Avian influenza

Last updated

Avian influenza, also known as avian flu or bird flu, is a disease caused by the influenza A virus, which primarily affects birds but can sometimes affect mammals including humans. [1] Wild aquatic birds are the primary host of the influenza A virus, which is enzootic (continually present) in many bird populations. [2] [3]

Contents

Symptoms of avian influenza vary according to both the strain of virus underlying the infection, and on the species of bird or mammal affected. Classification of a virus strain as either low pathogenic avian influenza (LPAI) or high pathogenic avian influenza (HPAI) is based on the severity of symptoms in domestic chickens and does not predict severity of symptoms in other species. [4] Chickens infected with LPAI display mild symptoms or are asymptomatic, whereas HPAI causes serious breathing difficulties, significant drop in egg production, and sudden death. [5] Domestic poultry may potentially be protected from specific strains of the virus by vaccination. [6]

Humans and other mammals can only become infected with avian influenza after prolonged close contact with infected birds. [7] In mammals including humans, infection with avian influenza (whether LPAI or HPAI) is rare. Symptoms of infection vary from mild to severe, including fever, diarrhea, and cough. [8]

Influenza A virus is shed in the saliva, mucus, and feces of infected birds; other infected animals may shed bird flu viruses in respiratory secretions and other body fluids (e.g., cow milk). [9] The virus can spread rapidly through poultry flocks and among wild birds. [9] A particularly virulent strain, influenza A virus subtype H5N1 (A/H5N1) has the potential to decimate domesticated poultry stocks and an estimated half a billion farmed birds have been slaughtered in efforts to contain the virus. [10]

Highly pathogenic avian influenza

Because of the impact of avian influenza on economically important chicken farms, a classification system was devised in 1981 which divided avian virus strains as either highly pathogenic (and therefore potentially requiring vigorous control measures) or low pathogenic. The test for this is based solely on the effect on chickens - a virus strain is highly pathogenic avian influenza (HPAI) if 75% or more of chickens die after being deliberately infected with it. The alternative classification is low pathogenic avian influenza (LPAI). [11] This classification system has since been modified to take into account the structure of the virus' haemagglutinin protein. [12] Other species of birds, especially water birds, can become infected with HPAI virus without experiencing severe symptoms and can spread the infection over large distances; the exact symptoms depend on the species of bird and the strain of virus. [11] Classification of an avian virus strain as HPAI or LPAI does not predict how serious the disease might be if it infects humans or other mammals. [11] [13]

Since 2006, the World Organization for Animal Health requires all LPAI H5 and H7 detections to be reported because of their potential to mutate into highly pathogenic strains. [14]

Virology

A transmission electron micrograph (TEM) of the reconstructed 1918 pandemic influenza virus. The bottom structure represents membrane debris from the cells used to amplify the virus. EM of influenza virus.jpg
A transmission electron micrograph (TEM) of the reconstructed 1918 pandemic influenza virus. The bottom structure represents membrane debris from the cells used to amplify the virus.

Avian influenza is caused by the influenza A virus which principally affects birds but can also infect humans and other mammals. [16] [17] Influenza A is an RNA virus with a genome comprising a negative-sense, RNA segmented genome that encodes for 11 viral genes. [18] The virus particle (also called the virion) is 80–120 nanometers in diameter and elliptical or filamentous in shape. [19] [20] There is evidence that the virus can survive for long periods in freshwater after being excreted in feces by its avian host, and can withstand prolonged freezing. [21]

There are two proteins on the surface of the viral envelope; hemagglutinin and neuraminidase. [4] These are the major antigens of the virus against which neutralizing antibodies are produced. Influenza virus epidemics and epizootics are associated with changes in their antigenic structure. [22]

Hemagglutinin (H) is an antigenic glycoprotein which allows the virus to bind to and enter the host cell. Neuraminidase (N) is an antigenic glycosylated enzyme which facilitates the release of progeny viruses from infected cells. [23] There are 18 known types of hemagglutinin, of which H1 thru H16 have been found in birds, and 11 types of neuraminidase. [16]

Subtypes

Subtypes of influenza A are defined by the combination of H and N proteins in the viral envelope; for example, "H5N1" designates an influenza A subtype that has a type-5 hemagglutinin (H) protein and a type-1 neuraminidase (N) protein. [7] The subtyping scheme only takes into account the two envelope proteins, not the other proteins coded by the virus' RNA. Almost all possible combinations of H (1 thru 16) and N (1 thru 11) have been isolated from wild birds. [24] Further variations exist within the subtypes and can lead to very significant differences in the virus's ability to infect and cause disease. [25]

Influenza virus nomenclature

Diagram of influenza nomenclature InfluenzaNomenclatureDiagram.svg
Diagram of influenza nomenclature

To unambiguously describe a specific isolate of virus, researchers use the internationally accepted Influenza virus nomenclature, [26] which describes, among other things, the species of animal from which the virus was isolated, and the place and year of collection. As an example - A/chicken/Nakorn-Patom/Thailand/CU-K2/04(H5N1):

Other examples include: A/duck/Hong Kong/308/78(H5N3), A/avian/NY/01(H5N2), A/chicken/Mexico/31381-3/94(H5N2), and A/shoveler/Egypt/03(H5N2). [27]

Genetic characterization

Analysis of the virus' genome enables researchers to determine the order of its nucleotides. Comparison of the genome of a virus with that of a different virus can reveal differences between the two viruses. [16] [28] Genetic variations are important because they can change amino acids that make up the influenza virus’ proteins, resulting in structural changes to the proteins, and thereby altering properties of the virus. Some of these properties include the ability to evade immunity and the ability to cause severe disease. [28]

Genetic sequencing enables influenza strains to be further characterised by their clade or subclade, revealing links between different samples of virus and tracing the evolution of the virus over time. [28]

Species barrier

Rarely, humans can become infected by the avian flu if they are in close contact with infected birds. Symptoms vary from mild to severe (including death), but these instances have not sustained transmission from one person to another. [4] [17]

