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1.
Chinese Journal of Disease Control & Prevention ; (12): 1415-1419, 2019.
Artigo em Chinês | WPRIM | ID: wpr-779532

RESUMO

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.

2.
Chinese Journal of Zoonoses ; (12): 188-191, 2018.
Artigo em Chinês | WPRIM | ID: wpr-703090

RESUMO

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.

3.
Chinese Journal of Experimental and Clinical Virology ; (6): 263-267, 2018.
Artigo em Chinês | WPRIM | ID: wpr-806182

RESUMO

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.

4.
Chinese Journal of Experimental and Clinical Virology ; (6): 62-65, 2017.
Artigo em Chinês | WPRIM | ID: wpr-807984

RESUMO

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.

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