Review of the Food-borne Zoonoses Research ... - ARCHIVE: Defra

Project code: OZ0609
Project title: Determining the role of maternal antibodies in the lag
phase of Campylobacter jejuni infection in chickens.
Start date (dd/mm/yy): 01/05/2005
End date (dd/mm/yy): 31/05/2006
£50,012
Total cost:
Affiliation: Veterinary Laboratories Agency
Sub-contractor(s):
Abstract of research
Campylobacter jejuni is the leading cause of bacterial enteritis in the UK. The handling
and/or consumption of contaminated poultry meat is believed to be a risk factor. The
avian intestine is considered the natural environment for the organism, and up to 90% of
poultry flocks in the UK are colonised asymptomatically. Thus, reduction or elimination of
the organism in poultry in order to reduce the number of human cases is an objective of
DEFRA and FSA. A number of intervention strategies have been proposed, including
increased bio-security, vaccination and competitive exclusion. Increased bio-security
alone has so far failed to consistently reduce the extent of colonisation, so a multipronged
approach would seem to offer the most promise. Commercial birds tend to
exhibit a lag-phase of infection, wherein they usually remain uncolonised during the first
2-3 weeks of life. Thereafter the organism spreads rapidly through the flock. The lagphase
represents a window-of-opportunity to apply intervention strategies. Moreover,
understanding the under-lying mechanisms could help in the development of successful
strategies. One likely contributory factor to the lag-phase, maternally-derived immunity,
was investigated. Previous DEFRA-funded work indicated that the susceptibility of
commercial birds to colonisation is inversely proportional to the levels of anti-C. jejuni
antibodies present in the chicks. These antibodies are vertically transmitted from infected
breeder hens. Their levels decline to background during the first 3-4 weeks of life. The
role of maternal immunity was studied by looking at the susceptibilities to colonisation of
chicks derived from SPF and commercial flocks and from experimental hens colonised
and uncolonised by C. jejuni.
Review summary
The role of the humoral antibody response, including passive transfer of maternal
antibodies, remains unclear, making development of a vaccine to prevent poultry
colonisation with Campylobacter more difficult. This project has contributed to filling this
knowledge gap, confirming that maternal antibodies play a role in the colonisation lag
phase, but that other unknown factors are also involved. It has also shown that any
exposure of very young chicks to campylobacter will result in colonisation. The results of
this work have assisted in formulation of policy, suggesting that attempting to keep
breeding stock free of campylobacter may not be a useful strategy in the effort to reduce
human campylobacteriosis.
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