Suchergebnisse

The African swine fever epizootic in central and eastern European Union member states has a newly identified component involving virus transmission by wild boar and virus survival in the environment. Insights led to an update of the 3 accepted African swine fever transmission models to include a fourth cycle: wild boar–habitat.

In 2007 African swine fever (ASF) arrived at a Black Sea harbour in Georgia and in 2014 the infection reached the European Union (EU), where it still expands its territory. ASF is a fatal viral disease affecting domestic pigs and wild boar of all ages with clinical presentations ranging from per-acute to chronic disease, including apparently asymptomatic courses. Until the detection of the first case inside the EU, infections in the current epidemic were mainly seen among pig farms with generally low biosecurity, and with incidental spill over to the wild boar population. In the EU, however, the infection survived locally in the wild boar population independently from outbreaks in domestic pigs, with a steady and low prevalence. Apart from the wild boar population and the habitat, the current epidemic recognizes humans as the main responsible for both long distance transmission and virus introduction in the domestic pig farms. This underlines the importance to include social science when planning ASF-prevention, −control, or -eradication measures. Based on experiences, knowledge and data gained from the current epidemic this review highlights some recent developments in the epidemiological understanding of ASF, especially concerning the role of wild boar and their habitats in ASF epidemiology. In this regard, the qualities of three epidemiological traits: contagiousity, tenacity, and case fatality rate, and their impact on ASF persistence and transmission are especially discussed.

To minimize the potential consequences of an introduction of foot-and-mouth disease (FMD) in Europe, European Union (EU) member states are required to present a contingency plan. This study used a simulation model to study potential outbreak scenarios in Sweden and evaluate the best control strategies. The model was informed by the Swedish livestock structure using herd information from cattle, pig, and small ruminant holdings in the country. The contact structure was based on animal movement data and studies investigating the movements between farms of veterinarians, service trucks, and other farm visitors. All scenarios of outbreak control included depopulation of detected herds, 3 km protection and 10 km surveillance zones, movement tracing, and 3 days national standstill. The effect of availability of surveillance resources, i.e., number of field veterinarians per day, and timeliness of enforcement of interventions, was assessed. With the estimated currently available resources, an FMD outbreak in Sweden is expected to be controlled (i.e., last infected herd detected) within 3 weeks of detection in any evaluated scenario. The density of farms in the area where the epidemic started would have little impact on the time to control the outbreak, but spread in high density areas would require more surveillance resources, compared to areas of lower farm density. The use of vaccination did not result in a reduction in the expected number of infected herds. Preemptive depopulation was able to reduce the number of infected herds in extreme scenarios designed to test a combination of worst-case conditions of virus introduction and spread, but at the cost of doubling the number of herds culled. This likely resulted from a combination of the small outbreaks predicted by the spread model, and the high efficacy of the basic control measures evaluated, under the conditions of the Swedish livestock industry, and considering the assumed control resources available. The results indicate that the duration and extent of FMD ...

To minimize the potential consequences of an introduction of foot-and-mouth disease (FMD) in Europe, European Union (EU) member states are required to present a contingency plan. This study used a simulation model to study potential outbreak scenarios in Sweden and evaluate the best control strategies. The model was informed by the Swedish livestock structure using herd information from cattle, pig, and small ruminant holdings in the country. The contact structure was based on animal movement data and studies investigating the movements between farms of veterinarians, service trucks, and other farm visitors. All scenarios of outbreak control included depopulation of detected herds, 3 km protection and 10 km surveillance zones, movement tracing, and 3 days national standstill. The effect of availability of surveillance resources, i.e., number of field veterinarians per day, and timeliness of enforcement of interventions, was assessed. With the estimated currently available resources, an FMD outbreak in Sweden is expected to be controlled (i.e., last infected herd detected) within 3 weeks of detection in any evaluated scenario. The density of farms in the area where the epidemic started would have little impact on the time to control the outbreak, but spread in high density areas would require more surveillance resources, compared to areas of lower farm density. The use of vaccination did not result in a reduction in the expected number of infected herds. Preemptive depopulation was able to reduce the number of infected herds in extreme scenarios designed to test a combination of worst-case conditions of virus introduction and spread, but at the cost of doubling the number of herds culled. This likely resulted from a combination of the small outbreaks predicted by the spread model, and the high efficacy of the basic control measures evaluated, under the conditions of the Swedish livestock industry, and considering the assumed control resources available. The results indicate that the duration and extent of FMD outbreaks could be kept limited in Sweden using the EU standard control strategy and a 3 days national standstill.

