Avian Flu Timelines
Key scientific and political milestones from around the world, charting the first appearance of H5N1 avian flu in Hong Kong in 1997 to its global spread today, and links to archives.
scientific / medical milestones
- 1998
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September
- New flu drugs announced
- Trial results announced for two new influenza drugs that target the virus's neuraminidase enzyme, Relenza and Tamiflu, at the Interscience Conference on Antimicrobial Agents and Chemotherapy. (see 'Neuraminidase inhibitors take bite out of influenza').
- 1999
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March
- Frozen bodies from 1918 reveal bird flu origins
- Studies of bodies frozen in permafrost reveal sequence of the 1918 flu virus, which could have entered humans directly from birds (see 'Spanish 'flu' keeps its secrets').
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November
- New flu drugs licensed in US and Europe
- Two new flu drugs, Relenza and Tamiflu, are licensed in US and Europe. (see 'Competition between flu drugs feverishly anticipated').
- 2001
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WHO boost to flu surveillance
- The World Health Organization (WHO) outlines its new global laboratory proposal, aimed at improving the range, speed and quality of influenza virus surveillance. (see 'The flu HQ').
- 2004
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January
- H5N1 virus gets more virulent
- WHO is developing vaccine candidates using H5N1 viruses isolated in 2003 and 2004, at laboratories in the U.S. and U.K. (see 'Avian flu raises vaccine questions').
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June
- H5N1 vaccines in development
- Tests on chickens and mice show that avian flu H5N1 virus isolated from ducks in 2004 is more virulent and harmful to mammals than in recent years. (see 'Avian flu grows more virulent').
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July
- Domestic ducks in China are the origin of H5N1
- Domestic ducks in southern China are found to be the likely origins of the avian flu virus, H5N1, that caused the initial human outbreak in Hong Kong in 1997 and subsequent deaths in Thailand and Vietnam, and which is now endemic in the poultry of south east Asia. (see 'Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia').
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August
- H5N1 infection in Chinese pigs
- Chinese scientists report H5N1 avian flu infection in pigs, raising concerns that the virus could exchange genes with human flu strains in this 'mixing vessel'. (see 'Pigs test positive for bird flu').
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December
- Chicken genome sequence announced
- Sequencing of the chicken-genome may help provide insight into which genes prevent the spread of bird flu from person to person. (see 'A physical map of the chicken genome').
- 2005
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January
- Rapid tests for bird flu
- Chinese authorities announce they have developed a new rapid test for bird flu that produces results in hours rather than days.
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February
- H5N1 strains available for vaccine research
- WHO has made prototype H5N1 vaccine strains available to a number of institutions and companies and several vaccines have been developed for clinical testing. (see 'Bird flu 2005: the ongoing story').
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June
- H5N1 shows resistance to drugs
- Bird flu becomes resistant to the low-cost amantadine family of antiviral drugs. Chinese officials deny that this is due to the use of the compound in chickens by Chinese farmers. (see 'China's chicken farmers under fire for antiviral abuse').
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July
- H5N1 infects geese in China
- Scientists describe cases and transmission of H5N1 among migratory geese in Western China. (see 'Avian flu: H5N1 virus outbreak in migratory waterfowl').
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August
- Sales boost for flu drug
- Vaccine manufacturer fined for smuggling
- The flu drug Relenza has a boost in sales after The Lancet reports that it is at least as effective as Tamiflu, but has fewer side effects. Patients show no evidence of resistance compared with up to 18% of those taking Tamiflu. The report recommend stockpiling both drugs. (see 'Threat of pandemic brings flu drug back to life').
- Vaccine manufacturer Maine Biological Labs is fined $500,000 for smuggling a chicken flu virus into the US back in 1998 in order to develop a vaccine for a poultry farm in Saudi Arabia. (see 'Maine company falls a-fowl for smuggling bird flu').
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September
- Pandemic response needs to be fast and broad
- Two independent studies suggest it would be possible to contain an emerging pandemic if the virus was detected quickly, if it did not spread too fast, if sufficient antiviral drugs were deployed around the outbreak's epicentre, and if strict quarantine and other measures were used. (see 'Strategies for containing an emerging influenza pandemic in Southeast Asia').
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October
- Bird origin for 1918 'Spanish flu'
- Sequencing of the 1918 pandemic flu virus reveals that it is likely to have derived originally from birds (see 'The 1918 flu virus is resurrected').
