279 research outputs found

    Efficiency of spatio-temporal vaccination regimes in wildlife populations under different viral constraints

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    Classical Swine Fever (CSF) is considered an endemic disease in European wild boar populations. In view of the high economic impact of the introduction of the virus into domestic pig units, huge efforts are invested in the preventive control of CSF in wild boar populations. Recent European Community guidelines favour oral mass vaccination against CSF in wild boar populations. The guidelines are explicit on the temporal structure of the vaccination protocol, but little is known about the efficacy of different spatial application schemes, or how they relate to outbreak dynamics

    Simulation of Spread of African Swine Fever, Including the Effects of Residues from Dead Animals

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    To study the spread of African swine fever (ASF) within a pig unit and the impact of unit size on ASF spread, a simulation model was created. In the model, an animal can be in one of the following stages: susceptible, latent, subclinical, clinical or recovered. Animals can be infectious during the subclinical stage and are fully infectious during the clinical stage. ASF virus (ASFV) infection through residues of dead animals in the slurries was also modeled in an exponentially fading-out pattern. Low and high transmission rates for ASFV were tested in the model. Robustness analysis was carried out in order to study the impact of uncertain parameters on model predictions. The results showed that the disease may fade out within the pig unit without a major outbreak. Furthermore, they showed that spread of ASFV is dependent on the infectiousness of subclinical animals and the residues of dead animals, the transmission rate of the virus and importantly the unit size. Moreover, increasing the duration of the latent or the subclinical stages resulted in longer time to disease fade out. The proposed model is a simple and robust tool simulating the spread of ASFV within a pig house taking into account dynamics of ASFV spread and the unit size. The tool can be implemented in simulation models of ASFV spread between herds

    Decision support beyond total savings—Eligibility and potential savings for individual participants from changes in the national surveillance strategy for bovine viral diarrhoea (BVD) in Ireland

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    Publication history: Accepted - 9 April 2018; Published online - 11 April 2018Surveillance and management of livestock diseases is often evaluated with reference to expected sector-wide costs. In contrast, we calculate losses or savings for individual herd owners of a change in monitoring strategy during a national cattle disease eradication programme: bovine viral diarrhoea (BVD) in Ireland. The alternative strategy differs in how the disease is identified; by its sample- rather than census-based approach; and by its greater cost per test. We examined the costs faced by each breeding herd if testing were conducted using serology on a sample of young stock, in contrast to the current method of tissue-tag testing of all newborn calves. Following best knowledge of the likely costs, the following input values were used: i) €2.50 per test for tissue-tag testing and €7.66 for serology, ii) serology conducted on a sample of 10 young stock per management group from either the 6–12 month or 9–18 month cohorts; iii) 3 scenarios for the number of management groups: one per herd (M∞), one per 100 cows (M100) and one per 50 cows (M50). We found that many herds would often not be able to supply a suitable sample of young stock for serology or would face higher testing costs than when using tissue tag testing. The largest number (25%) of herds would benefit from participating in the change if sampling were done in October. These could annually save between €2.1 million under M∞ and €0.8 million under M50 (€108 - €49 per herd). However, analysing herd-level data we found that 90% of all Irish breeding herds would save less than €1.42 per cow or €99 in total per annum under M∞, and €0.59 per cow or €36 in total under M50. In a sensitivity analysis, we allowed serology costs to vary between €2 and €10 per animal. Herds at the 10 t h percentile of most savings made from switching would save at most €155 (M∞ at €2 per serology test) but would not save anything under M50 at costs ≥ €10. We conclude that, under these assumptions, the expected reduction in testing costs for the majority of beneficiaries would barely outweigh the practical implications of the strategy switch or the risks to the eradication programme associated with sample based surveillance. This study does not assess the cost-effectiveness of alternatives post-eradication.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

    Epidemiology of age-dependent prevalence of Bovine Herpes Virus Type 1 (BoHV-1) in dairy herds with and without vaccination

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    Research Areas: Veterinary SciencesMany studies report age as a risk factor for BoHV-1 infection or seropositivity. However, it is unclear whether this pattern refects true epidemiological causation or is a consequence of study design and other issues. Here, we seek to understand the age-related dynamics of BoHV-1 seroprevalence in seasonal calving Irish dairy herds and provide decision support for the design and implementation of efective BoHV-1 testing strategies. We analysed seroprevalence data from dairy herds taken during two Irish seroprevalence surveys conducted between 2010 and 2017. Age-dependent seroprevalence profles were constructed for herds that were seropositive and unvaccinated. Some of these profles revealed a sudden increase in seroprevalence between adjacent age-cohorts, from absent or low to close to 100% of seropositive animals. By coupling the outcome of our data analysis with simulation output of an individual-based model at the herd scale, we have shown that these sudden increases are related to extensive virus circulation within a herd for a limited time, which may then subsequently remain latent over the following years. BoHV-1 outbreaks in dairy cattle herds afect animals independent of age and lead to almost 100% seroconversion in all age groups, or at least in all animals within a single epidemiological unit. In the absence of circulating infection, there is a year-on-year increase in the age-cohort at which seroprevalence changes from low to high. The fndings of this study inform recommendations regarding testing regimes in the context of contingency planning or an eradication programme in seasonal calving dairy herds.info:eu-repo/semantics/publishedVersio

