ObjectiveTo genotype the specimens from hand-foot-and-mouth disease (HFMD) cases in Dehong Prefecture, Yunnan Province in 2023 by gene sequencing, and to analyze the genetic characteristics of Coxsackievirus A4 (CVA4), CVA6, CVA10, CVA16 and enterovirus A71 (EV-A71), so as to clarify the serotypes of enteroviruses causing endemic HFMD and the genotype composition of CVA4, CVA6, CVA10, CVA16 and EV-A71 prevalent in HFMD, and to provide baseline genotype data for monitoring the dynamic changes of the five virus genotypes. MethodsStool specimens from HFMD cases in Dehong Prefecture in 2023 that tested positive for EV-A71, CVA16 and other enteroviruses by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) were first subjected to gene sequencing and typing of the VP4/VP2 junction region to determine the viral types. Subsequently, the complete VP1 gene of each virus was amplified in two segments using group-specific VP1 gene primers corresponding to enterovirus groups (i.e., enterovirus group A, B, and C) and sequenced (group A virus: primers 486/488 and 487/489, group B virus: primers 490/492 and 491/493, group C virus: primers 494/496 and 495/497). The representative reference sequences of VP1 genes for CVA4, CVA6, CVA10, CVA16 and EV-A71 were downloaded from the literature, and the VP1 gene phylogenetic tree was constructed using MEGA 6.0 software for genetic characterization. ResultsA total of 256 stool specimens were collected from HFMD cases in Dehong Prefecture in 2023, of which 94 tested positive for nucleic acid by RT-qPCR, yielding a positive rate of 36.72%. Of the 94 positive specimens, 83 were identified as group A viruses, and were classified into 5 serotypes (17 strains of CVA4, 3 of CVA6, 6 of CVA10, 49 of CVA16, and 8 of EV-A71). Nine strains were group B viruses, comprising 2 serotypes: 2 strains of echovirus type 3 (E3) and 7 strains of Coxsackievirus B type 5 (CVB5). The remaining 2 strains were group C viruses, both identified as poliovirus type 3 (PV3). Genetic analyses of the VP1 region showed that all 17 CVA4 strains were identified as subgenotype C2, all 3 CVA6 strains as subgenotype D3a, all 6 CVA10 strains as genotype C. Among the 49 CVA16 strains, 46 were identified as subgenotype B1a and 3 as subgenotype B1b, and all 8 EV-A71 strains were identified as subgenotype C4a. ConclusionIn 2023, group A viruses dominated the pathogenic spectrum of HFMD in Dehong Prefecture. Among them, CVA16 had the highest positivity rate. Genetic characteristic analyses showed that CVA4, CVA6, CVA10 and EV-A71 were each composed of a single genotype (subgenotype), while CVA16 was composed of two subgenotypes (B1a and B1b), with B1a being the predominant one. It is recommended that molecular epidemiological surveillance of HFMD pathogens, particularly group A viruses, be continuously strengthened in Dehong Prefecture.

To understand the epidemiological characteristics and antimicrobial resistance of Esche-richia coli in free-range Tibetan pig populations,fecal samples from these pigs were collected be-tween 2021 and 2023 for pathogen isolation and identification.The isolated strains underwent anal-ysis of pathogenicity categories,phylogenetic grouping,and antimicrobial susceptibility profiles,a-long with resistance gene detection and mouse pathogenicity testing.The results showed that 123 strains of E.coli were isolated from 132 fecal samples.Enteropathogenicity tests revealed that 42.28％were EAEC(52/123),7.32％were EPEC(9/123),and 3.25％were STEC/EHEC(4/123).Phylogenetic analysis indicated that 78.86％(97/123)belonged to group A,while 11.38％(14/123)belonged to group B1.Antimicrobial susceptibility tests for 22 drugs showed the highest resistance rate to amoxicillin at 98.37％(121/123),followed by sulfamethoxazole at 73.98％(91/123).Resistance rates for ampicillin,tetracycline,erythromycin,and trimethoprim ranged from 48.78％to 51.22％.Furthermore,78.86％(97/123)of the isolates were resistant to three or more antibiotics.The detection of 52 drug-resistance genes in 10 categories showed that 15 drug-resist-ance genes were detected,and the detection rate was 28.85％(15/52).Among individual resistance genes,tetA had the highest detection rate at 63.41％(78/123),followed by tetB and qnrS with de-tection rates of 48.78％(60/123)and 38.21％(47/123),respectively.This study demonstrates that EAEC is the predominant strain of E.coli in free-range Tibetan pigs,with groups A and B1 being the major phylogenetic groups.The isolates exhibited a high degree of multidrug-resistant pheno-types,and the detection rates of resistance genes were also high.E.coli carrying virulence genes cause different degrees of pathological changes in the mouse ileum.The research results have sig-nificant public health implications and provide theoretical basis for the prevention,treatment,and clinical medication of E.coli disease in Tibetan pigs.