- 2006
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January
- H5N1 mutates and infects humans more easily
- Scientists studying virus samples from the human outbreak of avian flu in Turkey have identified two mutations in the virus's sequence that may make the virus better adapted to humans. (see 'Alarms ring over bird flu mutations').
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April
- Domestic cats vulnerable to H5N1
- Scientists become increasingly concerned about the ability of domestic cats to become infected with the avian flu virus H5N1, as well as to excrete and transmit the virus to other cats, and raise the possibility that they may also have a role in spreading infection to humans and other species. (see 'Feline friend or potential foe?').
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May
- Migratory birds suspected initially of bringing H5N1 to Nigeria
- Scientists report that the highly pathogenic avian influenza virus strains found in farms in northern Nigeria and in Lagos state in February are likely to have arrived independently on at least three separate occasions, brought most likely by migratory birds, although trade cannot be ruled out. (see 'Avian Flu: Multiple introductions of H5N1 in Nigeria').
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August
- H5N1 vaccines fail to impress
- Preliminary results of tests in people of a vaccine against the H5N1 avian flu virus, show that two large doses should protect adults from infection.
- But critics note that vaccines that work at lower doses are urgently needed. (see 'Bird flu vaccine not up to scratch').
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September
- H5N1 deadliness blamed on "cytokine storm"
- New target for drug development
- A comparison of patients infected by the avian flu virus H5N1 with those suffering from human flu indicates that H5N1's deadliness is due to the strength of the immune response it triggers, including a 'cytokine storm'. (see 'Fatal outcome of human influenza A (H5N1) is associated with high viral load and hypercytokinemia').
- X-ray crystallography reveals a novel target in the H5N1 virus neuraminidase enzyme which could lead to the development of new drugs and overcome virus drug resistance. (see 'The structure of H5N1 avian influenza neuraminidase suggests new opportunities for drug design').
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November
- Scientists identify mutations that promote H5N1 infection in humans
- Scientists identify mutations that enable H5N1 viruses bind to human cells. These may serve as useful markers for assessing the pandemic potential of H5N1 samples isolated from birds. (see 'Haemagglutinin mutations responsible for the binding of H5N1 influenza A viruses to human-type receptors').
- 2007
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January
- Scientists pinpoint causes of H5N1 lethality
- Scientists for the first time study monkeys infected with a reconstructed version of the influenza virus that caused a worldwide pandemic in 1918. They find that the unprecedented lethality of the 1918 virus is linked to a massively over-reactive immune response in the host. (See 'Lethal infection of macaques with the 1918 influenza virus').
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April
- Three new H5N1 strains have emerged from a common source in China or Russia and spread west to Europe, the Middle East and North Africa
- A team of researchers spanning 11 countries have discovered that wild birds in Europe and north Africa are carrying 3 new strains of avian flu virus that have spread west, most likely from their origin in China or Russia. Some of the 36 samples studied harbour mutations linked to human deaths in 2006.
Emerging Infectious Diseases, 13 (5) May 2007
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May
- Antibodies from human survivors of avian flu offer a new therapeutic avenue
- The antibodies have been isolated from people who have recovered from infection, reproduced in the laboratory and shown to neutralise the H5N1 virus - at least in vitro and in mice.
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June
- Resistance to adamantanes is a by-product of escaping immune defences
- Researchers are surprised to find that resistance to adamantanes, which has risen to more than 90% in circulating influenza strains in the USA, is driven not by the use of antiviral drugs, but by selection pressure from the human immune system.
www.nature.com/news/2007/070618/full/070618-2.html
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July
- Europe approves the first cell-culture based influenza vaccine
- Produced from culture in canine kidney cells, the vaccine approved by the European Medicines Agency is the first of several in the pipeline aimed at speeding up manufacture of seasonal influenza vaccines. The traditional method involves the use of hens' eggs, which have to be specially produced and ordered up to 12 months in advance. Production of cell-based vaccines has the potential for greater flexibility in supply and demand, which is especially important in the event of a pandemic.
www.nature.com/news/2007/070702/full/nbt0707-701.html
- 2008
-
January
- Welcome to the Influenza Virus Tracking System (interim)
- The World Health Organization (WHO) is developing an electronic system to track influenza A(H5) viruses that have been shared by Member States with WHO through the Global Influenza Surveillance Network (GISN).
www.who.int/fluvirus_tracker
