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

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 688 ◽  
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.

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

Animals ◽  
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.

scholarly journals Live Attenuated African Swine Fever Viruses as Ideal Tools to Dissect the Mechanisms Involved in Cross-Protection

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1474
Author(s):  
Elisabeth Lopez ◽  
Juanita van Heerden ◽  
Laia Bosch-Camós ◽  
Francesc Accensi ◽  
Maria Jesus Navas ◽  
...  
Keyword(s):  
Vaccine Development ◽  
African Swine Fever Virus ◽  
Virulent Strain ◽  
Sequence Similarity ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Cross Protection ◽  
Sub Saharan Africa ◽  
Genotype I ◽  
Genotype Ii

African swine fever (ASF) has become the major threat for the global swine industry. Furthermore, the epidemiological situation of African swine fever virus (ASFV) in some endemic regions of Sub-Saharan Africa is worse than ever, with multiple virus strains and genotypes currently circulating in a given area. Despite the recent advances on ASF vaccine development, there are no commercial vaccines yet, and most of the promising vaccine prototypes available today have been specifically designed to fight the genotype II strains currently circulating in Europe, Asia, and Oceania. Previous results from our laboratory have demonstrated the ability of BA71∆CD2, a recombinant LAV lacking CD2v, to confer protection against homologous (BA71) and heterologous genotype I (E75) and genotype II (Georgia2007/01) ASFV strains, both belonging to same clade (clade C). Here, we extend these results using BA71∆CD2 as a tool trying to understand ASFV cross-protection, using phylogenetically distant ASFV strains. We first observed that five out of six (83.3%) of the pigs immunized once with 106 PFU of BA71∆CD2 survived the tick-bite challenge using Ornithodoros sp. soft ticks naturally infected with RSA/11/2017 strain (genotype XIX, clade D). Second, only two out of six (33.3%) survived the challenge with Ken06.Bus (genotype IX, clade A), which is phylogenetically more distant to BA71∆CD2 than the RSA/11/2017 strain. On the other hand, homologous prime-boosting with BA71∆CD2 only improved the survival rate to 50% after Ken06.Bus challenge, all suffering mild ASF-compatible clinical signs, while 100% of the pigs immunized with BA71∆CD2 and boosted with the parental BA71 virulent strain survived the lethal challenge with Ken06.Bus, without almost no clinical signs of the disease. Our results confirm that cross-protection is a multifactorial phenomenon that not only depends on sequence similarity. We believe that understanding this complex phenomenon will be useful for designing future vaccines for ASF-endemic areas.

scholarly journals Subunit Vaccine Approaches for African Swine Fever Virus

Vaccines ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 56 ◽  
Author(s):  
Natasha N. Gaudreault ◽  
Juergen A. Richt
Keyword(s):  
Western Europe ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Swine Industry ◽  
Fatal Disease ◽  
The Caucasus ◽  
Caucasus Region ◽  
Highly Virulent ◽  
Genotype Ii

African swine fever virus (ASFV) is the cause of a highly fatal disease in swine, for which there is no available vaccine. The disease is highly contagious and poses a serious threat to the swine industry worldwide. Since its introduction to the Caucasus region in 2007, a highly virulent, genotype II strain of ASFV has continued to circulate and spread into Eastern Europe and Russia, and most recently into Western Europe, China, and various countries of Southeast Asia. This review summarizes various ASFV vaccine strategies that have been investigated, with focus on antigen-, DNA-, and virus vector-based vaccines. Known ASFV antigens and the determinants of protection against ASFV versus immunopathological enhancement of infection and disease are also discussed.

scholarly journals Impaired T‐cell responses in domestic pigs and wild boar upon infection with a highly virulent African swine fever virus strain

2020 ◽  
Vol 67 (6) ◽  
pp. 3016-3032 ◽  
Author(s):  
Jane Hühr ◽  
Alexander Schäfer ◽  
Theresa Schwaiger ◽  
Laura Zani ◽  
Julia Sehl ◽  
...  
Keyword(s):  
T Cell ◽  
Wild Boar ◽  
Virus Strain ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
T Cell Responses ◽  
Fever Virus ◽  
Domestic Pigs ◽  
Cell Responses ◽  
Highly Virulent

scholarly journals Comparative Analysis of Full Genome Sequences of African Swine Fever Virus Isolates Taken from Wild Boars in Russia in 2019

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 521
Author(s):  
Ali Mazloum ◽  
Antoinette van Schalkwyk ◽  
Andrey Shotin ◽  
Alexey Igolkin ◽  
Ivan Shevchenko ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Resolving Power ◽  
Full Genome ◽  
Wild Boars ◽  
Sequence Identity ◽  
High Level ◽  
Virus Isolates ◽  
Genotype Ii