    Scientific Opinion on peste des petits ruminants

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    Peste des petits ruminants (PPR) is a severe viral disease of small ruminants caused by a Morbillivirus closely related to rinderpest virus. It is widespread in Africa and Asia and is currently also found in Turkey and Northern Africa. PPR is transmitted via direct contact, and the disease would mainly be transferred to infection-free areas by transport of infected animals. In the EU, it could only happen through illegal transport of animals. The risk of that depends on the prevalence in the country of origin and the number of animals illegally moved. The extent of the spread would depend mainly on the time during which it is undetected, the farm density, the frequency and distance of travel of animals. PPR has a high within-herd transmission rate, therefore contacts between flocks, e.g. through common grazing areas, should be avoided when PPR is present. If PPR enters EU areas with dense sheep population but low goat density, it may spread rapidly undetected, since goats are considered more susceptible than sheep. Effective measures in limiting the spread of PPR in the EU include prompt culling of infected herds, rapid detection, movement restriction, and disinfection. Live attenuated vaccines against PPR are available, safe and effective, and have been successfully used to control PPR epidemics, but no method exists for differentiating between infected and vaccinated animals; therefore, the development of one is recommended. Awareness-raising campaigns for farmers and veterinary staff to promote recognition of the disease should be considered. The cooperation of the EU with neighbouring countries should be encouraged to prevent the spread 20 of PPR and other transboundary diseases

    Update of the Scientific Opinion on the risks to plant health posed by Xylella fastidiosa in the EU territory

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    EFSA was asked to update the 2015 EFSA risk assessment on Xylella fastidiosa for the territory of the EU. In particular, EFSA was asked to focus on potential establishment, short‐ and long‐range spread, the length of the asymptomatic period, the impact of X. fastidiosa and an update on risk reduction options. EFSA was asked to take into account the different subspecies and Sequence Types of X. fastidiosa. This was attempted throughout the scientific opinion but several issues with data availability meant that this could only be partially achieved. Models for risk of establishment showed most of the EU territory may be potentially suitable for X. fastidiosa although southern EU is most at risk. Differences in estimated areas of potential establishment were evident among X. fastidiosa subspecies, particularly X. fastidiosa subsp. multiplex which demonstrated areas of potential establishment further north in the EU. The model of establishment could be used to develop targeted surveys by Member States. The asymptomatic period of X. fastidiosa varied significantly for different host and pathogen subspecies combinations, for example from a median of approximately 1 month in ornamental plants and up to 10 months in olive, for pauca. This variable and long asymptomatic period is a considerable limitation to successful detection and control, particularly where surveillance is based on visual inspection. Modelling suggested that local eradication (e.g. within orchards) is possible, providing sampling intensity is sufficient for early detection and effective control measures are implemented swiftly (e.g. within 30 days). Modelling of long‐range spread (e.g. regional scale) demonstrated the important role of long‐range dispersal and the need to better understand this. Reducing buffer zone width in both containment and eradication scenarios increased the area infected. Intensive surveillance for early detection, and consequent plant removal, of new outbreaks is crucial for both successful eradication and containment at the regional scale, in addition to effective vector control. The assessment of impacts indicated that almond and Citrus spp. were at lower impact on yield compared to olive. Although the lowest impact was estimated for grapevine, and the highest for olive, this was based on several assumptions including that the assessment considered only Philaenus spumarius as a vector. If other xylem‐feeding insects act as vectors the impact could be different. Since the Scientific Opinion published in 2015, there are still no risk reduction options that can remove the bacterium from the plant in open field conditions. Short‐ and long‐range spread modelling showed that an early detection and rapid application of phytosanitary measures, consisting among others of plant removal and vector control, are essential to prevent further spread of the pathogen to new areas. Further data collection will allow a reduction in uncertainty and facilitate more tailored and effective control given the intraspecific diversity of X. fastidiosa and wide host range.Additional co-authors: EFSA Panel on Plant Health (PLH), Wopke van der Werf, Antonio Vicent Civera, Jonathan Yuen, Lucia Zappalà, Donato Boscia, Gianni Gilioli, Rodrigo Krugner, Alexander Mastin, Anna Simonetto, Joao Roberto Spotti Lopes, Steven White, José Cortinas Abrahantes, Alice Delbianco, Andrea Maiorano, Olaf Mosbach‐Schulz, Giuseppe Stancanelli, Michela Guzzo, Stephen Parnel

