ABSTRACT
@#Avian influenza subtype A(HxNy) viruses are zoonotic and may occasionally infect humans through direct or indirect contact, resulting in mild to severe illness and death. Member States in the Western Pacific Region (WPR) communicate and notify the World Health Organization of any human cases of A(HxNy) through the International Health Regulations (IHR 2005) mechanism. This report includes all notifications in the WPR with illness onset dates from 1 November 2003 to 31 July 2022. During this period, there were 1972 human infections with nine different A(HxNy) subtypes notified in the WPR. Since the last report, an additional 134 human avian influenza infections were notified from 1 October 2017 to 31 July 2022. In recent years there has been a change in the primary subtypes and frequency of reports of human A(HxNy) in the region, with a reduction of A(H7N9) and A(H5N1), and conversely an increase of A(H5N6) and A(H9N2). Furthermore, three new subtypes A(H7N4), A(H10N3) and A(H3N8) notified from the People’s Republic of China were the first ever recorded globally. The public health risk from known A(HxNy) viruses remains low as there is no evidence of person-to-person transmission. However, the observed changes in A(HxNy) trends reinforce the need for effective and rapid identification to mitigate the threat of a pandemic from avian influenza if person-to-person transmission were to occur.
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Objective To investigate the spatial and temporal distribution of highly pathogenic avian influenza H5N1 based on Geography Information System (GIS),and to learn the mechanism of the occurrence and spread of H5N1.Methods A total of 2 069 officially confirmed cases of H5N1 outbreak reported to WHO and World Organization for Animal Health (OIE)from 2003 to 2012 were analyzed using a GIS based approach.Hot spot analysis (Getis-Ord Gi*)was used in the spatial and temporal analysis.Results From 2003 to 2012,2 069 cases of H5N1 outbreak was reported in Vietnam (1 055),Bangladesh (528)and Indonesia (209).The most of the outbreaks were reported in Ganges Delta,Mekong Delta,areas around Dacca and West Java.The occurrence,spread and distribution pattern of the disease varied within different spatial scale,and the epidemic showed a bipolar distribution in Vietnam,aradial distribution in Bangladesh and a shrinking pattern in Indonesia.Conclusion Highly pathogenic avian influenza H5N1 was first emerged in city and then spread through poultry trading or transportation,and finally caused epidemic in regions with high density poultry and intensive agriculture.Hot spot analysis had a great application value in disease surveillance and early warning.
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Objective To investigate the source of the first human case of avian influenza A (H5N1) infection in Beijing. Methods Interviewing the relatives of the case and other key persons, collecting and detecting samples of related biological, epidemiological and environmental data of the case were conducted. Later, the infection source was thoroughly investigated. Results The case ever contacted a slaughtered duck 5 days prior to the onset of illness, and the duck was bought from a stall of a wet market in Yanjiao area of Hebei province. Ten environmental samples were collected in this stall and the neighboring stall of the market. Another 6 samples were tested positive for H5N1 virus by PCR method, with 5 virus strains isolated. The whole-genome sequencing indicated that the amino acid homology between the H5N1 virus strains from the environment and the virus isolated from the case reached 99.8%-100%. Conclusion From both epidemiological and virological evidence, it was proved that the first human case of avian influenza A (H5N1) infection in Beijing was infected by a duck that carrying H5N1 virus the case contacted 5 days proceeding the onset of illness.