The global spread of (highly pathogenic) H5N1 in birds is considered a significant pandemic threat.
While prior H5N1 strains have been known, they were significantly different from the 2006 strain of H5N1 on a genetic level, making the global spread of this new strain unprecedented. The 2006 strain of H5N1 is a fast-mutating, highly pathogenic avian influenza virus (HPAI) found in multiple bird species. It is both epizootic (an epidemic in non-humans) and panzootic (a disease affecting animals of many species especially over a wide area). Unless otherwise indicated, "H5N1" in this article refers to the highly pathogenic 2006 strain of H5N1.
In the first two months of 2006 H5N1 spread to Africa and Europe in wild bird populations possibly signaling the beginning of H5N1 being endemic in wild migratory bird populations on multiple continents for decades, permanently changing the way poultry are farmed. In addition, the spread of highly pathogenic H5N1 to wild birds, birds in zoos and even sometimes to mammals (example: pet cats) raises many unanswered questions concerning best practices for threat mitigation, trying to balance reducing risks of human and nonhuman deaths from the current nonpandemic strain with reducing possible pandemic deaths by limiting its chances of mutating into a pandemic strain. Not using vaccines can result in the need to kill significant numbers of farm and zoo birds, while using vaccines can increase the chance of a pandemic.[ dubious ]
By April 2006, scientists had concluded that containment had failed due to the role of wild birds in transmitting the virus and were now emphasizing far more comprehensive risk mitigation and management measures. [1]
In June 2006 the World Health Organization predicted an upsurge in human deaths due to H5N1 during late 2006 or early 2007. In July and August 2006, significantly increased numbers of bird deaths due to H5N1 were recorded in Cambodia, China, Laos, Nigeria, and Thailand while continuing unabated a rate unparalleled in Indonesia. In September, Egypt and Sudan joined the list of nations seeing a resurgence of bird deaths due to H5N1; followed by Vietnam and South Korea in December.
January 5, 2006
January 7, 2006
January 8, 2006
January 10, 2006
January 16, 2006
January 18, 2006
January 21, 2006
January 29, 2006
January 30, 2006
February 4, 2006
February 6, 2006
February 7, 2006
February 8, 2006
February 9, 2006
February 10, 2006
February 11, 2006
February 12, 2006
February 13, 2006
February 14, 2006
February 15, 2006
February 17, 2006
February 18, 2006
February 19, 2006
February 20, 2006
February 21, 2006
February 23, 2006
February 25, 2006
February 27, 2006
February 28, 2006
March 1, 2006
March 2, 2006
March 3, 2006
March 4, 2006
March 5, 2006
March 6, 2006
March 8, 2006
March 9, 2006
March 10, 2006
March 12, 2006
March 14, 2006
March 15, 2006
March 16, 2006
March 17, 2006
March 18, 2006
March 19, 2006
March 20, 2006
March 21, 2006
March 24, 2006
March 26, 2006
March 29, 2006
March 30, 2006
March 31, 2006
April 3, 2006
April 4, 2006
April 5, 2006
April 6, 2006
April 10, 2006
April 11, 2006
April 12, 2006
April 18, 2006
May 5, 2006
May 11, 2006
May 13, 2006
May 15, 2006
May 16, 2006
May 21, 2006
May 24, 2006
May 25, 2006
May 30, 2006
June 2, 2006
June 17, 2006
June 23, 2006
June 30, 2006
July 5, 2006
July 7, 2006
July 22, 2006
July 26, 2006
July 28, 2006
August 5, 2006
August 10, 2006
August 12, 2006
August 18, 2006
August 25, 2006
September 7, 2006
September 13, 2006
September 25, 2006
September 27, 2006
October 4, 2006
October 11, 2006
October 16, 2006
October 31, 2006
November 2, 2006
November 13, 2006
December 12, 2006
December 18, 2006
December 19, 2006
December 24, 2006
Influenza A virus (IAV) is a pathogen that causes the flu in birds and some mammals, including humans. It is an RNA virus whose subtypes have been isolated from wild birds. Occasionally, it is transmitted from wild to domestic birds, and this may cause severe disease, outbreaks, or human influenza pandemics.
