Objective:To analyze the epidemiological and etiological characteristics of a death case of meningococcal meningitis in Hengyang city, Hunan Province in 2024.Methods:Epidemiological investigation of the death case was performed, and samples from the patient and close contacts were collected. Following cultivation and isolation, Neisseria meningitidis ( Nm) strains were analyzed by antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), and whole-genome sequencing for analyzing epidemiological and etiological characteristics. Phylogenetic analysis was carried out using core genomic multilocus sequence typing (cgMLST). Results:The case was a 16-year-old high school boarding student with fulminant meningococcal meningitis. He had shock symptoms, and died within 24 h of the onset of symptoms. Six Nm strains were isolated from the patient and his roommates, belonging to two distinct clades. Isolate 144569 from the patient was highly homologous to isolate 144572 from a close contact, both belonging to the highly pathogenic sublineage L44.1 of CC4821. The typical molecular features was C: P1.7-2, 14: F5-101: ST4821 (CC4821). The two strains carried the antimicrobial resistance genes of gyrA-71 and penA-552, indicating reduced susceptibility to quinolone and penicillin, which was with their resistance phenotype. The isolates from four close contacts clustered within the same clade, characterized by the molecular features of B: P1.18-25, 9-18: ST5829 (UA). Conclusions:The death case is caused by Nm serogroup C from highly pathogenic sublineage L44.1 of CC4821. The spread of this isolate has the potential risk of outbreaks of invasive meningococcal disease. It is necessary to enhanced the molecular epidemiological surveillance, particularly focusing on the transmission of multiple serogroups of Nm among adolescents and the increasing exposure risk.

Objective: To investigate the serotype and drug resistance of 815 Salmonella isolates from Hunan Province, so as to provide insights into management of Salmonella infections. Methods: Salmonella isolates were collected from stool samples of foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and serotyped. Antimicrobial susceptibility test was performed using the broth microdilution method. Results: A total of 10 groups and 39 serotypes were characterized in 815 Salmonella isolates. Among the 646 Salmonella isolates of human sources, 388 isolates were identified as serogroup B (60.06%), with S. typhimurium and its variants aspredominant serotypes (364 isolates, 56.35%), and among 169 foodborne isolates, 61 isolates were characterized as serogroup B (36.09%) with S. london as the predominant serotype (26 isolates, 15.38%). There were 597 antimicrobial resistant Salmonella isolates of human sources, with a drug resistance rate of 92.41%, and the percentage of ampicillin resistance was 81.58%. There were 140 foodborne antimicrobial resistant isolates, with a drug resistance rate of 82.84%, and the proportion of tetracycline resistance was 72.78%. However, Salmonella isolates from both humans and foods were sensitive to imipenem. In addition, there were 577 multidrug resistant Salmonella isolates, including 490 multidrug resistant isolates of human sources and 87 foodborne multidrug resistant isolates. Conclusions S. typhimurium and its variants and S. london were predominant serotypes of Salmonella isolates from 815 foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and a high rate of multidrug resistance was detected.

Objective:To confirm the first imported Chikungunya fever (CHIK) epidemic in Hunan province.Methods:Serum samples of patients and colleagues were collected. The nucleic acids of Dengue virus (DENV), Yellow fever virus (YFV), Chikungunya virus (CHIKV) were detected by real- time fluorescent quantitative PCR. The positive PCR products were sequenced. Phylogenetic tree was constructed.Results:The serum samples of the patient and one of the five colleagues were positive for CHIKV. The Blast comparison of gene sequence showed 99% homology with CHIKV sequences. The infected CHIKV belonged to ECSA genotype in the phylogenetic tree.Conclusions:The first imported CHIK epidemic in Hunan province was confirmed through the epidemiological survey and etiologic detection.

Objective:To understand the characteristics and differences of diarrhea-related symptoms caused by different pathogens, and the clinical features of various pathogens causing diarrhea.Methods:Etiology surveillance program was conducted among 20 provinces of China from 2010 to 2016. The acute diarrhea outpatients were collected from clinics or hospitals. A questionnaire was used to survey demographics and clinical features. VFeces samples were taken for laboratory detection of 22 common diarrhea pathogens, to detect and analyze the clinical symptom pattern characteristics of the patient’s.Results:A total of 38 950 outpatients were enrolled from 20 provinces of China. The positive rates of Rotavirus and Norovirus were the highest among the five diarrhea-causing viruses (Rotavirus: 18.29%, Norovirus: 13.06%). In the isolation and culture of 17 diarrhea-causing bacterial, Escherichia coli showed the highest positive rates (6.25%). The clinical features of bacterial diarrhea and viral diarrhea were mainly reflected in the results of fecal traits and routine examination, but pathogenic Vibrio infection was similar to viral diarrhea. Conclusion:Infectious diarrhea presents different characteristics due to various symptoms which can provide a basis for clinical diagnosis.

