Active animal health surveillance in European Union Member States: gaps and opportunities.

Animal health surveillance enables the detection and control of animal diseases including zoonoses. Under the EU-FP7 project RISKSUR, a survey was conducted in 11 EU Member States and Switzerland to describe active surveillance components in 2011 managed by the public or private sector and identify gaps and opportunities. Information was collected about hazard, target population, geographical focus, legal obligation, management, surveillance design, risk-based sampling, and multi-hazard surveillance. Two countries were excluded due to incompleteness of data. Most of the 664 components targeted cattle (26·7%), pigs (17·5%) or poultry (16·0%). The most common surveillance objectives were demonstrating freedom from disease (43·8%) and case detection (26·8%). Over half of components applied risk-based sampling (57·1%), but mainly focused on a single population stratum (targeted risk-based) rather than differentiating between risk levels of different strata (stratified risk-based). About a third of components were multi-hazard (37·3%). Both risk-based sampling and multi-hazard surveillance were used more frequently in privately funded components. The study identified several gaps (e.g. lack of systematic documentation, inconsistent application of terminology) and opportunities (e.g. stratified risk-based sampling). The greater flexibility provided by the new EU Animal Health Law means that systematic evaluation of surveillance alternatives will be required to optimize cost-effectiveness.

Systematic review of surveillance systems and methods for early detection of exotic, new and re-emerging diseases in animal populations.

In this globalized world, the spread of new, exotic and re-emerging diseases has become one of the most important threats to animal production and public health. This systematic review analyses conventional and novel early detection methods applied to surveillance. In all, 125 scientific documents were considered for this study. Exotic (n = 49) and re-emerging (n = 27) diseases constituted the most frequently represented health threats. In addition, the majority of studies were related to zoonoses (n = 66). The approaches found in the review could be divided in surveillance modalities, both active (n = 23) and passive (n = 5); and tools and methodologies that support surveillance activities (n = 57). Combinations of surveillance modalities and tools (n = 40) were also found. Risk-based approaches were very common (n = 60), especially in the papers describing tools and methodologies (n = 50). The main applications, benefits and limitations of each approach were extracted from the papers. This information will be very useful for informing the development of tools to facilitate the design of cost-effective surveillance strategies. Thus, the current literature review provides key information about the advantages, disadvantages, limitations and potential application of methodologies for the early detection of new, exotic and re-emerging diseases.

Identification of suitable areas for West Nile virus outbreaks in equid populations for application in surveillance plans: the example of the Castile and Leon region of Spain.

The introduction and rapid spread of West Nile virus (WNV) into new areas such as the American continent, associated also with the severity of the disease in humans and equids has increased concerns regarding the need to better prevent and control future WNV incursions. WNV outbreaks in equids usually occur under specific climatic and environmental conditions and, typically, before detection of WNV cases in humans. Targeting surveillance strategies in areas and time periods identified as suitable for WNV outbreaks in equids may act as an early-warning system to prevent disease in both equids and humans. This study used a GIS-based framework to identify suitable areas and time periods for WNV outbreak occurrence in one of the most important areas of equid production in Spain, i.e. Castile and Leon. Methods and results presented here may help to improve the early detection and control of future WNV outbreaks in Spain and other regions.

Constant Hepatitis E Virus (HEV) Circulation in Wild Boar and Red Deer in Spain: An Increasing Concern Source of HEV Zoonotic Transmission.

Hepatitis E is a viral zoonosis that affects multiple hosts. The complete dynamics of infection in wildlife are still unknown, but the previous fact facilitates the maintenance and circulation of the virus, posing a risk to human health in the case of meat consumption from susceptible animals. In Spain, it has been shown how domestic pigs, cattle and wildlife (i.e. wild boar and red deer) clearly interact in hunting farms, generating a complex epidemiological situation in terms of interspecies pathogen transmission. Therefore, in this study, we aimed to (i) evaluate the circulation of the virus in geographically close domestic (Iberian pigs) and wild animals (wild boar and deer) living in hunting areas from central Spain over an 8-year period (2003-2010) and (ii) to determine whether HEV could be used as a marker of domestic-wildlife contact. For these purposes, a longitudinal analysis of Iberian pig, wild boar and red deer samples (n = 287) through virological and serological tests was conducted to shed light upon the circulation events of HEV. Regarding HEV RNA detection by real-time RT-PCR, 10.12% samples (95% CI: 5.44-14.8) from wild boar and 16.05% samples (95% CI: 8.06-24.04) from red deer were positive. As for the Iberian pigs, none of the 48 samples was positive for HEV RNA detection. In the serological analysis, 43.75% (95% CI: 29.75-57.75) from Iberian pig, 57.40% (95% CI: 48.10-66.70) from wild boar and 12.85% (95% CI: 5.01-20.69) samples from red deer presented anti-HEV antibodies. Positive samples were distributed among all study years (2003-2010). These results depict the urgent need to improve the inspection and surveillance of these species and their products. In the case of HEV, it is clear that the stable and constant presence of the virus in wildlife and its contact with Iberian pigs pose a risk for human health as they are all destined for human consumption.

