I. Iglesias

An approach for mapping the vulnerability of European Union soils to antibiotic contamination.

Release of antibiotics into the environment through the agricultural reuse of animal manure is considered a cause of chronic environmental exposure that often leads to adverse ecotoxicological effects, as well as to the introduction of antibiotic-resistant bacteria into the environment. The vulnerability of soil to antibiotic contamination plays a major role in determining the extent of the contamination and the likelihood of the emergence of antibiotic resistance and the appearance of ecotoxicological effects. It depends on soil characteristics, which vary across Europe, and antibiotic characteristics, which vary across drug classes. Understanding how soil vulnerability varies geographically for different veterinary medicinal products would be very useful for resource allocation among surveillance programmes. This paper performs risk analysis of the EU region for 12 antimicrobials using a spatial assessment performed in four steps. First, antibiotic release was estimated based on livestock density. Then exposure was estimated based on antimicrobial soil contamination. Third, consequences were modelled based on soil uses. Finally, risk was estimated by combining release, exposure and consequences using spatial multicriteria decision analysis. A final risk value for soil vulnerability was calculated for each antibiotic studied and displayed in chloropletic maps (ArcGIS 9.3). Furthermore, the Getis-Ord Gi statistic was used to identify clusters of areas at high risk for antibiotic soil contamination. Enrofloxacin was the highest-risk antibiotic in the European Union, followed by tetracyclines, tylosin and sulfodiazine. The highest risk values were found in Belgium, Ireland, Netherlands, Switzerland, Denmark, Germany and the UK. The results suggest that this methodology can be used successfully for evaluating the contamination potential of antibiotics over large areas with limited input data. This work is a preliminary step towards prioritising the use of veterinary medicinal products (VMPs), orientating monitoring studies and antimicrobial surveillance programmes, and informing sustainable decision-making for interventions designed to mitigate the risk of VMPs.

Assessing the risk of African swine fever introduction into the European Union by wild boar.

The presence of African swine fever (ASF) in the Caucasus region and Russian Federation has increased concerns that wild boars may introduce the ASF virus into the European Union (EU). This study describes a semi-quantitative approach for evaluating the risk of ASF introduction into the EU by wild boar movements based on the following risk estimators: the susceptible population of (1) wild boars and (2) domestic pigs in the country of origin; the outbreak density in (3) wild boars and (4) domestic pigs in the countries of origin, the (5) suitable habitat for wild boars along the EU border; and the distance between the EU border and the nearest ASF outbreak in (6) wild boars or (7) domestic pigs. Sensitivity analysis was performed to identify the most influential risk estimators. The highest risk was found to be concentrated in Finland, Romania, Latvia and Poland, and wild boar habitat and outbreak density were the two most important risk estimators. Animal health authorities in at-risk countries should be aware of these risk estimators and should communicate closely with wild boar hunters and pig farmers to rapidly detect and control ASF.

Distribution, abundance and density of the wild boar on the Iberian Peninsula, based on the CORINE program and hunting statistics

Abstract. Wild boar population size in the Iberian Peninsula was estimated using hunting bag statistics from Spain and Portugal. Density was estimated assigning the wild boar population size to the “potential resources” or suitable habitats categorized by their importance to provide food and/or shelter to wild boars. Land uses were selected from CORINE, the EU database for land cover, using scientific literature and statistical significance for wild boar presence from published data. The hunting bag was 176245 and 15167 in Spain and Portugal, respectively. The average density was 0.373/km2 (min 0.014-max 2.22) in Spain and 0.13/km2 (min 0.00048-max 1.99) in Portugal, being 0.31/km2 (0.00048-2.22) over the entire Peninsula. Statistical analysis showed that wild boar presence was significantly (p < 0.05) associated to thirteen of the seventeen CORINE land uses selected. Agro-forestry, moors and heathland land use were not statistically significant but were included in the model due to their biological importance. Suitable habitats and distribution of wild boar were mapped for the Iberian Peninsula. This approach is a preliminary step intended to be useful in environmental management and animal health.

