scholarly journals R0 Estimation for the African Swine Fever Epidemics in Wild Boar of Czech Republic and Belgium

2019 ◽  
Vol 7 (1) ◽  
pp. 2 ◽  
Author(s):  
Andrea Marcon ◽  
Annick Linden ◽  
Petr Satran ◽  
Vincenzo Gervasi ◽  
Alain Licoppe ◽  
...  
Keyword(s):  
Czech Republic ◽  
Wild Boar ◽  
African Swine Fever ◽  
Reliable Data ◽  
Control Measures ◽  
Passive Surveillance ◽  
Wild Populations ◽  
Wild Pigs ◽  
Eradication Strategy ◽  
Growth Method

African swine fever (ASF) is a contagious haemorrhagic fever that affects both domesticated and wild pigs. Since ASF reached Europe wild boar populations have been a reservoir for the virus. Collecting reliable data on infected individuals in wild populations is challenging, and this makes it difficult to deploy an effective eradication strategy. However, for diseases with high lethality rate, infected carcasses can be used as a proxy for the number of infected individuals at a certain time. Then R0 parameter can be used to estimate the time distribution of the number of newly infected individuals for the outbreak. We estimated R0 for two ASF outbreaks in wild boar, in Czech Republic and Belgium, using the exponential growth method. This allowed us to estimate both R0 and the doubling time (Td) for those infections. The results are R0 = 1.95, Td = 4.39 for Czech Republic and R0 = 1.65, Td = 6.43 for Belgium. We suggest that, if estimated as early as possible, R0 and Td can provide an expected course for the infection against which to compare the actual data collected in the field. This would help to assess if passive surveillance is properly implemented and hence to verify the efficacy of the applied control measures.

scholarly journals What Do Lithuanian Hunters Think of African Swine Fever and Its Control—Perceptions

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 525
Author(s):  
Evelina Stončiūtė ◽  
Katja Schulz ◽  
Alvydas Malakauskas ◽  
Franz J. Conraths ◽  
Marius Masiulis ◽  
...  
Keyword(s):  
Wild Boar ◽  
Surveillance System ◽  
African Swine Fever ◽  
Study Data ◽  
Control Measures ◽  
Attitudes And Beliefs ◽  
Passive Surveillance ◽  
Wild Boar Population ◽  
In The Wild ◽  
Governmental Institutions

After the introduction of African swine fever (ASF) into Lithuania in 2014, continuous spread of the disease resulted in infection of the wild boar populations in most parts of Lithuania. The virus has been moving closer to other Western European countries where pig density is high. An efficient surveillance system detecting ASF cases early in domestic and wild animals is necessary to manage this disease. To make surveillance appropriate and effective, it is critical to understand how key players perceive the implemented control measures. This study investigated the attitudes and beliefs of hunters in Lithuania regarding currently implemented or proposed measures for the control of ASF in the wild boar population. Study data were collected through questionnaires distributed via the internet and by hunting associations in Lithuania. In total, 621 fully completed questionnaires were received and analyzed. All measures interfering with extensive hunting, like ban of driven or individual hunting or ban of supplementary feeding were considered as unacceptable and as ineffective measures to control ASF in wild boar. However, selective hunting of female wild boar was generally considered as an unethical act and therefore rejected. Some measures that seem to have been successful in other countries, like involvement of additional forces, were rejected by Lithuanian hunters, thus implementation of these measures could be difficult. The study highlighted that there is a need for improving important relationships with other stakeholders, since many hunters expressed a lack of trust in governmental institutions and regarded cooperation with them as insufficient. Hunters emphasized that their motivation to support passive surveillance measures could be improved with financial compensation and reduction of workload. The present study provides insights into hunters’ perceptions, which may be used as a foundation for additional discussions with these important stakeholders and for adapting measures to improve their acceptance if appropriate.

scholarly journals A Comparison of Perceptions of Estonian and Latvian Hunters With Regard to the Control of African Swine Fever

2021 ◽  
Vol 8 ◽  
Author(s):  
Nico Urner ◽  
Carola Sauter-Louis ◽  
Christoph Staubach ◽  
Franz Josef Conraths ◽  
Katja Schulz
Keyword(s):  
Wild Boar ◽  
Group Discussion ◽  
African Swine Fever ◽  
Control Measures ◽  
Disease Spread ◽  
Successful Implementation ◽  
Participatory Methods ◽  
The European Union ◽  
Passive Surveillance ◽  
Participatory Epidemiology

