Diagnostic test results and pathology associated with the 2007 Canadian H7N3 highly pathogenic avian influenza outbreak.
In September 2007, an H7N3 highly pathogenic avian influenza outbreak (HPAI) occurred on a multiple-age broiler breeder operation near Regina Beach, Saskatchewan, Canada. Mortality was initially observed in a barn that housed 24-wk-old roosters, with later involvement of 32-wk-old breeders. All birds on the affected premises were destroyed, and surveillance of surrounding farms demonstrated no further spread. The use of water from a dugout pond during periods of high demand, and the proximity of the farm to Last Mountain Lake, the northern end of which is a bird sanctuary, implicated wild aquatic birds as a possible source of the virus. Of particular note, the H7-specific real-time reverse transcription polymerase chain reaction assay that was in use at the time did not detect the virus associated with this outbreak. A Canadian national influenza A virus survey of wild aquatic birds detected no H7 subtype viruses in 2005 and 2006; however, H7 subtype viruses were detected in the fall of 2007. Phylogenetic analysis of a number of these H7 isolates demonstrated an evolutionary relationship with each other, as well as with the H7N3 HPAI virus that was isolated from the Saskatchewan broiler breeder farm.
Pasick
J
J
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, Manitoba R3E 3M4, Canada. jpasick@inspection.gc.ca
Berhane
Y
Y
Hisanaga
T
T
Kehler
H
H
Hooper-McGrevy
K
K
Handel
K
K
Neufeld
J
J
Argue
C
C
Leighton
F
F
D000818:Animals; D002170:Canada / Q000453:epidemiology; D002645:Chickens; D004196:Disease Outbreaks / Q000662:veterinary*; D009980:Influenza A virus / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology; D010802:Phylogeny