There are a number of factors that generally prevent the avian flu from causing epidemics in humans or other mammals. [29] [30] One of them is that the HA protein of avian influenza binds to alpha-2,3 sialic acid receptors, which are present in the respiratory tract and intestines of avian species, while human influenza HA binds to alpha-2,6 sialic acid receptors, which are present in the human upper respiratory tract. [31] [32] Other factors include the ability to replicate the viral RNA genome within the host cell nucleus, to evade host immune responses, and to transmit between individuals. [33]

Influenza viruses are constantly changing as small genetic mutations accumulate, a process known as antigenic drift. Over time, mutation may lead to a change in antigenic properties such that host antibodies (acquired through vaccination or prior infection) do not provide effective protection, causing a fresh outbreak of disease. [34]

The segmented genome of influenza viruses facilitates genetic reassortment. This can occur if a host is infected simultaneously with two different strains of influenza virus; then it is possible for the viruses to interchange genetic material as they reproduce in the host cells. [35] Thus, an avian influenza virus can acquire characteristics, such as the ability to infect humans, from a different virus strain. The presence of both alpha 2,3 and alpha 2,6 sialic acid receptors in pig tissues allows for co-infection by avian influenza and human influenza viruses. This susceptibility makes pigs a potential "melting pot" for the reassortment of influenza A viruses. [36]

Epidemiology

History

Avian influenza (historically known as fowl plague) is caused by bird-adapted strains of the influenza type A virus. [4] The disease was first identified by Edoardo Perroncito in 1878 when it was differentiated from other diseases that caused high mortality rates in birds; in 1955 it was established that the fowl plague virus was closely related to human influenza. In 1972 it became evident that many subtypes of avian flu were endemic in wild bird populations. [11]

Between 1959 and 1995, there were 15 recorded outbreaks of highly pathogenic avian influenza (HPAI) in poultry, with losses varying from a few birds on a single farm to many millions. Between 1996 and 2008, HPAI outbreaks in poultry have been recorded at least 11 times and 4 of these outbreaks have resulted in the death or culling of millions of birds. [11] Since then, several virus strains (both LPAI and HPAI) have become endemic among wild birds with increasingly frequent outbreaks among domestic poultry, especially of the H5 and H7 subtypes.

Transmission and prevention

The eight major flyways used by shorebirds (waders) on migration .mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{} Pacific Mississippi West Atlantic East Atlantic Mediterranean and Black Sea West Asia and Africa Central Asia and India East Asia and Australasia Main international flyways - bird migration-fr.svg
The eight major flyways used by shorebirds (waders) on migration
  Pacific
  Mississippi
  West Atlantic
  East Atlantic
  Mediterranean and Black Sea
  West Asia and Africa
  Central Asia and India
  East Asia and Australasia

Birds - Influenza A viruses of various subtypes have a large reservoir in wild waterbirds of the orders Anseriformes (for example, ducks, geese, and swans) and Charadriiformes (for example, gulls, terns, and waders) which can infect the respiratory and gastrointestinal tract without affecting the health of the host. [38] They can then be carried by the bird over large distances, especially during annual migration. Infected birds can shed avian influenza A viruses in their saliva, nasal secretions, and feces; susceptible birds become infected when they have contact with the virus as it is shed by infected birds. [39] The virus can survive for long periods in water and at low temperatures, and can be spread from one farm to another on farm equipment. [40] Domesticated birds (chickens, turkeys, ducks, etc.) may become infected with avian influenza A viruses through direct contact with infected waterfowl or other infected poultry, or through contact with contaminated feces or surfaces.

Avian influenza outbreaks in domesticated birds are of concern for several reasons. There is potential for low pathogenic avian influenza viruses (LPAI) to evolve into strains which are high pathogenic to poultry (HPAI), and subsequent potential for significant illness and death among poultry during outbreaks. Because of this, international regulations state that any detection of H5 or H7 subtypes (regardless of their pathogenicity) must be notified to the appropriate authority. [41] [42] It is also possible that avian influenza viruses could be transmitted to humans and other animals which have been exposed to infected birds, causing infection with unpredictable but sometimes fatal consequences.

When an HPAI infection is detected in poultry, it is normal to cull infected animals and those nearby in an effort to rapidly contain, control and eradicate the disease. This is done together with movement restrictions, improved hygiene and biosecurity, and enhanced surveillance. [40]

Humans - Avian flu viruses, both HPAI and LPAI, can infect humans who are in close, unprotected contact with infected poultry. Incidents of cross-species transmission are rare, with symptoms ranging in severity from no symptoms or mild illness, to severe disease that resulted in death. [43] [42] As of February, 2024 there have been very few instances of human-to-human transmission, and each outbreak has been limited to a few people. [44] All subtypes of avian Influenza A have potential to cross the species barrier, with H5N1 and H7N9 considered the biggest threats. [45] [46]

In order to avoid infection, the general public are advised to avoid contact with sick birds or potentially contaminated material such as carcasses or feces. People working with birds, such as conservationists or poultry workers, are advised to wear appropriate personal protection equipment. [47]

Other animals - a wide range of other animals have been affected by avian flu, generally due to eating birds which had been infected. [48] There have been instances where transmission of the disease between mammals, including seals and cows, may have occurred. [49] [50]

Pandemic potential

Influenza viruses have a relatively high mutation rate that is characteristic of RNA viruses. [51] The segmentation of the influenza A virus genome facilitates genetic recombination by segment reassortment in hosts who become infected with two different strains of influenza viruses at the same time. [52] [53] With reassortment between strains, an avian strain which does not affect humans may acquire characteristics from a different strain which enable it to infect and pass between humans - a zoonotic event. [39] It is thought that all influenza A viruses causing outbreaks or pandemics among humans since the 1900s originated from strains circulating in wild aquatic birds through reassortment with other influenza strains. [54] [55] It is possible (though not certain) that pigs may act as an intermediate host for reassortment. [56]

As of June 2024, there is concern about two subtypes of avian influenza which are circulating in wild bird populations worldwide, H5N1 and H7N9. Both of these have potential to devastate poultry stocks, and both have jumped to humans with relatively high case fatality rates. [57]

Surveillance

The Global Influenza Surveillance and Response System (GISRS) is a global network of laboratories that monitor the spread of influenza with the aim to provide the World Health Organization with influenza control information and to inform vaccine development. [58] Several millions of specimens are tested by the GISRS network annually through a network of laboratories in 127 countries. [59] As well as human viruses, GISRS monitors avian, swine, and other potentially zoonotic influenza viruses.