Since the first detected African swine fever (ASF) cases in Lithuanian wild boar in 2014, the virus has occurred in many other member states of the European Union (EU), most recently in Belgium in 2018 and in Germany in 2020. Passive surveillance and various control measures are implemented as part of the strategy to stop disease spread in the wild boar population. Within this framework, hunters perform important activities, such as the removal of carcasses, fencing or hunting. Therefore, the successful implementation of these measures largely depends on their acceptability by hunters. Methods of participatory epidemiology can be used to determine the acceptance of control measures. The use of participatory methods allows the involvement of key stakeholders in the design, the implementation and the analysis of control and surveillance activities. In the present study, two studies that had been conducted using participatory epidemiology with hunters in Estonia and Latvia were compared on the topics recruitment, participants, facilitators, focus group discussion (FGDs) and their contents. The aim was to evaluate similarities and differences in the two studies and to identify a broader spectrum of possibilities to increase the willingness of hunters supporting the fight against ASF. Evaluating all conducted FGDs in both countries showed primarily similarities in the perceptions and opinions of the hunters in Estonia and Latvia. One notable difference was that passive surveillance in Latvia was perceived mostly as topic of duty and ethics rather than an issue driven by incentives. Participatory methods have proven to be an effective tool in the evaluation of the acceptance of established ASF control systems. The results of this study point out further chances for improving the cooperation with hunters in the future. Nevertheless, the importance of gathering and analyzing the opinions of hunters in all ASF affected countries individually is highlighted.

scholarly journals African swine fever in the Lithuanian wild boar population in 2018: a snapshot

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Arnoldas Pautienius ◽  
Katja Schulz ◽  
Christoph Staubach ◽  
Juozas Grigas ◽  
Ruta Zagrabskaite ◽  
...  
Keyword(s):  
Wild Boar ◽  
Active Surveillance ◽  
African Swine Fever ◽  
Control Measures ◽  
Disease Spread ◽  
Passive Surveillance ◽  
Wild Boar Population ◽  
Prevalence Estimates ◽  
Risk Of Disease ◽  
Over Time

Abstract The first cases of African swine fever (ASF) were detected in the Lithuanian wild boar population in 2014. Since then, the disease spread slowly through the whole country, affecting both, wild boar and domestic pigs. In the other Baltic states, which both are also affected by ASF since 2014, the recent course of ASF prevalence suggests that the countries might be well under way of disease elimination. In contrast, in Lithuania the epidemic seems to be still in full progress. In the present study, we aimed to extend a previous prevalence study in Lithuania. Looking at ASF virus (ASFV) and seroprevalence estimates of wild boar in all months of 2018 and in all affected municipalities in Lithuania, the course of ASF was evaluated on a temporal and spatial scale. A non-spatial beta-binomial model was used to correct for under- or overestimation of the average prevalence estimates. Within 2018 no big differences between the prevalence estimates were seen over time. Despite of the lower sample size, highest ASFV prevalence estimates were found in dead wild boar, suggesting higher detection rates through passive surveillance than through active surveillance. Accordingly, with the maximum prevalence of 87.5% in May 2018, the ASFV prevalence estimates were very high in wild boar found dead. The number of samples originating from hunted animals (active surveillance) predominated clearly. However, the ASFV prevalence in those animals was lower with a maximum value of 2.1%, emphasizing the high value of passive surveillance. A slight increase of the seroprevalence in hunted wild boar could be seen over time. In the center of Lithuania, a cluster of municipalities with high ASFV and seroprevalence estimates was found. The results of the study indicate that ASFV is still circulating within the Lithuanian wild boar population, constituting a permanent risk of disease transmission into domestic pig holdings. However, additional, more recent data analyses are necessary to re-evaluate the course of ASF in Lithuania and thus, to be able to make a statement about the stage of the ASF epidemic in the country. This is of huge importance for Lithuania for evaluating control measures and their efficacy, but also for neighbouring countries to assess the risk of disease spread from Lithuania.

scholarly journals African Swine Fever in Two Large Commercial Pig Farms in LATVIA—Estimation of the High Risk Period and Virus Spread within the Farm

