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: Prevalence in a wild boar population (2017–2018)

2020 ◽  
Vol 65 (No. 4) ◽  
pp. 143-158 ◽  
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.

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 Genome Sequences of Three African Swine Fever Viruses of Genotypes IV and XX from Zaire and South Africa, Isolated from a Domestic Pig (Sus scrofa domesticus), a Warthog (Phacochoerus africanus), and a European Wild Boar (Sus scrofa)

2020 ◽  
Vol 9 (32) ◽  
Author(s):  
S. Ndlovu ◽  
A.-L. Williamson ◽  
L. Heath ◽  
O. Carulei
Keyword(s):  
South Africa ◽  
Wild Boar ◽  
Sus Scrofa ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Genome Sequences ◽  
Domestic Pig ◽  
European Wild Boar ◽  
Sus Scrofa Domesticus ◽  
Phacochoerus Africanus

ABSTRACT We report here the genome sequences of three African swine fever virus isolates obtained from a domestic pig (Zaire [Zaire]), a warthog (RSA/W1/1999 [South Africa]), and a European wild boar (RSA/2/2004 [South Africa]) belonging to genotypes IV, XX, and XX, respectively. This report increases the number of genotype XX, wild boar, and warthog reference sequences available.

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 The African swine fever virus isolate Belgium 2018/1 shows high virulence in European wild boar

2020 ◽  
Vol 67 (4) ◽  
pp. 1654-1659 ◽  
Author(s):  
Jutta Pikalo ◽  
Marie‐Eve Schoder ◽  
Julia Sehl ◽  
Angele Breithaupt ◽  
Maryléne Tignon ◽  
...  
Keyword(s):  
Wild Boar ◽  
Virus Isolate ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
European Wild Boar ◽  
High Virulence

Pathogenesis of African swine fever in domestic pigs and European wild boar

2013 ◽  
Vol 173 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Sandra Blome ◽  
Claudia Gabriel ◽  
Martin Beer
Keyword(s):  
Wild Boar ◽  
African Swine Fever ◽  
Domestic Pigs ◽  
European Wild Boar

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 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.

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