Vaccine

Poultry - it is possible to vaccinate poultry against specific strains of HPAI influenza. Vaccination should be combined with other control measures such as infection monitoring, early detection and biosecurity. [60] [61]

Humans - Several "candidate vaccines" are available in case of an avian virus acquires the ability to infect and transmit among humans. There are strategic stockpiles of vaccines against the H5N1 subtype which is considered the biggest risk. [62] [63] [64] A vaccine against the H7N9 subtype, which has also infected humans, has undergone a limited amount of testing. [65] In the event of an outbreak, the "candidate" vaccine would be rapidly tested for safety as well as efficacy against the zoonotic strain, and then authorised and distributed to vaccine manufacturers. [66]

Zoonotic influenza vaccine Seqirus is authorized for use in the European Union. [67] It is an H5N8 vaccine that is intended to provide acquired immunity against H5 subtype influenza A viruses. [67]

Influenza A virus subtype H5N1

The highly pathogenic influenza A virus subtype H5N1 is an emerging avian influenza virus that is causing global concern as a potential pandemic threat. It is often referred to simply as "bird flu" or "avian influenza", even though it is only one of many subtypes.

A/H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe, and Africa. Health experts are concerned that the coexistence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans. [68]

Influenza A/H5N1 was first recorded in a small outbreak among poultry in Scotland [69] in 1959, with numerous outbreaks subsequently in every continent. [70] The first known transmission of A/H5N1 to a human occurred in Hong Kong in 1997, when there was an outbreak of 18 human cases resulting in 6 deaths. It was determined that all the infected people had been exposed to infected birds in poultry markets. As the disease continued to spread among poultry flocks in the territory, the decision was made to cull all 1.6 million poultry in the area and to impose strict controls on the movement and handling of poultry.This terminated the outbreak. [71] [72]

There is weak evidence to support limited human-to-human transmission of A/H5N1 in 139 outreaks between 2005 and 2009 in Sumatra. The reproduction number was well below the threshold for sustained transmission. [73]

Between 2003 and October 2024, the World Health Organization has recorded 921 cases of confirmed H5N1 influenza, leading to 464 deaths. [74] The true fatality rate may be lower because some cases with mild symptoms may not have been identified as H5N1. [75]

Influenza A virus subtype H7N9

Live poultry market in Xining, China, 2008. Chicken market in Xining, Qinghai province, China.jpg
Live poultry market in Xining, China, 2008.

A significant outbreak of influenza A virus subtype H7N9 (A/H7N9) started in March 2013 when severe influenza affected 18 humans in China; six subsequently died. [76] It was discovered that a low pathogenic strain of A/H7N9 was circulating among chickens, and that all the affected people had been exposed in poultry markets. Further cases among humans and poultry in mainland China continued to be identified sporadically throughout the year, followed by a peak around the festival season of Chinese New Year (January and February) in early 2014 which was attributed to the seasonal surge in poultry production. Up to December 2013, there had been 139 cases with 47 deaths. [77]

Infections among humans and poultry continued during the next few years, again with peaks around the new year. In 2016 a virus strain emerged which was highly pathogenic to chickens. [78] [79] In order to contain the HPAI outbreak, the Chinese authorities in 2017 initiated a large scale vaccination campaign against avian influenza in poultry. Since then, the number of outbreaks in poultry, as well as the number of human cases, dropped significantly. In humans, symptoms and mortality for both LPAI and HPAI strains have been similar. [78] Although no human H7N9 infections have been reported since February 2019, the virus is still circulating in poultry, particularly in laying hens. It has demonstrated antigenic drift to evade vaccines, and remains a potential threat to the poultry industry and public health. [79]

Genetic and evolutionary analyses have shown that the A(H7) viruses in the Chinese outbreak probably transferred from domestic duck to chicken populations in China and then reassorted with poultry influenza A(H9N2) to generate the influenza A(H7N9) strain that affected humans. The genetic characteristics of A(H7N9) virus are of concern because of their pandemic potential, e.g. their potential to recognise human and avian influenza virus receptors which affects the ability to cause sustained human-to-human transmission, or the ability to replicate in the human host. [76]

Between February 2013 and February 2019 there were 1,568 confirmed human cases and 616 deaths associated with the outbreak in China. [80] [81] The majority of human cases have reported contact with poultry in markets or farms. Transmission between humans remains limited with some evidence of small family clusters. However, there is no evidence of sustained human-to-human transmission of A/H7N9 influenza. [78]

During early 2017, outbreaks of avian influenza A(H7N9) occurred in poultry in the USA. The strain in these outbreaks was of North American origin and is unrelated to the Asian lineage H7N9 which is associated with human infections in China. [78]

Domestic animals

A chicken being tested for flu A chicken being tested for Bird Flu.png
A chicken being tested for flu

Several domestic species have been infected with and shown symptoms of H5N1 viral infection, including cats, dogs, ferrets, pigs, and birds. [82]

Poultry

Attempts are made in the United States to minimize the presence of HPAI in poultry through routine surveillance of poultry flocks in commercial poultry operations. Detection of a HPAI virus may result in immediate culling of the flock. Less pathogenic viruses are controlled by vaccination. [83]

Dairy cows

During April 2024 avian influenza was first detected in dairy cows in several US states and subsequently spread more widely through the year. Influenza A(H5N1) was found to be present at high levels in the mammary glands and in the milk of affected cows. [84] [85] [86] It was shown that the virus can persist on milking equipment, which provides a probable transmission route for cow-to-cow and cow-to-human spread. [87] A number of humans who had been in contact with cows tested positive for the virus, with mild symptoms. [88] According to CDC 7 % of 115 dairy workers had evidence of recent infection in a study from Michigan and Colorado from June to August 2024- half of them asymptomatic. This is higher than estimates from prior transmission studies in poultry. All dairy workers had worked in cleaning the milk parlor and none had used personal protective equipment. [89]

