Science: Avian Influenza (updated Feb. 16, 2007)
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Updated: Feb. 16, 2007
The UK authorities on Feb. 5, 2007, culled around 160,0000 turkeys after the highly pathogenic H5N1 strain of avian influenza ("bird flu") was discovered on a farm in the village of Holton, in the county of Suffolk, in eastern England. Workers at the infected farm, which was owned by Bernard Matthews Ltd, Europe’s largest turkey producer, were offered anti-viral drugs and restrictions were imposed on the way that birds were housed and transported, whilst a buffer zone with a radius of 3km was created around the area of infection.
Immediate context
The infection was the second UK case of the H5N1 strain (and the first in domestic poultry) and the second reported case of the highly pathogenic strain in the EU in 2007, after Hungary reported an outbreak in a flock of geese in January. The first UK case of the H5N1 strain was confirmed in April 2006, when a wild swan was found dead in the Scottish coastal village of Cellardyke in Fife. Although there were no reported infections in humans in the latest outbreak, more than 241 people had been infected with H5N1 since 2003, most of them in east Asia, and over half had died from the disease. In February 2005, the World Health Organisation (WHO) had warned that a global pandemic of influenza based on the avian influenza virus "...may be imminent". The organisation called on countries to stockpile anti-viral drugs and advised that a pandemic could kill between seven and one hundred million people. The "bird flu" virus also created political problems for governments, including the ruling coalition in Romania, which in June 2006 defeated a no-confidence motion tabled by opposition legislators, who had accused the government of a "chaotic reaction" to an outbreak of avian influenza in the country. A state of emergency was declared in Ukraine in December 2005 after the H5N1 strain of "bird flu" was detected in domestic birds there. US President George W Bush had in November 2005 presented details of a US$7.1 billion plan to improve the country’s response to a potential global outbreak of "bird flu".
Reaction and outlook
Markos Kyprianou, the EU Health and Food Safety Commissioner, warned that "we should never feel that we are safe" from avian influenza, adding that the EU would "probably" suffer "more outbreaks" of the H5N1 virus in 2007. Nigel Dimmock, a leading UK-based virologist, believed the UK faced "more outbreaks" if the latest infection was found to have been caused by a wild bird. Within days of the culling of turkeys at Holton, three workers involved in the slaughter fell ill with respiratory problems, but all three later tested negative for the human form of "bird flu". Dr Jonathan van Tam of the UK Health Protection Agency said on Feb. 7 that it was very unlikely that any workers would test positive for "bird flu" because the authorities had taken all of the "necessary precautions" to protect them.
Historical context
Authorities in the Hong Kong Special Administrative Region (HKSAR) announced in December 1997 that they intended to slaughter 1.25 million chickens in the territory in order to contain the spread of the H5N1 variant of the "bird flu" virus, which had caused six deaths in Hong Kong and aroused fears of a global pandemic. There was evidence that the H5N1 virus had grown more virulent since the 1997-98 outbreak in Hong Kong. The virus appeared to have acquired the ability to replicate in mammals such as cats and pigs. US and UK researchers who had studied lung tissue from victims of the 1918 influenza pandemic reported in February 2004 that it was likely that the 1918 pandemic, responsible for 20 million to 40 million deaths worldwide, had started as a form of bird flu. In late January 2004 the first cases of human infection with the avian flu strain variant H5N1 were reported in Vietnam and Thailand. These human cases of the disease were transmitted through contact with infected poultry. In late September 2004, the first case of suspected human to human infection was reported.
Timeline links:
- October 2006 Two Indonesian laboratories announce that a 27-year-old woman who died in Central Java province was the 55th person in the country to die from the H5N1 avian influenza virus ("bird flu").
- June 2006 The ruling coalition in Romania defeats a no-confidence motion tabled by the opposition Social Democratic Party (PSD), which had accused the government of, amongst other things, a "chaotic reaction" to an outbreak of avian influenza ("bird flu").
- April 2006 In China the government confirms the country's 17th and 18th cases of avian influenza ("bird flu") in humans.
- April 2006 The first UK case of the H5N1 strain is confirmed when a wild swan is found dead in the Scottish coastal village of Cellardyke in Fife.
- March 2006 The World Health Organisation (WHO) announces that the H5N1 strain of avian influenza ("bird flu") has killed five young people in Azerbaijan since Feb. 23; the new global total of confirmed deaths from H5N1 rises to 103 people.
