Influenza A virus subtype H5N2 | |
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Virus classification ![]() | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Negarnaviricota |
Class: | Insthoviricetes |
Order: | Articulavirales |
Family: | Orthomyxoviridae |
Genus: | Alphainfluenzavirus |
Species: | |
Serotype: | Influenza A virus subtype H5N2 |
Influenza (flu) |
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H5 N2 is a subtype of the species Influenzavirus A (avian influenza virus or bird flu virus). 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. [1] On June 5, 2024, the first confirmed human case of H5N2 was reported in Mexico. [2]
In China, inactivated H5N2 has been effectively used as a poultry vaccine for H5N1. [3]
In December 2017, the Paris-based World Organisation for Animal Health (OIE) announced that the Russian ministry of agriculture detected highly pathogenic H5N2 that led to the culling of more than 660,000 birds in Kostroma Oblast, Central Federal District. [4] [5] Owners reported that the chickens stopped breathing and their combs became bluish. The factory was affected by the virus at least twice during the year. The investigation later found that the forage wasn't thermally disinfected before dispersion and water was of low quality. [5]
In Korea, ducks have been destroyed at the farm since quarantine officials detected the suspected low pathogenic H5N2 strain of avian influenza on December 1, 2004. [6]
In Japan, H5N2 virus was isolated or an anti-H5 antibody was identified from chickens in 40 chicken farms in Ibaraki Prefecture and in one chicken farm in Saitama Prefecture from June through December 2005. The strain was named as A/ chicken /Ibaraki/1/2005(H5N2). [7] About 5.7 million birds were destroyed in Ibaraki following the H5N2 outbreaks.[ citation needed ]
In Taiwan, an outbreak of H5N2 was confirmed in December 2008. [8]
In March 2012, the first documented occurrence in Taiwan of highly pathogenic avian influenza H5N2 was reported to the World Organization for Animal Health (OIE). The outbreak began in February 2012. [9]
In Sri Lanka outbreak of H5N2 in Bingiriya have been confirmed by the Health Ministry in January 2012. Around 5000-6000 chicken were destroyed, after some of them were confirmed having infected with H5N2. [10] [11]
In 2006, an H5N2 outbreak on a single farm in South Africa resulted in the destruction of all its sixty ostriches. The strain was similar to the one that caused outbreaks in South Africa 2004/2005. [12]
In 2012 a strain of highly pathogenic avian influenza is devastating the South African commercial ostrich industry with 41,000 birds already been reported culled. [13]
Low pathogenic avian influenza H5N2 virus in poultry later gained accentuated virulence in the United States [14] and Mexico. [15] A highly pathogenic strain of H5N2 caused flu outbreaks with significant spread to numerous farms, resulting in great economic losses in 1983 in Pennsylvania, USA in chickens and turkeys, in 1994 in Mexico in chickens and a minor outbreak in 1997 in Italy in chickens. [16]
In February 2004, an outbreak occurred in Texas and the affected flock was culled without any further transmission. [17]
In 2007, a low-pathogenic strain of H5N2 was found in samples collected from 25,000 turkeys in West Virginia in a routine testing prior to their slaughter. The birds showed no sign of illness or mortality. Measures were taken to prevent the virus from mutating and spreading. [18]
In 2015, an outbreak of H5N2 was identified in a series of chicken and turkey farming operations in the Midwestern region of the United States. Around 50.5 million birds were killed by the disease or via mass killing methods (primarily foam depopulation) in an attempt to contain the outbreak. [19] Nearly 30 million were killed in Iowa alone, the nation's largest egg producer. [20]
In January 2017, the US Department of Agriculture announced that H5N2 was discovered on a duck in Fergus County, Montana. [21]
In February 2009, a commercial turkey farm in Abbottsford, British Columbia (the Fraser Valley) was struck with a H5N2 outbreak, and 36 sites were quarantined as precautionary measure. [22]
In July 2016, a duck farm "near St. Catharines, Ontario" was the site of an outbreak of H5N2. The CFIA directed the biological heat treatment of the compost at the infected premises to ensure that a reservoir for the virus was destroyed. [23]
In late 2007 (December 21), an H5N2 outbreak was found in the Dominican Republic. 15 roosters and 2 hens were eliminated even though they had no visible sign of infection. [24]
