Avian influenza A virus (H7N7) epidemic in The Netherlands in 2003: course of the epidemic and effectiveness of control measures.
An epidemic of high-pathogenicity avian influenza (HPAI) A virus subtype H7N7 occurred in The Netherlands in 2003 that affected 255 flocks and led to the culling of 30 million birds. To evaluate the effectiveness of the control measures, we quantified between-flock transmission characteristics of the virus in 2 affected areas, using the reproduction ratio Rh. The control measures markedly reduced the transmission of HPAI virus: Rh before detection of the outbreak in the first infected flock was 6.5 (95% confidence interval [CI], 3.1-9.9) in one area and 3.1 in another area, and it decreased to 1.2 (95% CI, 0.6-1.9) after detection of the first outbreak in both areas. The observation that Rh remained >1 suggests that the containment of the epidemic was probably due to the reduction in the number of susceptible flocks by complete depopulation of the infected areas rather than to the reduction of the transmission by the other control measures.
Stegeman
Arjan
A
Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. j.a.stegeman@vet.uu.nl
Bouma
Annemarie
A
Elbers
Armin R W
AR
de Jong
Mart C M
MC
Nodelijk
Gonnie
G
de Klerk
Fred
F
Koch
Guus
G
van Boven
Michiel
M
D000818:Animals; D004196:Disease Outbreaks / Q000517:prevention & control / Q000662:veterinary*; D053126:Influenza A Virus, H7N7 Subtype; D009980:Influenza A virus / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D015233:Models, Statistical; D009426:Netherlands / Q000453:epidemiology; D011200:Poultry