Influenza A virus subtype H10N3 | |
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Treatment | N/A |
Frequency | ~160 animal cases in last 40 years |
Influenza (flu) |
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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.
Only around 160 cases of the virus have been reported in the 40 years before 2018, mostly in various waterfowl or wild birds. [1] Existing studies show that H10 influenza viruses are present in a wide range of domestic and wild avian species, as well as in mammals, showing potential for adaptation. [2] H10N3 has been isolated across a wide geographic distribution, including in species such as domestic poultry (chickens), [2] ducks, [3] [4] other waterfowl, and terrestrial birds. [5] In animals, the viruses display a complex pathology, with complex reassortments and mutations contributing to pathobiology patterns in chickens, ducks and mice indicative of a possible threat to humans, [6] although H10N3 is usually a less severe strain and is unlikely to cause a significant outbreak. [1]
The first human case of H10N3 was reported in Zhenjiang, in China's eastern province of Jiangsu. [1] [7] This index case was a patient admitted to the hospital with a fever and worsening respiratory symptoms on April 28, 2021, with a diagnosis of H10N3 confirmed in May 2021. None of the individual's close contacts developed any symptoms or signs of infection. The virus identified from this individual contains an HA cleavage site that is consistent with a "low pathogenicity avian influenza" (LPAI), and is also a reassortant strain, combining the HA and NA genes from H10N3 with internal genes from H9N2 viruses. [7]
According to China's National Health Commission (NHC), human cases of H10N3 have not been reported elsewhere in China. [8] There are no indications that the virus is easily transmissible among humans, with no confirmed cases of human-to-human transmission. [1] [9] Other types of avian-origin H10 influenza have been reported in human beings, including in Egypt, Australia and China, highlighting a potential public health hazard, although none of the strains so far detected have shown signs of human transmission. [2] [7]
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.
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. Wild aquatic birds are the primary host of the influenza A virus, which is enzootic 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.
Influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus (IAV). Some human-adapted strains of H1N1 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.
Influenza A virus subtype H2N2 (A/H2N2) is a subtype of Influenza A virus. H2N2 has mutated into various strains including the "Asian flu" strain, H3N2, and various strains found in birds. It is also suspected of causing a human pandemic in 1889. The geographic spreading of the 1889 Russian flu has been studied and published.
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.
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.
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. On June 5, 2024, the first confirmed human case of H5N2 was reported in Mexico.
H3N8 is a subtype of the species Influenza A virus that is endemic in birds, horses and dogs. It is the main cause of equine influenza and is also known as equine influenza virus. In 2011, it was reported to have been found in seals. Cats have been experimentally infected with the virus, leading to clinical signs, shedding of the virus and infection of other cats. In 2022 and 2023, three people in China were infected with H3N8, with one fatality, marking the first time a human has died from this strain of flu.
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.
H6N2 is an avian influenza virus with two forms: one has a low and the other a high pathogenicity. It can cause a serious problem for poultry, and also infects ducks as well. H6N2 subtype is considered to be a non-pathogenic chicken virus, the host still unknown, but could strain from feral animals, and/or aquatic bird reservoirs. H6N2 along with H6N6 are viruses that are found to replicate in mice without preadaptation, and some have acquired the ability to bind to human-like receptors. Genetic markers for H6N2 include 22-amino acid stalk deletion in neuraminidase (NA) protein gene, increased N-glycosylation, and a D144 mutation of the Haemagglutinin (HA) protein gene. Transmission of avian influenza viruses from wild aquatic birds to domestic birds usually cause subclinical infections, and occasionally, respiratory disease and drops in egg production. Some histological features presented in chicken infected with H6N2 are fibrinous yolk peritonitis, salpingitis, oophoritis, nephritis, along with swollen kidneys as well.
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.
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.
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.
Influenza, commonly known as "the flu" or just "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.
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.
The influenza A virus subtype H10N8 is an avian influenza virus. It is one of three H10 subtype avian influenza viruses isolated from domestic ducks in China, designated as SH602/H10N8, FJ1761/H10N3 and SX3180/H10N7.