Objective:To analyze the epidemiological and etiological characteristics of a dengue fever outbreak in Hunan province in 2018.Methods:Real-time PCR assay was performed for the laboratory diagnosis of 8 suspected dengue fever cases. Etiological surveillance was performed in 186 suspected dengue fever cases and fever cases who had close contacts with dengue fever patients. C6/36 cells was used for the virus isolation from acute phase serum. By sequencing the full length of E genes of 15 dengue virus strains, phylogenetic analysis was performed based on the sequences obtained, including reference sequences from the NCBI GenBank database, the serotypes and gene subtypes of the virus were analyzed to trace the possible source of transmission. An emergency monitoring of vector density and a retrospective survey of sero-epidemiology in healthy population were conducted in the epidemic area.Results:In the serum samples of 8 suspected patients, 6 were dengue virus RNA positive, and 4 were NS1 antigen positive. In 186 suspected patients, 96 were dengue virus nucleic acid, NS1 antigen or antibody positive in etiological test. A total of 64 dengue virus strains were isolated. The phylogenetic analysis showed that all the dengue virus strains belonged to type 2, which might be from Guangdong or Zhejiang provinces. The Bretub index was up to 65, indicating an extremely high risk of transmission. The positive rate of the dengue virus IgG antibody was 0.53%(2/377) in retrospective survey of 377 healthy people.Conclusion:The field epidemiologic and the molecular genetics analyses showed the outbreak of dengue fever in Hunan in 2018 was caused by imported cases and dengue virus 2.

Objective: To analyze the epidemiological characteristics of human brucellosis and trace back source of infection of human brucellosis in Hunan province during 2010-2018, and provide evidence for the prevention and control of human brucellosis. Methods: The surveillance data of human brucellosis in Hunan during 2010-2018 were analyzed with software Excel 2016 and ArcGIS 10.5, the epidemic characteristics were described using cases number, constituent ratio and rate. The conventional biotype methods were used for the identification of Brucella species, UTS-PCR was applied to further confirm the results from conventional biotype detections, then six virulence genes of two clinical Brucella strains were detected by PCR assay. Cluster analysis of two Brucella strains were performed with Multiple locus variable-number tandem repeat analysis (MLVA) for the investigation of the infection source of human brucellosis. Results: From 2010 to 2018, a total of 728 human brucellosis cases were reported in Hunan with the annual incidence rate of 0.12/100 000. The incidence rate was 2.50/100 000 in Chenzhou and 1.90/100 000 in Yongzhou, higher than those in other areas. The number of counties reporting cases increased from 5 in 2010 to 69 in 2018. Most cases were reported in age group 45-54 years, accounting for 38.32% (279/728). The cases in farmers accounted for 59.07% (430/728) of the total. The male to female ratio of the cases was 2.75 ∶ 1. The reported case number was highest during May-July, accounting for 45.33% (330/728). The incidence was high in summer and autumn, and the peak was in May. The conventional identification showed that two strains were all Brucella melitensis biovar 1, consistent with UTS-PCR amplification results. Six virulence genes were found in two isolated strains, suggesting that the Brucella melitensis strains in this study had strong virulence. MLVA results confirmed that two strains detected in Hunan had complete identical MLVA-16 genotype with strains isolated from goat and camel in Inner Mongolia Autonomous Region, indicating that there was molecular epidemiology relationship between these strains and the source of infection were originated from Inner Mongolia. Conclusions The epidemic of human brucellosis in Hunan is becoming serious, and disease has spread to general population and non-epidemic areas. Two Brucella melitensis strains detected in Hunan were originated from Inner Mongolia. The quarantine and inspection in animal transportation should be strengthened to prevent human outbreaks of brucellosis.

