, hilly areas, and plains, with an altitude ranging from 3.0 to 314.2 m. Total of 969 samples were captured, with no significant differences in collection numbers across different topographical units. Investigation and statistical results showed that the main blood-sucking and resting habitats of sandflies were poultry sheds and livestock pens. Sandfly density in poultry sheds (including adjacent storage areas, 0.4-69.0 flies/(trap·night) was significantly higher than that in livestock pens (0-7.0 flies/trap/night) (Mann-Whitney U, P=0.000 3). Number of 144 sandfly specimens was classified, as five species belonging to two genera: Phlebotomus stantoni (n=22), Sergentomyia bailyi (n=37), Se. hivernus (n=26), Se. iyengari (n=55), and Se. squamipleuris (n=4). The Sergentomyia hivernus is a new record in China. The morphological identification characteristics for the five species were supplemented and revised. Female Se. iyengari with Se. hivernus can be distinguished by the following four features: pigment patch shape (tangerine-segmented vs mushroom-shaped), arrangement of chitinous dots (2-3 rows vs 1 row), spermatheca morphology (long cylindrical vs. sausage-shaped), and degree of spermathecal head sunken (completely sunken vs. slightly sunken). Conclusion This study confirmed that poultry sheds and livestock pens are the primary blood-sucking and resting habitats for sandflies, and there are five species belong to subfamily Phlebotominae in Hainan Island, Se. hivernus is new Chinese record.

Objective By conducting a comparative investigation of the symbiotic microbiota between the dominant midge species in Hainan Province, Culicoides arakawae and Culicoides oxystoma, as well as between different sexes within each species, this study aimed to elucidate the baseline composition and differences of the microbial communities in these two Culicoides species, laying a theoretical foundation for formulating biological control strategies. Methods C. oxystoma and C. arakawae, which are widely distributed and abundant in Hainan, were selected. Genomic DNA was extracted from the midge microbiota, and the symbiotic microbial diversity of C. arakawae and C. oxystoma was investigated using 16S rRNA amplicon sequencing. Results The dominant bacterial phyla in the symbiotic microbiota of both C. arakawae and C. oxystoma were Proteobacteria, Bacteroidetes, and Firmicutes. Significant compositional differences were observed at the genus level, with the top 10 genera in relative abundance including Candidatus_Cardinium, Staphylococcus sp., etc. The most pronounced inter-species abundance difference was found in the Candidatus_Cardinium genus. Intra-specific, sex-based differences were also present; for example, the abundance of the Enterobacter genus was significantly higher in female C. arakawae than in males. Alpha diversity analysis revealed that the microbial diversity in C. oxystoma was significantly higher than in C. arakawae, and diversity was higher in females than in males within each species. The Simpson index values were as follows: female C. oxystoma (Fm-oxy, 5.96) > female C. arakawae (Fm-ara, 3.85) > male C. oxystoma (M-oxy, 3.55) > male C. arakawae (M-ara, 2.57). Beta diversity analysis indicated that inter-species differences in microbiota were significantly greater than intra-specific, sex-based differences. Principal Co-ordinates Analysis (PCoA) based on Bray-Curtis distances at the genus level revealed a clear separation between the arakawae (ara) and oxystoma (oxy) groups. The ara group clustered primarily in the second and third quadrants, while the oxy group was concentrated in the first and fourth. The first two principal coordinates (PCo1 and PCo2) explained 42.95% and 24.26% of the variance, respectively, with a statistically significant total of 67.21%. Differences in species and sex led to changes in microbial composition (from phylum to species level), although the core microbiota remained relatively stable. Functional prediction analysis (Tax4Fun) showed significant differences between the two species' microbiota in functions related to digestion, immunity, and environmental adaptation. In contrast, male individuals exhibited a higher abundance of functional genes associated with infectious diseases, neurodegenerative diseases, and immune-related pathways. Conclusion Symbiotic microbial communities differ significantly between the two Culicoides species, with females exhibiting higher microbial richness. A long-term co-evolutionary relationship exists between the microorganisms and their hosts. The observed differences in microbial community composition and function are likely associated with variations in their respective habitats and food sources.

Objective To investigate the species composition, spatial distribution patterns, and diversity of major host animals and their ectoparasitic fleas (vectors of rodent-borne diseases) in Xiangyun County, Yunnan Province, thereby providing foundational data and theoretical support for risk assessment, targeted monitoring, and scientific prevention and control of rodent-borne diseases in the region. Methods In September 2018 and September 2021, field surveys were conducted across eight townships of Xiangyun County, along an elevation gradient (1 700-2 700 m), in two typical habitats: forest and farmland. Host animals were captured using trap-night methods, and ectoparasitic fleas were collected from their bodies. In the laboratory, host animals were dissected, and samples were collected, and community ecology metrics were applied to analyze the community structure and diversity of host animals and their ectoparasitic fleas. Results A total of 522 small mammals were captured, belonging to 24 species, 13 genera, 6 families, and 4 orders, with an overall trapping rate of 13.05%. The dominant species were Apodemus chevrieri, Eothenomys miletus, and Mus pahari. Fleas were collected from 40 infested hosts, yielding 74 fleas belonging to 10 species, 10 genera, and 4 families, with an overall flea infestation rate of 7.66% and a flea index of 0.14. The dominant flea species were Ctenophthalmus quadratus, Leptopsylla segnis, Macrostylophora euteles, and Neopsylla specialis ssp. specialis. Compared to farmland, forest habitats exhibited greater heterogeneity and supported significantly higher species diversity of small mammals and their parasitic fleas (P<0.05). Along the elevational gradient, small mammal capture rates and species richness displayed a significant unimodal distribution, peaking in the mid-elevation zone Ⅱ (2 000-2 300 m), whereas flea infestation abundance and richness showed an opposite trend. Both the diversity and evenness indices of small mammals and fleas followed consistent elevational patterns, reaching their highest values in the highest elevation zone Ⅲ (2 300-2 700 m). Conclusion As a natural focus for both sylvatic and domestic plague, Xiangyun County also harbors hosts and vectors for multiple rodent-borne diseases, including hemorrhagic fever with renal syndrome (HFRS), leptospirosis, and scrub typhus. The area features high densities of host animals and vector fleas, diverse species, and stable community structures, creating ecological conditions conducive to disease outbreaks and epidemics. It is recommended to strengthen the systematic surveillance of the host-vector-pathogen chain. Furthermore, a dynamic assessment of epidemic risk should be conducted by integrating climate, agricultural, and pastoral data to implement precise prevention and control measures.

