Influenza a in humans. Influenza A (flu)

Type A Influenza: Symptoms, Treatment, and Prevention

influenza a in humans

This is mostly likely to affect the very young, the elderly, pregnant women, Indigenous people, and people with chronic health problems. Influenza A viruses are , single-stranded, segmented. Despite these varied shapes, the virions of all influenza type A viruses are similar in composition. Illness in people has ranged from mild to severe. Some subtypes are found in other infected animal species. Humans are the natural host for type B infection. There are 18 known types of hemagglutinin and 11 known types of neuraminidase, so, in theory, 198 different combinations of these proteins are possible.

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Influenza A virus

influenza a in humans

A variant of H1N1 was responsible for the Spanish flu pandemic that killed some 50 million to 100 million people worldwide over about a year in 1918 and 1919. Until now it is unclear whether these bat-derived viruses are circulating in any non-bat species and whether they pose a zoonotic threat. Before treating your condition, your doctor will need to check for the influenza virus. Similar to influenza A viruses, influenza B viruses can then be further classified into specific clades and sub-clades. . While in some milder cases the flu can resolve on its own without significant symptoms, severe cases of type A influenza can be life-threatening.

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Influenza A (flu)

influenza a in humans

Filamentous or intermediate sized particles simply extend along the long axis on the opposite side of the genome segments. This resulted in one of the variants eventually achieving higher fitness, becoming dominant, and in a brief interval of rapid , rapidly sweeping through the population and eliminating most other variants. Occasionally, viruses are transmitted from wild aquatic birds to domestic poultry, and this may cause an outbreak or give rise to human influenza. There are 18 different H subtypes and 11 different N subtypes. In 2011, researchers reported the discovery of an antibody effective against all types of the influenza A virus.

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Influenza A virus

influenza a in humans

About 100 molecules of neuraminidase are needed to make one virion. Influenza A is more serious than B and C. The seasonal is developed many months in advance of flu season. Furthermore, they are also the antigen proteins to which a host's antibodies can bind and trigger an immune response. Highly pathogenic avian influenza virus is on every top ten list available for potential agricultural bioweapon agents, generally following foot and mouth disease virus and Newcastle disease virus at or near the top of the list.

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Types of Influenza Viruses

influenza a in humans

H5N1 is endemic in birds in southeast Asia and represents a long-term pandemic threat. Two cases of humans with avian influenza have been confirmed in that region. Strains of all subtypes of influenza A virus have been isolated from wild birds, although disease is uncommon. However, when two or more damaged viruses infect the same cell multiple infection , viable progeny viruses can be produced provided each of the eight genomic segments is present in at least one undamaged copy. In this procedure, your doctor swabs your nose or throat.

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Types of Influenza Viruses

influenza a in humans

The seasonality of the disease in poultry, together with the control measures already implemented, are likely to reduce temporarily the frequency of H5N1 influenza outbreaks and the probability of human infection. There are 18 different known H H1 to H18 and 11 different known N antigens N1 to N11. Treatment is focused around relieving symptoms until your body clears the virus naturally. The spread of avian influenza A viruses from one ill person to another has been reported very rarely, and when it has been reported it has been limited, inefficient and not sustained. Testing is more accurate when the swab is collected during the first few days of illness. The hemagglutinin protein of the H1N2 virus is similar to that of the currently circulating H1N1 viruses, and the neuraminidase protein is similar to that of the current H3N2 viruses.

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Type A Influenza: Symptoms, Treatment, and Prevention

influenza a in humans

Subtypes are named by combining the H and N numbers — e. This is not always an option because it requires two blood specimens one taken during the first week of illness and another taken 3-4 weeks later. Growing avian influenza A viruses should only be done in laboratories with high levels of biosafety. About 3,000 matrix protein molecules are needed to make one virion. These antiviral medications are most effective when started within the first 48 hours of your illness.

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