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Ireland lost its official freedom from Schmallenberg virus (SBV) in October 2012. The route of introduction is uncertain, with long-distance displacement of infected Culicoides, biting midges, by suitable wind flows considered to be the most likely source. The authors investigated the potential introduction of SBV into Ireland through a Culicoides incursion event in the summer of 2012. They conducted SBV serology on archived bovine sera to identify the prospective dispersal window, then used atmospheric dispersion modelling during periods around this window to identify environmental conditions the authors considered suitable for atmospheric dispersal of Culicoides from potential infected source locations across Southern England. The authors believe that there was one plausible window over the summer of 2012, on August 10-11, based on suitable meteorological conditions. They conclude that a potential long-range transportation event of Culicoides appears to have occurred successfully only once during the 2012 vector competent season. If these incursion events remain at a low frequency, meteorological modelling has the potential to contribute cost-effectively to the alert and response systems for vectorborne diseases in the future.

Background: In Ireland bovine babesiosis is caused by the tick-borne blood parasite, Babesia divergens. A survey of veterinary practitioners and farmers in the 1980’s revealed an annual incidence of 1.7% associated with considerable economic losses. However, two subsequent surveys in the 1990’s indicated a decline in clinical babesiosis. Recent evidence from continental Europe suggests that, probably due to climate change, the distribution of the tick vector of B. divergens, Ixodes ricinus is extending to more northerly regions and higher altitudes. In addition, milder winters are thought to widen the window of tick activity. In order to determine whether any such changes have affected the incidence of bovine babesiosis in Ireland, a questionnaire survey of farmers and veterinarians was carried out and compared with data from previous surveys. Results: Our survey indicates that while the incidence of clinical disease has continued to decline, cases can occur at any time of year. In contrast to previous surveys, affected farms were the same size as unaffected ones. There was no correlation between disease risk and the presence of deer on the land. Disease severity and mortality rates were increased because many infections were advanced by the time they were detected and treated. Conclusion: While the precise reasons for the decline in the incidence of redwater are unknown, changes in agricultural practice are likely to be of importance. A reversal of the trend could be devastating, as vigilance among farmers and veterinarians is flagging and the national herd is losing its protective immunity to disease. European Commission Horizon 2020 Biomedicine and Molecular Biosciences (BMBS) COST Action TD1303

There has been a steady reduction in the levels of bovine tuberculosis (bTB) in Ireland for some years. This paper presents a number of methods employing geographical information systems to examine how this reduction is manifested in space and time. The focus of disease mapping has traditionally been placed on identifying areas with problems. There has been limited work done in visualising improvements. The authors describe recent spatial changes in the relative incidence of bTB in Ireland across an uniform hexagonal grid, comparing the mean of the annual animal level bTB incidence during the 10-year period from 1998 to 2007 to the years 2008 to 2012. The authors map bTB incidence trends for three successive five-year periods (1998–2002, 2003–2007 and 2008–2012). Finally, the authors investigate the change in extent and severity of interpolated bTB reactor density over time.

The advisability of evaluating the local impact of climate on herd bovine tuberculosis (bTB) occurrence has arisen due to recent climatic changes, manifested by more extreme weather events and changeable weather conditions, including changes in temperature, rainfall and vapour pressure deficit (VPD, a measure of atmospheric dryness) (Walsh 2012). Despite many studies on risk factors for herd bTB occurrence, there has been limited work evaluating the influence of weather variables. Wint and others (2002), Gilbert and others (2005) both over all of Great Britain, and Pfeiffer and others (2008, pp 86–88), in a region in southwest England found an association between the environmental variables atmospheric temperature and VPD with herd bTB occurrence, but no biological explanation was offered. In these studies, environmental variables were derived from remotely sensed data, rainfall variables were not included in the studies, and large numbers of explanatory variables were used sometimes on relatively small datasets. In this study, we conducted a preliminary evaluation of the influence of weather variables on bTB incidence in cattle herds together with well- established risk factors from 2005 to 2009 in the area of west county Wicklow (WW) in the east of Ireland. Complete data were obtained on herd- and animal-level bTB testing history from the Animal Health Computer System (AHCS), land usage from Herdfinder (each maintained by the Department of Agriculture, Food and the Marine, DAFM), and weather from Met Eireann for the period 2005–2009 at the time of study The area was chosen mainly as it has variation in weather, and herd bTB incidence was similar to the national average for the period under study. All herds registered …