Objective To investigate the larvicidal efficacy of curcumin against Anopheles stephensi larvae and the influence of larval density on its insecticidal activity, providing a reference for rational dose selection in mosquito control using curcumin. Methods The larvae of Anopheles stephensi were treated with gradient concentrations of curcumin, and the cumulative mortality rates were calculated at different time points. The larvicidal effect of curcumin on Anopheles stephensi larvae was analyzed using Probit analysis bioassay method to determine the lethal concentrations. Additionally, the impact of larval density on the insecticidal efficacy was compared and analyzed after treatment with low and high doses of curcumin. Results Curcumin exhibited obvious insecticidal activity against Anopheles stephensi larvae, characterized by a slow onset but prolonged duration of action, with a distinct concentration-dependent trend in its insecticidal activity. The cumulative mortality rate of larvae gradually increased over time beginning at 12 h post-treatment, with the efficacy of curcumin lasting at least 96 h. Based on linear regression analysis, the lethal concentration 50 (LC₅₀) values at 48, 72, and 96 h were calculated as 15.03, 8.45, and 6.61 mg/L, respectively; the lethal concentration 95 (LC₉₅) values were 88.92, 47.42, and 31.62 mg/L, respectively; and the lethal concentration 99 (LC₉₉) values were 185.35, 96.61, and 60.39 mg/L, respectively. The trend of decreasing cumulative mortality rate with increasing larval density was more obvious in the low-dose series groups. Following treatment with low-dose curcumin (10 mg/L), the cumulative mortality rates of mosquito larvae among different density groups differed significantly at both 72 h and 96 h (χ²=48.86 and 174.2, df=4, P<0.000 1). Following treatment with high-dose drug (40 mg/L), cumulative mortality rates differed significantly among the density groups at all four time points (χ²=35.71, 32.78, 15.87, and 47.54; df=4; P<0.000 1 for 24 h, 48 h, and 96 h; P<0.01 for 72 h). Conclusions Curcumin demonstrated significant larvicidal activity against Anopheles stephensi, with larval density being an important factor influencing its insecticidal efficacy. This suggests that curcumin, as a novel plant-derived insecticide, holds potential application value in the control of Anopheles stephensi.

Objective To investigate the species composition and distribution of main host animals and vector fleas in the natural foci of house mouse plague in Menghai County, so as to provide a reference for the surveillance and control of plague in this region. Methods In Menghai County, eight townships within an elevation range of 600-1 800 meters were selected as study areas. From December 13 to 24, 2021, investigations of host animals and their parasitic fleas were conducted using nocturnal cage trapping and diurnal clip trapping across three habitat types: residential areas, shrub-forest ecotones, and cultivated zones. Community ecology methodologies were applied to analyze species composition and spatial distribution patterns. Results A total of 446 plague host animals were captured, representing 17 species, 10 genera, 5 families, and 3 orders. The dominant species were Rattus tanezumi (40.81%), Eothenomys miletus (12.11%), and Rattus andamanensis (10.76%), with an overall capture rate of 6.40%. Capture rates significantly differed across habitats (χ²=202.477, P<0.001): 1.78% in residential areas, 6.50% in shrub-forest ecotones, and 13.68% in cultivated zones. The shrub-forest ecotones exhibited the highest species richness, diversity (Shannon index), and evenness, while residential areas showed the lowest values. Significant differences in capture rates were also observed across three elevation belts (χ²=9.154, P=0.010): 5.58% (Belt A), 7.20% (Belt B), and 7.94% (Belt C). Belt C demonstrated superior ecological indices: 15 species richness, Shannon diversity index of 2.320, and evenness index of 3.347. A total of 163 vector fleas were collected, representing 10 species, 7 genera, and 5 families. Dominant flea species included Ctenophthalmus lushuiensis (23.31%), Ctenophthalmus quadratus (19.02%), Xenopsylla cheopis (15.95%), Archaeopsylla dispar (11.66%), and Aviostivalius klossi bispiniformis (11.04%). The overall flea infestation rate was 15.47%, with a total flea index of 0.37. Notably, only Xenopsylla cheopis was detected in residential areas, displaying a flea index of 0.57. Conclusion In Menghai County, the primary plague reservoir Rattus tanezumi and the key transmission vector Xenopsylla cheopis are widely distributed, with notable dominance in residential areas. It is necessary to strengthen the surveillance of plague hosts and vectors in this area, promptly grasp the epidemic dynamics, and carry out preventive rodent and flea control when necessary to reduce the risk of plague occurrence and spread.

