On farm epidemiology of major enteric diseases
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Research partners: University of Nottingham
Sponsors: BPEX
Duration: 2006 – 2009
View the final report here
Overview
The objective of this project was to achieve a better understanding of the transmission of diseases by vectors on pig farms by studying their role in the epidemiology and control of key diseases – Lawsonia, PCV 2b and Brachyspira.
A set of case study farms was constructed in 2007 to include the following: mixed-age farms, breeder only farms, recently depopulated farms, empty farms and various other scenarios. Most farms were Lawsonia and PCV-2 positive, but farms that are positive and negative for Brachyspira hyodysentariae were targeted.
At each farm, numerous longitudinal vector samples and population-stratified faecal samples were collected over the (wet) summer of 2007. In 2008, selected farms were re-visited and sampled. Insects and invertebrates were collected via aerial sticky traps, motorised vacuum devices, floor and pitfall traps and sweep nets. Prominent groups of flies, beetles and other insects have been tabulated for each production phase within each farm. The findings of numerous Dipteroid flies on most farms and a heavy cockroach infestation on two farms were of note. The range and levels of insects was similar in 2007 and 2008.
DNA has been extracted from representative vectors and routine PCR techniques established for Brachyspira, PCV-2b and Lawsonia infections in both pigs and potential vectors. PCR-positive Lawsonia DNA from pigs and Eristalis fly stages on one farm was transported to a collaborative reference laboratory and tested by specialised sub-typing techniques. This established that Lawsonia of the same sub-type was present in both the pigs and larvae and adult flies on this pig farm.
Flies and cockroaches were challenged with Brachyspira hyodysenteriae and some apparently retained infection in their intestine for three days (cockroaches).
Communication of results will be via the scientific and farmer press later in the year, focusing on key issues such as how eradication or medication programs can be enhanced by new knowledge, such as what key vectors and transmitted sub-types may move around pig farms and interrupt eradication programs.
