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Bird Flu: WHO Timeline Of First Three Waves Of Outbreaks

A bird being vaccinated in Indonesia (epa) The following is the World Health Organization's (WHO) timeline of what it considers to have been the first three waves of the deadly H5N1 strain of bird flu, or avian influenza, beginning in mid-2003 and continuing into October 2005. Information related to bird flu cases in humans and corresponding research are presented in italics.

Early events in Asia

1996 -- Highly pathogenic H5N1 virus is isolated from a farmed goose in Guangdong Province, China.

1997 -- Outbreaks of highly pathogenic H5N1 are reported in poultry at farms and wet markets in Hong Kong. Human infections with H5N1 are reported in Hong Kong. Altogether, 18 cases (6 fatal) are reported in the first known instance of human infection with this virus.

February 2003 -- Two cases of H5N1 (one fatal) are confirmed in a Hong Kong family with a recent travel history to Fujian Province, China. A third family member died of severe respiratory disease while in mainland China, but no samples were taken.

Wave I

mid-2003 -- H5N1 virus begins to cause outbreaks in Asia, but these go undetected and unreported.

December 2003 -- Two tigers and two leopards, fed on fresh chicken carcasses, die unexpectedly at a zoo in Thailand. Subsequent investigation identifies H5N1 in tissue samples. This is the first report of influenza causing disease and death in big cats.

19 December 2003 -- Republic of Korea confirms highly pathogenic H5N1 as cause of poultry deaths at three farms.

8 January 2004 -- Vietnam reports H5N1 in poultry.

11 January 2004 -- Vietnam identifies H5N1 as cause of human cases of severe respiratory disease with high fatality. Sporadic cases are reported through mid-March.

12 January 2004 -- Japan reports H5N1 in poultry.

23 January 2004 -- Thailand reports H5N1 in poultry. Thailand reports two laboratory-confirmed cases of human infection with H5N1. Sporadic cases are reported through mid-March.

24 January 2004 -- Cambodia reports H5N1 in poultry.

27 January 2004 -- Lao PDR reports H5N1 in poultry.

1 February 2004 -- Investigation of a family cluster of cases that occurred in Vietnam in early January cannot rule out the possibility of limited human-to-human transmission.

2 February 2004 -- Indonesia reports H5N1 in poultry.

4 February 2004 -- China reports H5N1 in poultry.

20 February 2004 -- Anecdotal evidences suggests H5N1 infection in a single household of domestic cats in Thailand.

18 March 2004 -- Research: Case studies of 10 patients in Vietnam point to close contact with infected poultry as the probable source of infection in most cases, but conclude that, in two family clusters, limited human-to-human transmission within the family cannot be ruled out.

mid-March 2004 -- Reports of human cases end. In total, 12 cases (8 fatal) occurred in Thailand, and 23 cases (16 fatal) occurred in Vietnam.

Wave II

June-July 2004 -- China, Indonesia, Thailand, and Vietnam report recurrence of H5N1 in poultry.

8 July 2004 -- Research: Research identifies the dominant Z genotype in poultry, considers possible role of wild birds in spread, and concludes that H5N1 has found a new ecological niche in poultry but is not yet fully adapted to this host.

13 July 2004 -- Research shows that H5N1 has become progressively more lethal for mammals and can kill wild waterfowl, long considered a disease-free natural reservoir.

July 2004 -- A case report is published indicating atypical human H5N1 infection in Thailand (from March 2004), with fever and diarrhea but no respiratory symptoms. The report suggests that the clinical spectrum of disease may be broader than previously thought.

23 July 2004 -- Japan announces control of the H5N1 poultry outbreak and is considered disease-free by OIE.

7 August 2004 -- Malaysia reports H5N1 in poultry.

12 August 2004 -- Vietnam reports 3 new human cases, all fatal. Dates of hospital admission are from 19 July to 8 August.

20 August 2004 -- Chinese researchers report preliminary findings of H5N1 infection in pigs. No evidence suggests that pig infections are widespread, and the finding appears to have limited epidemiological significance.

2 September 2004 -- Research shows that domestic cats experimentally infected with H5N1 develop severe disease and can spread infection to other cats. Prior to this research, domestic cats were considered resistant to disease from all influenza A viruses.

7 September 2004 -- A 4th fatal case is reported in Vietnam.

9 September 2004 -- Thailand confirms a fatal case of human infection.

21 September 2004 -- Republic of Korea announces control of the H5N1 poultry outbreak and is considered disease-free by OIE.

28 September 2004 -- Thailand confirms 2 further human cases.

4 October 2004 -- Thailand confirms 4th human case.

11 October 2004 -- Outbreak begins in zoo tigers in Thailand said to have been fed chicken carcasses. In all, 147 tigers out of a population of 441 die or are euthanized.

22 October 2004 -- Highly pathogenic H5N1 is confirmed in two eagles illegally imported into Europe (Brussels) from Thailand.

25 October 2004 -- Thailand confirms 5th and final case in second wave.

29 October 2004 -- Research confirms that domestic ducks can act as silent reservoirs, excreting large quantities of highly pathogenic virus yet showing few if any signs of illness.

