Verdugo C.,Austral University of Chile |
Verdugo C.,Massey University |
Jones G.,Massey University |
Johnson W.,University of California at Irvine |
And 4 more authors.
Preventive Veterinary Medicine | Year: 2014
The study aimed to estimate the national- and island-level flock/herd true prevalence (HTP) of Mycobacterium avium subsp. paratuberculosis (MAP) infection in pastoral farmed sheep, beef cattle and deer in New Zealand. A random sample of 238 single- or multi-species farms was selected from a postal surveyed population of 1940 farms. The sample included 162 sheep flocks, 116 beef cattle and 99 deer herds from seven of 16 geographical regions. Twenty animals from each species present on farm were randomly selected for blood and faecal sampling. Pooled faecal culture testing was conducted using a single pool (sheep flocks) or two pools (beef cattle/deer herds) of 20 and 10 samples per pool, respectively. To increase flock/herd-level sensitivity, sera from all 20 animals from culture negative flocks/herds were individually tested by Pourquier® ELISA (sheep and cattle) or Paralisa™ (deer). Results were adjusted for sensitivity and specificity of diagnostic tests using a novel Bayesian latent class model. Outcomes were adjusted by their sampling fractions to obtain HTP estimates at national level. For each species, the posterior probability (POPR) of HTP differences between New Zealand North (NI) and South (SI) Islands was obtained.Across all species, 69% of farms had at least one species test positive. Sheep flocks had the highest HTP estimate (76%, posterior probability interval (PPI) 70-81%), followed by deer (46%, PPI 38-55%) and beef herds (42%, PPI 35-50%). Differences were observed between the two main islands of New Zealand, with higher HTP in sheep and beef cattle flocks/herds in the NI. Sheep flock HTP was 80% in the NI compared with 70% (POPR. =. 0.96) in the SI, while the HTP for beef cattle was 44% in the NI and 38% in the SI (POPR. =. 0.80). Conversely, deer HTP was higher in the SI (54%) than the NI (33%, POPR. =. 0.99). Infection with MAP is endemic at high prevalence in sheep, beef cattle and deer flocks/herds across New Zealand. © 2014 Elsevier B.V.
Mccaughey C.,Regional Virus Laboratory |
Murray L.J.,Queens University of Belfast |
Mckenna J.P.,Regional Virus Laboratory |
Menzies F.D.,Veterinary Epidemiology Unit |
And 5 more authors.
Epidemiology and Infection | Year: 2010
Human cases of Q fever appear to be common in Northern Ireland compared to the rest of the British Isles. The purpose of this study was to describe the seroepidemiology of Coxiella burnetii infection in cattle in Northern Ireland in terms of seroprevalence and determinants of infection. A total of 5182 animals (from a stratified systematic random sample of 273 herds) were tested with a commercial C. burnetii phase 2 IgG ELISA. A total of 62% of animals and 484% of herds tested positively. Results from a multilevel logistic regression model indicated that the odds of cattle being infected with Q fever increased with age, Friesian breed, being from large herds and from dairy herds. Large dairy herd animal prevalence was 125% compared to 21% for small beef herds. Preliminary seroprevalence in sheep (123%), goats (93%), pigs (0%) rats (97%) and mice (32%) using indirect immunofluorescence is reported. Copyright © Cambridge University Press 2009.
Abernethy D.A.,Veterinary Epidemiology Unit |
Moscard-Costello J.,Mall West |
Dickson E.,Mall West |
Harwood R.,Mall West |
And 4 more authors.
Preventive Veterinary Medicine | Year: 2011
An epidemiological investigation was undertaken of 41 bovine brucellosis outbreaks that occurred within a 10-month period, in a region where eradication measures appeared to be succeeding. The primary outbreak comprised three herds with significant within-herd spread and a high probability of multiple abortions. Direct contact between cattle at pasture was the most likely means of between-herd transmission for most (71%) outbreaks, with an attack rate of 28.1% in herds immediately neighbouring the primary outbreak herds and 11.3% in the next concentric ring of farms. Resolution of the incident was attributed to a rapid response by the veterinary authorities, detailed epidemiological investigations, repeated, prolonged testing of contact herds and employment of parallel testing. © 2010.
Doyle L.P.,Veterinary Epidemiology Unit |
Gordon A.W.,Agri Food and Biosciences Institute of Northern Ireland |
Abernethy D.A.,University of Pretoria |
Stevens K.,Lane College
Preventive Veterinary Medicine | Year: 2014
Compulsory bovine tuberculosis testing has been implemented since 1959 in Northern Ireland. Initial rapid progress in the eradication of the disease was followed by a situation where disease levels tended to fluctuate around a low level. This study explores recrudescence of bovine tuberculosis (bTB) in Northern Ireland herds by assessing risk factors associated with time from the six-month post-outbreak skin test until a further herd breakdown. Bovine herds (n= 3377) were recruited in 2002 and 2003 and their survival analysed using Kaplan-Meier survival estimates and a Cox proportional hazards model, with follow-up extending to August 2008. Exclusion criteria applied for study entry were bTB infection in a contiguous herd, changing of post restriction test to one of a higher risk status or chronic infection. Chronic infection was defined as any situation where disclosure preceded the post-outbreak test by two years or more. The application of these exclusion criteria meant that herds recruited to the study were largely cleared of infection and not directly contiguous to other infected herds. Of the 3377 herds, 1402 (41.5%) suffered a further herd breakdown before the end of follow-up. Median survival time was 582 days (interquartile range. = 336-1002 days). Breakdown severity (defined as the number of Single Intradermal Comparative Tuberculin Test (SICTT) reactors at disclosure test), local bTB prevalence, herd size and type were identified as significant risk factors (p<. 0.05), as was the purchase of higher numbers (n>. 27.38 per year) of cattle. Consistent with other studies this work shows bTB confirmation to not be predictive of a future herd breakdown. This work shows bTB history as not being a risk factor for a future breakdown. This result could be reflective of the exclusion criteria used in the study, which may have selected for incidents where historical status was of less importance. © 2014 Elsevier B.V.
Oosterlinck M.,Ghent University |
Pille F.,Ghent University |
Back W.,Ghent University |
Back W.,University Utrecht |
And 2 more authors.
Veterinary Journal | Year: 2010
Subtle lameness in horses may be difficult to diagnose and methods to evaluate lameness objectively are useful when equine clinicians fail to reach a consensus. The aim of this study was to determine whether equine pressure plate measurements are repeatable when used to calculate forelimb loading (peak vertical pressure [PVP], peak vertical force [PVF], vertical impulse [VI]) and symmetry ratios, and to establish if these data are similar to the 'gold standard' force plate values. Since plate dimensions are relatively small, ponies were used to enable recordings to be taken from both forelimbs in one trial. Five sound ponies were walked and trotted over a pressure plate which was embedded in a custom-made runway. For each pony, five valid trials were recorded during two different days. A trial was considered valid if complete prints of both fore hooves were recorded consecutively and if velocity was within a preset range. The PVP, PVF and VI values showed an acceptable variability (CV ≤ 16%), with PVF (130% of bodyweight [BW], n = 5) similar to previously reported force plate data (128% BW, n = 48). Mean symmetry ratios appeared to be high (>95%) and showed a low variability (CV < 5%). The stand-alone pressure plate permitted adequate registration of forelimb PVF, VI and limb symmetry with a high level of precision in sound ponies. © 2008 Elsevier Ltd. All rights reserved.