Cats

This section is an excerpt from Avian influenza in cats.[ edit ]
Cats with avian influenza exhibit symptoms that can result in death. The avian influenza viruses cats may get include H5N1 or H7N2, [90] which are subtypes. In order to get the virus, cats need to be in contact with waterfowl, poultry, or uncooked poultry that are infected. [91] Two of the main organs that the virus affects are the lungs and liver. [92]

Global aspects

Global measures

In 2005, the formation of the International Partnership on Avian and Pandemic Influenza was announced in order to elevate the importance of avian flu, coordinate efforts, and improve disease reporting and surveillance in order to better respond to future pandemics. New networks of laboratories have emerged to detect and respond to avian flu, such as the Crisis Management Center for Animal Health, the Global Avian Influenza Network for Surveillance, OFFLU, and the Global Early Warning System for major animal diseases. After the 2003 outbreak, WHO member states have also recognized the need for more transparent and equitable sharing of vaccines and other benefits from these networks. [93] Cooperative measures created in response to HPAI have served as a basis for programs related to other emerging and re-emerging infectious diseases.

Impact on national policies

HPAI control has also been used for political ends. In Indonesia, negotiations with global response networks were used to recentralize power and funding to the Ministry of Health. [94] In Vietnam policymakers, with the support of the Food and Agriculture Organization of the United Nations (FAO), used HPAI control to accelerate the industrialization of livestock production for export by proposing to increase the portion of large-scale commercial farms and reducing the number of poultry keepers from 8 to 2 million by 2010. [95]

Traditional Asian practices

Backyard poultry production was viewed as "traditional Asian" agricultural practices that contrasted with modern commercial poultry production and seen as a threat to biosecurity. Backyard production appeared to hold greater risk than commercial production due to lack of biosecurity and close contact with humans, though HPAI spread in intensively raised flocks was greater due to high density rearing and genetic homogeneity. [96] [97] Asian culture itself was blamed as the reason why certain interventions, such as those that only looked at placed-based interventions, would fail without looking for multifaceted solutions. [95]

Economic impact

Approximately 20% of the protein consumed in developing countries come from poultry. [96] A report by FAO totalled economic losses caused by avian influenza in South East Asia up to 2005 around US$10 billion. This had the greatest impact on small scale commercial and backyard producers. [98]

As poultry serves as a source of food security and liquid assets, the most vulnerable populations were poor small scale farmers. [95] The loss of birds due to HPAI and culling in Vietnam led to an average loss of 2.3 months of production and US$69–108 for households where many have an income of $2 a day or less. [98] The loss of food security for vulnerable households can be seen in the stunting of children under five in Egypt. Women are another population at risk as in most regions of the world, small flocks are tended to by women. Widespread culling also resulted in the decreased enrollment of girls in school in Turkey. [96]

See also

Notes

    Related Research Articles

    <i>Influenza A virus</i> Species of virus

    Influenza A virus (IAV) is the only species of the genus Alphainfluenzavirus of the virus family Orthomyxoviridae. It 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.

    <span class="mw-page-title-main">Influenza A virus subtype H5N1</span> Subtype of influenza A virus

    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.

    <span class="mw-page-title-main">Influenza pandemic</span> Pandemic involving influenza

    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 five major influenza pandemics 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.

    <span class="mw-page-title-main">Influenza A virus subtype H3N2</span> Virus subtype

    Influenza A virus subtype H3N2 (A/H3N2) is a subtype of influenza A virus (IAV). Some human-adapted strains of A/H3N2 are endemic in humans and are one cause of seasonal influenza (flu). Other strains of H1N1 are endemic in pigs and in birds. Subtypes of IAV are defined by the combination of the antigenic H and N proteins in the viral envelope; for example, "H1N1" designates an IAV subtype that has a type-1 hemagglutinin (H) protein and a type-1 neuraminidase (N) protein.

    <span class="mw-page-title-main">Global spread of H5N1</span> Spread of bird flu

    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 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 2008 highly pathogenic strain of H5N1.

    <span class="mw-page-title-main">Transmission and infection of H5N1</span> Spread of an influenza virus

    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.

    <span class="mw-page-title-main">Influenza A virus subtype H5N2</span> Virus subtype

    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. On June 5, 2024, the first confirmed human case of H5N2 was reported in Mexico.

    <span class="mw-page-title-main">Influenza A virus subtype H7N7</span> Virus subtype

    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.

    <span class="mw-page-title-main">Influenza A virus subtype H9N2</span> Virus subtype

    Influenza A virus subtype H9N2 (A/H9N2) is a subtype of the species Influenza A virus . Since 1998 a total of 86 cases of human infection with H9N2 viruses have been reported.

    <span class="mw-page-title-main">Influenza A virus subtype H7N2</span> Virus subtype

    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.

    <span class="mw-page-title-main">H5N1 genetic structure</span> Genetic structure of Influenza A virus

    The genetic structure of H5N1, a highly pathogenic avian influenza virus, is characterized by a segmented RNA genome consisting of eight gene segments that encode for various viral proteins essential for replication, host adaptation, and immune evasion.

    <span class="mw-page-title-main">Global spread of H5N1 in 2005</span> Pandemic threat

    The global spread of H5N1 in birds is considered a significant pandemic threat.

    <span class="mw-page-title-main">Global spread of H5N1 in 2004</span>

    The global spread of H5N1 in birds is considered a significant pandemic threat.

    <span class="mw-page-title-main">Fujian flu</span> Strains of influenza

    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.

    <span class="mw-page-title-main">Human mortality from H5N1</span>

    H5N1 influenza virus is a type of influenza A virus which mostly infects birds. H5N1 flu is a concern due to the its global spread that may constitute a pandemic threat. The yardstick for human mortality from H5N1 is the case-fatality rate (CFR); the ratio of the number of confirmed human deaths resulting from infection of H5N1 to the number of those confirmed cases of infection with the virus. For example, if there are 100 confirmed cases of a disease and 50 die as a consequence, then the CFR is 50%. The case fatality rate does not take into account cases of a disease which are unconfirmed or undiagnosed, perhaps because symptoms were mild and unremarkable or because of a lack of diagnostic facilities. The Infection Fatality Rate (IFR) is adjusted to allow for undiagnosed cases.