African swine fever: a global view of the current challenge

African Swine Fever (ASF) is an important contagious haemorrhagic viral disease affecting swine whose notification is mandatory due to its high mortality rates and the great sanitary and socioeconomic impact it has on international trade in animal and swine products.This disease only affects porcine species, both wild and domestic, and produces a variety of clinical signs such as fever and functional disorders of the digestive and respiratory systems. Lesions are mainly characterized by congestive-haemorrhagic alterations. ASF epidemiology varies significantly between countries, regions and continents, since it depends on the characteristics of the virus in circulation, the presence of wild hosts and reservoirs, environmental conditions and human social behaviour. Furthermore, a specific host will not necessarily always play the same active role in the spread and maintenance of ASF in a particular area.Currently, ASF is endemic in most sub-Saharan African countries where wild hosts and tick vectors (Ornithodoros) play an important role acting as biological reservoirs for the virus. In Europe, the disease has been endemic since 1978 on the island of Sardinia (Italy) and since 2007, when it was first reported in Georgia, in a number of Eastern European countries. It is also endemic in certain regions of the Russia Federation, where domestic pig and wild boar populations are widely affected. By contrast, in the affected eastern European Union (EU) countries where ASF is currently as epidemic, the on-going spread of the disease affects mainly wild boar populations located in restricted areas and, to a much less extent, domestic pigs. Unlike most livestock diseases, no vaccine or specific treatment is currently available for ASF. Therefore, disease control is mainly based on early detection and the application of strict sanitary and biosecurity measures. Epidemiology of ASF is very complex by the existence of different virus circulating, reservoirs and a number of scenarios, and the on-going spread of the disease through Africa and Europe. Survivor pigs can remain persistently infected for months which may contribute to virus transmission and thus the spread and maintenance of the disease, thereby complicating attempts to control it.

First Case of Highly Pathogenic Avian Influenza in Poultry in Spain

In October 2009, highly pathogenic avian influenza virus (HPAIV) was isolated for the first time in poultry in Spain. Sequencing analysis revealed that it was an H7N7 HPAIV. The progenitors of H7 HPAIV strains involved in recent European poultry outbreaks were simultaneously circulating in wild birds. The infected Spanish farm is located close to a reservoir abundant in wild birds. Epidemiological investigation found no links to other poultry holdings and those located in the control area were negative for AIV. Previous spatial risk analyses had identified the area where the infected holding is located to beat high relative risk for the introduction and presence of H5N1 HPAIV by wild birds. We suggest a risk-based surveillance scheme that targets smaller geographical units but maintains the number of wild birds being sampled, as early detection of potentially pathogenic AIV is crucial in preventing spread to poultry.

Virulence genes, antibiotic resistance and integrons in Escherichia coli strains isolated from synanthropic birds from Spain

The aim of this study was to determine the presence of virulence genes and antibiotic resistance profiles in 164 Escherichia coli strains isolated from birds (feral pigeons, hybrid ducks, house sparrows and spotless starlings) inhabiting urban and rural environments. A total of eight atypical enteropathogenic E. coli strains were identified: one in a house sparrow, four in feral pigeons and three in spotless starlings. Antibiotic resistance was present in 32.9% (54) of E. coli strains. The dominant type of resistance was to tetracycline (21.3%), ampicillin (19.5%) and sulfamethoxazole (18.9%). Five isolates had class 1 integrons containing gene cassettes encoding for dihydrofolate reductase A (dfrA) and aminoglycoside adenyltransferase A (aadA), one in a feral pigeon and four in spotless starlings. To our knowledge, the present study constitutes the first detection of virulence genes from E. coli in spotless starlings and house sparrows, and is also the first identification worldwide of integrons containing antibiotic resistance gene cassettes in E. coli strains from spotless starlings and pigeons.

Identifying areas for infectious animal disease surveillance in the absence of population data: highly pathogenic avian influenza in wild bird populations of Europe.