Small ruminants support the livelihoods of millions of poor pastoralist and sedentary households around the world. While pastoralists are generally not amongst the poorest in terms of assets, they are frequently marginalised in terms of their access to political power, health and education. This study was undertaken among pastoralist households keeping small ruminants in four regions of the country of Georgia. Small ruminants are an important cultural, social and economic asset in Georgia and are mainly managed in a transhumant pastoralist system. Georgia suffered its first, and so far only outbreak of peste des petits ruminants (PPR) in 2016. This qualitative interview study was designed to acquire contextual understanding of local small ruminant husbandry and the livelihood situations of the participating pastoralists, and to detect historical, unreported PPR outbreaks. Focus group discussions comprising participatory epidemiology tools and other forms of interviews were used to explore small ruminant management, disease spectrum and management, and animal health priorities. The participants had experienced a wide variety of animal health constraints, with intestinal worms, braxy, piroplasmosis, pasture-related problems, predators and lameness emerging as priorities. No historic, unreported PPR outbreak was detected in this study, and PPR was not a priority for participants. Instead, the day-to-day reality of animal health for the pastoralists was characterised by co-infections of mainly endemic pathogens, and problems related to other challenges such as access to land, feed and genetic resources. The rationale behind the participants' prioritisation of animal health problems was supported by the need to pay extra attention to animals in order to avoid risk factors, keep animals healthy and minimise the negative impact of diseases or management problems; the various epidemiological and clinical parameters of the prioritised diseases; the economic impact of the specific problems and the zoonotic potential of diseases and predation. Even within regions, and within seemingly socially and culturally homogenous groups, there were important local differences in the problems faced by pastoralists that affect their livestock management. This study underlines the importance of a contextualised understanding of the local disease panorama and complexities in the livelihood situations of rural people when designing actions to improve animal health in general or, more specifically, passive surveillance as well as prevention or control measures. Finally, it is concluded that to achieve such an understanding, there is a need for participatory, scoping-style studies that specifically acknowledge diversity and power relations.

Small ruminants support the livelihoods of millions of poor pastoralist and sedentary households around the world. While pastoralists are generally not amongst the poorest in terms of assets, they are frequently marginalised in terms of their access to political power, health and education. This study was undertaken among pastoralist households keeping small ruminants in four regions of the country of Georgia. Small ruminants are an important cultural, social and economic asset in Georgia and are mainly managed in a transhumant pastoralist system. Georgia suffered its first, and so far only outbreak of peste des petits ruminants (PPR) in 2016. This qualitative interview study was designed to acquire contextual understanding of local small ruminant husbandry and the livelihood situations of the participating pastoralists, and to detect historical, unreported PPR outbreaks. Focus group discussions comprising participatory epidemiology tools and other forms of interviews were used to explore small ruminant management, disease spectrum and management, and animal health priorities.The participants had experienced a wide variety of animal health constraints, with intestinal worms, braxy, piroplasmosis, pasture-related problems, predators and lameness emerging as priorities. No historic, unreported PPR outbreak was detected in this study, and PPR was not a priority for participants. Instead, the day-to-day reality of animal health for the pastoralists was characterised by co-infections of mainly endemic pathogens, and problems related to other challenges such as access to land, feed and genetic resources. The rationale behind the participants' prioritisation of animal health problems was supported by the need to pay extra attention to animals in order to avoid risk factors, keep animals healthy and minimise the negative impact of diseases or management problems; the various epidemiological and clinical parameters of the prioritised diseases; the economic impact of the specific problems and the zoonotic potential of ...

