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 6·3, 10·7 and 26·1%, 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.
A longitudinal study in England and Wales of two dairy, five beef-fattener and three beef-suckler herds was carried out to identify risk factors for young cattle excreting verocytotoxin-producing ...Escherichia coli O157 (VTEC O157). A total of 1383 cattle, selected into cohorts at 0–24 months were sampled between March 2000 and February 2001. Mixed-effects logistic regression was employed to identify significant associations between VTEC O157 isolation from rectal faecal samples and explanatory factors (P < 0·001 unless shown). The results revealed a positive association with feeding root crops and a negative association with animals fed silage, milk (P = 0·001) or grain (P = 0·027). Cattle in suckler herds (P = 0·001) and those changing group between sampling visits were identified as negatively associated with VTEC O157 presence. The recovery of VTEC O157 varied throughout the year. However, the winter period from December to February was a risk factor in the multivariable analysis. Cattle in pens were 4·7 times more likely to shed VTEC O157 than those group-housed or at pasture. VTEC O157 detected in pooled environmental faecal pats and biofilm of the water supply within a group's enclosure were positively associated with an animal's VTEC O157 status in the multivariable logistic regression, as was detection of VTEC O157 in the pooled faecal pats at the previous visit.
An abattoir survey was undertaken to determine the prevalence of foodborne zoonotic organisms colonizing cattle, sheep and pigs at slaughter in Great Britain. The study ran for 12 months from January ...2003, involved 93 abattoirs and collected 7703 intestinal samples. The design was similar to two previous abattoir surveys undertaken in 1999-2000 allowing comparisons. Samples were examined for VTEC O157, Salmonella, thermophilic Campylobacter and Yersinia enterocolitica. The prevalence of VTEC O157 faecal carriage was 4·7 % in cattle, 0·7 % in sheep and 0·3 % in pigs. A significant decrease in sheep was detected from the previous survey (1·7 %). Salmonella carriage was 1·4 % in cattle, a significant increase from the previous survey of 0·2 %. In sheep, faecal carriage was 1·1% a significant increase from the previous survey (0·1%). In pigs, carriage was 23·4%, consistent with the previous study. Thermophilic Campylobacter spp. were isolated from 54·6 % of cattle, 43·8 % of sheep and 69·3 % of pigs. Y. enterocolitica was isolated from 4·5 % of cattle, 8·0 % of sheep and 10·2 % of pigs.
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 (23.0% pigs) but in only 134 (5.3%) of carcase swabs. The predominant Salmonella serovars found in both types of sample were S. Typhimurium (11.1% caeca, 2.1% carcases) and S. Derby (6.3% caeca, 1.6% carcases). The main definitive phage types (DT) of S. Typhimurium found were DT104 (21.9% of caecal S. Typhimurium isolates), DT193 (18.7%), untypable strains (17.6%), DT208 (13.3%) and U302 (13.3%). Three isolates of S. Enteritidis (PTs 13A and 4) and one enrofloxacin-resistant S. Choleraesuis were also isolated. A positive 'meat-juice ELISA' was obtained from 15.2% of pigs at 40% optical density (O.D.) cut-off level and 35.7% 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. 0.2%) were recovered from cattle, one each of S. Typhimurium, DT193 and DT12. One sheep sample (0.1%) contained a Salmonella, S. Typhimurium DT41. In a small subsidiary validation exercise using 25 g of rectal faeces from 174 cattle samples, three (1.7%) 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.
The study investigates farms suspected of being sources of zoonotic human cryptosporidiosis. A variety of implicated farm animal species were sampled and tested to detect
Cryptosporidium oocysts and ...investigate genetic linkage with human patients. Risk factor information was collected from each farm and analysed by multivariable logistic regression to detect significant associations between factors and
Cryptosporidium in animals. The results showed that average sample prevalence of
Cryptosporidium infection was highest in cattle, sheep and pigs (∼40–50%), in the mid-range in goats and horses (20–25%) and lowest in rabbits/guinea pigs, chickens and other birds (∼4–7%). A single sample from a farm dog was also positive.
Cryptosporidium parvum, which has zoonotic potential, was the commonest species and was most likely to be present in cattle and, to a lesser extent, in sheep. In particular, young calves and lambs shed
C. parvum and this finding was corroborated in a statistical model which demonstrated that samples from groups of preweaned animals were 11 times, and immature animal groups six times, more likely to be positive than groups of adult animals, and that samples from a farm with a cattle enterprise were twice as likely to be positive than farms without a cattle enterprise. On seven out of eight farms, at least one
C. parvum isolate from an animal sample was indistinguishable at the gp60 locus from those found in the human patients, indicating that farm animals are a likely source of infection for humans.
Individual animal samples were collected from ten VTEC O157 positive farms approximately monthly over 11
months to investigate the shedding of VTEC O157 by youngstock. VTEC O157 was isolated from ...7.7% of the 6266 samples and 28.9% of the 1383 animals. On six of the farms VTEC O157 was isolated at multiple visits from several animals, whereas the remaining four farms had one or two positive animals at any one visit, with VTEC isolated from a maximum of four visits. A total of 92 animals were positive more than once (up to four sampling occasions) with a maximum of four negative samples between positive isolations. The results reveal a large variation in individual animal shedding patterns; the proportion of shedding animals on positive farms; and over time within the same farm. The lack of consistent shedding restricts the ability to target potential interventions to specific positive animals/groups or herds.
Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) infections are a threat to public health. VTEC O157 has been isolated from gulls but evidence of transmission to humans from birds has not ...been reported. We recount an incident of VTEC O157 infection affecting two sibling children who had no direct contact with farm animals. An outbreak control team was convened to investigate the source of infection, its likely mode of transmission, and to advise on control measures. Human and veterinary samples were examined and the human isolates were found to be identical to an isolate from a sample of bird (rook) faeces. Cattle, rabbit and environmental samples were negative. This report provides evidence that birds may act as intermediaries for human infection with VTEC O157.
Escherichia coli isolates were recovered from faecal samples taken from cattle, sheep and pigs at slaughter in England and Wales. Isolates (
n = 1227) selected at random from this collection were ...each hybridised in colony dot-blot experiments with an
eae gene probe that presumptively identified attaching–effacing
E. coli (AEEC). Of the 99 (8.1%)
eae positive isolates 72 were of ovine origin, 24 were of bovine origin and three of porcine origin. None were typed as O157:H7 whereas 78 were assigned to 23 serogroups and 21 were untypable. The most frequently isolated
eae positive serogroups were O156 (10), O26 (8), O103 (8), O108 (7) O56 (6) and O168 (6) of which serogroups O103 and O156 only were recovered from all three animal species. In tissue culture adherence assays, 36 representatives of
eae positive isolates of all serogroups and host of origin tested induced intimate attachment with varying degrees of actin accumulation and pedestal formation in the HEp-2 cells. The identity of the
eae type for these 36 was determined by specific PCR and the most prevalent intimin types were
eaeβ (15),
eaeγ (12) and
eaeε (4). Isolates were examined by PCR for the presence of other virulence determinants and five possessed
stx1 but none possessed
stx2. One O115
eaeε isolate possessed
cnf1 and 2,
hlyA,
etpD and
katP genes which is a novel combination of virulence determinants.
A 12-month abattoir study was undertaken from January 2003. We collected 7492 intestinal samples from cattle, sheep and pigs at slaughter. Rectal samples were taken from cattle and sheep and caecal ...samples from pigs. They were examined for verocytotoxigenic E. coli (VTEC) O157, Salmonella, thermophilic Campylobacter and Yersinia enterocolitica. Data were collected on the animal from which the sample came and this information was analysed to look at potential risk factors for carriage of these organisms. Logistic regression models were run where an adequate number of positive results were available. This revealed that VTEC O157 carriage in cattle was associated with the summer period and that age was a protective factor. Salmonella carriage in pigs was associated with lairage times >12 h, the North East and not feeding when there was no bedding available. In cattle, carriage was associated with the summer period, the Eastern region of GB and dairy animals. In sheep a spring seasonal effect was seen, which coincided with the lambing period. The carriage of thermophilic Campylobacter in cattle was associated with single-species abattoirs, with age a protective factor. In sheep, winter was a risk period with lairage management influential. For pigs, lairage times of <12 h were found to be associated with carriage. A seasonal trend for carriage of Y. enterocolitica in all species was demonstrated with the period December–May a risk. For cattle, age was also a risk factor; for sheep feeding in the lairage and for pigs being held overnight were risk factors.
This paper describes the validation of a solid-phase competition enzyme-linked immunosorbent assay (SPCE) for the serological detection of antibody to serotype O foot-and-mouth disease (FMD) in ...sheep, cattle and pigs.
The specificity of the SPCE was calculated from the results of testing known negative sera from sheep, cattle and pigs (
n=3030, 1418 and 1495, respectively). The mean percentage inhibition (PI) for known negative sheep, cattle and pig sera were 19.3, 24.1 and 20.8%, respectively. The specificity of the SPCE at a cut-off point (COP) of 60 PI was 99.50% for sheep sera, 99.44% for cattle sera and 100% for pig sera.
The analytical sensitivity of the SPCE was examined by testing sera from sheep, cattle and pigs. Based on the testing of serial bleeds from experimentally infected animals, seroconversion at the 60 PI COP occurred between 4 and 9 days post-infection or -exposure, similar to that observed using the virus neutralisation test (VNT) with a COP of 1/45. When applied to 267 sheep and 143 pig samples, that were obtained in Great Britain (GB) during the 2001 FMD UK outbreak, the SPCE identified more positive samples than did the VNT. Estimates of the accuracy, repeatability and reproducibility of the SPCE were verified during the large-scale serosurveillance necessitated by the 2001 outbreak. Results from field and experimental sera showed that when compared against the VNT, the sensitivity of the SPCE was less affected by the choice of virus strain used in the test.
Using the O
1 UKG 2001 FMD virus in the VNT with samples representative of the uninfected GB sheep population, the test specificity was 100% at a COP of 1/45.
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