November 2004 -- No further human cases are reported. Altogether, 5 cases (4 fatal) occurred in Thailand, and 4 cases (4 fatal) occurred in Vietnam in this second wave.

Wave III

December 2004 -- Poultry outbreaks ongoing in Indonesia, Thailand, and Vietnam and possibly also in Cambodia and Lao PDR.

30 December 2004 -- Vietnam reports a new case.

3 January 2005 -- Malaysia (Peninsular) announces control of the H5N1 poultry outbreak and is now considered disease-free by OIE.

6 January 2005 -- Vietnam reports 2 further cases.

14 January 2005 -- Total cases in Vietnam rise to 6. Sporadic cases continue to be reported over the coming months, making Vietnam the hardest-hit country.

27 January 2005 -- Research concludes that a girl in Thailand probably passed the virus to at least her mother in September 2004, causing fatal disease. This is the first published account of probable secondary human transmission, resulting in severe disease, of any avian influenza virus.

2 February 2005 -- Cambodia reports its first human case, which is fatal.

17 February 2005 -- Research retrospectively identifies at least one fatal atypical case in Vietnam (from February 2004), presenting with diarrhea and encephalitis, but normal chest X-rays.

29 March 2005 -- Cambodia reports its 2nd case, also fatal.

12 April 2005 -- Cambodia reports its 3rd case, also fatal.

30 April 2005 -- Wild birds begin dying at Qinghai Lake in central China, where hundreds of thousands of migratory birds congregate. Altogether, 6,345 birds from different species die in the coming weeks.

4 May 2005 -- Cambodia reports its 4th case, also fatal.

8 June 2005 -- China reports poultry outbreak in Xinjiang Autonomous Region.

30 June 2005 -- A WHO investigative team finds no evidence that H5N1 has improved its transmissibility in humans in Vietnam.

6 July 2005 -- Research on viruses isolated from dead birds in Qinghai Lake suggests the outbreak was caused by a new H5N1 variant that may be more lethal to wild birds and experimentally infected mice.

14 July 2005 -- Research on viruses isolated from dead birds in Qinghai Lake demonstrates transmission of the virus among migratory geese and suggests that the virus may be carried along winter migratory routes.

15 July 2005 -- Tests on three civets that died in late June in Vietnam detect H5N1, marking the first infection of this species with the virus. The endangered Owston's palm civets were raised in captivity; source of infection is unknown.

21 Jul 2005 -- Indonesia reports its first human case. Infection in two other family members is considered likely, but cannot be laboratory confirmed. Subsequent investigation is unable to determine the source of infection.

23 July 2005 -- Russia reports outbreaks of highly pathogenic avian influenza, subsequently confirmed as H5N1, in poultry in western Siberia. The outbreak spreads to affect six administrative regions in Siberia. Dead migratory birds are reported in the vicinity of outbreaks.

2 August 2005 -- Kazakhstan reports an outbreak of highly pathogenic avian influenza, subsequently confirmed as H5N1, in poultry in areas adjacent to Siberia. Dead migratory birds are reported in the vicinity of outbreaks.

5 August 2005 -- Vietnam now has 64 confirmed cases in the third wave, of which 21 were fatal.

10 August 2005 -- China reports outbreak in Tibet Autonomous Region.

12 August 2005 -- Mongolia reports the death of 89 migratory birds at two lakes. H5N1 is subsequently identified in these birds.

16 September 2005 -- Indonesia confirms its 2nd case.

22 September 2005 -- Indonesia confirms its 3rd case.

29 September 2005 -- Indonesia confirms its 4th case. Research describes the clinical features of H5N1 infection and reviews recommendations for the management of cases.

October 2005 -- Research on the evolution of human and animal viruses circulating in Asia in 2005 suggests that several amino acids located near the receptor-binding site are undergoing change, some of which may affect antigenicity or transmissibility.

6 October 2005 -- Research describes reconstruction of the lethal 1918 pandemic virus, concludes that this virus was entirely avian, and finds some similarities with H5N1.

10 October 2005 -- Indonesia confirms its 5th case.

13 October 2005 -- Highly pathogenic H5N1 is confirmed in poultry in Turkey.

15 October 2005 -- Highly pathogenic H5N1 is confirmed in poultry in Romania.

20 October 2005 -- Taiwan reports the detection of highly pathogenic H5N1 in a cargo of exotic songbirds smuggled from mainland China. Thailand reports its first new case since 8 October 2004.

23 October 2005 -- Highly pathogenic H5N1 is confirmed in an imported parrot, held in quarantine in the United Kingdom, that died three days earlier.

24 October 2005 -- China reports outbreak in Anhui Province. Thailand and Indonesia report more cases.

26 October 2005 -- China reports outbreak in Hunan, making this the sixth province reporting outbreaks during 2005. Croatia confirms H5N1 in wild birds.

SOURCE: World Health Organization

Affected Areas

Affected Areas

Click on the map for a closer view of the areas within RFE/RL's broadcast region where cases of diseased fowl have been confirmed. Last updated on February 20.

BIRD FLU, or avian influenza, continues to menace scattered areas from East Asia, where the disease first appeared, to Southeastern and Eastern Europe and beyond. Authorities around the world are bracing themselves -- and, more importantly, planning and taking measures to fight the disease wherever it appears.

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