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Title: Experimental infection with low and high pathogenicity H7N3 Chilean avian influenza viruses in Chiloe Wigeon (Anas sibilatrix) and Cinnamon Teal (Anas cyanoptera)

Author
item Sa E Silva, Mariana
item MATHIEU, CHRISTIAN - University Of Chile
item KWON, YONGKUK - National Institute Of Animal Science
item Pantin Jackwood, Mary
item Swayne, David

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2011
Publication Date: 9/27/2011
Citation: Sa E Silva, M., Mathieu, C.M., Kwon, Y., Pantin Jackwood, M.J., Swayne, D.E. 2011. Experimental infection with low and high pathogenicity H7N3 Chilean avian influenza viruses in Chiloe Wigeon (Anas sibilatrix) and Cinnamon Teal (Anas cyanoptera). Avian Diseases. 55(3):459-461.

Interpretive Summary: In 2001, a H7N3 low pathogenic avian influenza (LPAI) virus was isolated from a healthy cinnamon teal in Bolivia and in 2002, close genetically related H7N3 LPAI and high pathogenicity avian influenza (HPAI) viruses were isolated from infected poultry in Chile. In our study, two wild duck species (Chiloe wigeon and cinnamon teal), were exposed to H7N3 avian influenza (AI) viruses obtained from the 2002 Chilean outbreak. Both bird species became infected when given the virus in the nose, but the virus only spread to cinnamon teal housed in the same cage. None of the infected birds developed disease. This suggests the cinnamon teal could have been the primordial reservoir and transport host for the H7N3 Chilean outbreak virus.

Technical Abstract: Since 2002, H5N1 high pathogenicity avian influenza (HPAI) viruses have been associated with natural, lethal infections in wild aquatic birds which have been reproduced experimentally. Some aquatic bird species have been suggested as potential transporters of H5N1 HPAI virus via migration. However, a similar wild bird potential infectivity and spread for the 2002 Chilean H7N3 low pathogenicity avian influenza (LPAI) and HPAI viruses is unknown, but the closest viral relative was an H7N3 LPAI virus isolated from a migratory duck, a cinnamon teal, in Bolivia in 2001. Two different wild duck species common in Chile and neighboring countries, chiloe wigeon (Anas sibilatrix) and cinnamon teal (Anas cyanoptera), were intranasally inoculated with 10*6 mean infective doses (EID50) of LPAI virus (A/chicken/Chile/176822/02) or HPAI virus (A/chicken/Chile/184240-1/02), in order to study the infectivity, transmissibility and pathobiology of these viruses. None of the virus inoculated ducks had clinical signs or died, but most seroconverted by 14 days, indicating a productive virus infection. Both LPAI and HPAI viruses were isolated from oral swabs from two out of eight chiloe wigeons and from oral and/or cloacal swabs from all of the cinnamon teals at day 2 post inoculation. The virus was efficiently transmitted to cinnamon teal contacts but not to chiloe wigeon contacts. This study demonstrates that the cinnamon teal was susceptible to infection with both Chilean H7N3 LPAI and HPAI viruses, and potentially could have been involved as a primordial reservoir and transport host.