Aims: The objective of these surveys was to estimate the prevalence of faecal carriage of Salmonella in healthy pigs, cattle and sheep at slaughter, and of pig carcase contamination with Salmonella. These data can be used as a baseline against which future change in Salmonella prevalence in these species at slaughter can be monitored. Methods and Results: In this first randomized National Survey for faecal carriage of Salmonella in slaughter pigs, cattle and sheep in Great Britain, 2509 pigs, 891 cattle and 973 sheep were sampled in 34 pig abattoirs and 117 red meat abattoirs in England, Scotland and Wales. Carriage of Salmonella in 25 g caecal contents was identified in 578 (23AE0% pigs) but in only 134 (5AE3%) of carcase swabs. The predominant Salmonella serovars found in both types of sample were S. Typhimurium (11AE1% caeca, 2AE1% carcases) and S. Derby (6AE3% caeca, 1AE6% carcases). The main definitive phage types (DT) of S. Typhimurium found were DT104 (21AE9% of caecal S. Typhimurium isolates), DT193 (18AE7%), untypable strains (17AE6%), DT208 (13AE3%) and U302 (13AE3%). Three isolates of S. Enteritidis (PTs 13A and 4) and one enrofloxacin-resistant S. Choleraesuis were also isolated. A positive Ômeat-juice ELISAÔ was obtained from 15AE2% of pigs at 40% optical density (O.D.) cut-off level and 35AE7% at 10% cut-off. There was poor correlation between positive ELISA results or carcase contamination and the caecal carriage of Salmonella. The ratio of carcase contamination to caecal carriage rates was highest in abattoirs from the midland region of England and in smaller abattoirs. In cattle and sheep 1 g samples of rectal faeces were tested. Two isolates (i.e. 0AE2%) were recovered from cattle, one each of S. Typhimurium, DT193 and DT12. One sheep sample (0AE1%) contained a Salmonella, S. Typhimurium DT41. In a small subsidiary validation exercise using 25 g of rectal faeces from 174 cattle samples, three (1AE7%) isolates of Salmonella (S. Typhimurium DT104, S. Agama, S. Derby) were found. Conclusions: The carriage rate of Salmonella in prime slaughter cattle and sheep in Great Britain was very low compared with pigs. This suggests that future control measures should be focused on reduction of Salmonella infection on pig farms and minimizing contamination of carcases at slaughter. Significance and Impact of the Study: This work has set baseline figures for Salmonella carriage in these species slaughtered for human consumption in Great Britain. These figures were collected in a representative way, which enables them to be used for monitoring trends and setting control targets.

Aims: To investigate the relationship between livestock carriage of Yersinia enterocolitica and human disease. The biotypes/serotypes of strains recovered from the faeces of pigs, cattle and sheep at slaughter during a national survey in Great Britain in 1999-2000, were compared with those of strains isolated from human cases of yersiniosis during the same period. Methods and Results: The faecal carriage of Y. enterocolitica by cattle, sheep and pigs at slaughter was 6AE3, 10AE7 and 26AE1%, respectively. Yersinia enterocolitica biotype (BT) 1a was the most frequently isolated biotype from livestock (58%) and was the predominant biotype (53%) isolated from human cases over the same period. The main recognized pathogenic Y. enterocolitica biotype isolated from livestock was BT3 (O:5,27) (35% of sheep, 22% of pigs and 4% of cattle) but this biotype was not detected in any of the human isolates investigated. The major pathogenic biotypes of strains isolated from humans were BT3 (O:9) (24%) and BT4 (O:3) (19%) whereas of the veterinary isolates investigated, only pigs (11%) carried BT3 (O:9) strains. Conclusions: Because of significant overlaps in phenotypes of the veterinary and human strains it is not possible to comment on the correlation between host and pathogenicity, especially of biotype 1a. Significance and Impact of the Study: The data suggest that further investigations using methods with greater discriminatory power are required. However the data also suggests that pigs may be the primary reservoir for human pathogenic Y. enterocolitica infection.

SUMMARYA survey of Campylobacter species in the faeces or rectal contents of domestic animals was carried out using direct and enrichment culture methods. Campylobacters were isolated from 259 (31 00) of 846 faecal specimens. The highest isolation rate was found in pigs (66 0o); lower rates were found in cattle (24 0/s) and sheep (22 %). In pigs all the isolates were C. coli, in sheep and cattle about 7500 were C. jejuni. Only five isolations of C.fetus subsp.fetus were made, all from cattle. More pigs with diarrhoea had C. coli in their faeces than healthy pigs (770 vs 470), but such a clear difference in isolation rate between sick and healthy animals was not seen in cattle or sheep.The enrichment method increased the total isolation rate of C. jejuni and C. coli by 330, but for cattle specimens it increased it by 690 (from 6-5 00 to 21 00).However, the enrichment method failed to detect 160% of positive specimens (mainly C. coli), so direct and enrichment methods should be used for the culture of campylobacters from animal faeces. The results show that cattle, sheep and pigs constitute a large potential source of campylobacter infection for man.

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A study of randomly selected dairy farms in England and Wales was made between October 1999 and February 2001 to estimate the prevalence and incidence of Salmonella serovars. The farms were enrolled through five milk-buying companies, which represented 63 per cent of the dairy farms in England and Wales, and they were sampled on up to four occasions (449 farms at visit 1, 272 farms at visit 2, 251 farms at visit 3 and 243 farms at visit 4). In total, 19,296 samples of pooled faecal pats and slurry were collected. The farm-specific prevalence of all serovars of Salmonella ranged from 12.1 per cent (95 per cent confidence interval [CI] 8.2 to 16.0 per cent) to 24.7 per cent (95 per cent CI 19.4 to 30.1 per cent) at each visit. The most common serovars identified were Salmonella Dublin (3.7 to 6.6 per cent farm-specific prevalence at each visit), Salmonella Agama (1.8 to 7.6 per cent) and Salmonella Typhimurium (2.6 to 4.1 per cent) The prevalence varied by region and month of sampling and increased in late summer. The incidence rate of all serovars of Salmonella was 0.43 (95 per cent CI 0.34 to 0.54) cases per farm-year at risk. There was no significant difference between the incidence rates of the common serovars S Typhimurium (0.07), S Dublin (0.06) and S Agama (0.13). A total of 29 Salmonella serovars were isolated. Few of the isolates were resistant to the 16 antimicrobial agents tested, except the isolates of S Typhimurium dt104, of which 67.9 per cent were resistant to at least five of them.