Intervention strategies for low-pathogenic avian influenza control in Italy

Italian poultry production was affected by several outbreaks of low-pathogenicity avian influenza (LPAI) between 2000 and 2005. Intervention measures (IM), such as stamping out of infected and suspected farms, controlled marketing, restocking bans, movement restriction, and emergency vaccination, were put into force in the most affected areas of Lombardia and Veneto regions. These two regions also showed differences in terms of measures applied and timeliness of application. In this study we describe the epidemics and discuss the effectiveness of the IM put into effect. The regional surveillance systems provided the data on the epidemics and the IM description. The IM effectiveness was compared between the different epidemics and the Lombardia and Veneto regions, considering the number of farms involved, the duration of the epidemics, and the extension of the area affected. With regard to the IM applied, reductions in the number of outbreaks (from 388 in 2002-03 to 15 in 2005), the duration of the outbreaks (from more than 1 yr to approximately 1 mo), and the spatial extension of the outbreaks (from 89 to 8 municipalities involved) were observed. The emergency vaccination, depopulation, and pre-emptive slaughtering reduced significantly the spread of the epidemic. Comparing the dynamics of the epidemics, more effective results were observed in the Veneto region, where the IM were applied to a greater extent. Emergency vaccination and depopulation were effective in the eradication of the disease during an epidemic, but vaccination and farm density reduction showed the most effective results in controlling the spread of LPAI.