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Bovine viral diarrhoea virus (BVDV) is a significant pathogen of cattle, leading to severe economic and animal-welfare impacts. Furthermore, the pathogen has been associated with impacting the progression or spread of other pathogens (e.g. Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB)). During this study we investigated (i) risk factors for BVDV at a herd-level and (ii) whether there was any association between BVDV and herd-level bTB risk. The data for this study were gathered from a voluntary BVDV control programme in Northern Ireland (2013–2015) based on the identification of virus positive animals through tissue tag testing of calves. We assigned a herd-level BVDV status to 2827 participating herds, where a herd was assumed “infected” if one or more animals tested positive for BVDV. Two model suites were developed. Firstly, we assessed risk factors for BVDV herd status using multivariable logit random-effects modelling, aggregating to the calendar year level (2013–2015; n = 4828; model 1). Secondly, we aggregated data across the three years of the study to give an overall status for the whole study period (n = 2827; logistic model 2). Risk factors included year, herd-type, herd size, number of births, inward trade moves, calf mortality, and region. Furthermore, the herd-level bovine tuberculosis status (based on the single intradermal comparative cervical tuberculin (SICCT) test outcomes, or confirmation at post-mortem), or the size of bTB breakdowns (number of SICCT test positive animals), of herds was also investigated to assess whether there was an association (co-infection) with herd BVDV status. The final models suggested that BVDV herd status was positively associated with increased levels of calf mortality, herd size, number of births, the number of BVDV tests undertaken and the number of animals introduced to the herd. There was a significant univariable positive association between BVDV status, and SICCT breakdown risk, breakdown size and confirmed bTB status in model 2. However, there was no evidence of significant associations between bTB status (using SICTT status, confirmed status or herd breakdown size) and BVDV status in final multivariable models when controlling for other significant confounders. These results provide information for action for the future control and eradication of BVDV in Northern Ireland, though these data provide little support for the hypothesised association between BVDV and bTB status at herd-level. Further animal-level analyses are necessary to investigate whether there is support for a BVD-bTB co-infection association, including the impact of co-infection on the severity of infection. [ABSTRACT FROM AUTHOR]

In wildlife disease management there are few diseases for which vaccination is a viable option. The human vaccine BCG has been used for the control of bovine tuberculosis in badgers since 2010 and is expected to increase. Understanding the long-term effects of repeated vaccination campaigns on disease prevalence is vital, but modelling thus far has generally assumed that a vaccine provides perfect protection to a proportion of the population, and that animals exposed to a repeated vaccination have a second independent chance of becoming protected. We held a workshop with experts in the field to obtain consensus over the main pathways for partial protection in the badger, and then simulated these using an established model. The available data supported the possibility that some individuals receive no benefit from the BCG vaccine, others may result in a delayed disease progression and in the remaining animals, vaccine protected the individual from any onward transmission. Simulating these pathways using different levels of overall efficacy demonstrated that partial protection leads to a reduced effect of vaccination, but in all of the identified scenarios it was still possible to eradicate disease in an isolated population with no disease introduction. We also identify those potential vaccination failures that require further investigation to determine which of our proposed pathways is the more likely. • Tb in badgers spills over to cause economic loss in cattle. Badger vaccination does not provide complete protection. • A workshop was used to define potential partial protection effects of BCG vaccination in badgers. • An established simulation model was adapted to account for these less than perfect effect. • The output shows that disease elimination remains possible with partial protection, supporting its ongoing use in badgers. [ABSTRACT FROM AUTHOR]

Abstract: Zoonotic diseases such as bovine tuberculosis (TB) that infect wildlife and livestock are particularly difficult to eradicate where wild animals make extensive use of agricultural landscapes. Transmission of TB between cattle (Bos taurus) and wild elk (Cervus elaphus) in southwestern Manitoba, Canada remains poorly understood but there is a risk when comingling occurs on summer pasture. Elk use of cattle summer pastures was assessed using ecological data (187 VHF and 25 GPS collared elk monitored over four years representing 8% of the elk population). Local knowledge was documented by conducting interviews and participatory mapping exercises with 86 cattle producers (98% of those within the study area). Of the 294 cattle pastures mapped by farmers, 13% were used by radio-collared elk, 38% were reported by farmers as being used by elk, and 42% were identified as used by elk when both when all datasets were combined. Cattle pastures that had been used by elk and those that had no elk were compared using binary logistic regression based on each of the three datasets (i.e. farmer observations, radio-collared elk on pasture, and combined dataset). For all three datasets, distance to protected area and proportion of forest cover on the cattle pasture were identified as the most and second most important predictor variables, respectively. There was strong agreement among the relative probabilities of elk occurrence on each pasture derived from the resource selection function (RSF) models developed using farmer interviews and elk collaring data. The farmer interview and collar datasets were then combined to generate a final integrated RSF map summarizing the probability of elk–cattle comingling and were contrasted over each of four cattle grazing seasons (spring, early summer, late summer, and autumn). These predictive maps indicate that use of cattle pastures by elk is extensive, particularly in spring and early summer. Farmer observations indicate that elk and cattle share water sources and livestock mineral supplements on pasture. Local knowledge and conventional ecological data complement and validate one another and help us better understand the temporospatial aspects of shared space use among wildlife and livestock and more generally the risks of disease transmission in agricultural landscapes. [Copyright &y& Elsevier]