    A panzootic is an epizootic that spreads across a large region, or even worldwide. The equivalent in human populations is called a pandemic.

    <span class="mw-page-title-main">Influenza</span> Infectious disease

    Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia from the virus or a subsequent bacterial infection. Other complications include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease.

    <span class="mw-page-title-main">Influenza A virus subtype H7N9</span> Subtype of the influenza A virus

    Influenza A virus subtype H7N9 (A/H7N9) is a subtype of the influenza A virus, which causes influenza (flu), predominantly in birds. It is enzootic in many bird populations. The virus can spread rapidly through poultry flocks and among wild birds; it can also infect humans that have been exposed to infected birds.

    Since 2020, outbreaks of avian influenza subtype H5N1 have been occurring, with cases reported from every continent except Australia as of November 2024. Some species of wild aquatic birds act as natural asymptomatic carriers of a large variety of influenza A viruses, which can infect poultry, other bird species, mammals and humans if they come into close contact with infected feces or contaminated material, or by eating infected birds. 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.

    References

    1. ↑ "Avian Influenza A H5N1 - United Kingdom of Great Britain and Northern Ireland". www.who.int. Retrieved 2024-05-16.
    2. ↑ Li YT, Linster M, Mendenhall IH, Su YC, Smith GJ (December 2019). "Avian influenza viruses in humans: lessons from past outbreaks". British Medical Bulletin. 132 (1): 81–95. doi:10.1093/bmb/ldz036. PMC   6992886 . PMID   31848585.
    3. ↑ Joseph U, Su YC, Vijaykrishna D, Smith GJ (January 2017). "The ecology and adaptive evolution of influenza A interspecies transmission". Influenza and Other Respiratory Viruses. 11 (1): 74–84. doi:10.1111/irv.12412. PMC   5155642 . PMID   27426214.
    4. 1 2 3 4 "Avian Influenza in Birds". U.S. Centers for Disease Control and Prevention (CDC). 2022-06-14. Retrieved 2024-05-06.
    5. ↑ "Bird flu (avian influenza): how to spot and report it in poultry or other captive birds". Department for Environment, Food & Rural Affairs and Animal and Plant Health Agency. 2022-12-13. Retrieved 2024-05-06.
    6. ↑ "Vaccination of poultry against highly pathogenic avian influenza – Available vaccines and vaccination strategies". www.efsa.europa.eu. 2023-10-10. Retrieved 2024-05-09.
    7. 1 2 "Influenza Type A Viruses". U.S. Centers for Disease Control and Prevention (CDC). 2024-02-01. Retrieved 2024-05-03.
    8. ↑ "Avian influenza: guidance, data and analysis". GOV.UK. 2021-11-18. Retrieved 2024-05-09.
    9. 1 2 "Prevention and Antiviral Treatment of Bird Flu Viruses in People". Centers for Disease Control. 2024-04-19.
    10. ↑ Bourk I (26 April 2024). "'Unprecedented': How bird flu became an animal pandemic". www.bbc.com. Retrieved 2024-05-08.
    11. 1 2 3 4 5 Alexander DJ, Brown IH (April 2009). "History of highly pathogenic avian influenza". Revue Scientifique et Technique. 28 (1): 19–38. doi:10.20506/rst.28.1.1856. PMID   19618616.
    12. ↑ "Factsheet on A(H5N1)". www.ecdc.europa.eu. 2017-06-15. Retrieved 2024-05-21.
    13. ↑ "Current U.S. Bird Flu Situation in Humans". U.S. Centers for Disease Control and Prevention (CDC). 2024-04-05. Retrieved 2024-05-22.
    14. ↑ "National H5/H7 Avian Influenza surveillance plan". United States Department of Agriculture. Animal Plant Health Inspection Service. October 2013.
    15. ↑ "Recreated 1918 Influenza virions". U.S. Centers for Disease Control and Prevention (CDC). Archived from the original on 26 October 2020. Retrieved 24 April 2018.
    16. 1 2 3 "Types of Influenza Viruses". U.S. Centers for Disease Control and Prevention (CDC). 2023-03-30. Retrieved 2024-05-22.
    17. 1 2 "Influenza (Avian and other zoonotic)". World Health Organization. 3 October 2023. Retrieved 2024-05-06.
    18. ↑ Samji T (December 2009). "Influenza A: understanding the viral life cycle". The Yale Journal of Biology and Medicine. 82 (4): 153–159. PMC   2794490 . PMID   20027280.
    19. ↑ Noda T (2011). "Native morphology of influenza virions". Frontiers in Microbiology. 2: 269. doi: 10.3389/fmicb.2011.00269 . PMC   3249889 . PMID   22291683.
    20. ↑ Dadonaite B, Vijayakrishnan S, Fodor E, Bhella D, Hutchinson EC (August 2016). "Filamentous influenza viruses". The Journal of General Virology. 97 (8): 1755–1764. doi:10.1099/jgv.0.000535. PMC   5935222 . PMID   27365089.
    21. ↑ Shoham D, Jahangir A, Ruenphet S, Takehara K (2012-10-04). "Persistence of avian influenza viruses in various artificially frozen environmental water types". Influenza Research and Treatment. 2012: 912326. doi: 10.1155/2012/912326 . PMC   3471417 . PMID   23091712.
    22. ↑ "Avian Influenza". NIOSH Workplace Safety and Health Topic. National Institute for Occupational Safety and Health. 2018-10-17.
    23. ↑ Couch R (1996). "Chapter 58. Orthomyxoviruses Multiplication". In Baron S (ed.). Medical Microbiology. Galveston: The University of Texas Medical Branch at Galveston. ISBN   978-0-9631172-1-2. PMID   21413353. Archived from the original on May 3, 2009.
