Evaluation of the Presence of ASFV in Wolf Feces Collected from Areas in Poland with ASFV Persistence

African swine fever (ASF), caused by a DNA virus (ASFV) belonging to genus Asfivirus of the Asfarviridae family, is one of the most threatening diseases of suids. During last few years, it has spread among populations of wild boars and pigs in countries of Eastern and Central Europe, causing huge economical losses. While local ASF occurrence is positively correlated with wild boar density, ecology of this species (social structure, movement behavior) constrains long-range disease transmission. Thus, it has been speculated that carnivores known for high daily movement and long-range dispersal ability, such as the wolf (Canis lupus), may be indirect ASFV vectors. To test this, we analyzed 62 wolf fecal samples for the presence of ASFV DNA, collected mostly in parts of Poland declared as ASF zones. This dataset included 20 samples confirmed to contain wild boar remains, 13 of which were collected near places where GPS-collared wolves fed on dead wild boars. All analyzed fecal samples were ASFV-negative. On the other hand, eight out of nine wild boar carcasses that were fed on by telemetrically studied wolves were positive. Thus, our results suggest that when wolves consume meat of ASFV-positive wild boars, the virus does not survive the passage through intestinal tract. Additionally, wolves may limit ASFV transmission by removing infectious carrion. We speculate that in areas where telemetric studies on large carnivores are performed, data from GPS collars could be used to enhance efficiency of carcass search, which is one of the main preventive measures to constrain ASF spread.

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Wild Boar (Sus scrofa) Home Range and Habitat Use in Two Romanian Habitats

Acta Silvatica et Lignaria Hungarica ◽

10.2478/aslh-2018-0003 ◽

2018 ◽

Vol 14 (1) ◽

pp. 51-63 ◽

Cited By ~ 2

Author(s):

Ferenc Jánoska ◽

Attila Farkas ◽

Miklós Marosán ◽

József-Tamás Fodor

Keyword(s):

Habitat Use ◽

Wild Boar ◽

Activity Patterns ◽

Large Carnivores ◽

Minimum Convex Polygon ◽

Wild Boars ◽

Daily Movement ◽

Gps Collars ◽

Polygon Method ◽

Diverse Habitat

Abstract During our research we utilized data provided by GPS collars to compare the spatial patterns of wild boars living in lowland and high-hilly regions. Five wild boars were fitted with GPS Plus (Vectronic) type collars. The two aforementioned investigated habitat areas were as follows: a high-hilly hunting ground from the foot of the Bodoc Mountains (Covasna County), and the meeting point of Olt and Danube rivers in the southern part of the country (Teleorman County). The average daily wild boar activity varied between 2.9 and 3.1 km in the lowlands and between 3.6 and 4.9 km in the higher situated habitats. The average daily movement area calculated with the minimum convex polygon method was between 60.3 and 112.5 ha/day in the lowlands and between 113.5 and 125.2 ha/day in the high-hilly regions. The movement area of the wild boars calculated with the MCP method varied between 1,060 and 1,2001 hectares in lowlands and between 8,689 and 9,463 hectares in higher altitudes. Our data proved inadequate at testing whether or not large carnivores affect wild boar activity patterns. Habitat use analysis produced interesting results: even in a very diverse habitat, every collared individual preferred green forests. We found negative preference for agricultural fields in both habitats.

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Modelling the Spatial Distribution of ASF-Positive Wild Boar Carcasses in South Korea Using 2019–2020 National Surveillance Data

Animals ◽

10.3390/ani11051208 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1208

Author(s):

Jun-Sik Lim ◽

Timothée Vergne ◽

Son-Il Pak ◽

Eutteum Kim

Keyword(s):

