Avian influenza,also known as avian flu,is a bird flu caused by the influenza A virus,which can infect people. It is similar to other types of animal flu in that it is caused by a virus strain that has adapted to a specific host. The type with the greatest risk is highly pathogenic avian influenza (HPAI).
Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus which can cause illness in humans and many other species. A bird-adapted strain of H5N1,called HPAI A(H5N1) for highly pathogenic avian influenza virus of type A of subtype H5N1,is the highly pathogenic causative agent of H5N1 flu,commonly known as avian influenza. It is enzootic in many bird populations,especially in Southeast Asia. One strain of HPAI A(H5N1) is spreading globally after first appearing in Asia. It is epizootic and panzootic,killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread. Many references to "bird flu" and H5N1 in the popular media refer to this strain.
The 2000s in Hong Kong began a new millennium under the People's Republic of China (PRC).
An influenza pandemic is an epidemic of an influenza virus that spreads across a large region and infects a large proportion of the population. There have been six major influenza epidemics in the last 140 years,with the 1918 flu pandemic being the most severe;this is estimated to have been responsible for the deaths of 50–100 million people. The 2009 swine flu pandemic resulted in under 300,000 deaths and is considered relatively mild. These pandemics occur irregularly.
Influenza A virus subtype H3N2 (A/H3N2) is a subtype of viruses that causes influenza (flu). H3N2 viruses can infect birds and mammals. In birds,humans,and pigs,the virus has mutated into many strains. In years in which H3N2 is the predominant strain,there are more hospitalizations.
The global spread of H5N1 influenza in birds is considered a significant pandemic threat. While other H5N1 influenza strains are known,they are significantly different on a genetic level from a recent,highly pathogenic,emergent strain of H5N1,which was able to achieve hitherto unprecedented global spread in 2008. The H5N1 strain is a fast-mutating,highly pathogenic avian influenza virus (HPAI) found in multiple bird species. It is both epizootic and panzootic. Unless otherwise indicated,"H5N1" in this timeline refers to the recent highly pathogenic strain of H5N1.
Transmission and infection of H5N1 from infected avian sources to humans has been a concern since the first documented case of human infection in 1997,due to the global spread of H5N1 that constitutes a pandemic threat.
H5 N2 is a subtype of the species Influenzavirus A. The subtype infects a wide variety of birds,including chickens,ducks,turkeys,falcons,and ostriches. Affected birds usually do not appear ill,and the disease is often mild as avian influenza viral subtypes go. Some variants of the subtype are much more pathogenic than others,and outbreaks of "high-path" H5N2 result in the culling of thousands of birds in poultry farms from time to time. It appears that people who work with birds can be infected by the virus,but suffer hardly any noticeable health effects. Even people exposed to the highly pathogenic H5N2 variety that killed ostrich chicks in South Africa only seem to have developed conjunctivitis,or a perhaps a mild respiratory illness. There is no evidence of human-to-human spread of H5N2. On November 12,2005 it was reported that a falcon was found to have H5N2.
H7N4 is a subtype of the species Influenza A virus.
The social impact of H5N1 is the effect or influence of H5N1 in human society,especially the financial,political,social,and personal responses to both actual and predicted deaths in birds,humans,and other animals. Billions of dollars are raised and spent to research H5N1 and prepare for a potential avian influenza pandemic. Over ten billion dollars were lost,and over two hundred million birds were killed to contain H5N1. People reacted by buying less chicken causing poultry sales and prices to fall. Many individuals stockpiled supplies for a possible flu pandemic.
Disease surveillance is an epidemiological practice by which the spread of disease is monitored in order to establish patterns of progression. The main role of disease surveillance is to predict,observe,and minimize the harm caused by outbreak,epidemic,and pandemic situations,as well as increase knowledge about which factors contribute to such circumstances. A key part of modern disease surveillance is the practice of disease case reporting.
The global spread of H5N1 in birds is considered a significant pandemic threat.
The global spread of H5N1 in birds is considered a significant pandemic threat.
The global spread of H5N1 in birds is considered a significant pandemic threat.
Fujian flu refers to flu caused by either a Fujian human flu strain of the H3N2 subtype of the Influenza A virus or a Fujian bird flu strain of the H5N1 subtype of the Influenza A virus. These strains are named after Fujian,a coastal province in Southeast China.
Human mortality from H5N1 or the human fatality ratio from H5N1 or the case-fatality rate of H5N1 is the ratio of the number of confirmed human deaths resulting from confirmed cases of transmission and infection of H5N1 to the number of those confirmed cases. For example,if there are 100 confirmed cases of humans infected with H5N1 and 10 die,then there is a 10% human fatality ratio. H5N1 flu is a concern due to the global spread of H5N1 that constitutes a pandemic threat. The majority of H5N1 flu cases have been reported in southeast and east Asia. The case-fatality rate is central to pandemic planning. Estimates of case-fatality (CF) rates for past influenza pandemics have ranged from to 2-3% for the 1918 pandemic to about 0.6% for the 1957 pandemic to 0.2% for the 1968 pandemic. As of 2008,the official World Health Organization estimate for the case-fatality rate for the outbreak of H5N1 avian influenza was approximately 60%. Public health officials in Ontario,Canada argue that the true case-fatality rate could be lower,pointing to studies suggesting it could be 14-33%,and warned that it was unlikely to be as low as the 0.1–0.4% rate that was built into many pandemic plans.
The global spread of H5N1 in birds is considered a significant pandemic threat.
The 2009 flu pandemic in Hong Kong was part of the worldwide pandemic that started with the city's first reported case of influenza A virus subtype H1N1 infection,commonly called swine flu,on 1 May 2009,in a Mexican national who had travelled to Hong Kong via Shanghai. It was also the first reported case of in Asia. As of 25 November 2009,there have been 32,301 confirmed cases of swine flu in the city.
The 2009 flu pandemic in Asia,part of an epidemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu,afflicted at least 394,133 people in Asia with 2,137 confirmed deaths:there were 1,035 deaths confirmed in India,737 deaths in China,415 deaths in Turkey,192 deaths in Thailand,and 170 deaths in South Korea. Among the Asian countries,South Korea had the most confirmed cases,followed by China,Hong Kong,and Thailand.
Guan Yi is a Chinese virologist. In 2014,he was ranked as 11th in the world by Thomson Reuters among global researchers in the field of microbiology. He obtained his PhD in microbiology at the University of Hong Kong and is now a professor of microbiology at his alma mater. His research on the viral respiratory disease SARS helped the Chinese government avert the 2004 outbreak of this disease. He is the current director of the State Key Laboratory for Emerging Infectious Diseases University of Hong Kong. In early 2017,Guan warned that the H7N9 influenza virus "poses the greatest threat to humanity than any other in the past 100 years".
