Epidemiology of influenza virus reinfection in Guangxi, China: a retrospective analysis of a nine-year influenza surveillance data: Characteristics of influenza virus reinfection.

BACKGROUND: Epidemiological characteristic profile of the reinfection of the influenza virus has not been well described. METHODS: This study included all influenza cases of Guangxi, China from January 2011-December 2019 that were recorded in the National Notifiable Infectious Disease Reporting Information System (NIDRIS) within 24 hours after diagnosis. RESULTS: A total of 53,605.6 person-months and the median time of 8.7 months were observed for reinfection. The median age at the first influenza virus infection was 4.5 (interquartile range=2.0-7.5) years. The cumulative reinfection incidence was 2% at 6 months, 4% at 12 months, 5% at 24 months, and 7% after 59 months. Living in the rural area (hazard ratio [HR]=1.37 [95% confidence interval (CI), 1.29-1.45]), age ≤6 years (HR=11.43 [95% CI, 9.47-13.80]) were independent risk factors associated with influenza reinfection. Among 49 patients experiencing two laboratory tests, 32 patients (65.3%) were found to be infected with different virus types. The interval between two consecutive laboratory-confirmed episodes of the four groups differed (p=0.148): the maximum was 72.9 months and the minimum was 1.2 months. CONCLUSIONS: The reinfection of the influenza virus in Guangxi was independently and positively associated with living the rural area and younger age. The unusually high frequency of reinfection points to a need for further prospective longitudinal studies to better investigate the sufficient impact on different subtypes.

Genetic Characterization of Two Human Cases Infected with the Avian Influenza A (H5N6) Viruses - Guangxi Zhuang Autonomous Region, China, 2021.

WHAT IS KNOWN ABOUT THIS TOPIC?: H5N6 has replaced H5N1 as a dominant avian influenza virus (AIV) subtype in southern China. The increasing genetic diversity and geographical distribution of H5N6 pose a serious threat to the poultry industry and human health. WHAT IS ADDED BY THIS REPORT?: A total of 2 cases of H5N6 that occurred from February 2021 to July 2021 in Guangxi, China were reported in this study. Phylogenetic analysis of gene was constructed, and some mutations of HA gene, PB2 gene, PA gene, M1 gene, NS1 gene, the receptor-binding site were detected. The evolutionary origins of the internal genes were different. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: As a multi-source reassortant virus, the H5N6 highly pathogenic AIV is continuously evolving. There is an urgent need to strengthen the surveillance of drug-resistant strains and novel variants.

A Population-Based Acute Meningitis and Encephalitis Syndromes Surveillance in Guangxi, China, May 2007-June 2012.

OBJECTIVES: Acute meningitis and encephalitis (AME) are common diseases with the main pathogens being viruses and bacteria. As specific treatments are different, it is important to develop clinical prediction rules to distinguish aseptic from bacterial or fungal infection. In this study we evaluated the incidence rates, seasonal variety and the main etiologic agents of AME, and identified factors that could be used to predict the etiologic agents. METHODS: A population-based AME syndrome surveillance system was set up in Guigang City, Guangxi, involving 12 hospitals serving the study communities. All patients meeting the case definition were investigated. Blood and/or cerebrospinal fluid were tested for bacterial pathogens using culture or RT-PCR and serological tests for viruses using enzyme-linked immunosorbent assays. Laboratory testing variables were grouped using factor analysis. Multinomial logistic regression was used to predict the etiology of AME. RESULTS: From May 2007 to June 2012, the annual incidence rate of AME syndrome, and disease specifically caused by Japanese encephalitis (JE), other viruses, bacteria and fungi were 12.55, 0.58, 4.57, 0.45 and 0.14 per 100,000 population, respectively. The top three identified viral etiologic agents were enterovirus, mumps virus, and JE virus, and for bacteria/fungi were Streptococcus sp., Cryptococcus neoformans and Staphylococcus sp. The incidence of JE and other viruses affected younger populations and peaked from April to August. Alteration of consciousness and leukocytosis were more likely to be caused by JE, bacteria and fungi whereas CSF inflammation was associated with bacterial/fungal infection. CONCLUSIONS: With limited predictive validity of symptoms and signs and routine laboratory tests, specific tests for JE virus, mumps virus and enteroviruses are required to evaluate the immunization impact and plan for further intervention. CSF bacterial culture cannot be omitted in guiding clinical decisions regarding patient treatment.