Spatial Distribution ◽

Risk Factor ◽

South Korea ◽

Wild Boar ◽

African Swine Fever Virus ◽

Significant Risk ◽

African Swine Fever ◽

Credible Interval ◽

Imperfect Detection ◽

Wild Boars

In September 2019, African swine fever (ASF) was reported in South Korea for the first time. Since then, more than 651 ASF cases in wild boars and 14 farm outbreaks have been notified in the country. Despite the efforts to eradicate ASF among wild boar populations, the number of reported ASF-positive wild boar carcasses have increased recently. The purpose of this study was to characterize the spatial distribution of ASF-positive wild boar carcasses to identify the risk factors associated with the presence and number of ASF-positive wild boar carcasses in the affected areas. Because surveillance efforts have substantially increased in early 2020, we divided the study into two periods (2 October 2019 to 19 January 2020, and 19 January to 28 April 2020) based on the number of reported cases and aggregated the number of reported ASF-positive carcasses into a regular grid of hexagons of 3-km diameter. To account for imperfect detection of positive carcasses, we adjusted spatial zero-inflated Poisson regression models to the number of ASF-positive wild boar carcasses per hexagon. During the first study period, proximity to North Korea was identified as the major risk factor for the presence of African swine fever virus. In addition, there were more positive carcasses reported in affected hexagons with high habitat suitability for wild boars, low heat load index (HLI), and high human density. During the second study period, proximity to an ASF-positive carcass reported during the first period was the only significant risk factor for the presence of ASF-positive carcasses. Additionally, low HLI and elevation were associated with an increased number of ASF-positive carcasses reported in the affected hexagons. Although the proportion of ASF-affected hexagons increased from 0.06 (95% credible interval (CrI): 0.05–0.07) to 0.09 (95% CrI: 0.08–0.10), the probability of reporting at least one positive carcass in ASF-affected hexagons increased from 0.49 (95% CrI: 0.41–0.57) to 0.73 (95% CrI: 0.66–0.81) between the two study periods. These results can be used to further advance risk-based surveillance strategies in the Republic of Korea.

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Clinical Course and Gross Pathological Findings in Wild Boar Infected with a Highly Virulent Strain of African Swine Fever Virus Genotype II

Pathogens ◽

10.3390/pathogens9090688 ◽

2020 ◽

Vol 9 (9) ◽

pp. 688 ◽

Cited By ~ 1

Author(s):

Antonio Rodríguez-Bertos ◽

Estefanía Cadenas-Fernández ◽

Agustín Rebollada-Merino ◽

Néstor Porras-González ◽

Francisco J. Mayoral-Alegre ◽

...

Keyword(s):

Wild Boar ◽

Clinical Course ◽

African Swine Fever Virus ◽

Virulent Strain ◽

African Swine Fever ◽

Pathological Findings ◽

Wild Boars ◽

Gross Pathology ◽

Highly Virulent ◽

Genotype Ii

African swine fever (ASF) is a notifiable disease that in recent years has spread remarkably in Europe and Asia. Eurasian wild boar (Sus scrofa) plays a key role in the maintenance and spread of the pathogen. Here we examined gross pathology of infection in wild boar with a highly virulent, hemadsorbing genotype II ASF virus (ASFV) strain. To this end, six wild boars were intramuscularly inoculated with the 10 HAD50 Arm07 ASFV strain, and 11 wild boars were allowed to come into direct contact with the inoculated animals. No animals survived the infection. Clinical course, gross pathological findings and viral genome quantification by PCR in tissues did not differ between intramuscularly inoculated or contact-infected animals. Postmortem analysis showed enlargement of liver and spleen; serosanguinous effusion in body cavities; and multiple hemorrhages in lungs, endocardium, brain, kidneys, urinary bladder, pancreas, and alimentary system. These results provide detailed insights into the gross pathology of wild boar infected with a highly virulent genotype II ASFV strain. From a didactic point of view, this detailed clinical course and macroscopic description may be essential for early postmortem detection of outbreaks in wild boar in the field and contribute to disease surveillance and prevention efforts.

