APSS 2013 Proceedings - The University of Sydney

Aust. Poult. Sci. Symp. 2013.....24
Figure 3 - Seroconversion of breeders to IBH
The serological test was also used on broilers to generate data on airsacculitis
that showed sero-conversion to adenovirus of 89.6% of flocks with a low incidence of
airsacculitis at slaughter (Ankouche et al. 2007), indicating a high prevalence of
adenoviruses in normal broiler flocks in Quebec. We used the same test to generate
broiler data according to age. The data from selected flocks showed the patterns
illustrated in Figure 4. The data indicated maternal antibodies in a majority of flocks
before 15 days of age, no maternal antibodies between 18 and 25 days of age and
separation into two groups of flocks with and without seroconversion. Flocks bled at
the beginning of clinical symptoms did not show seroconversion. Interestingly, the
flocks with no seroconversion after 30 days of age were mainly from a company
complex with a more thorough cleaning and disinfection program than the rest of the
Quebec industry and which has never had a clinical case of IBH.
Data were also generated with the serological data for serotypes 8 and 11
showing that some serotypes are not transmitted or present if natural immunization is
used (Figure 5). A review of the serotypes and genotypes isolated in Canada showed
the high prevalence of serotypes 8 and 11 in these IBH outbreaks (Ojkic et al, 2008).
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