Timeline data on avian flu

* Timeline data on avian flu can be found at the article on the causative agent species called Influenza A virus.
* Timeline data on the global spread of the strain that is the current pandemic concern (called Asian lineage HPAI A(H5N1)) can be found at Global spread of H5N1.
* Timeline data on creation of a flu vaccine for H5N1 can be found at H5N1 clinical trials.

Subtypes of the causative agent species of avian flu include

* H1N1
* H1N2
* H2N2
* H3N2
* H3N8
* H5N1
* H5N2
* H5N3
* H5N8
* H5N9
* H5N8
* H7N1
* H7N2
* H7N3
* H7N4
* H7N7
* H9N2
* H10N7

Information concerning research about it can be found at

* Center for Biologics Evaluation and Research
* OIE/FAO Network of Expertise on Avian Influenza
* Flu research
* Flu vaccine
* H5N1 genetic structure
* ICEID
* Influenza Genome Sequencing Project
* Influenza pandemic
* Cytokine storm
* International Partnership on Avian and Pandemic Influenza
* National Influenza Centers
* Pandemic Preparedness and Response Act
* Reporting disease cases
* Transmission and infection of H5N1

Illustrative examples of correct usage

In technical contexts, correct usage of terms is necessary because precise distinctions are the essence of the communication.

* "Avian influenza strains are those well adapted to birds"[1]
* "An outbreak of influenza A (H5N1), also known as 'avian flu' or 'bird flu,' has been reported in several countries throughout Asia."[10]
* "Avian influenza virus usually refers to influenza A viruses found chiefly in birds, but infections can occur in humans."[11]
* "Of the few avian influenza viruses that have crossed the species barrier to infect humans, H5N1 has caused the largest number of cases of severe disease and death in humans. Unlike normal seasonal influenza, where infection causes only mild respiratory symptoms in most people, the disease caused by H5N1 follows an unusually aggressive clinical course, with rapid deterioration and high fatality." Seasonal influenza is human flu.[12]
* "avian influenza HA bind alpha 2-3 sialic acid receptors while human influenza HA bind alpha 2-6 sialic acid receptors. Swine influenza viruses have the ability to bind both types of sialic acid receptors."[13]
* Sometimes a virus contains both avian adapted genes and human adapted genes. Both the H2N2 and H3N2 pandemic strains contained avian flu virus RNA segments. "While the pandemic human influenza viruses of 1957 (H2N2) and 1968 (H3N2) clearly arose through reassortment between human and avian viruses, the influenza virus causing the 'Spanish flu' in 1918 appears to be entirely derived from an avian source (Belshe 2005)."[2]

[edit] Illustrative examples of imprecise usage

In nontechnical contexts, imprecise usage of terms is typical when discussing complex things.

* "A 1,000 square mile quarantine zone to combat an outbreak of bird flu was lifted in Scotland today - despite the spread of a similar disease south of the border." Here "bird flu" is used to mean "Asian lineage HPAI A(H5N1) flu" (which is a bird flu) and contrasted with flu from an avian adapted strain of H7N3 (which is also a bird flu).[14]

H5N1

, "avian flu" is being commonly used to refer to infection from a particular subtype of Influenza A virus, H5N1, which can cause severe illness in humans who are infected. Currently, this strain is transmitted by contact with infected birds, and has been transmitted from one person to another only in a few cases. H5N1 flu is therefore not pandemic now and is not currently capable of causing a pandemic. Only if H5N1 mutates into a form that can be readily transmitted from one person to another could it cause a pandemic.

Low Pathogenic versus Highly Pathogenic Avian Influenza A Viruses

Avian influenza A virus strains are further classified as low pathogenic (LPAI) or highly pathogenic (HPAI) on the basis of specific molecular genetic and pathogenesis criteria that require specific testing. Most avian influenza A viruses are LPAI viruses that are usually associated with mild disease in poultry. In contrast, HPAI viruses can cause severe illness and high mortality in poultry. More recently, some HPAI viruses (e.g., H5N1) have been found to cause no illness in some poultry, such as ducks. LPAI viruses have the potential to evolve into HPAI viruses and this has been documented in some poultry outbreaks. Avian influenza A viruses of the subtypes H5 and H7,including H5N1, H7N7, and H7N3 viruses, have been associated with HPAI, and human infection with these viruses have ranged from mild (H7N3, H7N7) to severe and fatal disease (H7N7, H5N1). Human illness due to infection with LPAI viruses has been documented, including very mild symptoms (e.g., conjunctivitis) to influenza-like illness. Examples of LPAI viruses that have infected humans include H7N7, H9N2, and H7N2.
In general, direct human infection with avian influenza viruses occurs very infrequently, and has been associated with direct contact (e.g., touching) infected sick or dead infected birds (domestic poultry).

Human Influenza Viruses and Avian Influenza A Viruses

Humans can be infected with influenza types A, B, and C viruses. Subtypes of influenza A that are currently circulating among people worldwide include H1N1, H1N2, and H3N2 viruses.

Wild birds are the natural host for all known subtypes of influenza A viruses. Typically, wild birds do not become sick when they are infected with avian influenza A viruses. However, domestic poultry, such as turkeys and chickens, can become very sick and die from avian influenza, and some avian influenza A viruses also can cause serious disease and death in wild birds.

Types, Subtypes, and Strains

There are three types of influenza viruses: A, B, and C. Only influenza A viruses are further classified by subtype on the basis of the two main surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Influenza A subtypes and B viruses are further classified by strains.

Avian influenza virus

usually refers to influenza A viruses found chiefly in birds, but infections can occur in humans. The risk is generally low to most people, because the viruses do not usually infect humans. However, confirmed cases of human infection have been reported since 1997.…more