scholarly journals Comparative Pathology of Domestic Pigs and Wild Boar Infected with the Moderately Virulent African Swine Fever Virus Strain “Estonia 2014”

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 662
Author(s):  
Julia Sehl ◽  
Jutta Pikalo ◽  
Alexander Schäfer ◽  
Kati Franzke ◽  
Katrin Pannhorst ◽  
...  
Keyword(s):  
Wild Boar ◽  
Viral Antigen ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Kinetic Experiment ◽  
Domestic Pigs ◽  
Hunting Bag ◽  
North Eastern ◽  
The Baltic

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.

scholarly journals Comparative Pathology of Domestic Pigs and Wild Boar Infected with the Moderately Virulent African Swine Fever Virus Strain “Estonia 2014”

2020 ◽  
Author(s):  
Julia Sehl ◽  
Jutta Pikalo ◽  
Alexander Schäfer ◽  
Kati Franzke ◽  
Katrin Pannhorst ◽  
...  
Keyword(s):  
Wild Boar ◽  
Viral Antigen ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Kinetic Experiment ◽  
Domestic Pigs ◽  
Hunting Bag ◽  
North Eastern ◽  
The Baltic

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.

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 Evaluation of Lesions and Viral Antigen Distribution in Domestic Pigs Inoculated Intranasally with African Swine Fever Virus Ken05/Tk1 (Genotype X)

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 768
Author(s):  
Pedro J. Sánchez-Cordón ◽  
Tobias Floyd ◽  
Daniel Hicks ◽  
Helen R. Crooke ◽  
Stephen McCleary ◽  
...  
Keyword(s):  
Viral Antigen ◽  
African Swine Fever Virus ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Virus Genome ◽  
Virus Antigen ◽  
Fever Virus ◽  
Control Measures ◽  
Vascular Lesions ◽  
Domestic Pigs

The understanding of the pathogenic mechanisms and the clinicopathological forms caused by currently circulating African swine fever virus (ASFV) isolates is incomplete. So far, most of the studies have been focused on isolates classified within genotypes I and II, the only genotypes that have circulated outside of Africa. However, less is known about the clinical presentations and lesions induced by isolates belonging to the other twenty-two genotypes. Therefore, the early clinicopathological identification of disease outbreaks caused by isolates belonging to, as yet, not well-characterised ASFV genotypes may be compromised, which might cause a delay in the implementation of control measures to halt the virus spread. To improve the pathological characterisation of disease caused by diverse isolates, we have refined the macroscopic and histopathological evaluation protocols to standardise the scoring of lesions. Domestic pigs were inoculated intranasally with different doses (high, medium and low) of ASFV isolate Ken05/Tk1 (genotype X). To complement previous studies, the distribution and severity of macroscopic and histopathological lesions, along with the amount and distribution of viral antigen in tissues, were characterised by applying the new scoring protocols. The intranasal inoculation of domestic pigs with high doses of the Ken05/Tk1 isolate induced acute forms of ASF in most of the animals. Inoculation with medium doses mainly induced acute forms of disease. A less severe but longer clinical course, typical of subacute forms, characterised by the presence of more widespread and severe haemorrhages and oedema, was observed in one pig inoculated with the medium dose. The severity of vascular lesions (haemorrhages and oedema) induced by high and medium doses was not associated with the amount of virus antigen detected in tissues, therefore these might be attributed to indirect mechanisms not evaluated in the present study. The absence of clinical signs, lesions and detectable levels of virus genome or antigen in blood from the animals inoculated with the lowest dose ruled out the existence of possible asymptomatic carriers or persistently infected pigs, at least for the 21 days period of the study. The results corroborate the moderate virulence of the Ken05/Tk1 isolate, as well as its capacity to induce both the acute and, occasionally, subacute forms of ASF when high and medium doses were administered intranasally.

scholarly journals Techniques of blood sampling for detection of African swine fever virus in wild boar and domestic pigs in the field conditions

2021 ◽  
pp. 285-294
Author(s):  
A. S. Pershin ◽  
A. R. Shotin ◽  
E. O. Morozova ◽  
A. S. Igolkin ◽  
O. A. Manuylova ◽  
...  
Keyword(s):  
Wild Boar ◽  
Immunosorbent Assay ◽  
Filter Paper ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Blood Sampling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunoperoxidase Technique ◽  
Domestic Pigs

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.

scholarly journals The Role of Interleukine-10 and Interferon-γ as Potential Markers of the Evolution of African Swine Fever Virus Infection in Wild Boar

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 757
Author(s):  
Sandra Barroso-Arévalo ◽  
Jose A. Barasona ◽  
Estefanía Cadenas-Fernández ◽  
José M. Sánchez-Vizcaíno
Keyword(s):  
Wild Boar ◽  
Vaccine Candidate ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Interferon Γ ◽  
Fever Virus ◽  
Control Group ◽  
Challenge Virus ◽  
Ifn Γ

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.

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