Blood samples were collected opportunistically at routine post mortem examination from 199 sheep which came from 152 flocks. The location of each submitting flock was mapped. Sera were tested using a goose blood haemagglutination inhibition assay for louping ill virus. There was an animal level prevalence of 8.5%, and a flock level prevalence of 9.8%. The greatest proportion of seropositive animals was identified among the animals older than 24 months of age. The elevation of the land associated with positive flocks was greater than that of negative flocks. Lesions of non-suppurative meningoencephalitis were observed in three of the 199 animals. Deposited by bulk import

An understanding of livestock movement is critical to effective disease prevention, control and prediction. However, livestock movement in Ireland has not yet been quantified. This study has sought to define the survival and dispersal of a defined cohort of cattle born in Co. Kerry during 2000. The cohort was observed for a maximum of four years, from January 1, 2000 to December 31, 2004. Beef and dairy animals moved an average 1.31 and 0.83 times, respectively. At study end, 18.8% of the beef animals remained alive on Irish farms, including 6.7% at the farm-of-birth, compared with 48.6% and 27.7% for dairy animals respectively. Beef animals werae dispersed to all Irish counties, but mainly to Cork, Limerick, Tipperary and Galway. Dairy animals mainly moved to Cork, Limerick, and Tipperary, with less animals going to Galway, Meath and Kilkenny. The four-year survival probability was 0.07 (male beef animals), 0.25 (male dairy), 0.38 (female beef), and 0.72 (female dairy). Although there was considerable dispersal, the number of moves per animal was less than expected. Deposited by bulk import

A descriptive analysis, to investigate the potential risk factors that might have contributed to the increased incidence of bovine tuberculosis (BTB) herd-breakdowns in the reference area of Co. Donegal during the fifth year of the four-area project (FAP), was performed. Seventy two different herds were restricted for BTB during the FAP; 10 of these herds were restricted twice, resulting in a total of 82 BTB breakdowns. During the first four years of the FAP, the number of BTB herd breakdowns in the area varied from a lowest of nine to a maximum of 18 per year, and were geographically dispersed. In the fifth year of the study a considerable increase in the number of BTB breakdowns (n = 32) was observed, and there was a spatial 'cluster' of infected herds in the eastern part of the study area. The increased number of BTB breakdowns during the fifth year most likely occurred because of the recrudescence of infection, herd-to-herd transmission and, to a lesser extent, purchase of infected cattle. Infected badgers remain as a possible but less likely source of infection, especially as an explanation for the cluster of infected herds. The analysis supports the hypothesis that BTB in herds is a problem that cannot be addressed successfully by dedicating our efforts to the elimination of single risk factors. Neither is it a problem that needs to be investigated only at the herd level, but rather at the area level, including groups of contiguous herds. Deposited by bulk import

Bovine spongiform encephalopathy (BSE) is a prion disease spread by the inclusion in cattle feed of meat and bone meal made from cattle infected with the BSE agent. In the Republic of Ireland, a reinforced feed ban on mammalian meat and bone meal (MMBM) was introduced on 17th October 1996 to stop further infection of cattle. Between then and July 2010, 44 cases of BSE from 40 herds have been born, termed "born after the reinforced ban" or "BARB" cases. The objectives of this project were: (a) to describe the epidemiology of these BARB cases, (b) to determine area-level risk factors for BSE herds and how they related to the stage of the BSE epidemic, and (c) to evaluate whether the spatial pattern of BSE cases was non-random and had changed over time. The BSE epidemic was divided into three phases: cases born prior to 1991, born 1991-October 1996 and BARB cases. To determine the area level risk factors for BSE herds, a case-control study was conducted for each phase of the epidemic. We selected four control herds for each herd with one or more BSE cases. A grid of hexagons of 10 km diameter was created covering the territory of the Republic of Ireland and BSE herds and control herds were assigned to a hexagon. The numbers of cattle herds, dairy herds, piggeries and poultry holdings within the hexagons containing these case and control herds were enumerated. To evaluate the spatial pattern of BSE cases, standardised mortality ratios were calculated for each hexagon, and Oden's Ipop was used to investigate clustering. The descriptive analysis showed "feeding of concentrates" as the only common factor to all BARB cases for which information existed. The case-control study identified being a dairy herd as a risk factor during the pre-1991 phase of the BSE epidemic. Dairy herd type, a large proportion of local herds which were dairy and large numbers of piggeries and poultry holdings locally were also risk factors during the 1991-1996 phase. For the post-October 1996 phase (BARBs), dairy herd type and large numbers of other herds locally were risk factors. The spatial pattern of BSE cases changed over the three phases of the epidemic and was non-random, with evidence of clustering. The evidence supports the hypothesis that BARB cases do not arise spontaneously but rather are caused by the same food-borne infectious route as other BSE cases.