2020 ◽  
Vol 7 (3) ◽  
pp. 105 ◽  
Author(s):  
Kristīne Lamberga ◽  
Edvīns Oļševskis ◽  
Mārtiņš Seržants ◽  
Aivars Bērziņš ◽  
Arvo Viltrop ◽  
...  
Keyword(s):  
High Risk ◽  
Wild Boar ◽  
Early Stage ◽  
African Swine Fever ◽  
Control Measures ◽  
Virus Spread ◽  
Passive Surveillance ◽  
Early Disease Detection ◽  
Risk Period ◽  
Commercial Farms

African swine fever (ASF) was first detected in Latvia in wild boar at the Eastern border in June 2014. Since then ASF has continued to spread in wild boar populations covering almost whole territory of the country. Sporadic outbreaks occurred at the same time in domestic pig holdings located in wild boar infected areas. Here we present the results of the epidemiological investigation in two large commercial farms. Several parameters were analyzed to determine the high risk period (HRP) and to investigate the ASF virus spread within the farm. Clinical data, mortality rates and laboratory results proved to be good indicators for estimating the HRP. The measures for early disease detection, particularly the enhanced passive surveillance that is targeting dead and sick pigs, were analyzed and discussed. Enhanced passive surveillance proved to be a key element to detect ASF at an early stage. The study also showed that ASF virus might spread slowly within a large farm depending mainly on direct contacts between pigs and the level of internal biosecurity. Findings suggest improvements in outbreak prevention, control measures and may contribute to a better understanding of ASF spreading patterns within large pig herds. Culling of all pigs in large commercial farms could be reconsidered under certain conditions.

scholarly journals Evaluation of the Efficiency of Active and Passive Surveillance in the Detection of African Swine Fever in Wild Boar

2019 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Vincenzo Gervasi ◽  
Andrea Marcon ◽  
Silvia Bellini ◽  
Vittorio Guberti
Keyword(s):  
Wild Boar ◽  
Active Surveillance ◽  
Disease Surveillance ◽  
Virus Detection ◽  
African Swine Fever ◽  
First Year ◽  
Passive Surveillance ◽  
European Wild Boar ◽  
Absolute Probability ◽  
Host Parasite

African swine fever (ASF) is one of the most severe diseases of pigs and has a drastic impact on pig industry. Wild boar populations play the role of ASF genotype II virus epidemiological reservoir. Disease surveillance in wild boar is carried out either by testing all the wild boar found sick or dead for virus detection (passive surveillance) or by testing for virus (and antibodies) all hunted wild boar (active surveillance). When virus prevalence and wild boar density are low as it happens close to eradication, the question on which kind of surveillance is more efficient in detecting the virus is still open. We built a simulation model to mimic the evolution of the host-parasite interaction in the European wild boar and to assess the efficiency of different surveillance strategies. We constructed a deterministic SIR model, which estimated the probability to detect the virus during the 8 years following its introduction, using both passive and active surveillance. Overall, passive surveillance provided a much larger number of ASF detections than active surveillance during the first year. During subsequent years, both active and passive surveillance exhibited a decrease in their probability to detect ASF. Such decrease, though, was more pronounced for passive surveillance. Under the assumption of 50% of carcasses detection, active surveillance became the best detection method when the endemic disease prevalence was lower than 1.5%, when hunting rate was >60% and when population density was lower than 0.1 individuals/km2. In such a situation, though, the absolute probability to detect the disease was very low with both methods, and finding almost every carcass is the only way to ensure virus detection. The sensitivity analysis shows that carcass search effort is the sole parameter that increases proportionally the chance of ASF virus detection. Therefore, an effort should be made to promote active search of dead wild boar also in endemic areas, since reporting wild boar carcasses is crucial to understand the epidemiological situation in any of the different phases of ASF infection at any wild boar density.

scholarly journals African Swine Fever Virus (ASFV) in Poland in 2019—Wild Boars: Searching Pattern

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 45
Author(s):  
Maciej Frant ◽  
Anna Gal ◽  
Łukasz Bocian ◽  
Anna Ziętek-Barszcz ◽  
Krzysztof Niemczuk ◽  
...  
Keyword(s):  
Wild Boar ◽  
Logistic Regression Model ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Passive Surveillance ◽  
Domestic Pig ◽  
Wild Boars ◽  
Preventive Actions ◽  
Control And Prevention ◽  
Epidemiological Situation

