UK Pig Disease Quarterly Surveillance Report (to September 2005)

By Veterinary Laboratories Agency - This report monitors trends in the major endemic pig diseases and utilises the farmfile and VIDA (Veterinary Investigation Disease Analysis) databases. The report is compiled using disease data gathered by the network of 15 VLA regional laboratories which carry out disease investigation in the field.

9 January 2006

5 minute read

Quarterly Surveillance Report Pigs: Vol.9 No.3
July - September 2005 - Published Nov 2005

Contents

OVERVIEW (here)

NOTIFIABLE DISEASES:

ZOONOTIC DISEASES:

ENDEMIC DISEASES:

VLA PIG PUBLICATIONS

Highlights: Third Quarter 2005

General impression that pig health is better than in recent years.
Nevertheless, investigations indicate that disease, particularly respiratory disease, is significantly underestimated on farm.
Sickness and deaths are too often attributed to PMWS on farm. Subsequent investigations identify various diseases are involved, and not always PMWS.
However, PCV2-associated diseases are occurring in older pigs, sometimes without showing the typical wasting signs of PMWS.

Overview

The GB DAPP (GB Deadweight Average Pig Price) continued at around 106p/kg dw during July but then gradually declined to end the quarter at under 104p/kg dw. Further details on DAPP and various trends are available on BPEX webpages, such as http://www.bpex.org/bphs/default.asp, where details of the British Pig Health Scheme are also available. Other topical issues on the BPEX website include reference to the possibility that EU plans to introduce wider testing of British pigs for trichinella might be reduced, and that China has recommenced importation of breeding pigs from Britain.

NOTIFIABLE DISEASES:

No suspect incidents of swine fever or Aujeszky’s disease were reported that required statutory laboratory investigations.

ZOONOTIC DISEASES AND FOOD SAFETY: FOOD SAFETY INCIDENTS

No suspect incidents involving pigs were reported. A summary of suspect animal toxicoses with potential food safety implications in England and Wales between 1990 and 2002 (Sharpe RT and Livesey CT, Veterinary Record, 2005, 157, 465-469) identified only six pig-related incidents out of 838 (0.7%) investigated. These six involved mycotoxins twice, and copper, metaldehyde, organophosphorus, and rodenticide once each.

SALMONELLAS & SALMONELLOSIS:

The third quarter produced a downward trend in diagnoses of salmonellosis since 2003 – see histogram, which shows VIDA incidents of salmonellosis in pigs (as a percentage of diagnosable submissions) July to September 1999-2005:

This decline is more pronounced than for the second quarter, reaching statistical significance for the third quarter 2005 compared with the third quarter 2003. There was no indication of a decline for the first quarter annual comparisons.

The decline in diagnoses of salmonellosis is reflected in the reduced number of Zoonoses Order salmonella incidents. The 30 incidents recorded for the third quarter of 2005 compares with an average 43 such incidents for the same quarter over the previous four years. Much of the reduction was due to fewer incidents due to Salmonella enterica serotype Typhimurium. The commonest definitive type (DT) was again U288 (7 of 16 Typhimurium incidents recorded in the third quarter this year). U288 was first reported in pigs (Zoonoses Order) in 2002 subsequently becoming the predominant DT in pigs.

Serotype Choleraesuis was recorded once; the isolate was from a farm where it was previously recorded in 1998, suggesting recrudescence. In the latest incident ten deaths occurred within a group of 60 ten-week-old pigs. Serotype Bovismorbificans was isolated from 35kg finisher pigs on entry to the finisher unit from an outdoor breeding herd. It was isolated from 20 percent of pooled faecal samples collected just before pigs left the finishing unit. There were no clinical signs of disease on the unit. The isolate was phage typed as PT13. This is quite different from PT24 recently associated with a German outbreak of human salmonellosis attributed to the consumption of raw pork products.

A Zoonoses Order investigation visit was made to a closed unit that had exceptionally high management standards, where salmonellas were originally isolated from clinically affected pigs in one finishing house. At the onset of clinical signs, the farmer had prevented access to the building by anyone other than himself. He designated a pair of overalls and boots specifically for use in this house and these were left at the house entrance. Foot dips were in place, and cleansing and disinfection standards were enhanced. Despite these control measures, salmonellas were isolated from all three finishing houses on the unit at the time of the visit, as well as from rat and bird droppings, the tractor footwell and the midden outflow.

Eight Zoonoses Action Plan (ZAP, see http://www.bpex.org/zap/default.asp) advisory visits were completed bringing the total number of VLA visits to 39. Salmonellas were isolated from 22 percent of samples collected this quarter compared with 33 percent of all samples collected during the 39 visits.

BRUCELLOSIS

Brucellas were not isolated under the surveillance initiative to provide evidence that pig herds remain free of Brucella suis; an organism that has never been isolated from pigs or hares in the UK.