JOHNE'S disease is a chronic, granulomatous enteritis of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). The ‘gold standard’ for diagnosis is individual faecal culture (IFC) of MAP. Johne's disease has been a scheduled and notifiable disease in the Republic of Ireland since 1955. The introduction of the single European market in 1992 facilitated the free movement of animals and goods within the European Union. Between 1992 and 2004, approximately 85,000 cattle (predominantly breeding stock) were imported into Ireland (Barrett and others 2006). Between 1932 and 1992, only 92 cases of Johne's disease were reported to the Irish Department of Agriculture, Fisheries and Food (DAFF) veterinary laboratory services, while between 1995 and 2002, 232 infected animals were reported (Barrett and others 2006). These observations indicate that the prevalence of Johne's disease in Ireland has increased since the introduction of the single European market. Hence, the recent epidemiology of Johne's disease in Ireland may be different from that in other countries where the disease has been endemic at a higher prevalence for longer. Although the recent prevalence (Good and others 2009) and economic impact of clinical (Barrett and others 2006) and subclinical (Hoogendam and others 2009) Johne's disease in Irish dairy herds have been reported, there are no published studies examining the risk factors for detection of MAP by IFC in Irish dairy herds. This short communication describes a case-control study aiming to identify the risk factors associated with detection of MAP by IFC in Irish dairy herds. Case herds (n=86) were defined as herds with one or more IFC-MAP-positive results in the DAFF laboratory database from samples voluntarily submitted by private veterinary practitioners between 1995 and 2007. Control herds (n=125) were defined as herds with no IFC-MAP-positive results in DAFF's laboratory database in the same period and with no ELISA-positive …

The principal wildlife reservoir of Mycobacterium bovis in Ireland is the European badger. Studies in the Republic of Ireland (RoI) have shown that badgers culled in association with cattle herd tuberculosis breakdowns (focal culling) have a higher prevalence of infection than the badger population at large. This observation is one rationale for the medium term national strategy of focal badger culling. A vaccination strategy for the control of bovine tuberculosis (bTB) in badgers is a preferred long-term option. The Bacillus Calmette-Guérin (BCG) vaccine has been shown to decrease disease severity in captive badgers under controlled conditions. As the vaccine has been tested in a controlled environment with precise information on infection pressure, it cannot be assumed a priori that the effects of vaccination are similar in the wild, where other environmental and/or ecological factors prevail. For this reason we have designed a vaccine field trial to assess the impact of vaccination on the incidence of TB infection in a wild badger population. The selected study area for the vaccine trial (approximately 755 square kilometers) is divided into three zones each of which has similar characteristics in terms of size, number of main badger setts, cattle herds, cattle and land classification type. Three vaccination levels (100%, 50% and 0%) will be allocated to the three zones in a way that a gradient of vaccination coverage North to South is achieved. The middle zone (zone B) will be vaccinated at a 50% coverage but zone A and C will be randomly allocated with 100% or 0% vaccination coverage. Vaccination within zone B will be done randomly at individual badger level. The objective of this paper is to describe the design of a field tuberculosis vaccination trial for badgers, the epidemiological methods that were used to design the trial and the subsequent data analysis. The analysis will enable us to quantify the magnitude of the observed vaccination effect on M. bovis transmission in badgers under field conditions and to improve our knowledge of the biological effects of vaccination on susceptibility and infectiousness.

Background There is considerable international research regarding the link between human demographics and pet ownership. In several international studies, pet ownership was associated with household demographics including: the presence of children in the household, urban/rural location, level of education and age/family structure. What is lacking across all these studies, however, is an understanding of how these pets are spatially distributed throughout the regions under study. This paper describes the spatial distribution of pet dog and pet cat owning households on the island of Ireland. Results In 2006, there were an estimated 640,620 pet dog owning households and 215,542 pet cat owning households in Ireland. These estimates are derived from logistic regression modelling, based on household composition to determine pet dog ownership and the type of house to determine pet cat ownership. Results are presented using chloropleth maps. There is a higher density of pet dog owning households in the east of Ireland and in the cities than the west of Ireland and rural areas. However, in urban districts there are a lower proportion of households owning pet dogs than in rural districts. There are more households with cats in the urban areas, but the proportion of households with cats is greater in rural areas. Conclusions The difference in spatial distribution of dog ownership is a reflection of a generally higher density of households in the east of Ireland and in major cities. The higher proportion of ownership in the west is understandable given the higher proportion of farmers and rural dwellings in this area. Spatial representation allows us to visualise the impact of human household distribution on the density of both pet dogs and pet cats on the island of Ireland. This information can be used when analysing risk of disease spread, for market research and for instigating veterinary care.

