Pigs raised in the United Kingdom are unlikely to be the source of UK human infections.

During 2007-2009 a UK-wide, 3-year stratified randomized survey of UK chicken broiler flocks was conducted to estimate the prevalence of Campylobacter-infected batches of birds at slaughter. Thirty-seven abattoirs, processing 88·3% of the total UK slaughter throughput, were recruited at the beginning of the survey. Of the 1174 slaughter batches sampled, 79·2% were found to be colonized with Campylobacter, the majority of isolates being C. jejuni. Previous partial depopulation of the flock [odds ratio (OR) 5·21], slaughter in the summer months (categorized as June, July and August; OR 14·27) or autumn months (categorized as September, October and November; OR 1·70) increasing bird age (40-41 days, OR 3·18; 42-45 days, OR 3·56; ⩾46 days, OR 13·43) and higher recent mortality level in the flock (1·00-1·49% mortality, OR 1·57; ⩾1·49% mortality, OR 2·74) were all identified as significant risk factors for Campylobacter colonization of the birds at slaughter. Time in transit to the slaughterhouse of more than 2·5 h was identified as a protective factor (OR 0·52).

To date there has been little research in the UK on farmer adoption of biosecurity measures to control food-borne zoonoses that have little or no impact on animal health or production but which threaten public health. Campylobacteriosis and salmonellosis are the two most common causes of food-borne infectious intestinal disease in people in Great Britain, causing approximately 57,000 and 13,000 reported cases in 2007 respectively (Anon 2008a) with an important cost to society. Poultry are an important source of both infections, while pigs may also contribute to human salmonellosis. However, these infections in poultry and pigs seldom cause disease. Research has shown that improved farm biosecurity may reduce the prevalence of these infections in livestock and if the majority of farmers were prepared to enhance biosecurity then there could be an important impact on public health. This article reports on the findings of two studies of farmer attitudes to and cost of the adoption of on-farm biosecurity measures to reduce the risk of animal diseases and therefore enhance food safety. One study, of Campylobacter infection among broiler flocks, is based on a survey of farmers faced with a hypothetical biosecurity intervention, while the other study, of Salmonella infection among pigs, is based on the participation of a group of farmers in an intervention study. In both cases, the results show a clear inverse relationship between the willingness of farmers to adopt a biosecurity measure and its estimated cost. This finding has implications for the success of on-farm biosecurity-enhancement policies based on voluntary adoption by farmers. In particular, financial inducements or penalties to farmers could be necessary to facilitate adoption of these measures.

No abstract

An abattoir-based study was undertaken between January and May 2013 to estimate the prevalence of Salmonella spp. and Yersinia spp. carriage and seroprevalence of antibodies to Toxoplasma gondii and porcine reproductive and respiratory syndrome virus (PRRSv) in UK pigs at slaughter. In total, 626 pigs were sampled at 14 abattoirs that together process 80% of the annual UK pig slaughter throughput. Sampling was weighted by abattoir throughput and sampling dates and pig carcasses were randomly selected. Rectal swabs, blood samples, carcass swabs and the whole caecum, tonsils, heart and tongue were collected. Salmonella spp. was isolated from 30·5% [95% confidence interval (CI) 26·5-34·6] of caecal content samples but only 9·6% (95% CI 7·3-11·9) of carcass swabs, which was significantly lower than in a UK survey in 2006-2007. S. Typhimurium and S. 4,[5],12:i:- were the most commonly isolated serovars, followed by S. Derby and S. Bovismorbificans. The prevalence of Yersinia enterocolitica carriage in tonsils was 28·7% (95% CI 24·8-32·7) whereas carcass contamination was much lower at 1·8% (95% CI 0·7-2·8). The seroprevalence of antibodies to Toxoplasma gondii and PRRSv was 7·4% (95% CI 5·3-9·5) and 58·3% (95% CI 53·1-63·4), respectively. This study provides a comparison to previous abattoir-based prevalence surveys for Salmonella and Yersinia, and the first UK-wide seroprevalence estimates for antibodies to Toxoplasma and PRRSv in pigs at slaughter.