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

Abstract of research
OZ0608
The adoption of on-farm control measures by the poultry industry is needed to reduce the
number of Campylobacter-infected birds that enter processing plants, and therefore the
number of human cases of campylobacteriosis associated with poultry meat
consumption. Enhanced biosecurity on poultry farms would be expected to control other
zoonoses, for example Salmonella, and improve the health, productivity and welfare of
poultry flocks. However, the epidemiology of Campylobacter in poultry is complex and
the development of suitable control strategies is problematic. This project was designed
to meet this challenge by bringing together scientists from a range of disciplines including
bacteriology, epidemiology, statistics and socio-economics. A close collaboration with
industry will ensure timely communication of the research outputs and that a sustainable,
practical and cost-effective control package which is more likely to be adopted is
developed. The diversity of poultry production systems (e.g., conventional, organic and
free-range) will be addressed by the project.
In project OZ0608 a novel intensive, retrospective environmental testing strategy was
adopted, based on a design developed by DG Newell. A real-time PCR-based test was
developed and validated to allow rapid identification of flock colonising C. jejuni/coli
strains from DNA prepared from recovered colonies and aliquots of enriched cultures
from flock and environmental samples. This test was implemented during a preliminary
field study. Using a standardised sampling strategy, samples taken from the poultry
house and surrounding farm environment at each visit during the crop cycle were
enriched and plated, but in this new approach isolates and enriched cultures were then
stored at –80 o C until isolates were recovered from the faeces or caeca of the target flock.
A strain-specific probe was designed against the flock strain and used to screen DNA
prepared from the strain(s) first isolated from the chickens and compared with traditional
cultural isolation and characterisation of isolated colonies to determine potential sources
of flock colonising campylobacters. This approach was then used to determine potential
sources of flock colonisation in a large scale study involving 26 target flocks on 15 farms.
A practical control package was developed progressively throughout the project. A
qualitative farmer survey to determine the attitudes to the control of Campylobacter in
broiler flocks was conducted followed by a quantitative study of farmers‘ attitudes. Both
surveys were carried out to gain information on (i) current farm practices (ii) biosecurity
control measures currently in place and (iii) those that could be adopted as well as
constraints to adoption. The cost-effectiveness of a set of control measures were
evaluated using standard techniques of cost-effectiveness analysis. Ten interventions,
including hygiene barriers in anterooms, visitor restrictions, and the use of handwash and
alcohol sprays were put into place on two farms to help provide information on adoption
of control measures, effects on Campylobacter prevalence and time to establishment of
colonisation. Finally, a cross-sectional and longitudinal study was performed to
determine differences in time to colonisation between conventional flocks and organic
and free-range flocks. The information generated by these activities, together with the
Quantitative Risk Assessment and field studies were all used to inform the development
of a workable and cost-effective control package.
OZ0610
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