    Pest categorisation of Sternochetus mangiferae

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    The European Commission requested EFSA to conduct a pest categorisation of Sternochetus mangiferae (Coleoptera: Curculionidae), a monophagous pest weevil whose larvae exclusively feed on mango seeds, whereas adults feed on mango foliage. S. mangiferae is a species with reliable methods available for identification. It is regulated in the EU by Council Directive 2000/29/EC where it is listed in Annex IIB as a harmful organism whose introduction into EU Protected Zones (PZ) (Alentejo, Algarve and Madeira in Portugal, and Granada and Malaga in Spain) is banned. S. mangiferae is native to South East Asia and has spread to other mango-growing areas in Africa, South America and Oceania, causing significant damage. Larvae of S. mangiferae have been detected several times in mango fruit imported into the EU. In 2013, an outbreak was declared in one PZ in Spain. Official measures taken achieved eradication, which was officially declared in January 2018. The EFSA Plant Health Panel concludes that S. mangiferae could establish again and spread in the mango-growing areas of southern EU. Considering the criteria within the remit of EFSA to assess the status as a potential Union quarantine pest (QP), as a potential protected zone quarantine pest (PZQP) or as a potential regulated non-quarantine pest (RNQP), S. mangiferae meets with no uncertainties the criteria for consideration as a potential Union QP, as it is absent from the EU, potential pathways for entry exist, and its establishment would cause an economic impact. The criterion of the pest being present in the EU, which is a prerequisite for RNQP and PZ QP, is not met

    Pest categorisation of Conotrachelus nenuphar

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    The EFSA Panel on Plant Health performed a pest categorisation of Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), for the EU. C. nenuphar is a well-defined species, recognised as a serious pest of stone and pome fruit in the USA and Canada where it also feeds on a range of other hosts including soft fruit (e.g. Ribes, Fragaria) and wild plants (e.g. Crataegus). Adults, which are not good flyers, feed on tender twigs, flower buds and leaves. Females oviposit into host fruit; if oviposition occurs in young fruit, the fruit usually falls prematurely reducing yield; oviposition in older fruit causes surface blemishes and the fruit distorts as it develops reducing marketability. Larvae develop within host fruit but exit to pupate in soil. Adults overwinter in leaf litter. C. nenuphar is not known to occur in the EU and is listed in Annex IAI of Council Directive 2000/29/EC. Fruit infested shortly before harvest and soil with leaf litter accompanying plants for planting could potentially provide a pathway into the EU. Considering the climatic similarities between North America and Europe, and that hosts occur widely within the EU, C. nenuphar has potential to establish within the EU. There could be one or two generations per year, as in North America. Impacts could be expected, e.g. in Prunus spp. and apples. Phytosanitary measures are available to reduce the likelihood of introduction of C. nenuphar. All of the criteria assessed by EFSA for consideration as a potential Union quarantine pest are met. C. nenuphar does not meet the criteria of occurring in the EU nor plants for planting being the principal means of spread. Hence it does not satisfy all of the criteria that are within the remit of EFSA to assess for it to be regarded as a Union regulated non-quarantine pest (RNQP)

    Guidance on the assessment criteria for applications for new or modified stunning methods regarding animal protection at the time of killing

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    This guidance defines the process for handling applications on new or modified stunning methods and the parameters that will be assessed by the EFSA Animal Health and Welfare (AHAW) Panel. The applications, received through the European Commission, should contain administrative information, a checklist of data to be submitted and a technical dossier. The dossier should include two or more studies (in laboratory and slaughterhouse conditions) reporting all parameters and methodological aspects that are indicated in the guidance. The applications will first be scrutinised by the EFSA’s Applications Desk (APDESK) Unit for verification of the completeness of the data submitted for the risk assessment of the stunning method. If the application is considered not valid, additional information may be requested from the applicant. If considered valid, it will be subjected to assessment phase 1 where the data related to parameters for the scientific evaluation of the stunning method will be examined by the AHAW Panel. Such parameters focus on the stunning method and the outcomes of interest, i.e. immediate onset of unconsciousness or the absence of avoidable pain, distress and suffering until the loss of consciousness and duration of the unconsciousness (until death). The applicant should also propose methodologies and results to assess the equivalence with existing stunning methods in terms of welfare outcomes. Applications passing assessment phase 1 will be subjected to the following phase 2 which will be carried out by the AHAW Panel and focuses on the animal welfare risk assessment. In this phase, the Panel will assess the outcomes, conclusions and discussion proposed by the applicant. The results of the assessment will be published in a scientific opinion.info:eu-repo/semantics/publishedVersio
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