This study used techniques in Geographical Information Systems (GIS) to explore the spatial patterns of bovine tuberculosis (TB) in the whole island of Ireland over an 11-year period. This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context. The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006. The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval. Deposited by bulk import

Bovine brucellosis is a major animal health problem in the Republic of Korea. Further, a number of human cases of brucellosis have recently been detected. This paper provides an overview of surveillance (to detect new cases) and control (to clear infection following case detection) of bovine brucellosis in the Republic of Korea during 2000-2006. Using data from AIMS (the national animal infectious disease data management system), we conducted separate descriptive analyses, initially using farm and then episode as our unit of interest. An episode was defined as a period of compulsory herd trading restriction, following detection of infection with Brucella abortus in one or more cattle. We also identified risk factors for two measures of disease control: episode duration (logistic generalised estimating equation model) and time to re-restriction (Cox's proportional-hazard model). There were 8530 and 52,739 reactor farms and reactor cattle, respectively, during 2000-2006. From 2004 to 2006, there was a substantial increase in the number of new outbreaks, particularly within the beef sector. The probability of a prolonged episode (>150 days) and the hazard of a second episode each increased with herd size. Further, the hazard of a second episode was higher in 2005 (compared with other years) and in the southeast of Korea (compared with other provinces). The effect of outbreak size on control varied between the beef and dairy sectors. The increase in beef cattle reactors in 2004-2006 is closely aligned to an increase in surveillance effort. Nonetheless, it is likely that this is a genuine reflection of the recent establishment and spread of brucellosis in the Korean beef cattle population. The recent increase in surveillance coverage in the beef sector is central to national eradication efforts. Current strategies to control infection following detection have generally been effective, leading to rapid clearance of infection on most farms. Control becomes problematic with increasing herd size. This work provides a detailed insight into surveillance and control of bovine brucellosis in Korea, and should assist both policy-makers and field veterinarians to improve the effectiveness of national eradication efforts.

We investigated the impact of targeted removal of badgers on the subsequent bovine tuberculosis (BTB) risk in cattle herds in county Laois, Ireland. The study period was 1989-2005. For each of 122 targeted badger-removal licenses (permit to remove badgers in the proximity of cattle herds undergoing a serious BTB episode), the herd number (index herd) for which the license was given was obtained. The herds in the proximity of the index herd were identified from another database. The main "exposure" in our study was the geographical location of herds relative to the area in which targeted badger removal was conducted. We categorized herds into five different exposure groups: herds were classified as non-exposed and denoted as group 0 (reference group) if they were located 500 m or more from the edge of any parcel of land of the index herd; group 1, was the index herds, group 2 the immediate (contiguous) neighbors of the index herd, group 3 herds were not immediate neighbors but within 150 m and group 4 herds were between 150 m and 500 m distance from the edge of any parcel of land of the index herd, respectively. We conducted a survival analysis (allowing multiple failures per herd) to compare the hazard of having a BTB episode in any of the four groups of exposed herds vs. the hazard in herds in the reference group. We controlled for other known risk factors as well taking into account a temporal component. Our analysis showed that the hazard ratio for the index herds (group 1) were non-significantly increased, indicating that there was no difference in the hazard of failing a BTB test (after the targeted badger removal was conducted) between index herds and reference herds. For the rest of the herds farther away from badger removal activities the hazards were lower than herds in areas not under badger removal. The hazard in the reference group decreased over the study period.