Objective: To understand the epidemiologic characteristics and pathogen spectrum of hand, foot and mouth disease (HFMD) in Hunan Province during 2008—2017 and provide the basis for the prevention and control strategy of hand, foot and mouth disease. Methods: Collecting data from national disease reporting information system throughout 2008—2017, the descriptive epidemiological method were used to analyze the data of HFMD monitoring and the result of pathogenic agent detection. Results: A total of 1, 255, 530 HFMD cases were reported throughout 2008—2017, including 10097 severe cases and 394 deaths. The average annual attack rate is 190.38/100, 000. The peak incidence of HFMD occurred in summer and fall. The reported incidence is on the rise. The number of critically ill and the number of deaths is declining. Proportion of male cases was higher than that of females. The majority of the children were those under 5 years of age. Enterovirus (EV)-A71, coxsackievirus (CV)-A16 and other other EV positive cases accounted for 33.29%, 20.04% and 46.67% of laboratory diagnosed cases. Conclusions The epidemic of hand, foot and mouth disease in Hunan has obvious seasonal and population characteristics. There are different dominant pathogens causing HFMD in different years.

Objective: To establish a real-time fluorescence recombinase acid amplification (RAA) method for the detection of adenovirus type 3(HAdV-3)without extraction nucleic acid. Methods: According to the conserved sequence of adenovirus type 3 gene, a pair of primers and a probe were designed, and a real-time fluorescence RAA without extracting nucleic acid was established and optimizing the condition of DNA-free extraction. The sensitivity of the method was analyzed by a series of dilution and the specificity of the method was evaluated by detecting the original samples of other respiratory viruses. The clinical samples of HAdV-3 were detected and compared with the traditional real-time fluorescence quantitative PCR method for nucleic acid extraction. Results: The sensitivity of the real-time fluorescence RAA method was as high as that of qPCR in the detection of 10 series diluted HAdV-3 strains. The highest corresponding CT value of qPCR was 36.87. The sensitivity of the real-time fluorescence RAA method was similar to that of the real-time fluorescence quantitative PCR method . There was no cross-reaction to other common types of respiratory viruses. The two method were used to detect 56 clinical samples at the same time, and the result were completely consistent. Conclusions We provide the first report of the real-time fluorescent RAA assays for the detection of HAdV-3 without extracting nucleic acid and it has high sensitivity and specificity. Is suitable for rapid detection of HAdV-3 in clinical laboratories and on-site unite.

Objective To understand the epidemiologic characteristics and pathogen spectrum of hand,foot and mouth disease (HFMD) in Hunan Province during 2008-2017 and provide the basis for the prevention and control strategy of hand,foot and mouth disease.Methods Collecting data from national disease reporting information system throughout 2008-2017,the descriptive epidemiological method were used to analyze the data of HFMD monitoring and the result of pathogenic agent detection.Results A total of 1,255,530 HFMD cases were reported throughout 2008-2017,including 10097 severe cases and 394 deaths.The average annual attack rate is 190.38/100,000.The peak incidence of HFMD occurred in summer and fall.The reported incidence is on the rise.The number of critically ill and the number of deaths is declining.Proportion of male cases was higher than that of females.The majority of the children were those under 5 years of age.Enterovirus (EV)-A71,coxsackievirus (CV)-A16 and other other EV positive cases accounted for 33.29％,20.04％ and 46.67％ of laboratory diagnosed cases.Conclusions The epidemic of hand,foot and mouth disease in Hunan has obvious seasonal and population characteristics.There are different dominant pathogens causing HFMD in different years.

Objective: To make etiological diagnosis and evaluate the protective effects of post-exposure prophylaxis(PEP) in an event of one dog injured seven persons. Methods: Direct immunofluorescence assay (DFA) and nested polymerase chain reaction (PCR) were employed to detect nucleoprotein and nucleoprotein(N) gene of rabies virus in the brain tissues of the dog, the positive samples were sequenced for the full length of N gene of rabies virus, then the homology of the N gene of rabies virus was analyzed after the phylogenetic tree was constructed. Rapid fluorescent focus inhibition test (RFFIT) was applied to detect the rabies virus neutralizing antibodies(RVNA) on day 0, 14 and 40 after PEP. Results: The cerebral, cerebellar and hippocampal tissues were positive by DFA and nested PCR. The phylogenetic tree indicated the rabies virus belonged to the rabies virus genotype I. The homology of the nucleotide and amino acid of the rabies virus N gene were over 86% with the vaccine strains. The titer of the RVNA increased significantly from the day 0 to day 14 after PEP, the lowest was 5.78 IU/ml and the highest was 26.15 IU/ml. On the day 40, the highest RVNA titer was 51.96 IU/ml. No rabies cases occurred in a one year follow-up visit. Conclusions Normative PEP can effectively prevent the occurrence of rabies cases.