Genetic characteristics of highly pathogenic avian influenza A(H5N6) virus in Suzhou City / 中华疾病控制杂志

Objective To analyze host adaptability and drug resistance variation of highly pathogenic avian influenza (HPAI) A(H5N6) viruses obtained from outbreaks in Suzhou City. Methods Real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay was used for influenza virus detection in pharynx or anus swabs of dead birds and suspected cases. Full genome of H5N6 positive samples were sequenced by using Sanger method. Hemagglutinin (HA) and neuramidinase (NA) phylogenetic trees were constructed by MEGA software. Results A child was laboratory confirmed to have A(H5N6) viruses infection in November 2018. A outbreak of avian flu in poultry in W district during the Spring Festival was laboratory confirmed as a A(H5N6) epidemic situation. Avian-origin H5N6 viruses possessed D198N and Q226H resistance mutations. The homology of HA and NA genes of Suzhou strains were 98.01%-100.0% and 98.16%-100.0%, respectively. These H5N6 strains belonged to 2.3.4.4 H5 clad. Multiple basic amino acid at the cleavage site of HA implied the highly pathogenic characteristics of Suzhou H5N6 strains. Conclusion H5N6 is a kind of malti-sourse reassortment virus, which is still evolving. Multiple loci of Suzhou H5N6 strains of this epidemic were identified to have drifted. The prevalence of drug-resistant mutations should be closely monitored in order to timely take effective measures to prevent serious damage to public health and poultry production industries.

Pathogenicity of clade 2.3.4.4 H5N6 highly pathogenic avian influenza virus in three chicken breeds from South Korea in 2016/2017

In 2016, novel H5N6 highly pathogenic avian influenza virus emerged in Korea. During the outbreak, the virus caused the largest culling, especially in brown chicken lines. We determined the pathogenicity and transmissibility of the virus in 2 white chicken lines of the specific pathogen-free chickens, broilers and brown chicken line of Korean native chicken (KNC). A KNC had a longer virus shedding period and longer mean death time than others. Our study showed that this characteristic in the KNC might have contributed to a farm-to-farm transmission of the brown chicken farms.

Loboratory diagnosis and preliminary viral sequence analysis of the first case of human infection with avian influenza A (H5N6) virus in Fujian province / 中华实验和临床病毒学杂志

Objective@#To provide effective reference of laboratory detection and prevention-control in avian influenza epidemic via analyzing the detection result of the first case infected avian influenza H5N6 virus in Fujian province.@*Methods@#The viral RNA was extracted from the patient’s throat swab and specimens of surrounding environment, and detected by real-time RT-PCR. The gene sequences of HA and NA gene segments were obtained by RT-PCR and sequencing, the evolution characteristics of the virus were elementarily analyzed by bioinformatics.@*Results@#The avian influenza H5N6 virus was confirmed from the patient’s throat swab, termed influenza A/Fujian-Sanyuan/21099/2017(H5N6)virus. The throat swabs of case from 5 different time points were collected and the H5N6 nucleic acid were detected from the first three times collection. Among 43 specimens of surrounding environment, there were 16 H5 virus samples. The HA and NA gene segments of A/Fujian-Sanyuan/21099/2017 were closely related to A/Cygnus atratus/Hubei/2Z2-O/2016(H5N8) and A/chicken/Hubei/ZYSJF16/2016(H5N6), with a similarity of 99.6% and 99.0% respectively. The cleavage site of HA gene contained multiple basic amino acids.@*Conclusions@#The suspected case was the first case infected with avian influenza H5N6 virus in Fujian province, and the HA and NA genes of virus were highly similar to those of H5N8 and H5N6 virus respectively.

Investigation and analysis on the first case of human infected with avian influenza (H5N6) in Anhui Province / 中国人兽共患病学报

We analyzed epidemiological and clinical characteristics of the case of human infected with avian influenza (H5N6) in Anhui Province and provided evidences for drawing up the prevention and control measures.We did an epidemiolog ical investigation on the case,close contacts and infection source of the infected case;relevant specimens were collected and tested in laboratories.The data gathered were analyzed with descriptive epidemiology method.The first case of human infected with avian influenza (H5N6) in Anhui was a single case and did not showed signs of human-to-human transmission.The early clinical manifestations and signs was lack of specificity.This case had definite contact with sick/dead poultry one week before the onset of the disease.Two environmental specimen of live poultry market which was the source of sick/dead poultry had been detected and the results were H5N6 positive.This case was a local infection case and contacting with sick/dead poultry was the source of infection,while there was no evidence of human to human transmission.

Novel reassortants of clade 2.3.4.4 H5N6 highly pathogenic avian influenza viruses possessing genetic heterogeneity in South Korea in late 2017

Novel H5N6 highly pathogenic avian influenza viruses (HPAIVs) were isolated from duck farms and migratory bird habitats in South Korea in November to December 2017. Genetic analysis demonstrated that at least two genotypes of H5N6 were generated through reassortment between clade 2.3.4.4 H5N8 HPAIVs and Eurasian low pathogenic avian influenza virus in migratory birds in late 2017, suggesting frequent reassortment of clade 2.3.4.4 H5 HPAIVs and highlighting the need for systematic surveillance in Eurasian breeding grounds.