All the Irish cattle herds considered “clear” of bovine tuberculosis (BTB) having a single animal with a tuberculous lesion at slaughter during 2003 were identified. We performed a descriptive and logistic regression analysis to investigate whether selected risk factors had an association with the result of the herd test immediately after the tuberculous lesion was found (“Factory Lesion Test”, FLT). At the FLT, only 19.7% ( n = 338) of these 1713 herds had 1 or more standard reactors. The lesioned animal was home-bred in 46% of the “source” herds; these herds had an increased risk (23.4%) of having at least 1 standard reactor animal relative to herds with a purchased-lesioned animal (16.6%) (RR = 1.41). Our logistic models identified a number of important risk factors; two that appeared most important in predicting the FLT outcome were the time spent (residency) by the lesioned animal in the “source” herd, and the presence, or not, of the lesioned animal in a previous BTB episode in either the “source” herd, or the seller's herd in the case the lesioned animal was purchased. Our models fit the data well based on the Hosmer–Lemeshow test, however their sensitivity and specificity were very low (57% and 61% respectively). Surveillance of the cattle population for BTB using lesions found at slaughter is an essential component of an overall control program. Nonetheless, due to the poor predictability of the variables we measured, complete herd investigations are needed to help explain the FLT outcome of a herd.

This study investigated the distribution of bovine spongiform encephalopathy (BSE) in herds of cattle in Ireland over the years 1996 through 2000, prior to the introduction of widespread active surveillance. Mappings of index herds, herd density, and standardized morbidity ratios, by county, were employed to help visualize areas of potential clustering of BSE. The hypothesis of spatial clustering was tested using a spatial scan statistic applied to the location of the herd where exposure likely occurred. Both Bernoulli and Poisson spatial models indicated marked clustering of BSE herds centred on Monaghan county, with secondary clusters detected by Bernoulli approaches and some Poisson models in Wexford and Cork. The number of cases increased with time, but clear temporal-spatial clusters were rarely detected, except in the case of a cluster in Wexford. The focussed spatial scan analyses using the location of large-scale feed suppliers provided support for the hypothesis that clustering of BSE may be associated with feed source. The results of our analyses provided strong evidence in support of the hypothesis that herds, in which animals were most likely to have been exposed to the BSE agent, cluster geographically.

We investigated whether strains (restriction fragment length polymorphism, RFLP-types) of Mycobacterium bovis isolated from badgers and from cattle clustered among and within four areas in Ireland. The spatial scan test and nearest-neighbor analysis were used as the spatial cluster-detection techniques. In addition, for each of the major strains, associations between the distance to badger setts and the "centroid" of the cattle farm were assessed in a logistic model. Overall, between September 1997 and May 2000, 316 and 287 M. bovis samples, from badgers and cattle, respectively, were strain-typed. The distribution of strains in badgers, and separately in cattle, differed among areas. Within each of the four large areas, badgers and cattle tended to have similar strains; this is consistent with the sharing of M. bovis strains within an area. In more detailed within-area analyses, some spatial clusters of M. bovis strains were detected, separately, in both cattle and badgers. Almost half of the infected badger setts with a specific strain were located outside of the "detected" clusters. There was no association between the number of infected badgers with a specific M. bovis strain within 2 or 5 km distances to cattle herds, and the risk of the same strain in cattle. We speculate about the dynamic nature of badger movements, as an explanation for the absence of more clusters of most of the strains of M. bovis isolated from badgers, and its impact on trying to study transmission of M. bovis between cattle and badger.

We described the distribution of badger populations in four different areas in the Republic of Ireland. The data came from periodic targeted badger-removal and subsequent post-mortem examinations conducted between 1989 and September 1997, and from a formal badger-removal project in the same areas from 1997 through 1999. Records were complete for 2292 badgers regarding the date of capture, tuberculosis status, geographical area and specific sett from where the badgers were snared. Of 3187 setts, 2290 had no badgers recorded against them (i.e. were inactive). The badger-level prevalence of tuberculosis differed among areas (range 13-29%). Badger populations were highly clustered by sett, and this result was similar over the four study areas. The median number of badgers per active sett was 2. Tuberculous badgers also clustered within a sett. The third quartile of tuberculous badgers was 1 per active sett. The prevalence of tuberculous badgers within a sett was not related to the total number of badgers. There was little evidence of spatial clustering with only one local cluster of tuberculous setts in each of three areas, and none in the fourth area. After adjusting for the number of badgers per sett, only one area had spatial clusters identified.