A large number (n=591) of H5N1 highly pathogenic avian influenza virus (HPAIV) outbreaks have been reported in wild birds of Europe from October 2005 through January 2009. Consequently, prevention and control strategies have been implemented in response to the outbreaks and considerable discussion has taken place regarding the need for implementing surveillance programs in high-risk areas with the objective of early detecting and preventing HPAIV epidemics. However countries ability to define the temporal and spatial extension of the high risk areas has been impaired by the lack of information on the distribution of susceptible wild bird populations in the region. Here, a technique for the detection of time-space disease clustering that does not require information on the distribution of susceptible populations and that has been referred to as the time-space permutation model of the scan statistic was used to identify areas and times of the year in which epidemics of H5N1 HPAIV were most likely to occur in wild bird populations of Europe from October, 2005, through December, 2008. The scan statistic was parameterized considering pre-existing knowledge on the epidemiological and ecological characteristics of the disease in the region. Robustness of the results was assessed using a generalized linear regression model to compare the outcomes of 36 alternative parameterizations of the scan statistic. Ten significant time-space clusters of H5N1 HPAI outbreaks were detected in six European countries. Results were sensitive (P<0.05) to the definition of the maximum spatial size defined for the clusters. Results presented here will help to identify high risk areas for HPAIV surveillance in the European Union. Assumptions, results, and implications of the analytical model are extensively presented and discussed in order to facilitate the use of this approach for the identification of high risk areas for infectious animal disease surveillance in the absence of population data.

Evaluating surveillance in wild birds by the application of risk assessment of avian influenza introduction into Spain

Early detection of highly pathogenic avian influenza (HPAI) in its natural reservoirs is a prerequisite for preventing disease spread to humans. The risk of introduction of H5N1 HPAI was assessed in order to design a risk-based surveillance system in Spain. Areas at highest risk for H5N1 HPAI followed a northeast-southwest direction, with two significant clusters located in the north and the southwest of the country. Most (83%) of the veterinary units (VUs) obtained fewer samples than would have been expected if samples had been collected using a risk-based design. In October 2009, a HPAI outbreak was reported for the first time in a Spanish layer farm located in a VU at high risk for HPAI, but no samples were collected. This risk-based surveillance approach will increase the cost-effectiveness of HPAI surveillance in Spain and can be easily extended to and adopted by other countries and regions throughout the world.

Environmental Risk Factors Associated with H5N1 HPAI in Ramsar Wetlands of Europe

Abstract The objective of this study was to identify environmental characteristics of European Ramsar wetlands, which are natural habitats for waterbirds, that could have contributed as risk factors for H5N1 HPAI (highly pathogenic avian influenza) in water birds (2006–2009). Ramsar wetlands in which H5N1 outbreaks were reported were considered infected (positive), and a case-control study was conducted using a logistic regression model in order to identify environmental risk factors associated with disease. Forestry (odds ratio, OR  =  6.90) and important area for water birds with mixosaline water (OR  =  6.31), as well as distance to the nearest positive wetland (OR  =  0.66), which was included into the model to adjust for spatial dependence, were associated with status of the wetlands. The model was used to estimate the risk for H5N1 HPAI on each European Ramsar wetland. Results will help to identify wetlands at high risk for H5N1 HPAI infection, wetlands that could be selectively targeted as part of a surveillance program aimed at early detection and prevention of future H5N1 HPAI epidemics.

Association between number of wild birds sampled for identification of H5N1 avian influenza virus and incidence of the disease in the European Union

Fourteen European Union (EU) countries have been affected by highly pathogenic avian influenza (HPAI) of the subtype H5N1 since 2005. Many of the H5N1 HPAI cases have been identified in wild bird populations from aquatic habitats. The objective of this contribution was to assess the association between the H5N1 HPAI incidence, estimated by a co-kriging approach, and the number of wild birds sampled for H5N1 HPAI surveillance in EU countries. The probability that a sample for H5N1 HPAI surveillance collected in the EU was obtained from a given country was associated (P<0.01) with the probability that a H5N1 HPAI case reported in the EU was located in the same country. The relation between probability of sampling and probability of infection in the Netherlands and in Spain was significantly higher (P<0.01) than that estimated in other EU countries, suggesting that political or social factors may have selectively influenced the number of samples for H5N1 HPAI surveillance collected in those two countries. The approach presented here will be useful for post hoc comparison of the relation between probability or risk for disease and the intensity of surveillance activities among administrative divisions of a region.