In October 2017, the Dominican Department of Agriculture announced that H5N2 was discovered on several chicken in Moca, Dominican Republic, in a northern province of the country. [25]
In May and June 2008, there were three outbreaks of low-pathogenic H5N2 avian flu in birds at three locations in the central, northern, and southern parts of Haiti. [26]
Japan's Health Ministry said in January, 2006 that poultry farm workers in Ibaraki prefecture may have been exposed to H5N2 (which was not previously known to infect humans) in 2005. [27] Data were collected from 257 workers at 35 chicken farms by Ibaraki prefectural government. It was determined that their H5N2 antibody titers after the outbreak were significantly higher than those collected prior to the outbreak. [28]
On June 5, 2024, the World Health Organization recognized the first laboratory-confirmed case of H5N2 in a human in Mexico in a patient who died. Health officials in Mexico stated that the source of the infection had not been identified. Scientists said that the infection was unrelated to the 2020–2024 H5N1 outbreak. It was also reported that the patient had been bedridden for three weeks before contracting the illness. [2] However, on June 7, Mexican health officials stated that the patient's death was caused by chronic diseases, and not by H5N2. [29]
Influenza A virus (IAV) is a pathogen with strains that infect birds and some mammals, as well as causing seasonal flu in humans. Mammals in which different strains of IAV circulate with sustained transmission are bats, pigs, horses and dogs; other mammals can occasionally become infected.
Avian influenza, also known as avian flu or bird flu, is a disease caused by the influenza A virus (IAV) which primarily affects birds but can sometimes affect mammals including humans. Wild aquatic birds are the primary host of Influenza A virus (IAV), which is endemic in many bird populations.
Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus, which causes influenza (flu), predominantly in birds. It is enzootic in many bird populations, and also panzootic. A/H5N1 virus can also infect mammals that have been exposed to infected birds; in these cases, symptoms are frequently severe or fatal.
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.
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.
Influenza A virus subtype H7N3 (A/H7N3) is a subtype of the species Influenza A virus.
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.
H5N1 genetic structure is the molecular structure of the H5N1 virus's RNA.
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.
The Goose Guangdong virus refers to the strain A/Goose/Guangdong/1/96 (Gs/Gd)-like H5N1 HPAI viruses. It is a strain of the Influenzavirus A subtype H5N1 virus that was first detected in a goose in Guangdong in 1996. It is an HPAI virus, meaning that it can kill a very high percentage of chickens in a flock in mere days. It is believed to be the immediate precursor of the current dominant strain of HPAI A(H5N1) that evolved from 1999 to 2002 creating the Z genotype that is spreading globally and is epizootic and panzootic, killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread.
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.
The global spread of H5N1 in birds is considered a significant pandemic threat.
In 2015, an outbreak of avian influenza subtype H5N2 was identified in a series of chicken and turkey farming operations in the Midwestern United States. By May 30, more than 43 million birds in 15 states had been destroyed as a result of the outbreak, including nearly 30 million in Iowa alone, the nation's largest egg producer. In the Midwestern U.S., the average price of eggs had increased 120% between April 22 and May 30. The effects however were seen nationwide, with prices in California up 71% in the same timeframe.
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.
Since 2020, global outbreaks of avian influenza subtype H5N1 have been occurring, with cases reported from every continent as of May 2024. In late 2023, H5N1 was discovered in the Antarctic for the first time, raising fears of imminent spread throughout the region, potentially leading to a "catastrophic breeding failure" among animals that had not previously been exposed to avian influenza viruses. The main virus involved in the global outbreak is classified as H5N1 clade 2.3.4.4b, however genetic diversification with other clades such as 2.3.2.1c has seen the virus evolve in ability to cause significant outbreaks in a broader range of species including mammals.