Bovine babesiosis is caused by the tick-borne blood parasite, Babesia divergens. A survey of veterinary practitioners and farmers in Ireland in the 1980's revealed an annual incidence of 1.7% associated with considerable economic losses. However, two subsequent surveys in the 1990's indicated a decline in clinical babesiosis. Recent evidence from continental Europe suggests that, probably due to climate change, the distribution of the tick vector of B. divergens, Ixodes ricinus is extending to more northerly regions and higher altitudes. In addition, milder winters are thought to increase the window of tick activity. In order to determine whether any such changes have affected the incidence of bovine babesiosis in Ireland, a questionnaire survey of farmers and veterinarians was carried out and compared against data from previous surveys. Our results indicate that while the incidence of clinical disease has continued to decline, cases occurred at any time of year. In contrast to previous surveys, affected farms were the same size as unaffected ones and there was no correlation between disease risk and the presence of deer on the land. Disease severity and mortality rates were increased because many infections were advanced by the time they were detected and treated. While the precise reasons for the decline in the incidence of redwater are unknown, a reversal of the trend could be devastating, as vigilance among farmers and veterinarians is flagging and the national herd is losing its protective immunity to disease.

This study investigated possible associations between soil types, land use and badger numbers in an area of the Irish Midlands where badger removal had been conducted during 1989-1994. For this purpose, the area was divided into approximately 2500 geo-referenced square grids of 0.5 degrees km per side. For the outcomes (setts per grid, badgers per grid and tuberculous badgers per grid), Poisson models of land use, of soil type, and a combination of these two were developed. Influential grids were removed and the models adjusted for over-dispersion in the badger outcomes. Mineral-based soils, dry and very-dry peat soils supported increased numbers of setts and badgers. High-quality pasture was the major land use (pastures often are found on mineral-based soils) and supported increased numbers of setts, badgers, and tuberculous badgers. "Natural" areas also supported more setts and broad-leaf forested areas were associated with increased tuberculous badger numbers. Discontinuous urban areas tended to decrease sett numbers per grid. Hedgerow length was not an important predictor given the information on soil type and land use. Spatial correlations existed for badger setts in 1 degrees km grids, for badger numbers in 1.5 degrees km grids, and for tuberculous badgers in 2 degrees km grids. The latter two grids have approximately the same area as the territory size used by a social group of badgers. There were no spatial correlations at the smallest (0.5 km) grid size.

The conclusion from the randomised badger culling trial was that localised badger culling not only fails to control but can actually increase the incidence of bovine tuberculosis in cattle. Professor Simon More and colleagues from University College Dublin question that conclusion, arguing that the data do not provide sufficient evidence to rule out alternative hypotheses.

Selected demographic features and trends in bovine tuberculosis (BTB) from 1995 to 2010 are described for the countries of the UK and the Republic of Ireland, using standardised definitions and measures. All countries experienced a reduction in the number of cattle and herds and in the proportion of dairy herds, while average herd size increased. In general, the trends indicate a stable situation of very low BTB prevalence in Scotland and, over most of the period, a rising prevalence in England and Wales. The prevalence in the Republic of Ireland declined while Northern Ireland experienced both a rise and fall. Differences in demography, BTB programme structure and test results were noted, particularly between the island of Ireland and Great Britain. Further investigation of these differences may provide valuable insights into risk factors for BTB and optimisation of existing BTB programmes.

Bovine tuberculosis (bTB) continues to be a problem in cattle herds in Ireland and Britain. It has been suggested that failure to eradicate this disease is related to the presence of a wildlife reservoir (the badger). A large-scale project was undertaken in the Republic of Ireland during 1997–2002 to assess whether badger removal could contribute to reducing risk of cattle herd breakdowns in four areas. During the period of that “four area” study, there was a significant decrease in risk in intensively culled (removal) areas relative to reference areas. In the present study, we revisit these areas to assess if there were any residual area effects of this former intervention a decade on (2007–2012). Over the study period there was an overall declining trend in bTB breakdown risk to cattle herds. Cattle herds within former removal areas experienced significantly reduced risk of breakdown relative to herds within former reference areas or herds within non-treatment areas (OR: 0.53; P < 0.001). Increased herd breakdown risk was associated with increasing herd size (OR: 1.92-2.03; P < 0.001) and herd bTB history (OR: 2.25-2.40; P < 0.001). There was increased risk of herd breakdowns in areas with higher badger densities, but this association was only significant early in the study (PD*YEAR interaction; P < 0.001). Badgers were culled in areas with higher cattle bTB risk (targeted culling). Risk tended to decline with cumulative culling effort only in three counties, but increased in the fourth (Donegal). Culling badgers is not seen as a viable long-term strategy. However, mixed policy options with biosecurity and badger vaccination, may help in managing cattle breakdown risk. Electronic supplementary material The online version of this article (doi:10.1186/s13567-014-0109-4) contains supplementary material, which is available to authorized users.