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Selected aspects related to epidemiology, pathogenesis, immunity, and control of African swine fever

Journal of Veterinary Research ◽

10.1515/jvetres-2016-0017 ◽

2016 ◽

Vol 60 (2) ◽

pp. 119-125 ◽

Cited By ~ 3

Author(s):

Grzegorz Woźniakowski ◽

Magdalena Frączyk ◽

Krzysztof Niemczuk ◽

Zygmunt Pejsak

Keyword(s):

Wild Boar ◽

Viral Infections ◽

Specific Treatment ◽

African Swine Fever ◽

New Era ◽

Wild Boars ◽

Domestic Pigs ◽

Rate Of Spread ◽

International Transport ◽

Socio Economic Impact

Abstract African swine fever (ASF) is currently one of the most severe viral infections of domestic pigs, wild boars, and other hosts belonging to Suidae family. ASF is also considered as the most complex and devastating infectious and haemorrhagic disease of swine due to its severe socio-economic impact and transboundary character. ASF it is a notifiable disease and due to the lack of specific treatment and vaccine, the disease can be only limited by the administrative measures comprising wild boar hunting and stamping out of affected pigs. ASF occurred for the first time in Kenya in 1921 while in Europe (Portugal) the virus was detected at the end of the 1950s. In spite of successful eradication of this threat in a number of affected regions, the virus remains endemic in both feral and domestic pigs in Africa and Sardinia. The ‘new era’ of ASF started in 2007 after its re-introduction to Georgia. Following its intensive expansion, the virus spread to other Caucasian countries, including the territory of the Russian Federation. In 2014 the virus reached Ukraine, Belarus, and, consequently, European Union countries: Lithuania, Latvia, Estonia, and Poland. The occurrence of ASF in wild boars and pigs had a severe impact on both epidemiology and economy because of the national and international transport and trade consequences. Up to date, starting from the February 2014, eighty ASF cases in wild boar and three outbreaks in domestic pigs have been diagnosed. Taking into account the diverse rate of spread in Poland, this review aims to present and discuss the current state of knowledge on ASF including its epidemiology, pathology, transmission, and perspectives of control.

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

Agriculture ◽

10.3390/agriculture11010045 ◽

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.

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Towards risk-based surveillance of African Swine Fever in Switzerland

10.1101/2021.05.17.444420 ◽

2021 ◽

Author(s):

Maria Elena Vargas-Amado ◽

Luís Pedro Carmo ◽

John Berezowski ◽

Claude Fischer ◽

Maria João Santos ◽

...

Keyword(s):

High Risk ◽

Wild Boar ◽

Disease Transmission ◽

Forest Cover ◽

Disease Risk ◽

Animal Health ◽

African Swine Fever ◽

Early Disease ◽

Domestic Pig ◽

Domestic Pigs

African Swine Fever (ASF) has emerged as a disease of great concern to swine producers and government disease control agencies because of its severe consequences to animal health and the pig industry. Early detection of an ASF introduction is considered essential for reducing the harm caused by the disease. Risk-based surveillance approaches have been used as enhancements to early disease epidemic detection systems in livestock populations. Such approaches may consider the role wildlife plays in hosting and transmitting a disease. In this study, a novel method is presented to estimate and map the risk of introducing ASF into the domestic pig population through wild boar intermediate hosts. It makes use of data about hunted wild boar, rest areas along motorways connecting ASF affected countries to Switzerland, outdoor piggeries, and forest cover. These data were used to compute relative wild boar abundance as well as to estimate the risk of both disease introduction into the wild boar population and disease transmission to domestic pigs. The way relative wild boar abundance was calculated adds to the current state of the art by considering the effect of beech mast on hunting success and the probability of wild boar occurrence when distributing relative abundance values among individual grid cells. The risk of ASF introduction into the domestic pig population by wild boar was highest near the borders of France, Germany, and Italy. On the north side of the Alps, areas of high risk were located on the unshielded side of the main motorway crossing the Central Plateau, which acts as a barrier for wild boar. The results of this study can be used to focus surveillance efforts for early disease detection on high risk areas. The developed method may also inform policies to control other diseases that are transmitted by direct contact from wild boar to domestic pigs.

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African swine fever virus (ASFV) in Poland: Prevalence in a wild boar population (2017–2018)

Veterinární Medicína ◽

10.17221/105/2019-vetmed ◽

2020 ◽

Vol 65 (No. 4) ◽

pp. 143-158 ◽

Cited By ~ 1

Author(s):

MP Frant ◽

M Lyjak ◽

L Bocian ◽

A Barszcz ◽

K Niemczuk ◽

...

