10 May 2002

UK-wide project to find salmonella level in herd

This years Pig and Poultry

Fair promises advice and

innovation aplenty as well

as a chance to debate

some hot topics at

seminars on both days.

Hannah Velten kicks off

our special with a preview

of the salmonella session

NEW research to determine the level of salmonella infection in the national pig herd and to find practical ways to reduce its incidence will be unveiled at this years Pig and Poultry Fair.

Alasdair Cook, an epidemiologist at the Vet Lab Agency, Weybridge, says salmonella must be addressed for two key reasons: "The bacteria poses a serious risk to public health, causing clinical disease in humans.

"It is also commercially important to promote salmonella control, keeping us in line with Denmark and other EU states," adds Mr Cook.

More than 16,000 cases of salmonellosis were confirmed by the Public Health Lab Service in 2000. Most cases are sporadic and the source is seldom known, but 44 outbreaks were associated with food and four of these were attributed to red meat.

VLA now plans to conduct a DEFRA-funded on-farm research programme, headed by Mr Cook. Initially, up to 400 pig units will be sampled to see how many are infected with salmonella and what proportion of each herd are infected. This will begin within a year, with randomly selected units asked to join the study.

There are already indications of salmonella levels within the UK pig herd, says Mr Cook. An abattoir study of 2500 finishers in 1999 showed that 25% had salmonella infection in their intestines. And out of 2243 general pig samples submitted to the VLA in 2000, 313 indicated infection.

"However, pigs may not show clinical symptoms of salmonella and not all samples taken were suitable for salmonella detection," he adds.

A pilot study of 30 units began in November 2001. Dung samples from pen floors are analysed at VLA. "These detect whether pigs are actively infected with salmonella and which type it is – there are hundreds of strains, of which about 200 cause human disease."

Meat juice tests will be done on samples from carcasses. "When antibodies are present, it indicates exposure to infection during the pigs lifetime."

Findings from the first stage monitoring programme will be used to give the industry, stakeholders, the Food Standards Agency, supermarkets and consumers a realistic estimate of infection levels, says Mr Cook.

"It is purely to inform rather than find a solution. However, the second-stage intervention programme should help to determine a package of practical controls to reduce salmonella incidence on-farm." A code of practice for control of salmonella on pig farms is already available from DEFRA.

But, reducing levels will not be simple, warns Mr Cook. "In Denmark, they have found out there is no single, easy solution to salmonella control. The aim of eliminating salmonella in the short-term is unrealistic."

During the intervention stage, selected units will be randomly divided into two groups – those trying out a control package and those changing nothing. Samples will be taken to monitor whether an impact is seen.

"Many units will already be practising some procedures, such as all-in/all-out housing, minimal mixing of pigs and boot dips outside houses, but the aim is to clarify formal protocols.

"We want to stimulate discussion between ourselves, vets and producers as to how feasible and practical strategies could control salmonella," adds Mr Cook.

While the research priority is salmonella, it is hoped that strategies will also reduce incidence of other disease, benefiting production levels.

Mr Cook is also keen to point out that although this VLA research is entirely farm-based, it does not mean responsibility for controlling salmonella stops at the farm-gate. &#42

On-farm research to assess the level of salmonella in UK pig herds is about to begin, says Alasdair Cook.

&#8226 True picture of infection levels.

&#8226 Determine control package.

&#8226 No single solution.


National Agricultural Centre, Stoneleigh, Warks.

Seminars will be held on both days, focusing on pig health and welfare.

10.30am DEFRAs vision for a sustainable pig industry, Gavin Ross, DEFRA.

11.30am PMWS/PDNS – What next?, Roger Harvey, Stowe Vet Group and Derek Armstrong, MLC.

12.30pm Harmonising European pig welfare standards, Sandra Edwards, Newcastle University and Michael Baxter (Wed)/Fiona Walters (Thurs), DEFRA.

1.15pm The challenge of salmonella testing and control, Alasdair Cook, VLA-Weybridge and Derek Armstrong, MLC.

2.00pm Is good welfare good business?, Malcolm Pye, Food Animal Initiative and Martin Cooke, Tesco.

Admission, catalogue and parking are free. The show is open from 9am to 5pm. For more information visit the web-site www.pigandpoultry.org.uk (024-7685 8277).