To understand the epidemiological characteristics and antimicrobial resistance of Esche-richia coli in free-range Tibetan pig populations,fecal samples from these pigs were collected be-tween 2021 and 2023 for pathogen isolation and identification.The isolated strains underwent anal-ysis of pathogenicity categories,phylogenetic grouping,and antimicrobial susceptibility profiles,a-long with resistance gene detection and mouse pathogenicity testing.The results showed that 123 strains of E.coli were isolated from 132 fecal samples.Enteropathogenicity tests revealed that 42.28％were EAEC(52/123),7.32％were EPEC(9/123),and 3.25％were STEC/EHEC(4/123).Phylogenetic analysis indicated that 78.86％(97/123)belonged to group A,while 11.38％(14/123)belonged to group B1.Antimicrobial susceptibility tests for 22 drugs showed the highest resistance rate to amoxicillin at 98.37％(121/123),followed by sulfamethoxazole at 73.98％(91/123).Resistance rates for ampicillin,tetracycline,erythromycin,and trimethoprim ranged from 48.78％to 51.22％.Furthermore,78.86％(97/123)of the isolates were resistant to three or more antibiotics.The detection of 52 drug-resistance genes in 10 categories showed that 15 drug-resist-ance genes were detected,and the detection rate was 28.85％(15/52).Among individual resistance genes,tetA had the highest detection rate at 63.41％(78/123),followed by tetB and qnrS with de-tection rates of 48.78％(60/123)and 38.21％(47/123),respectively.This study demonstrates that EAEC is the predominant strain of E.coli in free-range Tibetan pigs,with groups A and B1 being the major phylogenetic groups.The isolates exhibited a high degree of multidrug-resistant pheno-types,and the detection rates of resistance genes were also high.E.coli carrying virulence genes cause different degrees of pathological changes in the mouse ileum.The research results have sig-nificant public health implications and provide theoretical basis for the prevention,treatment,and clinical medication of E.coli disease in Tibetan pigs.

OBJECTIVETo compare the determination methods of fiber number concentration between China and WHO.

METHODSIndividual fiber samplings were conducted at a RCF manufacturing enterprise for 40 types of work. Flow rate was set as 2 L/min and lasted 2 to 4 hours. We used acetone-triacetin to prepare samples. The rules of two methods were used to count fibers for each sample respectively. The differences between the results of two methods were compared using the sign-rank test, and the correlation between the two methods' counting results were evaluated by the Spearsman rank correlation analysis.

RESULTSThe results of WHO counting rule were higher than those of Chinese counting rule for the same sample. The ratios of WHO method to Chinese method ranged from 1.88 to 3.70. Paired sign-rank test found the statistically significant differences of the results between the two methods (P<0.01). The rank correlation coefficient of the results by two rules counting ranged between 0.621 to 0.975, suggested positive correlation (P<0.01). The possible reasons of the difference between the two methods included the difference between the shapes of asbestos fiber and man-made mineral fiber, and counting rules of two methods.

CONCLUSIONThe results of WHO counting method is higher than those of Chinese counting method. High correlations between the results of the two methods were observed.

Asbestos ; analysis ; Chemistry Techniques, Analytical ; methods ; China ; Humans ; Mineral Fibers ; analysis ; Specimen Handling ; World Health Organization