Keyword(s):

Wild Boar ◽

Active Surveillance ◽

African Swine Fever Virus ◽

Winter Season ◽

African Swine Fever ◽

Disease Spread ◽

Passive Surveillance ◽

Wild Boar Population ◽

Wild Boars ◽

In The Wild

African swine fever (ASF) was first described in 1921 in Kenya. The latest epidemic of ASF started in 2007 in Georgia. The virus was introduced to Poland in 2014. Since the beginning of the epidemics, the National Veterinary Research Institute in Pulawy (NVRI) has been testing wild boar samples from restricted areas and other parts of Poland to conduct passive and active surveillance for ASFV in these groups of animals. The aim of this study was to summarise the last two years of the ASF epidemiological status in Poland and the attempt to find disease patterns in the wild boar population. The period between 2017 and 2018 brought a massive number of new ASF cases in Poland. The number of ASF-positive wild boars jumped from 91 in 2016 to 1 140 in 2017 (approximately a 12 × increase), and 2018 was even worse, with the disease affecting 4 083 animals (2 435 cases; one case could even be 10 animals or more if they are found in one place next to each other). The percentage of positive wild boars found dead (passive surveillance) in the restricted area increased in 2018 to 73.1% from 70.8% in 2017. The chance of obtaining positive results in this group was six times higher in December and 4.5 times higher in January than in August and September. The percentage of positive wild boars detected through active surveillance reached 1.5% in 2018. The data suggested that, not only in Poland, but also in other ASF-affected countries, during the epizootic stage of the disease spread the most important measure is an effective passive surveillance of dead wild boars especially, in the winter season rather than in the summer.

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How do genetic relatedness and spatial proximity shape African swine fever infections in wild boar?

10.22541/au.162591098.83705488/v1 ◽

2021 ◽

Author(s):

Tomasz Podgórski ◽

Kim Pepin ◽

Anna Radko ◽

Angelika Podbielska ◽

Magdalena Łyjak ◽

...

Keyword(s):

Wild Boar ◽

Contact Zone ◽

Disease Transmission ◽

Genetic Relatedness ◽

African Swine Fever ◽

Infection Risk ◽

Disease Spread ◽

Spatial Proximity ◽

Transmission Rates ◽

Close Relatives

The importance of social and spatial structuring of wildlife populations for disease spread, though widely recognized, is still poorly understood in many host-pathogen systems. In particular, system specific kin relationships among hosts can create contact heterogeneities and differential disease transmission rates. Here, we investigate how distance-dependent infection risk is influenced by genetic relatedness in a novel wild boar ( Sus scrofa) - African swine fever (ASF) system. We hypothesized that the infection risk would correlate positively with proximity and relatedness to ASF-infected individuals but expected those relationships to weaken with distance between individuals due to decay in contact rates and genetic similarity. ASF infection risk was shaped by the number of infected animals throughout the zone of potential contact (0-10 km) but not beyond it. This effect was the strongest at close distances (0-2 km) and weakened further on (2-10 km), consistent with decreasing probability of contact. Overall, there was a positive association between genetic relatedness to infectees and infection risk within the contact zone but this effect varied in space. In the high-contact zone (0-2 km), infection risk was not influenced by relatedness when controlled for the number of ASF-positive animals. However, infections were more frequent among close relatives indicating that familial relationships could have played a role in ASF transmission. In the medium-contact zone (2-5 km), infection risk and frequency of paired infections were associated with relatedness. Relatedness did not predict infection risk in low- and no-contact zones (5-10 and >10 km, respectively). Together, our results indicate that the number of nearby infected individuals overrides the effect of relatedness in shaping ASF transmission rates which nevertheless can be higher among close relatives. Highly localized transmission highlights the possibility to control the disease if containment measures are employed quickly and efficiently.

