Past Outbreaks of Avian Influenza in North America
- Avian influenza A viruses are routinely detected in wild birds. Around the world and in North America, avian influenza A outbreaks occur in poultry from time to time.
- Outbreaks of some avian influenza A viruses in poultry have been associated with illness and death in humans in Asia, Africa, Europe, the Pacific, and the Near East.
- While very rare, some avian influenza A viruses have also caused illness in humans in North America.
North American Outbreaks Among Poultry With No Known Transmission to Humans
Low pathogenic avian influenza A outbreaks
Since 1997, based on the World Organization for Animal Health (OIE) reporting criteria for avian influenza in commercial poultry, the United States has experienced sporadic incidents of low pathogenic avian influenza (LPAI) in commercial poultry.
Information about LPAI outbreaks that have occurred in North America (including the United States) and around the world since January 2005 can be found on the World Organisation for Animal Health (OIE) web site in the World Animal Health Information Database (WAHID). Information about LPAI outbreaks that have occurred in North America (including the United States) and around the world before January 2005 can be found on the World Organisation for Animal Health (OIE) web site in the World Animal Health Information Database (WAHID) Handistatus II.
Highly pathogenic avian influenza A outbreaks
Since 1997, based on the World Organization for Animal Health (OIE) reporting criteria for avian influenza in commercial poultry, the United States has experienced one incident of highly pathogenic avian influenza (HPAI) in poultry that was restricted to one poultry farm.
H5N2 in Texas, 2004
In February 2004, an outbreak of HPAI (H5N2) virus was detected and reported in a flock of 7,000 chickens in south-central Texas. This was the first outbreak of HPAI in the United States in 20 years.1,2 No transmission of HPAI (H5N2) virus to humans was reported.
Avian Influenza A Virus Transmission to Humans in North America
Outbreaks of some avian influenza viruses among poultry have been associated with illness and death in humans in Asia, Africa, Europe, the Pacific, and the Near East. While very rare, avian influenza A viruses have also caused illness in humans in North America.
H7N3 in Canada, 2004
On February 19, 2004, the Canadian Food Inspection Agency announced an outbreak of avian influenza A (H7N3) in poultry in the Fraser Valley region of British Columbia. Culling operations and other measures were performed in an effort to control the spread of the virus. This was initially a LPAI outbreak that evolved into an HPAI outbreak. Health Canada reported two cases of laboratory-confirmed influenza A (H7): one in a person involved in culling operations on March 13-14, and the other in a poultry worker who had close contact with poultry on March 22-23. Both patients developed conjunctivitis (eye infection) and mild illness. Their illnesses resolved after treatment with the antiviral medication oseltamivir.3,4
Although these are the only laboratory-confirmed cases of avian influenza A (H7) in humans during this outbreak in Canada, approximately 10 other poultry workers exhibited conjunctival and/or upper respiratory symptoms after having contact with poultry. Use of personal protective equipment is mandatory for all persons involved in culling activities, and compliance with prescribed safety measures is monitored. For more information about this outbreak, visit the Canadian Food Inspection Agency website.
H7N2 in New York, 2003
In November 2003, a case of avian influenza A virus infection was detected in an adult male from New York, who was hospitalized for respiratory tract illness. A low pathogenic avian influenza A (H7N2) virus was isolated from a respiratory specimen from the patient. The patient’s acute symptoms resolved. The source of this person's infection is unknown.5,6
H7N2 in Virginia, 2002
In 2002, a person involved with culling activities developed influenza-like illness when a low pathogenic avian influenza A (H7N2) outbreak occurred among turkeys and chickens at commercial farms in Virginia. Serological testing confirmed infection with avian influenza A (H7N2) virus; no human-to-human transmission was evident and the person made a full recovery.5,7Top of Page
- Pelzel AM, McCluskey BJ, Scott AE. Review of the highly pathogenic avian influenza outbreak in Texas, 2004. J Am Vet Med Assoc. 2006 Jun 15;228(12):1869-75.
- Lee CW, Swayne DE, Linares JA, et al. H5N2 avian influenza outbreak in Texas in 2004: the first highly pathogenic strain in the United States in 20 years? J Virol. 2005 Sep;79(17):11412-21.
- Skowronski DM, Tweed SA, Petric M, et al. Human illness and isolation of low-pathogenicity avian influenza virus of the H7N3 subtype in British Columbia, Canada. J Infect Dis. 2006 Mar 15;193(6):899-900.
- Tweed SA, Skowronski DM, David ST, et al. A. Human illness from avian influenza H7N3, British Columbia. Emerg Infect Dis. 2004 Dec;10(12):2196-9.
- CDC. Update: Influenza Activity --- United States and Worldwide, 2003—04 Season, and Composition of the 2004—05 Influenza Vaccine. MMWR 2004; 53(25).
- Ostrowsky B, Huang A, Terry W, et al. Low Pathogenic Avian Influenza A (H7N2) Virus Infection in Immunocompromised Adult, New York, USA, 2003. Emerg Infect Dis. 2012 Jul;18(7):1128-31.
- Edwards LE, Terebuh P, Adija A, et al. Serological diagnosis of human infection with avian influenza A (H7N2) virus [Abstract 60, Session 44]. Presented at the International Conference on Emerging Infectious Diseases 2004, Atlanta, Georgia, February 22--March 3, 2004.
- Page last reviewed: June 21, 2012
- Page last updated: June 21, 2012
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