Objective To systematically elucidate the sequence characteristics of extracellular signal-regulated kinase(ERK) protein in Anopheles stephensi, as well as its spatiotemporal expression patterns in various developmental stages and across tissues, thereby providing a theoretical basis for exploring its potential roles in mosquito immune regulation and the transmission of mosquito-borne diseases such as malaria. Methods ERK homologs from 13 species were retrieved from NCBI/VectorBase for multiple sequence alignment, domain annotation, and phylogenetic analysis (MEGA 12). Western blotting was performed to detect total ERK and phospho-ERK (p-ERK) levels across five developmental stages: egg, larva, pupa, and adult male and female. RT-qPCR and Western blotting were used to analyze ERK mRNA and protein expression in five tissues of 3-4-day-old female mosquitoes: head, thorax, midgut, fat body, and ovary. Results Sequence alignment and phylogenetic analysis revealed that An. stephensi ERK shares over 80% sequence similarity with other mosquito species, Drosophila, and even mammals, with a highly conserved kinase catalytic domain. Phylogenetic clustering placed Anopheles members into a distinct branch (bootstrap support = 89%). One-way ANOVA followed by Tukey's HSD test demonstrated that total ERK expression exhibited a gradient pattern of "eggs > pupae > adults and larvae" (P<0.01), with no significant difference among female adults, male adults and larvae (P>0.05); whereas p-ERK levels peaked in female mosquitoes and were significantly higher than in all other stages (P<0.001). Pairwise comparisons between midgut and other tissues (head, thorax, fat body, and ovary) showed that ERK mRNA expression was highest in the midgut (all P<0.001); for total ERK, expression in the midgut and thorax was significantly higher than in the head and ovary (all P<0.001); for p-ERK, the midgut and thorax were significantly higher than the other tissues (all P<0.01), indicating that these two tissues may serve as the key site of ERK activation. Conclusions ERK in An. stephensi is highly conserved and exhibits distinct spatiotemporal expression: highly expressed in eggs for early development, strongly phosphorylated in females to meet reproductive-immune requirements, and enriched in the midgut and thorax, potentially functioning as a hub of innate immunity and energy metabolism. The present study lays the foundation for dissecting the role of ERK in the regulation of mosquitos immune response against pathogen.

Objective To document the first spillover transmission of wild rodent plague to Rattus tanezumi in Lijiang City during spring 2022, and implement control measures, thereby providing a scientific basis for regional plague prevention. Methods Field investigations were conducted on plague hosts and vectors in the epidemic area in Lijiang City in 2022. Specimens of rodents and fleas were collected and subjected to bacteriological testing, nucleic acid detection, as well as colloidal gold-based detection of plague F1 antigen and antibodies, reverse hemagglutination, indirect hemagglutination, and up-converting phosphor technology(UPT) assays. Multiple methods were applied for comprehensive assessment of the plague epidemic. Integrated control measures such as rodent and flea eradication were implemented in the affected area. Results During the outbreak investigation, 12 dead rodents were collected, of which 5 tested positive for Yersinia pestis. Among these, three rodents tested positive for antigen, nucleic acid, and culture simultaneously. These included Rattus tanezumi, Apodemus chevrieri, and Eothenomys miletus. Two specimens were positive for antigen and nucleic acid, identified as Dremomys pernyi and an unidentifiable rodent remnant. A total of 191 live rodents were captured, with Apodemus chevrieri being the dominant species, accounting for 87.43% (167/191). Bacteriological examination of visceral organs from all live-captured rodents yielded negative results. Among 47 serum samples collected from live rodents, the seroprevalence was 23.40% (11/47). Ectoparasite examination of 73 live rodents revealed 185 fleas, with an infestation rate of 38.22% (73/191) and a flea index of 0.97 (185/191). Neopsylla specialis specialis constituted 64.86% (120/185) of the collected fleas. Bacteriological testing of flea gastric contents showed negative across all specimens. Through comprehensive interventions including epidemiological investigations, rodent and flea eradication, specialized training, and health education, the epidemic was effectively controlled. Conclusion This outbreak was identified as an epizootic plague epidemic, Rattus tanezumi infection may have been transmitted from wild rodents infected with plague. Enhanced animal plague surveillance and early warning systems is essential to prevent epizootic outbreaks.

Objective To monitor the composition and distribution of plague host animals and vector fleas in Jianchuan County, Yunnan Province, assess the risk of plague occurrence and prevalence, and provide a reference basis for the monitoring, prevention, and control of wild rodent plague in Yunnan Province. Methods From 2011 to 2023, systematic surveillance and ecological investigations were performed on host animals and their ectoparasitic fleas across four distinct habitat types (residential areas, vegetable cultivation plots, agricultural fields, and shrubland) within the plague natural focus of Jianchuan County. Rodent species and flea populations were taxonomically classified and identified through morphological characterization. Subsequently, comprehensive analyses were conducted to examine the community structure and species diversity patterns of both rodent and flea populations. Results A total of 24 550 host animals were captured, belonging to 5 orders, 7 families, 17 genera, and 25 species. The average annual capture rate was 7.94%, with statistically significant differences among years (χ²=3 711 600.00, P<0.001). The capture rate of host animals in shrublands was the highest (16.02%), and the variation among different habitats was statistically significant (χ²=10 061.501, P<0.001). The dominant species in residential areas were Rattus norvegicus, Rattus tanezumi, and Mus musculus, accounting for 35.99%, 35.76%, and 15.72%, respectively. In wild habitats (vegetable gardens, farmlands, and shrublands), the dominant species were Eothenomys miletus (48.70%) and Apodemus chevrieri (36.93%). The overall flea infection rate of host animals was 29.83%, with a total flea index of 2.82. Significant differences in flea infestation rates were observed among years (χ²=195.963, P<0.001). The dominant species of ectoparasitic fleas on host animals were Ctenophthalmus quadratus, Frontopsylla spadix spadix, and Neopsylla specialis specialis. accounting for 46.76%, 28.91%, and 19.95%, respectively. Although the species richness of host animals and their ectoparasitic fleas was relatively low in residential areas, the species diversity and evenness index were relatively high. The community similarity of host animals and their ectoparasitic fleas in agricultural areas and shrubland habitats was high. Conclusion The community structure of host animals and vector fleas in the plague focus area of Jianchuan County is stable but unevenly distributed, posing a high risk of prevalence. It is necessary to focus surveillance on high densities of dominant species and ecologically imbalanced habitats, strengthen public education, and achieve early detection and control to reduce the risk of transmission.