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Territorial pattern between outbreaks of ASF among wild and domestic pigs in Ukraine

Scientific Messenger of LNU of Veterinary Medicine and Biotechnology ◽

10.32718/nvlvet10403 ◽

2021 ◽

Vol 23 (104) ◽

pp. 18-22

Author(s):

Ye. O. Dudnyk

Keyword(s):

Wild Boar ◽

African Swine Fever ◽

Weak Links ◽

Wild Boars ◽

Domestic Pigs ◽

Wild Pigs ◽

Animal Populations ◽

Focus Of Infection ◽

Epizootic Process

The article presents the results of the analysis of the epizootic situation in Ukraine regarding African swine fever among domestic and wild pigs from 2012 to 2020 and identifies the main sources of virus spread as well as weak links in the biological safety system of farms. When studying the statistical material of the Food and Agriculture Organization of the United Nations (FAO) and the State Service of Ukraine on Food Safety and Consumer Protection regarding animal morbidity, revealed a territorial pattern between the outbreaks of African swine fever among wild boars and domestic pigs of private farms and pig-breeding complexes, and proved the involvement of the European boar in the epizootic process as a natural reservoir and mobile focus of infection. Calculated the number of outbreaks of African swine fever among wild boars and domestic pigs within the same region and district, and studied the sequence of the emergence of foci on limited territories. Analyzed the natural focality of the disease, the probability of infection transmission to the domestic pig farm sector, and the role of infected objects in the spread of the virus among wild animal populations. From 2012 to 2020 inclusive, according to FAO statistics, 537 cases of African swine fever were recorded in Ukraine, 21.7 % of which were associated with wild boars. In 2017 and 2018, the role of the European wild boar in the epizootic process is best reflected, when 10.9 % (2017) and 20.4 % (2018) of outbreaks of African swine fever among domestic animals recorded in the same administrative districts, where during a year this desiase was detected among wild pigs. When analyzing statistical data of the recent years, the effectiveness of introducing more detailed monitoring of African swine fever among wild boars using modern laboratory methods and improving biosafety measures in the private sector and directly on hunting grounds has been proved. Further research is based on predicting the dynamics of the spread of African swine fever in Ukraine and the role of wild boar in this epizootic process. In addition, the role of wild boar in the spread of African swine fever in other countries and the most effective foreign methods of disease control and prevention will be analyzed.

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Passive surveillance of African Swine Fever (ASF) in wild boars as an effective tool for prevention, control and eradication of ASF: A new approach

Medycyna Weterynaryjna ◽

10.21521/mw.6518 ◽

2022 ◽

Vol 77 (04) ◽

pp. 65146-2022

Author(s):

MIROSŁAW WELZ ◽

BARTŁOMIEJ POPCZYK ◽

KRZYSZTOF NIEMCZUK ◽

ŁUKASZ BOCIAN ◽

KRZYSZTOF JAŻDŻEWSKI ◽

...

Keyword(s):

Wild Boar ◽

Early Stage ◽

African Swine Fever ◽

Infectious Agent ◽

Epidemiological Surveillance ◽

Passive Surveillance ◽

Sample Collection ◽

New Approach ◽

Wild Boars ◽

Wild Fauna

The latest recommendations of the European Commission and the scientific opinions of the EFSA and other bodies define the passive surveillance of ASF in wild boars as a key means of epidemiological surveillance and a basic tool for the eradication of the ASF virus from the natural environment in the areas where this disease occurs, especially in the early stage of its development. The key to eradication is the management of the wild boar population and its reduction to a low and controlled number, so as to diminish the virus pressure in the environment and lessen the risk to pig farms. Wild boar hunting should take place in a planned manner that is adapted to the epizootic situation (as part of centrally managed hunting and sanitary culling). The most intensive hunting should take place in ASF-free areas, with the use of tailored methods and the latest technologies. Periodic hunting moratoria and restrictions on any activity in newly infected zones are necessary. This approach provides for phased eradication of the infectious agent by culling or capturing wild boars, as well as identifying and safely removing their carcasses and remains. When passive ASF surveillance in wild fauna is undertaken, data on the incidence of the disease in wild boars are obtained by the Veterinary Inspectorate without its active participation. The inspectorate is notified of any suspicion or occurrence of the disease, including discoveries of carcasses of animals of susceptible species. Then it acts according to an established plan including clinical examination of suspected or sick animals, anatomopathological examinations and sample collection for laboratory tests. The article describes the use of passive ASF surveillance in wild boars as a tool to prevent, control and combat ASF in Poland.

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