Discussion
A key assumption of this study was that HPAI H5N1 is endemic in
Purbalingga District. The concept of endemicity assumes firstly that the
virus is permanently present. H5 virus was detected throughout the
period of active sampling, and in all enterprise types (albeit at very
low levels in backyard and commercial poultry). Therefore, we conclude
that H5N1 HPAI may be assumed to be endemic in Purbalingga District, and
that all poultry enterprise types have at least the potential to
contribute to HPAI spread and persistence. Extrapolating this, if the
conditions in Purbalingga District can be considered representative of a
wider area (e.g. Java), it is likely that H5N1 HPAI is endemic in this
wider area (although it may not be endemic in all areas, all year
round).