    24. ↑ "FluGlobalNet - Avian Influenza". science.vla.gov.uk. Retrieved 2024-06-05.
    25. ↑ Eisfeld AJ, Neumann G, Kawaoka Y (January 2015). "At the centre: influenza A virus ribonucleoproteins". Nature Reviews. Microbiology. 13 (1): 28–41. doi:10.1038/nrmicro3367. PMC   5619696 . PMID   25417656.
    26. ↑ "A revision of the system of nomenclature for influenza viruses: a WHO memorandum". Bulletin of the World Health Organization. 58 (4): 585–591. 1980. PMC   2395936 . PMID   6969132. This Memorandum was drafted by the signatories listed on page 590 on the occasion of a meeting held in Geneva in February 1980.
    27. ↑ Payungporn S, Chutinimitkul S, Chaisingh A, Damrongwantanapokin S, Nuansrichay B, Pinyochon W, et al. (April 2006). "Discrimination between highly pathogenic and low pathogenic H5 avian influenza A viruses". Emerging Infectious Diseases. 12 (4): 700–701. doi:10.3201/eid1204.051427. PMC   3294708 . PMID   16715581.
    28. 1 2 3 "Influenza Virus Genome Sequencing and Genetic Characterization". Centers for Disease Control and Prevention. 2024-02-27. Retrieved 2024-05-24.
    29. ↑ Petric PP, Schwemmle M, Graf L (July 2023). "Anti-influenza A virus restriction factors that shape the human species barrier and virus evolution". PLOS Pathogens. 19 (7): e1011450. doi: 10.1371/journal.ppat.1011450 . PMC   10325056 . PMID   37410755.
    30. ↑ Koçer ZA, Jones JC, Webster RG (December 2013). Atlas RM, Maloy S (eds.). "Emergence of Influenza Viruses and Crossing the Species Barrier". Microbiology Spectrum. 1 (2). doi:10.1128/microbiolspec.OH-0010-2012. PMID   26184958.
    31. ↑ Bertram S, Glowacka I, Steffen I, Kühl A, Pöhlmann S (September 2010). "Novel insights into proteolytic cleavage of influenza virus hemagglutinin". Reviews in Medical Virology. 20 (5): 298–310. doi:10.1002/rmv.657. PMC   7169116 . PMID   20629046. The influenza virus HA binds to alpha 2–3 linked (avian viruses) or alpha 2–6 linked (human viruses) sialic acids presented by proteins or lipids on the host cell surface.
    32. ↑ Kuchipudi SV, Nelli RK, Gontu A, Satyakumar R, Surendran Nair M, Subbiah M (February 2021). "Sialic Acid Receptors: The Key to Solving the Enigma of Zoonotic Virus Spillover". Viruses. 13 (2): 262. doi: 10.3390/v13020262 . PMC   7915228 . PMID   33567791.
    33. ↑ Long JS, Mistry B, Haslam SM, Barclay WS (January 2019). "Host and viral determinants of influenza A virus species specificity". Nature Reviews. Microbiology. 17 (2): 67–81. doi:10.1038/s41579-018-0115-z. PMID   30487536.
    34. ↑ "How Flu Viruses Can Change". U.S. Centers for Disease Control and Prevention (CDC). 2022-12-12. Retrieved 2024-05-22.
    35. ↑ Steel J, Lowen AC (2014), Compans RW, Oldstone MB (eds.), "Influenza a Virus Reassortment", Influenza Pathogenesis and Control - Volume I, Current Topics in Microbiology and Immunology, vol. 385, Cham: Springer International Publishing, pp. 377–401, doi:10.1007/82_2014_395, ISBN   978-3-319-11155-1, PMID   25007845
    36. ↑ Schnitzler SU, Schnitzler P (December 2009). "An update on swine-origin influenza virus A/H1N1: a review". Virus Genes. 39 (3): 279–292. doi:10.1007/s11262-009-0404-8. PMC   7088521 . PMID   19809872. If an avian virus mutates or reassorts and gains the ability to bind to α2,6 linked sialic acids, it might cross the species barrier and infect humans. Swine tissues express both forms of sialic acid and can be coinfected with human and avian viruses. Thus, pigs serve as a melting vessel for human, avian and swine influenza strains.
    37. ↑ Thompson D, Byrkjedal I (2001). Shorebirds. Colin Baxter Photography Ltd. ISBN   978-1841070759.
    38. ↑ "Mitigation strategy for avian influenza in wild birds in England and Wales". GOV.UK - Department for Environment Food & Rural Affairs. 18 March 2024. Retrieved 2024-07-25.
    39. 1 2 "Transmission of Bird Flu Viruses Between Animals and People". U.S. Centers for Disease Control and Prevention (CDC). 2024-05-15. Retrieved 2024-06-10.
    40. 1 2 "Avian Influenza". WOAH - World Organisation for Animal Health. Retrieved 2024-06-10.
    41. ↑ "Prevention and Control of H5 and H7 Avian Influenza in the Live Bird Marketing System". United States Department of Agriculture. August 2020. Retrieved 15 June 2024.
    42. 1 2 "Questions and Answers on Avian Influenza". An official website of the European Commission. 11 June 2024. Retrieved 2024-06-11.
    43. ↑ "Avian Influenza A Virus Infections in Humans". U.S. Centers for Disease Control and Prevention (CDC). 2024-05-30. Retrieved 2024-06-11.
    44. ↑ "Reported Human Infections with Avian Influenza A Viruses". Centers for Disease Control and Prevention. 2024-02-01. Retrieved 2024-06-11.
    45. ↑ "Zoonotic influenza". Wordl Health Organization. Retrieved 2024-06-16.
    46. ↑ "The next pandemic: H5N1 and H7N9 influenza?". Gavi, the Vaccine Alliance. Retrieved 2024-06-16.
    47. ↑ "Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations". U.S. Centers for Disease Control and Prevention. 2024-06-05. Retrieved 2024-06-13.
    48. ↑ "Bird flu 'spills over' to otters and foxes in UK". BBC News. 2023-02-02. Retrieved 2024-06-11.