Molecular characteristics of the untranslated segment-specific region of the hemagglutinin segments in H5N6 and H7N9 influenza viruses in Shenzhen / 中华实验和临床病毒学杂志

Objective@#Exploring the molecular characteristic of global and Shenzhen district H5N6 and H7N9 influenza viruses HA untranslated regions(UTRs).@*Methods@#Mega7.0 and DNAStar 7.1.0 were used to construct phylogenetic tree and nucleotide analysis.@*Results@#From 2014 to 2015, 3 strains of H5N6 influenza virus from Shenzhen were compared with the other H5NX influenza viruses, the nucleotide homology of HA-3’UTR was 77.4%-100%, which did not have obvious mutated sites. The nucleotide homology of H5N6-HA-5’UTR was 91.7%-100%, and the sites of 24 and 31 sites were mutated. From 2013 to 2014, 11 strains of H7N9 influenza virus from Shenzhen were compared with the other H7NX influenza viruses, the nucleotide homology of H7N9-HA-5’UTR was 76.8%-100%, which had multi-mutated sites on 2-6, 9, 10, 12 and 15-17 positions.@*Conclusions@#HA-UTR from human-infected H5N6 and H7N9 influenza viruses isolated in Shenzhen district has unique molecular characteristics, its conserved region has relatively high homology and the segment-specific region has genetic polymorphism.

Development and application of dual real time RT-PCR for avian influenza H5N6 virus / 中华实验和临床病毒学杂志

Objective@#To establish a TaqMan-MGB probe-based real-time fluorescence RT-PCR assay for avian influenza H5N6 virus used in rapid diagnosis for suspected cases and surveillance for outer environment of live poultry markets.@*Methods@#Based on the conservative sequences of avian influenza H5N6 virus for HA and NA gene published on GenBank, specific primers and TaqMan-MGB probes were designed to develop and optimize for the dual real-time RT-PCR assay. Specificity, sensitivity, repeatability and comparison tests were carried out.@*Results@#This dual real-time RT-PCR detection can be completed within 80 minutes. There was no cross-reaction with other subtypes of influenza virus and common respiratory pathogens. The minimum detection limit could be up to 10 copies/reaction. The correlation coefficient of standard curve for the gene of H5 and N6 were 0.999 and 0.993, and the coefficients of variation for cycle threshold were range from 0.151%-0.549%and 0.213%-0.575%, respectively. The positive and negative coincidence rates of the validation test were 100%.@*Conclusions@#This TaqMan-MGB probe-based dual real-time RT-PCR for avian influenza H5N6 virus was rapid, specific and sensitive. It will have a good use in early emergency detection of suspected cases and continuous monitoring of external environment in live poultry trade market.

Detection results from first case of human infection with avian influenza (H5N6) in Hubei Province, China / 中国人兽共患病学报

We analyzed the laboratory detection results from the first case of human infected with avian influenza (H5N6) in Hubei Province,in order to provide a better basis for preventing and controlling human avian influenza in the future and a detected strategy for the detection of suspected cases of human avian influenza for the staff in the laboratory.The case data of epidemiological survey and related laboratory detection results of specimens of infection virus from the different time piont and kinds of specimens were analyzed by descriptive epidemiological methods.The H5N6 nucleic acid from the only early sputum specimens were detected,and while the others were not detected.In conclusion the different specimens of the doubtful H5N6 case should be collected,and the early sputum samples are very important and should be collected and detected.

Research development of human infection with H5N6 avian influenza virus / 军事医学

Avian influenza virus is a new recombinant virus , which can cause severe respiratory symptoms ,such as short course,acute disease,and a high mortality rate.The purpose of this paper was to summarize the current status of this virus in terms of its epidemiology ,genetic evolution and virulence .By introducing the advancement in the research of this subtype virus, we hope to provide data and evidence ,for effective surveillance and prevention of this virus .

Recent outbreaks of highly pathogenic avian influenza viruses in South Korea

Outbreaks of H5 highly pathogenic avian influenza viruses (HPAIVs) have caused economic loss for the poultry industry and posed a threat to public health. In South Korea, novel reassortants of HPAIVs such as H5N6 and H5N8 had been circulating in poultry. Here, we will discuss the identity of recent novel reassortants of Korean H5 HPAIVs and the recent advances in vaccine development, which will be useful for controlling HPAIV transmission in poultry and for effectively preventing future epidemics and pandemics.

H5N6 influenza virus infection, the newest influenza

The most recent new emerging infection is the H5N6 influenza virus infection. This infection has just been reported from China in early May 2014. The disease is believed to be a cross species infection. All indexed cases are from China. Of interest, the H5N6 influenza virus is the primary virus for avian. The avian H5N6 influenza virus in avian population is a low virulent strain. However, the clinical manifestation in human seems severe. In this mini-review, the authors summarize and discuss on this new emerging influenza.

Investigation and analysis on the first case of human infected with avian influenza (H5N6) in Yunnan Province,China / 中国人兽共患病学报

We analyzed the epidemiological investigation results of the first case of human infected with avian influenza (H5N6) ,and summarized epidemiological characteristics of this case to provide reference to H 5N6 case screening and investiga‐tion in future works .We retrospectively described and analyzed the investigation progress ,specimen detection results of epi‐demic spot and intimate contact people ,and summarize epidemiological characteristics of this case .Result showed that the first case of human infected with H5N6 in Yunnan was a single case ,and did not showed human‐to‐human transmission .This case had contacts with wild bird and had birds’ market activity before diagnoses ;some environment specimen of birds market near patient’s home has detection results of H5N6 positive .This is a cases of local infection and did not show human‐to‐human transmission .From the investigation ,we could deduced that the transmission route is from birds to human or from birds to en‐vironment and then to human .