Objective This study aims to analyze the composition, diversity, and functional characteristics of both cuticle surface and internal bacterial communities in Culex pipiens pallens with different levels of resistance to cypermethrin, and to provide a reference for further exploring the role of bacterial communities in mosquito insecticide resistance mechanisms. Methods Resistant strains of Cx. pipiens pallens, designated as the third (RT) and sixth (RS) generations, were selected from a susceptible strain (SS) using cypermethrin for this study. 16S rRNA high-throughput sequencing technology was employed to compare the compositional changes in the cuticle surface and internal bacterial communities among the SS, RT, and RS groups, and PICRUSt2 was used for functional prediction. Results In total, the cuticle surface bacterial community from the three groups of Cx. pipiens pallens were classified into 30 phyla, 61 classes, 136 orders, 215 families, and 442 genera; the internal bacterial community of Cx. pipiens pallens comprised 11 phyla, 19 classes, 56 orders, 87 families, and 123 genera. Alpha diversity analysis revealed that both the diversity and richness of the internal bacterial community in the susceptible Cx. pipiens pallens (SS group) were higher than those in the resistant Cx. pipiens pallens (RT and RS groups) (Simpson index: H=10.500, P=0.005; Shannon index: H=9.500, P=0.009; Chao 1 index: H=12.545, P=0.002; ACE index: H=12.522, P=0.002). Beta diversity analysis indicated statistically significant compositional differences in both the cuticle surface (R=0.917, P=0.001) and internal (R=0.976, P=0.001) bacterial communities among the three groups. At the phylum level, the total relative abundance of Actinobacteriota, Proteobacteria, Firmicutes, and Bacteroidota exceeded 98%, with the RS group showing the highest relative abundance of Proteobacteria (cuticle surface bacterial communities: H=9.380, P=0.009; internal bacterial communities: H=8.660, P=0.013). At the genus level, compared with the SS group, the relative abundance of Yersinia in the resistant groups was significantly increased (H=13.291, P=0.001). PICRUSt2 functional prediction indicated that the relative abundances of functional pathways in the cuticle surface and internal bacterial communities of the RS group were significantly higher than those in the SS group, including metabolism of cofactors and vitamins (Z=-2.263, P=0.035; Z=-3.536, P<0.001), folding, sorting and degradation (Z=-3.041, P=0.004; Z=-2.192, P=0.043), cell motility (Z=-3.465, P<0.001; Z=-3.182, P=0.002), cellular community-prokaryotes (Z=-3.536, P<0.001; Z=-3.182, P=0.002), membrane transport (Z=-3.536, P<0.001; Z=-3.182, P=0.002), and drug resistance: antimicrobial (Z=-3.536, P<0.001; Z=-3.536, P<0.001). Conclusion The resistance of Cx. pipiens pallens to cypermethrin is associated with the structure of its cuticle surface and internal bacterial communities, providing a theoretical basis for exploring control strategies for insecticide-resistant mosquitoes from the perspective of bacterial communities.

Objective To understand the distribution of wild rats and Schistosoma japonicum infection in schistosomiasis-endemic areas in Hubei Province, and to provide a basis for accelerating the elimination of schistosomiasis and implementing targeted prevention and control measures. Methods Schistosoma japonicum infection in wild rats was investigated in snail-breeding habitats of schistosomiasis-endemic villages across 14 counties (cities, districts) in Hubei Province from 2019 to 2023. Mouse traps (cages) were deployed overnight to capture wild rats, and ​Schistosoma japonicum infection status was detected through parallel testing using liver compression microscopy, mesenteric vein compression microscopy, Kato-Katz method, and miracidium hatching method. At the same time, elk feces from Père David's deer (Elaphurus davidianus) in the Shishou Milu National Nature Reserve and wild feces from snail-infested environments in monitoring villages were collected and tested using the miracidium hatching method. Spatial autocorrelation analysis was employed to analyze and identify patterns in wild rat density. Results From 2019 to 2023, a total of 11 073 mouse traps (cages) were deployed across 163 environments, with a recovery trap rate of 96.76%. A total of 361 wild rats were captured, predominantly Apodemus agrarius and Rattus norvegicus, yielding a rat density of 3.37%. The infection rate of Schistosoma japonicum in wild rats was 0. Among the 14 counties (cities, districts), no statistically significant differences in wild rat density were observed among 11 counties (cities, districts), excluding Jingzhou District, Gong'an County, and Yangxin County. Yangxin County exhibited higher rat density compared to Gong'an County and Jingzhou District. No significant correlation was found between wild rodent density at survey sites and the distance from the survey environment to the nearest residential area. Spatial autocorrelation in wild rat density was observed in the monitoring areas of Hubei Province in 2020 and 2023, exhibiting a spatial clustering pattern. From 2019 to 2023, High-value (H-H) clustering areas of wild rat density in Hubei Province were mainly distributed across 7 environments in Yangxin County and 1 environment in Qianjiang City. A total of 134 wild fecal samples were collected, all of which tested negative. Conclusion In recent years, Schistosoma japonicum infection has been detected in wild rats in schistosomiasis-endemic areas of Hubei Province. However, the spatial clustering of wild rats still exists. To prevent the importation and resurgence of schistosomiasis outbreaks, continued surveillance of S. japonicum infection in wild rats is warranted, with strengthened monitoring and control in clustering areas.

