Avian influenza virus HA and NA subtype combinations detected in wild birds and poultry, the Netherlands, 2006 to 2011.

For wild birds, subtypes were based on virus isolates. For poultry, subtypes were based on antibody detection, virus detection and/or virus isolation. Numbers refer to wild birds and numbers between brackets refer to poultry farms. Subtype combinations indicated with an asterisk were significant more frequently detected in poultry than in wild birds, with * = P <0.05 and ** = P <0.01 (Fisher’s exact test).