Identification of Suitable Areas for African Horse Sickness Virus Infections in Spanish Equine Populations.

African horse sickness (AHS) is one of the most important vector-borne viral infectious diseases of equines, transmitted mainly by Culicoides spp. The re-emergence of Culicoides-borne diseases in Europe, such as the recent bluetongue (BT) or Schmallenberg outbreaks, has raised concern about the potential re-introduction and further spread of AHS virus (AHSV) in Europe. Spain has one of the largest European equine populations. In addition, its geographical, environmental and entomological conditions favour AHSV infections, as shown by the historical outbreaks in the 1990s. The establishment of risk-based surveillance strategies would allow the early detection and rapid control of any potential AHSV outbreak. This study aimed to identify the areas and time periods that are suitable or at high risk for AHS occurrence in Spain using a GIS-based multicriteria decision framework. Specifically risk maps for AHS occurrence were produced using a weighted linear combination of the main risk factors of disease, namely extrinsic incubation period, equine density and distribution of competent Culicoides populations. Model results revealed that the south-western and north-central areas of Spain and the Balearic Islands are the areas at the highest risk for AHSV infections, particularly in late summer months. Conversely, Galicia, Castile and Leon and La Rioja can be considered as low-risk regions. This result was validated with historical AHS and BT outbreaks in Spain, and with the Culicoides vector distribution area. The model results, together with current Spanish equine production features, should provide the foundations to design risk-based and more cost-effective surveillance strategies for the early detection and rapid control potential of AHS outbreaks in Spain.

Natural Immunity of Sheep and Lambs Against the Schmallenberg Virus Infection.

Since the first reports of the Schmallenberg disease (SBD) outbreaks in late 2011, the disease has spread across Europe, affecting cattle and sheep farms. While Schmallenberg virus (SBV) causes a mild clinical disease in adults, infection of pregnant females may lead to the production of typical congenital malformations (CMFs) in their offspring. It is speculated that the immunity acquired after a SBV infection is effective in preventing further infections. However, this has not been proven in naturally infected sheep, especially if they are pregnant when reinfected. The aim of this study was to monitor the natural immunity in SBV-infected sheep. Twenty-four ewes from the only Spanish farm with a SBV OIE-notified outbreak were sampled. Subsequently, nine pregnant ewes were inoculated with SBV infectious plasma under controlled conditions. Six of them were euthanized before delivery, and their fetuses were inspected for lesions indicative for the SBV infection. The three remaining ewes were allowed to deliver one lamb each. Inoculation of the lambs was scheduled at approx. 3 months after birth. All samples were analyzed for viral RNA by RT-PCR, and for antibodies by an indirect ELISA and a virus neutralization test (VNT). The majority of the 24 ewes showed a serological reaction against SBV. The three ewes that were allowed to lamb down demonstrated variable degrees of seroconversion which corresponded to the levels of immune reaction observed in their lambs. Moreover, no viral RNA was detected, no lesions were observed in the fetuses, and no clinical signs were detected in the inoculated animals. These findings suggest that the immunity acquired by sheep following a natural SBV infection could be sufficient to stop SBV reinfection. However, vaccination could be a valuable tool to control SBV infections and associated economic losses as it affords a more uniform and predictable protection at the flock/herd level.

Farm-level risk factors for the occurrence, new infection or persistence of tuberculosis in cattle herds from South-Central Spain.

Eradication of tuberculosis (TB) in cattle is a priority in the EU. However, and despite the resources invested, TB eradication is still a goal yet to be accomplished. As a consequence, the identification of risk factors contributing to TB transmission and persistence is key to a better understand and, ultimately, more cost-effectively control and eradicate this complex zoonotic disease worldwide. This study aimed to identify the factors contributing to the TB occurrence, new infection, and persistence in one of the most TB-prevalent regions in the South-Central part of Spain (SCS), Ciudad Real (CR), and for which high quality and detailed information on cattle and wild ungulate demographics, management, and sanitary status was available for up to 5 years (2007-2011). Multilevel logistic modeling was used for this purpose. Results of this study revealed that the risk for TB (occurrence, new infection, and/or persistence) in cattle herds from CR is related to TB-persistence on farm in previous years, extensive production systems (beef and bullfighting being more risky that dairy) and large farm in terms of cattle number. Also, the presence and proximity of fenced hunting estates (which are usually intensively managed) significantly contributed to the risk of TB occurrence and persistence in CR. This association suggests that wild ungulates may play a role as TB-reservoirs and transmit TB to cattle in the CR, a region where TB is endemic and is associated with extensive farming of beef cattle. To the best of author's knowledge this is the first study to (i) evaluate the wild ungulate-domestic interface at a farm level using detailed information over an extensive region and period of time (2007-2011) and (ii) to identify a direct association between TB in cattle and the proximity and management practices of wild ungulates. Methods and results presented here may support policies to better prevent and control TB in the SCS and in other regions/countries with similar epidemiological conditions.