[Investigation of a family clustering of human infection with avian influenza A (H7N9) virus in Nanning, Guangxi].

OBJECTIVE: To understand the transmission mode of human infection with avian influenza A (H7N9) virus. METHODS: Field epidemiological investigation was conducted for a family clustering of human infection with H7N9 virus in Hengxian county, Guangxi Zhuang Autonomous Region in February 2014. Two patients and their 82 close contacts were surveyed. The samples collected from the patients, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (rRT-PCR), and the samples from patients were used for virus isolation. The samples from 5 close contacts were tested with RT-PCR. The clinical data, exposure histories of the patients and the detection results of the isolates and their homology were analyzed. RESULTS: Patient A became ill 4 days after her last exposure to poultry in Zhongshan, Guangdong province, and returned to her hometown in Hengxian 2 days after onset. Patient B was patient A's 5 years old son, who had no known exposure to poultry but slept with patient A for 4 days. He developed symptoms 4 days after last contact with his mother. Two strains of H7N9 virus were isolated from the two patients. The 2 isolates were highly homogenous (almost 100%) indicated by gene sequencing and phylogenetic tree. None of the other 81 close contacts developed symptoms of H7N9 virus infection. CONCLUSION: Patients B was infected through close contact with patient A, indicating that avian H7N9 virus can spread from person to person, but the transmissibility is limited and non-sustainable.

[Surveillance and research on acute meningitis, encephalitis syndrome in Guangxi, China].

OBJECTIVE: To estimate disease burden and epidemiological characteristics of acute meningitis/encephalitis, and provide the basis for the disease control strategy development. METHODS: A syndrome surveillance system was established in Guigang city with a population of 5 020 000. For the suspected cases, serum and CSF were collected, and bacterial culture, latex agglutination test, real-time PCR and ELISA tests were carried out. All involved cases were identified to 6 categories according to WHO case definition. RESULTS: 1424 suspected cases were evaluated in a surveillance of 30 months, yielding the incidence, mortality and mortality of 11.35/100 000 (1424/12 546 500 person years), 0.43/100 000 (54/12 546 500 person years), 3.79% (54/1424) respectively. A total of 103 and 51 cases were confirmed for JE, bacterial meningitis, with a incidence of 0.82/100 000 (103/12 546 500 person years), 0.41/100 000 (51/12 546 500 person years). 96.10% (99/103) of JE cases and 37.30% (19/51) bacterial meningitis cases occurred in < 10 years old children and < 5 years old children. A clinical misdiagnosis rate of 19.42% (20/103) and 15.69% (8/51) were observed for JE and bacterial meningitis. CONCLUSION: Acute encephalitis, meningitis syndrome can cause a higher burden of disease, of which the main components of viral encephalitis. Most of syndrome is occurred in summer and autumn, mainly reported in children of younger than 10 years old. A quite misdiagnosis would be made among meningitis and encephalitis syndrome cases.

[Identification and analysis of an SEO strain of hemorrhagic fever with renal syndrome hantavirus from Guangxi].

OBJECTIVE: To identify hantavirus from lung specimens of rats captured in Guangxi. METHODS: Rats were collected from various areas in Guangxi in combination with plague surveillance and rat lung specimens were examined by ELISA for hantavirus antigen, and M segment of positive specimen was partially amplified with RT-PCR and sequenced. Phylogenetic analysis was conducted for genotyping. RESULTS: From a total of 306 rat lung specimens, a strain of SEO hantavirus was detected from lung specimen of a Norvegicus that was from coastal area of Guangxi Qinzhou city. CONCLUSIONS: For the first time SEO hantanvirus was detected in the coastal area of Guangxi Qinzhou city, its epidemiological significance needs further study.