In this study, we report on the full genome phylogenetic analysis of four ASFV isolates obtained from wild boars in Russia. These samples originated from two eastern and two western regions of Russia in 2019. Phylogenetic analysis indicated that the isolates were assigned to genotype II and grouped according to their geographical origins. The two eastern isolates shared 99.99% sequence identity with isolates from China, Poland, Belgium, and Moldova, whereas the western isolates had 99.98% sequence identity with isolates from Lithuania and the original Georgia 2007 isolate. Based on the full genome phylogenies, we identified three single locus targets, MGF-360-10L, MGF-505-9R, and I267L, that yielded the same resolving power as the full genomes. The ease of alignment and a high level of variation make these targets a suitable selection as additional molecular markers in future ASFV phylogenetic practices.

scholarly journals First Oral Vaccination of Eurasian Wild Boar Against African Swine Fever Virus Genotype II

2019 ◽  
Vol 6 ◽  
Author(s):  
Jose A. Barasona ◽  
Carmina Gallardo ◽  
Estefanía Cadenas-Fernández ◽  
Cristina Jurado ◽  
Belén Rivera ◽  
...  
Keyword(s):  
Wild Boar ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Virus Genotype ◽  
Oral Vaccination ◽  
Genotype Ii

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 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 Virus Armenia/07 Virulent Strain Controls Interferon Beta Production through the cGAS-STING Pathway

2019 ◽  
Vol 93 (12) ◽  
Author(s):  
Raquel García-Belmonte ◽  
Daniel Pérez-Núñez ◽  
Marco Pittau ◽  
Juergen A. Richt ◽  
Yolanda Revilla
Keyword(s):  
Wild Boar ◽  
Immune Modulation ◽  
Molecular Mechanisms ◽  
African Swine Fever Virus ◽  
Virulent Strain ◽  
African Swine Fever ◽  
Fever Virus ◽  
Type I ◽  
Sting Pathway ◽  
First Time

ABSTRACT African swine fever virus (ASFV) is a complex, cytoplasmic double-stranded DNA (dsDNA) virus that is currently expanding throughout the world. Currently, circulating virulent genotype II Armenia/07-like viruses cause fatal disease in pigs and wild boar, whereas attenuated strains induce infections with various levels of chronic illness. Sensing cytosolic dsDNA, mainly by the key DNA sensor cyclic GMP-AMP synthase (cGAS), leads to the synthesis of type I interferon and involves signaling through STING, TBK1, and IRF3. After phosphorylation, STING translocates from the endoplasmic reticulum to the Golgi compartment and to the perinuclear region, acting as an indispensable adaptor connecting the cytosolic detection of DNA to the TBK1-IRF3 signaling pathway. We demonstrate here that attenuated NH/P68, but not virulent Armenia/07, activates the cGAS-STING-IRF3 cascade very early during infection, inducing STING phosphorylation and trafficking through a mechanism involving cGAMP. Both TBK1 and IRF3 are subsequently activated and, in response to this, a high level of beta interferon (IFN-β) was produced during NH/P68 infection; in contrast, Armenia/07 infection generated IFN-β levels below those of uninfected cells. Our results show that virulent Armenia/07 ASFV controls the cGAS-STING pathway, but these mechanisms are not at play when porcine macrophages are infected with attenuated NH/P68 ASFV. These findings show for the first time the involvement of the cGAS-STING-IRF3 route in ASFV infection, where IFN-β production or inhibition was found after infection by attenuated or virulent ASFV strains, respectively, thus reinforcing the idea that ASFV virulence versus attenuation may be a phenomenon grounded in ASFV-mediated innate immune modulation where the cGAS-STING pathway might play an important role. IMPORTANCE African swine fever, a devastating disease for domestic pigs and wild boar, is currently spreading in Europe, Russia, and China, becoming a global threat with huge economic and ecological consequences. One interesting aspect of ASFV biology is the molecular mechanism leading to high virulence of some strains compared to more attenuated strains, which produce subclinical infections. In this work, we show that the presently circulating virulent Armenia/07 virus blocks the synthesis of IFN-β, a key mediator between the innate and adaptive immune response. Armenia/07 inhibits the cGAS-STING pathway by impairing STING activation during infection. In contrast, the cGAS-STING pathway is efficiently activated during NH/P68 attenuated strain infection, leading to the production of large amounts of IFN-β. Our results show for the first time the relationship between the cGAS-STING pathway and ASFV virulence, contributing to uncover the molecular mechanisms of ASFV virulence and to the rational development of ASFV vaccines.

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