    49. ↑ "Study of H5N1 avian flu seal deaths reveals multiple lineages". Center for Infectious Disease Research and Policy. 2023-03-15. Retrieved 2024-06-13.
    50. ↑ Kozlov M (June 2024). "Huge amounts of bird-flu virus found in raw milk of infected cows". Nature. doi:10.1038/d41586-024-01624-1. PMID   38840011.
    51. ↑ Sanjuán R, Nebot MR, Chirico N, Mansky LM, Belshaw R (October 2010). "Viral mutation rates". Journal of Virology. 84 (19): 9733–9748. doi:10.1128/JVI.00694-10. PMC   2937809 . PMID   20660197.
    52. ↑ Kou Z, Lei FM, Yu J, Fan ZJ, Yin ZH, Jia CX, et al. (December 2005). "New genotype of avian influenza H5N1 viruses isolated from tree sparrows in China". Journal of Virology. 79 (24): 15460–15466. doi:10.1128/JVI.79.24.15460-15466.2005. PMC   1316012 . PMID   16306617.
    53. ↑ The World Health Organization Global Influenza Program Surveillance Network (October 2005). "Evolution of H5N1 avian influenza viruses in Asia". Emerging Infectious Diseases. 11 (10): 1515–1521. doi:10.3201/eid1110.050644. PMC   3366754 . PMID   16318689.Figure 1 shows a diagramatic representation of the genetic relatedness of Asian H5N1 hemagglutinin genes from various isolates of the virus
    54. ↑ Taubenberger JK, Morens DM (April 2010). "Influenza: the once and future pandemic". Public Health Reports. 125 (Suppl 3): 16–26. doi:10.1177/00333549101250S305. PMC   2862331 . PMID   20568566.
    55. ↑ Webster RG, Bean WJ, Gorman OT, Chambers TM, Kawaoka Y (March 1992). "Evolution and ecology of influenza A viruses". Microbiological Reviews. 56 (1): 152–179. doi:10.1128/mr.56.1.152-179.1992. PMC   372859 . PMID   1579108.
    56. ↑ "Factsheet on swine influenza in humans and pigs". European Centre for Disease Control. 2017-06-15. Retrieved 2024-06-13.
    57. ↑ "Global AIV with Zoonotic Potential". The Food and Agriculture Organization (FAO) of the United Nations. 29 July 2020. Retrieved 2024-06-24.
    58. ↑ Lee K, Fang J (2013). Historical Dictionary of the World Health Organization. Rowman & Littlefield. ISBN   9780810878587.
    59. ↑ "70 years of GISRS – the Global Influenza Surveillance & Response System". World Health Organization. 19 September 2022. Retrieved 2024-06-13.
    60. ↑ "Vaccination of poultry against highly pathogenic avian influenza – Available vaccines and vaccination strategies". efsa.europa.eu. 2023-10-10. Retrieved 2024-05-09.
    61. ↑ "Making a Candidate Vaccine Virus (CVV) for a HPAI (Bird Flu) Virus". U.S. Centers for Disease Control and Prevention (CDC). 2024-06-03. Retrieved 2024-06-15.
    62. ↑ "Vaccines for pandemic influenza". European Medicines Agency. Retrieved 2024-06-15.
    63. ↑ Keown A (February 4, 2020). "FDA Approves Seqirus' Audenz as Vaccine Against Potential Flu Pandemic". BioSpace. Archived from the original on February 5, 2020. Retrieved February 5, 2020.
    64. ↑ "Audenz". U.S. Food and Drug Administration (FDA). January 31, 2020. STN: 125692. Archived from the original on August 6, 2020. Retrieved February 5, 2020.PD-icon.svg This article incorporates text from this source, which is in the public domain .
    65. ↑ Zheng D, Gao F, Zhao C, Ding Y, Cao Y, Yang T, et al. (2018-09-14). "Comparative effectiveness of H7N9 vaccines in healthy individuals". Human Vaccines & Immunotherapeutics. 15 (1): 80–90. doi:10.1080/21645515.2018.1515454. PMC   6363152 . PMID   30148691.
    66. ↑ "Making a Candidate Vaccine Virus (CVV) for a HPAI (Bird Flu) Virus". U.S. Centers for Disease Control and Prevention (CDC). 2024-06-03. Retrieved 2024-06-22.
    67. 1 2 "Zoonotic Influenza Vaccine Seqirus EPAR". European Medicines Agency (EMA). 9 October 2023. Retrieved 26 September 2024.
    68. ↑ Poovorawan Y, Pyungporn S, Prachayangprecha S, Makkoch J (July 2013). "Global alert to avian influenza virus infection: from H5N1 to H7N9". Pathogens and Global Health. 107 (5): 217–223. doi:10.1179/2047773213Y.0000000103. PMC   4001451 . PMID   23916331.
    69. ↑ "1880-1959 Highlights in the History of Avian Influenza (Bird Flu) Timeline". Centers for Disease Control and Prevention. 2024-06-10. Retrieved 2024-07-14.
    70. ↑ Weston P (2024-03-26). "'Cautious optimism' as penguins test positive for bird flu but show no symptoms". The Guardian. ISSN   0261-3077 . Retrieved 2024-07-14.
    71. ↑ Sencer DJ (2024). "Outbreak in Hong Kong, 1997 · Influenza: Complex Virus/Complex History · CDC Museum Digital Exhibits". CDC Museum. Retrieved 2024-07-14.
    72. ↑ "Recommendations for Worker Protection and Use of Personal Protective Equipment (PPE) to Reduce Exposure to Highly Pathogenic Avian Influenza A H5 Viruses : Avian Influenza (Flu)". Centers for Disease Control and Prevention. Retrieved 2015-07-25.
    73. ↑ Aditama TY, Samaan G, Kusriastuti R, Sampurno OD, Purba W, Santoso H, et al. (2012-01-04). "Avian influenza H5N1 transmission in households, Indonesia". PLOS ONE. 7 (1): e29971. Bibcode:2012PLoSO...729971A. doi: 10.1371/journal.pone.0029971 . PMC   3251608 . PMID   22238686.
    74. ↑ "Avian influenza A(H5N1) virus". www.who.int. Retrieved 2024-05-28.
    75. ↑ Li FC, Choi BC, Sly T, Pak AW (June 2008). "Finding the real case-fatality rate of H5N1 avian influenza". J Epidemiol Community Health. 62 (6): 555–9. doi:10.1136/jech.2007.064030. PMID   18477756. S2CID   34200426.