Objective To investigate the genotype distribution of the voltage-gated sodium channel (VGSC) gene in wild Aedes albopictus field populations in Shanghai, characterize knockdown resistance (KDR) gene mutations and their trends, and provide scientific guidance for mosquito-borne disease control strategies in the region. Methods Larvae/pupae of Aedes albopictus were collected from 13 sites across 12 districts in Shanghai between September and October 2024. After being reared to adulthood in the laboratory, healthy female mosquitoes were selected for genetic analysis. Genomic DNA was extracted using a spin column method. Primers targeting Domain Ⅱ, Ⅲ, and Ⅳof the VGSC gene were designed for PCR amplification. Amplicons were verified by agarose gel electrophoresis, sequenced, and analyzed using SeqMan software to identify mutation sites and genotypes. Mutation frequencies were calculated using Excel, and regional differences were compared via chi-square tests (P<0.05 considered statistically significant). Results A total of 455 Aedes albopictus mosquitoes were analyzed, revealing an overall mutation rate of 79.8% (363/455), with all 13 populations exhibiting varying mutation frequencies. The frequencies of mutant alleles were 5.0% for V1016G (GGA/G, 45/910), 4.3% for I1532T (ACC/T, 39/910), and for the F1534 locus, 48.5% for F1534S (TCC/S, 441/910) and 14.0% for F1534C (TGC/C, 127/910). No individuals carrying simultaneous mutations at all three loci were detected. However, 52 individuals (11.4%) harbored mutations at two loci: 2 individuals (0.4%) with concurrent mutations at V1016 and F1534, and 50 individuals (11.0%) with concurrent mutations at I1532 and F1534. Conclusion The Aedes albopictus population in Shanghai exhibits rapid KDR mutation evolution, with predominant combined mutations at loci I1532 (I/T) and F1534 (F/S) stably distributed across most surveillance regions. Vigilance is warranted regarding synergistic resistance development. A dynamic monitoring system, coupled with insecticide rotation and precision application, should be integrated into multi-dimensional resistance management strategies to delay resistance gene spread and accumulation.

Objective By investigation of the density distribution, population composition, and degree of infestation of cockroaches in different habitats in 14 prefecture-level cities in Liaoning Province from 2020 to 2024, this study provided a detailed analysis of the dynamic patterns of their seasonal fluctuation, and provided theoretical support for development of scientific and effective cockroaches prevention and control strategies. Methods From 2020 to 2024, the sticky trap method was used to monitor cockroaches density in six habitats including farm product markets, supermarkets, hotels, restaurants, hospitals, and residential areas in 14 prefecture-level cities in Liaoning Province. The surveillance results of cockroaches were statistically analyzed using Excel 2010 and SPSS 27.0 software. The density and species composition of cockroaches were analyzed, and the density difference and seasonal fluctuation trend of cockroaches in different years and different habitats were compared. Results A total of 19 998 cockroaches were captured in Liaoning Province from 2020 to 2024, with a cockroach density of 0.32 cockroaches per paper (19 998/63 215), and the infestation rate was 5.57% (2 707/48 616). The captured population was mainly Blattella germanica, accounting for 97.33% (19 465/19 998) of the total. The density of cockroaches in different habitats was highest in farm product markets, reached 1.25 cockroaches per paper, followed by supermarkets with a density of 0.44 cockroaches per paper, and the lowest was in hotels and hospitals with a density of 0.05 cockroaches per paper. Among the surveillance sites in the province, Yingkou had the highest density of cockroaches, reached 2.43 cockroaches per paper, followed by Tieling with a density of 0.70 cockroaches per paper, Fuxin and Jinzhou was with the lowest density of only 0.01 cockroaches per paper. Among the surveillance sites in the province, Huludao and Yingkou had relatively high cockroaches infestation rate, at 13.20% and 11.85% respectively. Jinzhou has the lowest infestation rate, at only 0.97%. The peak of cockroaches density and infestation rate occurred from July to September. The seasonal fluctuation of cockroaches density differed significantly in different years (χ²=44.504, P<0.05) and in different habitats (χ²=41.913, P<0.05). Conclusion Blattella germanica was the dominant species of cockroaches in Liaoning Province. Farm product markets and supermarkets has a relatively high density of cockroaches. Therefore, it is necessary to strengthen the monitoring and control of cockroaches in these places.