African swine fever (ASF) was introduced to Poland in 2014. Despite the implementation of preventive actions focused on the reduction of wild boar populations and the introduction of biosecurity rules in domestic pig farms, the disease has been continuously spreading to new areas. The aim of this paper was to analyze the dynamics of ASFV spread in wild boar populations in Poland and to summarize the 2019 epidemiological situation. Using a logistic regression model, it has been shown that there is a significant correlation between the month, ASF affected area and ASF prevalence among wild boars. According to EU definitions, Part II and Part III zones had a total of 3065 (65.2%) ASF-positive death wild boars. In addition, there were 36 post-accident (road-killed) wild boars (2.6%) and 612 hunted animals (1.5%) in this area. These results showed the importance of passive surveillance and its advantages overactive surveillance in ASF control and prevention. The data indicated a greater chance of a positive result in the winter months (January, February, March) than in reference September, where the ASF prevalence was the lowest. This observation confirms the preliminary theory about the seasonality of the disease in wild boar populations and its connection with winter.

scholarly journals Predicting spread and effective control measures for African swine fever– should we blame the boars?

2019 ◽  
Author(s):  
Rachel A. Taylor ◽  
Tomasz Podgórski ◽  
Robin R. L. Simons ◽  
Sophie Ip ◽  
Paul Gale ◽  
...  
Keyword(s):  
At Risk ◽  
Wild Boar ◽  
Control Strategies ◽  
Control Measure ◽  
African Swine Fever ◽  
Control Measures ◽  
Effective Control ◽  
Risk Of Infection ◽  
Long Distance ◽  
Baltic Countries

SummaryAfrican swine fever (ASF) has been causing multiple outbreaks in Russia, Poland and the Baltic countries in recent years and is currently spreading westwards throughout Europe and eastwards into China, with cases occurring in wild boar and domestic pigs. Curtailing further spread of ASF requires full understanding of the transmission pathways of the disease. Wild boars have been implicated as a potential reservoir for the disease and one of the main modes of transmission within Europe. We developed a spatially explicit model to estimate the risk of infection with ASF in boar and pigs due to the natural movement of wild boar that is applicable across the whole of Europe. We demonstrate the model by using it to predict the probability that early cases of ASF in Poland were caused by wild boar dispersion. The risk of infection in 2015 is computed due to wild boar cases in Poland in 2014, compared against the reported cases in 2015 and then the procedure is repeated for 2015-2016. We find that long- and medium-distance spread of ASF (i.e. >30km) is very unlikely to have occurred due to boar dispersal, due in part to the generally short distances boar will travel (<20km on average). We also predict what the relative success of different control strategies would have been in 2015, if they were implemented in 2014. Results suggest that hunting of boar reduces the number of new cases, but a larger region is at risk of ASF compared to no control measure. Alternatively, introducing boar-proof fencing reduces the size of the region at risk in 2015, but not the total number of cases. Overall, our model suggests wild boar movement is only responsible for local transmission of disease, thus other pathways are more dominant in medium and long distance spread of the disease.

scholarly journals African swine fever (ASF) in wild boar

2018 ◽  
Vol 74 (12) ◽  
pp. 6148-2018
Author(s):  
ZYGMUNT PEJSAK ◽  
MARIAN TRUSZCZYŃSKI ◽  
KAZIMIERZ TARASIUK
Keyword(s):  
Early Detection ◽  
Wild Boar ◽  
Large Scale ◽  
Current Knowledge ◽  
African Swine Fever ◽  
The European Union ◽  
Passive Surveillance ◽  
Surveillance Strategy ◽  
Feral Pigs ◽  
Scientific Opinion

