Field sera were collected in a longitudinal study conducted
to estimate HPAI prevalence in farmed duck
populations [26]. In this study, 54 “moving” duck flocks
in 6 districts of Central Java, Indonesia, were sampled at
monthly intervals between November 2008 and April
2009 [26]. The highest bird-level seroprevalence was
observed in December 2008. Therefore, December 2008
represented the month with the largest range of HI titres
and serum samples collected in this month were used
for the current study. Sera from a total of 518 ducks
were available and were tested at the DIC Wates. From
all ducks also cloacal and an oropharyngeal swabs were
collected. The swab samples were then tested at the DIC
Wates in pools of five for subtype H5 virus RNA using
influenza RT-PCR as described in an earlier study [27].
All pools of our study birds tested H5 virus RNA
negative.