Objective To determine the insecticide resistance levels of rural Aedes albopictus populations in Guangzhou, assess the impact of dengue vector control on insecticide resistance, and discuss the rational use of insecticides and resistance management strategies. Methods In July 2024, larval samples of Aedes albopictus were collected from four rural residential sampling sites within a 20-40 km radius of Guangzhou (with a distance of ≥20 km between each site). In the past three years, Dongxiang and Suishi villages had reported 18 and 3 cases of dengue fever, respectively; Xinhai and Donglong villages had reported none. The insecticide resistance levels of field-collected mosquitoes across all sampling sites were evaluated against beta-cypermethrin (conventional insecticide) along with propoxur and temephos (non-conventional insecticides). Insecticide resistance was determined by the larval immersion bioassays. Using the median lethal concentration (LC₅₀) of a specific sampling site as the control, Probit regression analysis was conducted for each insecticide to determine whether inter-site differences in resistance were statistically significant. Results Using the LC₅₀ of the sensitive population as the base, the test insects from Dongxiang village showed high resistance to beta-cypermethrin (116.85-fold), while those from Suishi and Donglong villages showed moderate resistance (21.41-fold and 12.63-fold, respectively); the test insects from Xinhai village showed moderate resistance to temephos (10.79-fold); all four populations demonstrated low-level resistance to propoxur, with resistance ratios ranging from 3.24 to 4.42. Using Xinhai as the reference population for beta-cypermethrin, resistance in Dongxiang and Suishi was significantly higher (P<0.05). In Dongxiang, resistance to temephos and propoxur was significantly lower than that to beta-cypermethrin (P<0.05). Conclusion In rural areas of Guangzhou where dengue outbreaks have been reported, Aedes albopictus exhibits high resistance to commonly used insecticides but lower resistance to less frequently used agents. In areas without dengue cases, resistance levels to all tested insecticides remain low. Local governments should scientifically use insecticides through environmental sanitation management, insecticide combinations, insecticide rotation, or the use of synergists to avoid or delay the development of resistance in Aedes albopictus during the handling of outbreaks.

Objective To understand the changes in antigen genotypes of clinical isolates of Bordetella pertussis (Bp) in Shandong province from 2014 to 2022, aiming to provide a reference for the optimization of pertussis vaccines. Methods Bp strains were clinically isolated from patients at the Children's Hospital Affiliated to Shandong University between 2014 and 2022. The major antigen genes ptxA, ptxC, ptxP, prn, fim2, fim3, and tcfA of Bp isolates were amplified by PCR to determine their antigen genotypes. Genotype distributions were compared across time periods, differences between vaccinated and unvaccinated infection groups were assessed, and findings were compared with the antigen genotypes of vaccine strains currently used in China. Results Six antigen genotype profiles were identified among Bp isolates in Shandong Province during 2014-2022, of which the most prevalent antigen genotype was ptxA1/ptxC1/ptxP1/prn1/fim2-1/fim3-1/tcfA2 (73.27%), followed by ptxA1/ptxC4/ptxP3/prn150/fim2-1/fim3-1/tcfA2 (22.78%). The prevalence of genotypes ptxC1, ptxP1, and prn1 was highest in 2014-2016, followed by 2020-2022, and lowest in 2017-2019; however, these temporal differences were not statistically significant (P>0.05). In contrast, ptxC4, ptxP3, and prn150 were not detected before 2020 and only appeared in the 2020-2022 period, a statistically significant emergence (P<0.001). Among the isolates from 2020-2022, no significant difference in prevalence was observed between ptxC1 and ptxC4, ptxP1 and ptxP3, or prn1 and prn150 (P>0.05). The differences in antigen genotypes between the vaccinated and unvaccinated groups were not statistically significant (P>0.05). Finally, compared with the vaccine strain, the major change of Bp epidemic strains in Shandong Province was the substitution of ptxA1 for ptxA2. Conclusions From 2014 to 2022, the predominant antigen genotype among circulating Bp strains in Shandong Province was ptxA1/ptxC1/ptxP1/prn1/fim2-1/fim3-1/tcfA2. After 2020, the major changes were as follows: ptxC1 shifted to ptxC4, ptxP1 shifted to ptxP3, and prn1 shifted to prn150. The genotypes of epidemic Bp strains differ from the vaccine strain, primarily marked by the replacement of ptxA2 with ptxA1. Continued surveillance of Bp antigen genotypes in Shandong Province is warranted to inform the development of new pertussis vaccines.

Objective To investigate the role of fibroblast activation protein (FAP) in the pathogenesis of liver fibrosis induced by Echinococcus multilocularis infection. Methods In this study, a murine model of Echinococcus multilocularis infection was established in female C57BL/6 mice by injecting Echinococcus multilocularis saline suspension through the portal vein, with infections lasting for 1, 3, and 6 months. Subsequently, liver tissues were extracted from the mice, and histopathological changes in the liver tissues were examined using hematoxylin-eosin (HE) staining and Sirius red staining. The expression levels of α-smooth muscle actin (α-SMA), collagen type Ⅰ (COL1A1), and FAP were detected by immunohistochemistry to evaluate the degree of hepatic fibrosis. RT-qPCR and Western blot were employed to quantify the mRNA and protein levels of α-SMA, COL1A1, collagen type III (COL3A1), and FAP in mouse liver tissue. Correlation analysis was performed to determine the relationship between FAP expression and liver fibrosis. Results In the mouse models of liver fibrosis infected with Echinococcus multilocularis for 1, 3, and 6 months, HE staining revealed progressive aggravation of hepatic pathological changes over time, and Sirius red staining showed a significant, time-dependent increase in collagen fiber tissue (positive areas: 1 372±769.2, 2 952±555.5, and 6 594±1 708.0, respectively) (all P<0.01). Immunohistochemistry, Western blot, and RT-qPCR results indicated that time-dependent increases in the expression of α-SMA, COL1A1, and FAP (α-SMA positive areas: 1 533±669.7, 3 005±690.5, and 6 596±1 649.0; COL1A1 positive areas: 1 990±432.8, 3 849±627.6, and 6 527±1 027.0; FAP positive areas: 956.9±192.5, 1 875±414.0, and 3 537±888.3) (all P<0.01). Moreover, the positive area of FAP was positively correlated with the positive areas of Sirius Red staining (R²=0.645 2, P<0.01), α-SMA (R²=0.651 5, P<0.01), and COL1A1 (R²=0.811 8, P<0.01). Conclusion FAP may be involved in the occurrence and development of liver fibrosis induced by Echinococcus multilocularis infection and holds promise as a potential biomarker for assessing the degree of liver fibrosis and as a therapeutic target for liver fibrosis.

