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.
On 4 February 2020, the Saudi Arabian government reported an outbreak of the highly pathogenic H5N8 virus on a poultry farm. The outbreak, which occurred in the central Sudair region, killed more than 22,000 birds in a few weeks.[1]
H5N8 spreads to Russia and Central Asia
In the summer months, H5N8 was detected in wild birds in western Russia and Kazakhstan. Because this included waterbirds that migrate into northern and western Europe, it was considered likely that the virus would be detected there later in the year (as would be confirmed in October–November).[2]
International spread in late 2020 and early 2021
On October 22, the agriculture minister Carola Schouten of the Netherlands confirmed that H5N8 had been found in samples from wild birds in the country.[3] As a countermeasure, it was required that birds in poultry farms were kept indoors and isolated. From late October to mid-November, it had spread to three chicken farms and a duck farm in the country, and the 320,000 birds in the farms had been eradicated to stop the spread.[4] Shortly after the first detection in the Netherlands, it was confirmed in the United Kingdom (October: poultry; November: wild birds and poultry), Germany (October: wild birds; November: wild birds and poultry), Republic of Ireland (October and November: wild birds), Belgium (November: wild birds), Denmark (November: wild birds and poultry), France (November: poultry) and Sweden (November: poultry).[2] These outbreaks resulted in countermeasures that were similar to those already taken in the Netherlands.[5][6]
According to official confirmed reports from the Ministry of Agriculture Forestry and Fisheries of Japan, multiple dead chickens were found in 49 poultry farms: 16 on Shikoku Island, 15 on Kyushu Island, ten in Kanto region, five in western Honshu, one each on Awaji Island, Gifu Prefecture and Toyama Prefecture, Japan from November 5, 2020, to February 25, 2021. According to a local official confirmed the report, these cases were the highly pathogenic H5N8 type flu.[citation needed]
On November 10, South Korea's agriculture ministry said it had confirmed the highly pathogenic H5N8 strain of bird flu in samples from wild birds in the central west of the country and issued its bird flu warning.[7]
The H5N8 avian influenza was reported in two districts of Indian state of Kerala in early January 2021 which killed hundreds of birds in late December 2020. Thousands of birds were culled. Avian influenza outbreaks of unknown subtypes were later also reported in five other states of India.[11][12][13] 160,000 birds in two poultry farms in Barwala, Panchkula and Raipur Rani are to be culled. 437,000 birds died in this poultry belt between mid-December and 8 January 2021.[14] By 9 January 2021, seven states confirmed the outbreak.[15]
On January 15, authorities in Namibia suspended the importation and transit of poultry from European countries where an outbreak of the Avian influenza subtype H5N8 has been reported.[16]
On January 20, Iraq reported an outbreak of highly pathogenic H5N8 bird flu on a farm in the city of Samarra, which killed 63,700 birds out of the 68,800-strong flock, according to the Paris-based World Organisation for Animal Health (OIE). The remaining birds were subsequently culled.[17]
On February 1, the Ministry of Agriculture and Rural Affairs of China reported an outbreak of highly pathogenic H5N8 in wild Swans at the Winter Palace, Beijing.[18]
On February 2, authorities in Brandenburg, Germany, culled 14,000 turkeys on a farm due to a confirmed outbreak of H5N8 in the Uckermark area.[19]
On February 9, Algeria reported an outbreak of H5N8 on a poultry farm in the town of Aïn Fakroun. The outbreak killed 50,000 birds, with the remaining 1,200 birds in the flock being culled, according to a report from the Agriculture Ministry.[20]
Afghanistan reported an outbreak of H5N8 bird flu on a poultry farm in Herat Province on February 25. The outbreak killed 794 birds, while the remaining 22,000-strong flock were subsequently culled, according to the World Organisation for Animal Health.[21]
Warwickshire, UK reported an outbreak on November 8, 2021. A 3km protection zone and a 10km surveillance zone have been established.[22]
Avian flu was detected at a poultry farm in Akita Prefecture in northeastern Japan, prompting the culling of roughly 143,000 chickens, according to the prefectural government on November 10, 2021.[23]
2022 outbreaks
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From February to April 2022, avian flu outbreaks in United States have resulted in the culling of more than 22.8 million birds in 24 states.[24]
Avian flu has affected England. In Norfolk, Suffolk and parts of Essex, poultry has been mandated to be kept indoors after the affected areas were placed in an Avian Influenza Prevention Zone.[25]
In October 2022, wildlife experts patrolling the Norfolk Broads were looking for swans that showed signs of being ill and had to euthanatize them on the spot.[26]
2023 outbreaks
In the beginning of the year, an outbreak of H5N8 began in Argentina. In February 2023, Argentina confirmed its first poultry case in Río Negro Province and decided to suspend poultry exports due to the case. By that date, other 25 cases had been detected in wild birds across the country.[27] Currently experts are predicting large outbreaks in penguin populations on Antarctica later this year.[citation needed]
Human cases confirmed
On 20 February 2021, Russian authorities reported the first known human cases of H5N8 as seven farm workers tested positive. There is no evidence of human-to-human transmission and the cases were described as "mild" or asymptomatic. The World Health Organization was notified.[28][29]
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.
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 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.
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 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 50 die, then there is a 50% 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.
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 87 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.
Since 2020, global cases of avian influenza subtype H5N1 have been rising, with cases reported from every continent as of February 2023 except for Australia and Antarctica. 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 virus involved in the outbreak is classified in H5 clade 2.3.4.4b.
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