Avian flu (as well referred to as bird grippe or even avian grippe) occurs as nature and severity of influenza virus that is hosted by birds, but will live in many mintage of mammals. It was number one identified around Italy in the early 1900s and is now known to survive worldwide. Avian grippe viruses compose a Influenzavirus The genus of the Orthomyxoviridae family and come negative-stranded, segmented RNA viruses. The strain of the H5N1-type of avian grippe that emerged inside 1997 has been identified as the virtually all in all probability source of a first influenza pandemic.

Infection

Tries of avian flu might breed in various nature and severity of fauna, including birds, pigs, horses, seals, whales and humans. All the same, uncivilized fowl act as natural asymptomatic carriers, spreading it to more susceptible domesticated equities. Avian grippe spreads within everyone's thoughts & in manure. It might too exist as transmitted by exposed provender, water supply, devices & vesture; notwithstanding, no grounds to believe that a virus can hold up within swell cooked meat. A incubation period is 3 to Five years. Illness around beast alter, however virulent strains can cause dying inside two or three years.

Around human being, avian influenza is the causal agent of similar symptoms to other types of flu. [http://www.bupa.co.uk/health_information/html/health_news/270104avianflu.html] These include fever, cough, sore throat, muscle aches, conjunctivitis &, in severe instances, severe eupneic problems and pneumonia that may be deadly. the nature and severity of the nausea might depend to a big a portion on the state people individual's immune system & if a victim has been contaminated to the strain prior to, and is so partly resistant. Once, the son by having H5N1 had diarrhea followed rapidly by the coma without developing respiratory or even flu-such as illness, suggesting non-standard illness. [http://content.nejm.org/cgi/content/short/352/7/686]

Subtypes pathogenic to humans
Whole avian influenzThe (AI) viruses come nature and severity A flu in the virus personal of Orthomyxoviridae and all known subtypes of grippe The virus could breed in birds. Flu nature and severity The is subdivided into subtypes according to hemagglutinin (H) and neuraminidase (N) protein spikes from either a central virus core. There are SixteeNorth H types, apiece by having as much as Ix North subtypes, giving the likely for Gross different H & N combinations. Additionally, totally AI viruses fall into one of Deuce pathotypes: moo (LPAI) & high (HPAI) pathogenicity, based on their virulence in poultry populations.

These are despised that in case a avian flu virus undergoes antigenic shift to a point where it potty cross the mintage barrier (e.g., from either birds to homo), a newly subtype created can be two extremely contagious & extremely deadly inside human being. Such the subtype may induced the spherical pandemic similar to the Spanish Flu that killed as much as 50 million population inside 1918.

Even so, there are real transmitted differences between a subtypes that generally breed in two humans & birds. Inside subtypes of avian flu viruses there likewise come different strains. Avian flu H5 & H7 viruses may be incurred inside each "low pathogenic� or “high pathogenic� forms depending on genetic features and the severity of the illness they cause in poultry; influenza H9 virus has been identified only in a “low pathogenic� form.

H1N1
H1N1 was the first identified strain of Type A influenza. In early October 2005, researchers announced that they had successfully reconstructed the Spanish Flu virus. The gene sequence indicates that the 1918 epidemic was caused by H1N1, normally considered a strain of swine flu (which itself falls under avian influenza) that in this case passed directly from birds to humans. The reconstructed virus is very different from normal human viruses in that it infects lung cells which would normally be impervious to the virus [http://news.yahoo.com/s/ap/20051006/ap_on_he_me/pandemic_flu;_ylt=ApmVvpKqjuQsYrD46ESjkZms0NUE;_ylu=X3oDMTA3b2NibDltBHNlYwM3MTY-].

H5N1

H5N1 is a highly pathogenic form of avian influenza. Since 1997, outbreaks of H5N1 have caused the death or culling of tens of millions of birds. Over 100 people have been infected by H5N1, with a mortality rate of over 50%. H5N1 has been the focus of much concern amid warnings that the H5N1 strain will likely evolve into a form that causes a global human pandemic with a very high mortality rate.

Other strains
Since 1997 the H5N1, H7N2, H7N3, H7N7, and H9N2 have been confirmed in humans.

;H2N2 ;H3N2 ;H7N2 ;H7N3 ;H7N7 ;H9N2 Prevention and treatment

Although avian influenza in humans can be detected with standard influenza tests, these tests have not always proved reliable. In March 2005, the World Health Organization announced that seven people from Vietnam who initially tested negative for bird flu were later found to have carried the virus. All seven have since recovered from the disease. Currently (6/05) the most reliable test (microneutralization) requires use of the live virus to interact with antibodies from the patient's blood; because live virus is required, for safety reasons the test can only be done in a level three laboratory [http://www.canada.com/health/story.html?id=63cbe9ea-a151-4877-b1e1-aa522176ff6f].

Antiviral drugs are sometimes effective in both preventing and treating the disease, but no virus has ever been really cured in medical history. Vaccines, however, take at least four months to produce and must be prepared for each subtype.

Further, as a result of widespread use of the antiviral drug amantadine as a preventive or treatment for chickens in China starting in the late 1990s, some strains of the avian flu virus in Asia have developed drug resistance against amantadine [http://www.washingtonpost.com/wp-dyn/content/article/2005/06/17/AR2005061701214.html]. Chickens in China have received an estimated 2.6 billion doses of amantadine since early 2004. This use of amantadine for poultry goes against international livestock regulations, but China kept it secret until recently, in a manner reminiscent of the secrecy around the early spread of SARS.

Potential pandemic

The World Health Organization (WHO) has warned of a substantial risk of an influenza epidemic in the near future, most probably of the H5N1 type of avian influenza. In response, countries have begun planning in anticipation of an outbreak. While short-term strategies to deal with an outbreak focus on limiting travel and culling and vaccinating poultry, long-term strategies require substantial changes in the lifestyles of the most at-risk populations.

The WHO divides a pandemic into six phases, ranging from minimal risk of an outbreak to full scale pandemic. Most health authorities categorize the situation as of 2005 at Phase 3, by which is meant that human infections of a new sub-type has occurred but there is little evidence of sustained human-to-human transmission.