This paper contains main points of the scientific opinion prepared by EFSA in 2018 on the request of the European Commission on the ASF epidemic in wild boar in Eastern – Central Europe, which started in 2014 and is existing and increasing until the present time. The first point is providing an estimate of the wild boar density in the European Union (EU). The next item is presenting the opinion on the latest epidemiological data to identify thresholds in wild boar density that do not allow sustaining the disease in different settings. The third question and answer concerns wild boar and feral pigs depopulation methods or population reduction methods. The fourth chapter is reviewing fencing methods demonstrating to temporarily protect crops from damage, caused by wild boar or feral swine. Currently there is no evidence , that large –scale fences have been effective for the containment of wild boar or feral pigs. The answer to the fifth question on surveillance strategy contains information on sample size, frequency of sampling and identification of possible risk groups for early detection of ASFV in naïve wild boar population. Passive surveillance is according to the opinion of EFSA the most effective and efficient method of surveillance for early detection of ASF in wild boar. For early detection through passive surveillance , the aim is to test as many “found dead” animals as possible. Based on current knowledge and experiences for an intervention to be successful, there is a need to detect an ASF incursion while it is spatially contained. The sixth topic of the EFSA scientific opinion requests to review successful methodologies used in the past, as for example the mentioned passive surveillance. It is recommended that this should be done in discussion among specialists from the UE countries. Good collaborations with hunters is recommended.

scholarly journals A Review of Environmental Risk Factors for African Swine Fever in European Wild Boar

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2692
Author(s):  
Hannes Bergmann ◽  
Katja Schulz ◽  
Franz J. Conraths ◽  
Carola Sauter-Louis
Keyword(s):  
Risk Factors ◽  
Wild Boar ◽  
Environmental Risk ◽  
Disease Surveillance ◽  
African Swine Fever ◽  
Environmental Risk Factors ◽  
Control Measures ◽  
Reference Scenario ◽  
Disease Occurrence ◽  
Forest Coverage

A detailed understanding of environmental risk factors for African swine fever (ASF) in wild boar will be not only essential for risk assessments but also for timely and spatially informed allocation of resources in order to manage wild boar-targeted ASF control measures efficiently. Here, we review currently known environmental risk factors that can influence the occurrence of ASF virus infection in wild boar when compared to disease occurrence in wild boar of a non-exposed reference scenario. Accordingly, the exposure of wild boar to environmental risk factors related to (1) climate, (2) land cover, (3) human activity, (4) wild boar and (5) ASF were evaluated. As key environmental risk factors in this review, increased ASF occurrence in wild boar was associated with seasonal patterns, forest coverage, presence of water, human presence, farming activities, wild boar density and ASF nearness. The review highlights inconsistencies in some of these risk factor associations with disease detection in space and time and may provide valuable insights for the investigation of ASF transmission dynamics. The examined risk information was applied to consider potential improvements of the ASF control strategy in wild boar regarding disease surveillance, hunting, wild boar carcass searches and ASF barrier implementation.

scholarly journals The African Swine Fever Epidemic in Wild Boar (Sus scrofa) in Lithuania (2014–2018)

2020 ◽  
Vol 7 (1) ◽  
pp. 15 ◽  
Author(s):  
Petras Mačiulskis ◽  
Marius Masiulis ◽  
Gediminas Pridotkas ◽  
Jūratė Buitkuvienė ◽  
Vaclovas Jurgelevičius ◽  
...  
Keyword(s):  
Wild Boar ◽  
Population Decline ◽  
African Swine Fever ◽  
Control Measures ◽  
Disease Spread ◽  
Wild Boar Population ◽  
Baltic States ◽  
Long Distance ◽  
First Case ◽  
The Baltic

In January 2014 the first case of African swine fever (ASF) in wild boar of the Baltic States was reported from Lithuania. It has been the first occurrence of the disease in Eastern EU member states. Since then, the disease spread further affecting not only the Baltic States and Poland but also south-eastern Europe, the Czech Republic and Belgium. The spreading pattern of ASF with its long-distance spread of several hundreds of kilometers on the one hand and the endemic situation in wild boar on the other is far from being understood. By analyzing data of ASF cases in wild boar along with implemented control measures in Lithuania from 2014–2018 this study aims to contribute to a better understanding of the disease. In brief, despite huge efforts to eradicate ASF, the disease is now endemic in the Lithuanian wild boar population. About 86% of Lithuanian’s territory is affected and over 3225 ASF cases in wild boar have been notified since 2014. The ASF epidemic led to a considerable decline in wild boar hunting bags. Intensified hunting might have reduced the wild boar population but this effect cannot be differentiated from the population decline caused by the disease itself. However, for ASF detection sampling of wild boar found dead supported by financial incentives turned out to be one of the most effective tools.

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