- March 2006 Tests conducted by the World Health Organisation (WHO) confirm that the death of a 10-month-old baby was caused by the H5N1 virus.
- February 2006 The World Health Organisation (WHO) director in Vietnam, Hans Troedsson, says that although Vietnam has been the country worst hit by the H5N1 avian influenza virus (bird flu), it is as also the first to contain it successfully.
- February 2006 Russian scientists claim to have successfully adapted the gamma-interferon vaccine against the H5N1 strain of avian influenza virus; The Lancet medical journal reports that a US research team has succeeded in protecting mice against infection by the H5N1 virus.
- January 2006 Turkey reports its first human cases of the potentially fatal H5N1 strain of avian influenza ("bird flu").
- December 2005 In Ukraine a state of emergency is declared in three regions of the Crimean peninsula after the H5N1 strain of "bird flu" is detected in domestic birds there.
- November 2005 US President George W Bush presents details of a US$7.1 billion plan to improve the US response to a potential global outbreak of bird flu.
- October 2005 Romania reports the first cases of avian influenza (bird flu) in Europe, raising fears that the deadly virus is spreading rapidly along bird migratory routes from Asia.
- October 2005 It is confirmed in Thailand that a 48-year-old man has died from the H5N1 virus.
- October 2005 The EC introduces measures to combat bird flu.
- September 2005 Bird flu death toll rises to six in Indonesia.
- July 2005 An international conference on avian influenza is held.
- June 2005 China confirms bird flu outbreak in Xinjiang Uighur Autonomous Region.
- May 2005 Chinese authorities conduct cull of birds and cattle.
- May 2005 Minister is dismissed after North Korean outbreak.
- May 2005 WHO introduces new regulations on controlling epidemics.
- April 2005 The 50th victim of avian influenza dies in Vietnam.
- February 2005 Vietnam appeals for UN help with H5N1 avian influenza outbreak.
- February 2005 WHO warns of risk of avian influenza pandemic with between seven and million and 100 million deaths.
- January 2005 One million birds are culled in Vietnam; 12th human victim is confirmed.
- December 2004 Japanese authorities confirm first human case of avian flu in Japan.
- September 2004 Strains of H5NI virus are detected in the bodies of pigs in China.
- September 2004 Thailands records a suspected case of human-to-human transmission.
- September 2004 WHO criticises vaccine manufacturers for doing too little to prepare for a potential avian flu pandemic.
- August 2004 Avian influenza returns to Vietnam.
- July 2004 The H5N1 strain of the bird flu virus is confirmed in China’s Anhui province.
- March 2004 WHO summit on avian influenza warns of "inevitable" influenza pandemic.
- March 2004 China claims to have "stamped out" avian influenza.
- February 2004 Chinese authorities confirm outbreak of H5N1 virus among poultry in the southern province of Guangdong; National Bird Flu Prevention Headquarters established.
- February 2004 Reports indicate that H5N1 virus has spread to feline species.
- February 2004 WHO reports possible first case of human to human H5N1 infection.
- February 2004 FAO Emergency meeting on avian influenza is held; 32 cases of the H5N1 virus infecting humans are confirmed, all in Thailand or Vietnam.
- February 2004 Researchers reconstruct the protein that enabled a strain of avian influenza to infect humans in 1918.
- January 2004 Chinese authorities order the mass slaughter of poultry following outbreaks of avian influenza in south-east Asia.
- January 2004 Japan, EU and other countries ban poultry imports from Thailand.
- January 2004 Deaths in Vietnam are linked to H5N1 avian influenza; WHO considers it unlikely that the virus could be transmitted from person to person.
- January 2004 Outbreak of bird flu in Indonesia leads to cull of 4.7 million chickens.
- May 2003 An outbreak of avian influenza in Germany.
- April 2003 An outbreak of avian influenza in the Netherlands.
- April 2003 An outbreak of avian influenza in Belgium.
- February 2003 H5N1 is confirmed in human death in Hong Kong.
- February 2002 Hong Kong authorities slaughter 860,000 chickens to check the spread of avian influenza.
- May 2001 Hong Kong authorities announce completion of a cull of 1.25 million chickens, geese, ducks, pigeons, and quail.
- December 1997 Authorities in the Hong Kong Special Administrative Region (HKSAR) announce plans to slaughter 1.25 million chickens in the territory in response to H5N1 outbreak.