An update on the African swine fever (ASF) situation in the 10 affected Member States (MS) in the EU and in two neighbouring countries from the 1 September 2019 until the 31 August 2020 is provided. The dynamics of the proportions of PCR‐ and ELISA‐positive samples since the first ASF detection in the country were provided and seasonal patterns were investigated. The impact of the ASF epidemic on the annual numbers of hunted wild boar in each affected MS was investigated. To evaluate differences in the extent of spread of ASF in the wild boar populations, the number of notifications that could be classified as secondary cases to a single source was calculated for each affected MS and compared for the earliest and latest year of the epidemic in the country. To evaluate possible risk factors for the occurrence of ASFV in wild boar or domestic pigs, a literature review was performed. Risk factors for the occurrence of ASF in wild boar in Romanian hunting grounds in 2019 were identified with a generalised linear model. The probability to find at least one PCR‐confirmed ASF case in wild boar in a hunting ground in Romania was driven by environmental factors, wild boar abundance and the density of backyard pigs in the hunting ground area, while hunting‐related variables were not retained in the final model. Finally, measures implemented in white zones (ASF‐free zones that are geographically adjacent to an area where ASF is present in wild boar) to prevent further spread of ASF were analysed with a spatially, explicit stochastic individual‐based model. To be effective, the wild boar population in the white zone would need to be drastically reduced before ASF arrives at the zone and it must be wide enough. To achieve the necessary pre‐emptive culling targets of wild boar in the white zone, at the start of the establishment, the white zone should be placed sufficiently far from the affected area, considering the speed of the natural spread of the disease. This spread is faster in denser wild boar populations. After a ...

This report provides a descriptive analysis of the African swine fever (ASF) Genotype II epidemic in the affected Member States in the EU and two neighbouring countries for the period from 1 September 2020 to 31 August 2021. ASF continued to spread in wild boar in the EU, it entered Germany in September 2020, while Belgium became free from ASF in October 2020. No ASF outbreaks in domestic pigs nor cases in wild boar have been reported in Greece since February 2020. In the Baltic States, overall, there has been a declining trend in proportions of polymerase chain reaction (PCR)‐positive samples from wild boar carcasses in the last few years. In the other countries, the proportions of PCR‐positive wild boar carcasses remained high, indicating continuing spread of the disease. A systematic literature review revealed that the risk factors most frequently significantly associated with ASF in domestic pigs were pig density, low levels of biosecurity and socio‐economic factors. For wild boar, most significant risk factors were related to habitat, socio‐economic factors and wild boar management. The effectiveness of different control options in the so‐named white zones, areas where wild boar densities have been drastically reduced to avoid further spread of ASF after a new introduction, was assessed with a stochastic model. Important findings were that establishing a white zone is much more challenging when the area of ASF incursion is adjacent to an area where limited control measures are in place. Very stringent wild boar population reduction measures in the white zone are key to success. The white zone needs to be far enough away from the affected core area so that the population can be reduced in time before the disease arrives and the timing of this will depend on the wild boar density and the required population reduction target in the white zone. Finally, establishing a proactive white zone along the demarcation line of an affected area requires higher culling efforts, but has a higher chance of success to stop ...

An update on the African swine fever (ASF) situation in the 10 affected Member States (MS) in the EU and in two neighbouring countries from the 1 September 2019 until the 31 August 2020 is provided. The dynamics of the proportions of PCR‐ and ELISA‐positive samples since the first ASF detection in the country were provided and seasonal patterns were investigated. The impact of the ASF epidemic on the annual numbers of hunted wild boar in each affected MS was investigated. To evaluate differences in the extent of spread of ASF in the wild boar populations, the number of notifications that could be classified as secondary cases to a single source was calculated for each affected MS and compared for the earliest and latest year of the epidemic in the country. To evaluate possible risk factors for the occurrence of ASFV in wild boar or domestic pigs, a literature review was performed. Risk factors for the occurrence of ASF in wild boar in Romanian hunting grounds in 2019 were identified with a generalised linear model. The probability to find at least one PCR‐confirmed ASF case in wild boar in a hunting ground in Romania was driven by environmental factors, wild boar abundance and the density of backyard pigs in the hunting ground area, while hunting‐related variables were not retained in the final model. Finally, measures implemented in white zones (ASF‐free zones that are geographically adjacent to an area where ASF is present in wild boar) to prevent further spread of ASF were analysed with a spatially, explicit stochastic individual‐based model. To be effective, the wild boar population in the white zone would need to be drastically reduced before ASF arrives at the zone and it must be wide enough. To achieve the necessary pre‐emptive culling targets of wild boar in the white zone, at the start of the establishment, the white zone should be placed sufficiently far from the affected area, considering the speed of the natural spread of the disease. This spread is faster in denser wild boar populations. After a focal ASF introduction, the white zone is always close to the infection hence pre‐emptive culling measures in the white zone must be completed in short term, i.e. in a few months.