Objective To investigate the serotypes, molecular typing, antimicrobial resistance, and virulence factor characteristics of Salmonella isolates from foodborne disease cases in Changsha City, and to explore the relationships between serotypes, antimicrobial resistance, and virulence. Methods A total of 57 Salmonella strains isolated in Changsha in 2024 were analyzed. Serotypes were identified using the serum agglutination tests; antimicrobial susceptibility testing was performed using the broth microdilution method; whole-genome sequencing was conducted for multilocus sequence typing (MLST), antimicrobial resistance gene and virulence factor detection, with phylogenetic tree analysis performed to assess their correlations. Results The Salmonella isolation rate was 10.65% (57/535), distributed across serogroups B, C, D, E, and J, comprising 13 serotypes, with Salmonella Typhimurium (61.40%, 35/57) being the dominant serotype. A total of 15 ST types were detected, with ST34 being the predominant type (45.61%, 26/57). The 15 ST types were further differentiated into 38 core-genome sequence type (cgST), with cgST17987 being the most frequent (14.04%, 8/57). Eight clonal groups with identical cgST types were identified, with ST34 exhibiting high cgST diversity (15 types). The SNP-based phylogenetic tree and cgMLST minimum spanning tree showed high consistency in major branch structures, with the former's Salmonella Typhimurium clone group (ST34 tight cluster) fully corresponding to the latter's cgST18020 complex. The isolates exhibited high resistance rates to streptomycin (82.46%), tetracycline (75.44%), and ampicillin (73.68%), with multidrug-resistant strains accounting for 80.70%. The most prevalent resistance genes were aac(6')-Iaa, aph(6)-Id, aph(3'')-Ib, bla_TEM-1B, sul2, and floR. The 57 Salmonella strains primarily carried virulence factors related to fimbrial adhesion, non-fimbrial adhesion, secretion systems, regulation, and transport proteins. Conclusion In this study, Salmonella isolates were predominantly of the ST34 clone lineage, exhibiting high clonal relatedness and low genetic diversity, indicative of recent transmission. The isolates displayed broad antimicrobial resistance profiles, with rare occurrences of high-risk resistance genes such as bla_NDM-5, while harboring multiple virulence factors. These findings highlight the urgency of antimicrobial resistance control and the necessity for enhanced surveillance and monitoring.

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 >20~40 years (OR=1.194, 95%CI:1.101-1.294), >40~60 years (OR=1.212, 95%CI:1.107-1.328), >60 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.

Objective To retrospectively review the data of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections, investigate their clinical distribution and drug resistance, and detect Staphylococcal Cassette Chromosome mec (SCCmec) and pvl genes in the isolates. This study aims to characterize the epidemiological features of MRSA, predict its trends, and provide a reference for infection control and clinical therapeutic strategies. Methods MRSA data from 2020 to 2024 were extracted from the Laboratory Information System (LIS) and WHONET databases of three Grade III-A general hospitals. Non-redundant isolates from clinical specimens of hospitalized patients with antimicrobial susceptibility records were included. Detection rates, drug resistance rates, specimen sources, and high-risk departments were analyzed. A random selection of 129 cryopreserved MRSA isolates underwent PCR amplification for mecA, SCCmec types Ⅰ-Ⅴ, and pvl genes. Results A total of 3 065 eligible MRSA isolates were identified across the three hospitals. The annual MRSA detection rates over five years ranged from 49.7% to 56.2%, with significant inter-hospital differences (all P<0.01); hospital B exhibited the highest rate (57.3%-63.6%). MRSA demonstrated 100.0% susceptibility to linezolid, vancomycin, and teicoplanin, and low-level resistance to rifampicin and chloramphenicol. Isolates were mainly derived from sputum (50.8%), blood (14.6%), and secretions (13.9%). ICU contributed 47.4% of MRSA isolates. Among the 129 tested strains, mecA carriage was observed in 98.5% (127/129). The predominant SCCmec types wereⅢ (47.3%, 61/129) and Ⅱ (40.3%, 52/129), with type Ⅳb detected in 7.8% (10/129) of the samples. The pvl gene positivity rate was 7.0% (9/129). Conclusion Over the five-year period, MRSA detection rates in three hospitals were notably higher than national averages for the same period, albeit with a slow downward trend. The MRSA isolates exhibited multidrug resistance to various antimicrobial agents, although no strains resistant to vancomycin or linezolid were found.