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 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.
Influenza A virus subtype H7N7 (A/H7N7) is a subtype of Influenza A virus, a genus of Orthomyxovirus, the viruses responsible for influenza. Highly pathogenic strains (HPAI) and low pathogenic strains (LPAI) exist. H7N7 can infect humans, birds, pigs, seals, and horses in the wild; and has infected mice in laboratory studies. This unusual zoonotic potential represents a pandemic threat.
Influenza A virus subtype H7N2 (A/H7N2) is a subtype of the species Influenza A virus. This subtype is one of several sometimes called bird flu virus. H7N2 is considered a low pathogenicity avian influenza (LPAI) virus. With this in mind, H5 & H7 influenza viruses can re-assort into the Highly Pathogenic variant if conditions are favorable.
H5N8 is a subtype of the influenza A virus and is highly lethal to wild birds and poultry. H5N8 is typically not associated with humans. However, seven people in Russia were found to be infected in 2021, becoming the first documented human cases.
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.
The 2007 Bernard Matthews H5N1 outbreak was an occurrence of avian influenza in England caused by the H5N1 subtype of Influenza virus A that began on 30 January 2007. The infection affected poultry at one of Bernard Matthews' farms in Holton in Suffolk. It was the third instance of H5N1-subtype detected in the United Kingdom and a range of precautions were instituted to prevent spread of the disease including a large cull of turkeys, the imposition of segregation zones, and a disinfection programme for the plant.
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.
Influenza A virus subtype H7N9 (A/H7N9) is a bird flu strain of the species Influenza virus A. Avian influenza A H7 viruses normally circulate amongst avian populations with some variants known to occasionally infect humans. An H7N9 virus was first reported to have infected humans in March 2013, in China. Cases continued to be reported throughout April and then dropped to only a few cases during the summer months. At the closing of the year, 144 cases had been reported of which 46 had died. It is known that influenza tends to strike during the winter months, and the second wave, which began in October, was fanned by a surge in poultry production timed for Lunar New Year feasts that began at the end of January. January 2014 brought a spike in reports of illness with 96 confirmed reports of disease and 19 deaths. As of April 11, 2014, the outbreak's overall total was 419, including 7 in Hong Kong, and the unofficial number of deaths was 127.
H5N6 is a subtype of the species Influenza A virus. Infected birds shed the virus in their saliva, mucous, and feces. The virus was first detected in poultry in 2013, since then spreading among wild bird populations and poultry around the world. Humans can be infected through unprotected contact with infected birds or contaminated surfaces. The virus transmits by getting into a person's eyes, nose, mouth, and through inhalation. Human infections are rare. Since 2014, at least 65 cases have occurred in humans. 29 people have died. A spike in human cases was reported in 2021. There have been no confirmed cases of human-to-human transmission. Some infections have been identified where no direct contact with infected birds or contaminated surfaces has been known to had occurred. Only one infected woman has said that she never came into any contact with poultry.
From April to September 2017 in the Philippines, an outbreak of H5N6 avian influenza or bird flu affected poultry in at least three towns in Central Luzon; San Luis in Pampanga and Jaen and San Isidro in Nueva Ecija.
In the early 2020s, an ongoing outbreak of avian influenza subtype H5N8 has been occurring at poultry farms and among wild bird populations in several countries and continents, leading to the subsequent cullings of millions of birds to prevent a pandemic similar to that of the H5N1 outbreak in 2008. The first case of human transmission of avian flu, also known as bird flu, was reported by Russian authorities in February 2021, as several poultry farm workers tested positive for the virus.
Influenza A virus subtype H10N3 is a subtype of viruses that causes influenza (flu). It is mostly present in wild avian species. The first human case was reported in 2021.