    76. 1 2 "Factsheet on A(H7N9)". European Centre for Disease Prevention and Control. 2017-06-15. Retrieved 2024-07-15.
    77. ↑ Li Q, Zhou L, Zhou M, Chen Z, Li F, Wu H, et al. (April 24, 2013). "Preliminary Report: Epidemiology of the Avian Influenza A (H7N9) Outbreak in China". New England Journal of Medicine. 370 (6): 520–32. doi:10.1056/NEJMoa1304617. PMC   6652192 . PMID   23614499.{{cite journal}}: CS1 maint: overridden setting (link)
    78. 1 2 3 4 "Risk assessment of avian influenza A(H7N9) – eighth update". UK Health Security Agency. 8 January 2020. Retrieved 2024-07-15.
    79. 1 2 Liu Y, Chen Y, Yang Z, Lin Y, Fu S, Chen J, et al. (June 2024). "Evolution and Antigenic Differentiation of Avian Influenza A(H7N9) Virus, China". Emerging Infectious Diseases. 30 (6): 1218–1222. doi:10.3201/eid3006.230530. ISSN   1080-6040. PMC   11138980 . PMID   38640498.
    80. ↑ "Avian Influenza A(H7N9) virus". Food and Agricultural Organization of the United Nations. 1 June 2022. Retrieved 2024-07-15.
    81. ↑ CDC (2024-06-03). "2010-2019 Highlights in the History of Avian Influenza (Bird Flu) Timeline". Avian Influenza (Bird Flu). Retrieved 2024-07-16.
    82. ↑ "USGS National Wildlife Health Center – Avian Influenza Wildlife Chart". Archived from the original on 2018-02-06. Retrieved 2010-10-06.
    83. ↑ Thacker E, Janke B (February 2008). "Swine influenza virus: zoonotic potential and vaccination strategies for the control of avian and swine influenzas". The Journal of Infectious Diseases. 197 (Suppl 1): S19–S24. doi: 10.1086/524988 . PMID   18269323.
    84. ↑ Thomas P. "Bird Flu Spreads to Cattle, Raising Fears on Farms". WSJ. Archived from the original on 2024-04-04. Retrieved 2024-04-04.
    85. ↑ Burrough E, Magstadt D, Main R (29 April 2024). "Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus Infection in Domestic Dairy Cattle and Cats, United States, 2024". Emerging Infectious Diseases. 30 (7): 1335–1343. doi:10.3201/eid3007.240508. PMC   11210653 . PMID   38683888. Archived from the original on 29 April 2024. Retrieved 30 April 2024.
    86. ↑ Caserta L, Frye E, Butt S, Dimitrov K, Diel D (25 July 2024). "Spillover of highly pathogenic avian influenza H5N1 virus to dairy cattle". Nature. doi: 10.1038/s41586-024-07849-4 . PMC   11485258 . Retrieved 27 July 2024.
    87. ↑ Schnirring L (24 May 2024). "H5N1 avian flu viruses can persist on milking equipment surfaces". University of Minnesota. CIDRAP. Archived from the original on 23 May 2024. Retrieved 24 May 2024.
    88. ↑ Goodman B (2024-10-08). "As bird flu outbreak expands in California, dairy farms report it's worse than they expected". CNN. Retrieved 2024-10-10.
    89. ↑ Mellis AM (2024). "Serologic Evidence of Recent Infection with Highly Pathogenic Avian Influenza A(H5) Virus Among Dairy Workers — Michigan and Colorado, June–August 2024". MMWR. Morbidity and Mortality Weekly Report. 73. doi:10.15585/mmwr.mm7344a3. ISSN   0149-2195. PMC   11542770 .
    90. ↑ Lee CT (28 July 2017). "Outbreak of Influenza A(H7N2) Among Cats in an Animal Shelter With Cat-to-Human Transmission—New York City, 2016". academic.oup.com. Retrieved 2024-05-16.
    91. ↑ Thiry E, Addie, Diane, Belák, Sándor, Boucraut-Baralon, Corine, Egberink, Herman, Frymus, Tadeusz, et al. (1 July 2009). "H5N1 avian influenza in cats. ABCD guidelines on prevention and management". Journal of Feline Medicine & Surgery. 11 (7): 615–618. doi:10.1016/j.jfms.2009.05.011. PMC   7128855 . PMID   19481042.
    92. ↑ Marschall J, Hartmann K (1 August 2008). "Avian influenza A H5N1 infections in cats". Journal of Feline Medicine & Surgery. 10 (4): 359–365. doi:10.1016/j.jfms.2008.03.005. PMC   10832898 . PMID   18619884. S2CID   29347001.
    93. ↑ "Avian and Pandemic Influenza: The Global Response". Avian Influenza Action Group, United States Department of State. Oct 2008.
    94. ↑ Hameiri S (2014). "Avian influenza, 'viral sovereignty', and the politics of health security in Indonesia". The Pacific Review. 27 (3): 333–356. doi:10.1080/09512748.2014.909523. S2CID   154302060.
    95. 1 2 3 Porter N (2012). "Risky zoographies: The limits of place in avian flu management". Environmental Humanities. 1 (1): 103–121. doi: 10.1215/22011919-3609994 .
    96. 1 2 3 Alders R, Awuni JA, Bagnol B, Farrell P, de Haan N (2014). "Impact of avian influenza on village poultry production globally". EcoHealth. 11 (1): 63–72. doi:10.1007/s10393-013-0867-x. PMID   24136383. S2CID   6701416.
    97. ↑ Porter N (2013). "Bird flu biopower: Strategies for multispecies coexistence in Viet Nam". American Ethnologist. 40 (1): 132–148. doi:10.1111/amet.12010.
    98. 1 2 McLeod A, Morgan N, Prakash A, Hinrichs J (2005). Economic and social impacts of avian influenza. Food and Agriculture Organisation (Report).

    Further reading

    World Health Organisation (WHO)

    Food and Agriculture Organization of the UN (FAO)

    World Organisation for Animal Health (OIE)

    United States

    Europe

    This page is based on this Wikipedia article
    Text is available under the CC BY-SA 4.0 license; additional terms may apply.
    Images, videos and audio are available under their respective licenses.