Objective To analyze the epidemiological and clustering epidemic characteristics of fever with thrombocytopenia syndrome (SFTS) in Changzhou City, Jiangsu Province, China, and to find out the loopholes in the disposal of the epidemic, thereby providing a scientific basis for the prevention and control of the epidemic in Changzhou City. Methods Descriptive epidemiological methods were used to characterize the case profiles across demographic, temporal, geographical, healthcare-seeking, and clustered outbreak dimensions in Changzhou City from 2021 to 2024. Between-group differences in characteristics were analyzed using chi-square tests or Fisher's exact probability tests, as statistically appropriate. Results A total of 61 SFTS cases were reported in Changzhou City from 2021 to 2024, with an incidence rate of 0.28/100 000, and a cumulative total of 17 deaths, with a case fatality rate of 27.87%. The male-to-female ratio was 1:1.03, with a median age of 66 (58.25, 72.75) years. A statistically significant difference in age distribution was observed between the clinical improvement group and the mortality group (P<0.01). The predominant occupational category among participants was farmers. The onset of the disease was mainly in summer and fall, with most of the cases concentrated in Liyang City and Jintan District, and the median time from onset to diagnosis was 5 d. 95.08% (58/61) of the cases were confirmed in tertiary and above medical institutions. Three SFTS household cluster outbreaks were reported between 2021 and 2024, of which two were caused by close caregiving during the hospitalization of relatives. Among the two primary cases, one died, while the two subsequent cases were both cured. The other cluster was caused by direct contact with the blood of the deceased and contaminated materials. The primary case died, and one of the two subsequent cases also died. Conclusion The incidence of SFTS in Changzhou City is showing an increasing and spreading trend. It is crucial to enhance health education for high-risk populations in key areas and to strengthen the case detection capabilities of primary healthcare institutions in high-incidence townships. For suspected cases, especially those at risk, viral nucleic acid testing should be conducted as early as possible; hospital discharge management and tracking should be strengthened; and infection control should be done in households and communities to prevent clustered outbreaks..

Objective To investigate antimicrobial resistance profiles, virulence factor distribution, molecular genotyping, and epidemiological characteristics of foodborne Salmonella Typhimurium in Fuzhou City, Jiangxi Province, and to provide molecular epidemiological evidence for preventing and controlling foodborne infections caused by this pathogen. Methods Antimicrobial susceptibility testing and whole-genome sequencing were performed on 65 S. Typhimurium strains isolated from active foodborne disease surveillance in Fuzhou City between 2021 and 2023. These genomic data, combined with case information, were analyzed to determine the ‌resistance profiles, virulence factors, and molecular typing. Results Among the 65 S. Typhimurium isolates, the highest resistance rate was observed for ampicillin (92.31%). No resistance to imipenem was found, and all isolates were susceptible to polymyxin E. The prevalence of multidrug-resistant (MDR) strains, defined as resistance to three or more antimicrobial classes, was 70.77%. MLST typing identified ST34 as the predominant type (69.23%). Furthermore, cgMLST showed a greater number of subclusters within ST34, with allelic differences exceeding 10 loci for the vast majority of strains. A total of 57 resistance genes belonging to 12 classes were identified, with universal carriage of ‌aac(6')-Iaa (100.00%), followed by sul2, blaTEM-1B, aph(3'')-Ib, and aph(6)-Id (carriage rates >70%). The monophasic variant of S. Typhimurium (4,[5],12:i:-) carried more resistance genes than S. Typhimurium, and 96.92% of isolates harbored genes conferring resistance to ≥3 antimicrobial classes. The overall concordance between phenotypic susceptibility results and genotypic predictions was 97.94% (667/681). Among 145 virulence factors detected, 140 (96.55%) constituted the core virulome shared by all isolates. Of the non-core factors, the detection rate of the shdA gene showed a significant upward trend annually (P<0.001). Infections were most common in children aged ≤3 years (87.69%), with a seasonal peak from June to September (70.18%). Conclusion Foodborne S. Typhimurium in Fuzhou City exhibits a high level of antibiotic resistance. The epidemiology pattern is predominantly sporadic, yet a risk of localized, homologous outbreaks exists. Enhanced prevention and control measures targeting infections in infants and young children during summer and autumn are crucial. The monophasic variant 4,[5],12:i:- carries more resistance genes and displays greater genetic diversity than typical S. Typhimurium. Strains carry numerous virulence factors with minimal differences, indicating overall strong pathogenicity. This study provides valuable surveillance data for local Salmonella infection control, offers evidence-based guidance for rational antibiotic use in clinical settings, and supports the formulation of strategies for foodborne disease prevention.

Objective This report analyzes the investigation and emergency response to a case of imported chikungunya fever, along with the monitoring of mosquito vectors in the same period, to provide a reference basis for the prevention and control of chikungunya fever. Methods An epidemiological investigation was conducted in 2024 to study a case of chikungunya fever, including case search, emergency surveillance of mosquito vectors, and mosquito control measures. Pearson χ² test was used to analyze mosquito surveillance data, including larval density in different habitats. Results Investigation revealed that the case had traveled to the Maldives with his wife from May 24 to June 1, 2024. After returning to Shanghai, he developed a fever on June 3. He visited Hospital A on June 4 and received treatments, including antipyretics and psychological counseling for stress relief, with no symptom improvement. On June 5, he presented to Hospital B, where an acute-phase serum sample was collected and sent to the CDC for nucleic acid testing for both dengue and chikungunya viruses. On June 7, the laboratory confirmed a positive result for chikungunya virus nucleic acid. The patient recovered following isolation and treatment, and no secondary cases were reported. Surveillance of Aedes vectors in July showed a Breteau index (BI) of 8.85 and a mosquito ovitrap index (MOI) of 7.19. A comparison of MOI in different habitats in 2024 revealed no statistically significant difference (χ²=5.45, P>0.05). ). Mosquito control and emergency surveillance were initiated on the day of diagnosis. After three consecutive days of mosquito control measures, the BI in the core area dropped rapidly from 10 to 3 by June 11, and the human-bait tent trap index dropped from an initial 4 mosquitoes/(trap·h) to 2 mosquitoes/(trap·h). Through sustained vector control measures, the BI and tent trap indices in the core area and precautionary area were maintained within safe limits throughout the outbreak period. Conclusion There is a risk of local transmission caused by imported chikungunya fever cases in Jing'an District, Shanghai. Early diagnosis and timely implementation of mosquito control measures are essential to prevent potential local epidemics.