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 ◽  
...  
Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 662
Author(s):  
Julia Sehl ◽  
Jutta Pikalo ◽  
Alexander Schäfer ◽  
Kati Franzke ◽  
Katrin Pannhorst ◽  
...  

Endemically infected European wild boar are considered a major reservoir of African swine fever virus in Europe. While high lethality was observed in the majority of field cases, strains of moderate virulence occurred in the Baltic States. One of these, “Estonia 2014”, led to a higher number of clinically healthy, antibody-positive animals in the hunting bag of North-Eastern Estonia. Experimental characterization showed high virulence in wild boar but moderate virulence in domestic pigs. Putative pathogenic differences between wild boar and domestic pigs are unresolved and comparative pathological studies are limited. We here report on a kinetic experiment in both subspecies. Three animals each were euthanized at 4, 7, and 10 days post infection (dpi). Clinical data confirmed higher virulence in wild boar although macroscopy and viral genome load in blood and tissues were comparable in both subspecies. The percentage of viral antigen positive myeloid cells tested by flow cytometry did not differ significantly in most tissues. Only immunohistochemistry revealed consistently higher viral antigen loads in wild boar tissues in particular 7 dpi, whereas domestic pigs already eliminated the virus. The moderate virulence in domestic pigs could be explained by a more effective viral clearance.


Author(s):  
Julia Sehl ◽  
Jutta Pikalo ◽  
Alexander Schäfer ◽  
Kati Franzke ◽  
Katrin Pannhorst ◽  
...  

Endemically infected European wild boar are considered a major reservoir of African swine fever virus in Europe. While high lethality was observed in the majority of field cases, strains of moderate virulence occurred in the Baltic States. One of these, “Estonia 2014”, led to a higher number of clinically healthy, antibody-positive animals in the hunting bag of North-Eastern Estonia. Experimental characterization showed high virulence in wild boar but moderate virulence in domestic pigs. Putative pathogenic differences between wild boar and domestic pigs are unresolved and comparative pathological studies are limited. We here report on a kinetic experiment in both subspecies. Three animals each were euthanized at 4, 7 and 10 days post infection (dpi). Clinical data confirmed higher virulence in wild boar although macroscopy and viral genome load in blood and tissues were comparable in both subspecies. The percentage of viral antigen positive myeloid cells tested by flow cytometry did not differ significantly in most tissues. Only immunohistochemistry revealed consistently higher viral antigen loads in wild boar tissues in particular 7 dpi, whereas domestic pigs already eliminated the virus. The moderate virulence in domestic pigs could be explained by a more effective viral clearance.


2021 ◽  
pp. 285-294
Author(s):  
A. S. Pershin ◽  
A. R. Shotin ◽  
E. O. Morozova ◽  
A. S. Igolkin ◽  
O. A. Manuylova ◽  
...  

It is thought that due to the high virulence of the African swine fever virus its circulation in the Russian Federation is accompanied by a low seroprevalence. However taking into account a long-term ASF unfavourable situation, the introduction of the virus into the wild boar population, and the occurrence of attenuated viral variants, the significance of serological testing aimed at the detection of viral antibodies is increasing. To collect field samples of biological material from animals for molecular genetic, virological, and serological tests, filter paper, as well as swabs, can be used. The specificity and sensitivity of enzyme-linked immunosorbent assay when testing blood absorbed by filter paper are worse than those shown when testing sera, but they allow effective detection of African swine fever virus antibodies. It was demonstrated that blood absorbed on filter paper can be used for the immunoblot analysis, but the optimum performance could be achieved when the immunoperoxidase technique in combination with samples, taken by swabs was used. When comparing results of enzyme-linked immunosorbent assay performed on sera collected from domestic pigs (infected with ASFV isolates Antonovo 07/14 and Sobinka 07/15), and blood from ear veins absorbed on filter paper the sensitivity was 88.9%, specificity – 90.6%. However, the use of the immunoperoxidase technique for testing blood from swabs showed 100% coincidence with ELISA, while testing of sera with immunoperoxidase technique was superior to ELISA in sensitivity. This means blood sampling using swabs may be recommended for tests after proper validation. This technique can be especially useful for collecting data about infected wild boars because effective eradication strategies are impossible without such data.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 757
Author(s):  
Sandra Barroso-Arévalo ◽  
Jose A. Barasona ◽  
Estefanía Cadenas-Fernández ◽  
José M. Sánchez-Vizcaíno

African swine fever virus (ASFv) is one of the most challenging pathogens to affect both domestic and wild pigs. The disease has now spread to Europe and Asia, causing great damage to the pig industry. Although no commercial vaccine with which to control the disease is, as yet, available, some potential vaccine candidates have shown good results in terms of protection. However, little is known about the host immune mechanisms underlying that protection, especially in wild boar, which is the main reservoir of the disease in Europe. Here, we study the role played by two cytokines (IL-10 and IFN-γ) in wild boar orally inoculated with the attenuated vaccine candidate Lv17/WB/Rie1 and challenged with a virulent ASFv genotype II isolate. A group of naïve wild boar challenged with the latter isolate was also established as a control group. Our results showed that both cytokines play a key role in protecting the host against the challenge virus. While high levels of IL-10 in serum may trigger an immune system malfunctioning in challenged animals, the provision of stable levels of this cytokine over time may help to control the disease. This, together with high and timely induction of IFN-γ by the vaccine candidate, could help protect animals from fatal outcomes. Further studies should be conducted in order to support these preliminary results and confirm the role of these two cytokines as potential markers of the evolution of ASFV infection.


Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1078 ◽  
Author(s):  
Albert Ros-Lucas ◽  
Florencia Correa-Fiz ◽  
Laia Bosch-Camós ◽  
Fernando Rodriguez ◽  
Julio Alonso-Padilla

African swine fever virus is the etiological agent of African swine fever, a transmissible severe hemorrhagic disease that affects pigs, causing massive economic losses. There is neither a treatment nor a vaccine available, and the only method to control its spread is by extensive culling of pigs. So far, classical vaccine development approaches have not yielded sufficiently good results in terms of concomitant safety and efficacy. Nowadays, thanks to advances in genomic and proteomic techniques, a reverse vaccinology strategy can be explored to design alternative vaccine formulations. In this study, ASFV protein sequences were analyzed using an in-house pipeline based on publicly available immunoinformatic tools to identify epitopes of interest for a prospective vaccine ensemble. These included experimentally validated sequences from the Immune Epitope Database, as well as de novo predicted sequences. Experimentally validated and predicted epitopes were prioritized following a series of criteria that included evolutionary conservation, presence in the virulent and currently circulating variant Georgia 2007/1, and lack of identity to either the pig proteome or putative proteins from pig gut microbiota. Following this strategy, 29 B-cell, 14 CD4+ T-cell and 6 CD8+ T-cell epitopes were selected, which represent a starting point to investigating the protective capacity of ASFV epitope-based vaccines.


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