Table 1.
Avian influenza virus prevalence in wild birds in the Netherlands, 2006–2011.
Total number of wild birds sampled for virus detection in time presented per month (A) and per year (B).
Table 2.
Avian influenza virus seroprevalence in poultry in the Netherlands, 2007–2009.
Total number of poultry farms sampled for antibody detection in time presented per month (A) and per year (B).
Table 3.
The total number of avian influenza viruses isolated from poultry in the Netherlands between 2006 and 2011 with their genetically closest relatives based on genetic analyses of the hemagglutinin and neuraminidase gene segment.
Fig 1.
Avian influenza virus subtype distribution in wild birds and poultry, the Netherlands, 2006–2011.
Subtype distribution shown for poultry and wild bird species for the hemagglutinin, HA (A) and neuraminidase, NA (B). Distribution based on 70 poultry cases (70 HA and 32 NA known) and 542 wild bird virus isolates (i.e. 250 mallards, 20 other ducks, 40 geese, 16 swans, 201 gulls and 15 waders). Subtype distribution in wild birds in time shown for the HA (C) and NA (D) was based on virus isolates. Subtype distribution in poultry in time shown for the HA (E) and NA (F) was based on antibody detection and/or virus isolation. Black dots indicated number of virus positive farms per month.
Table 4.
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).
Fig 2.
Wild bird distribution and environmental characteristics near primary infected, secondary infected and avian influenza virus negative poultry farms in the Netherlands.
For poultry farms located near bird monitoring areas (n = 703: consisting of 6 primary infected, 19 secondary infected and 678 AIV negative farms) number of mallards (A), Eurasian wigeons (B) and greater white-fronted geese (C) within 1000 meters around farms (mean±SE) was investigated. For all poultry farms (n = 2,064: consisting of 18 primary infected, 47 secondary infected and 1,999 AIV negative farms) surface of water (D), forest (E) and farmland (F) within 100 meters around farms (mean±SE) was investigated. Black bars indicates primary infected farms, grey indicates secondary infected farms and white indicates AIV negative farms. Asterisk indicates statistically significant differences (P < 0.05, Mann-Whitney test).