scholarly journals Absence of Long-Term Protection in Domestic Pigs Immunized with Attenuated African Swine Fever Virus Isolate OURT88/3 or BeninΔMGF Correlates with Increased Levels of Regulatory T Cells and Interleukin-10

2020 ◽  
Vol 94 (14) ◽  
Author(s):  
Pedro J. Sánchez-Cordón ◽  
Tamara Jabbar ◽  
Dave Chapman ◽  
Linda K. Dixon ◽  
María Montoya
Keyword(s):  
T Cells ◽  
Immune System ◽  
Regulatory T Cells ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Interleukin 10 ◽  
Fever Virus ◽  
Effective Protection ◽  
Domestic Pigs

ABSTRACT Following short immunization protocols, naturally attenuated African swine fever virus (ASFV) isolate OURT88/3 and deletion mutant BeninΔMGF have previously been shown to induce high percentages of protection in domestic pigs against challenge with virulent virus. The results obtained in the present study show that a single intramuscular immunization of domestic pigs with OURT88/3 or BeninΔMGF followed by a challenge with the virulent Benin 97/1 isolate at day 130 postimmunization did not trigger the mechanisms necessary to generate immunological memory able to induce long-term protection against disease. All pigs developed acute forms of acute swine fever (ASF). Gamma interferon-producing cells peaked at day 24 postimmunization, declining thereafter. Surprisingly, the levels of regulatory T cells (Tregs) and interleukin-10 (IL-10) were elevated at the end of the experiment, suggesting that regulatory components of the immune system may inhibit effective protection. IMPORTANCE The duration of immunity for any vaccine candidate is crucial. In the case of African swine fever virus vaccine candidates, this issue has received little attention. Attenuated viruses have proven protective following short immunization protocols in which pigs were challenged a few weeks after the first immunization. Here, the duration of immunity and the immune responses induced over a duration of 130 days were studied during prechallenge and after challenge of pigs immunized with the naturally attenuated isolate OURT88/3 and an attenuated gene-deleted isolate, BeninΔMGF. After a single intramuscular immunization of domestic pigs with the OURT88/3 isolate or BeninΔMGF virus, animals were not protected against challenge with the virulent Benin 97/1 ASFV genotype I isolate at day 130 postimmunization. The levels of regulatory T cells and IL-10 were elevated at the end of the experiment, suggesting that regulatory components of the immune system may inhibit effective protection.

scholarly journals Substitution of warthog NF-κB motifs into RELA of domestic pigs is not sufficient to confer resilience to African swine fever virus

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephen McCleary ◽  
Rebecca Strong ◽  
Ronan R. McCarthy ◽  
Jane C. Edwards ◽  
Emma L. Howes ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Domestic Pigs

scholarly journals Lack of evidence for long term carriers of African swine fever virus - a systematic review

2019 ◽  
Vol 272 ◽  
pp. 197725 ◽  
Author(s):  
Karl Ståhl ◽  
Susanna Sternberg-Lewerin ◽  
Sandra Blome ◽  
Arvo Viltrop ◽  
Mary-Louise Penrith ◽  
...  
Keyword(s):  
Systematic Review ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus

scholarly journals Identification of a Continuously Stable and Commercially Available Cell Line for the Identification of Infectious African Swine Fever Virus in Clinical Samples

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 820 ◽  
Author(s):  
Ayushi Rai ◽  
Sarah Pruitt ◽  
Elizabeth Ramirez-Medina ◽  
Elizabeth A. Vuono ◽  
Ediane Silva ◽  
...  
Keyword(s):  
Cell Line ◽  
Virus Isolation ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Clinical Samples ◽  
Outbreak Strain ◽  
Domestic Pigs ◽  
Current Outbreak ◽  
High Degree

African swine fever virus (ASFV) is causing outbreaks both in domestic pigs and wild boar in Europe and Asia. In 2018, the largest pig producing country, China, reported its first outbreak of African swine fever (ASF). Since then, the disease has quickly spread to all provinces in China and to other countries in southeast Asia, and most recently to India. Outbreaks of the disease occur in Europe as far west as Poland, and one isolated outbreak has been reported in Belgium. The current outbreak strain is highly contagious and can cause a high degree of lethality in domestic pigs, leading to widespread and costly losses to the industry. Currently, detection of infectious ASFV in field clinical samples requires accessibility to primary swine macrophage cultures, which are infrequently available in most regional veterinary diagnostic laboratories. Here, we report the identification of a commercially available cell line, MA-104, as a suitable substrate for virus isolation of African swine fever virus.

scholarly journals Extension of Sylvatic Circulation of African Swine Fever Virus in Extralimital Warthogs in South Africa

2021 ◽  
Vol 8 ◽  
Author(s):  
Anthony F. Craig ◽  
Mathilde L. Schade-Weskott ◽  
Henry J. Harris ◽  
Livio Heath ◽  
Gideon J. P. Kriel ◽  
...  
Keyword(s):  
South Africa ◽  
Invasive Species ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Serological Evidence ◽  
The South ◽  
Domestic Pigs ◽  
The Past ◽  
The North

Sylvatic circulation of African swine fever virus (ASFV) in warthogs and Ornithodoros ticks that live in warthog burrows historically occurred in northern South Africa. Outbreaks of the disease in domestic pigs originated in this region. A controlled area was declared in the north in 1935 and regulations were implemented to prevent transfer of potentially infected suids or products to the rest of the country. However, over the past six decades, warthogs have been widely translocated to the south where the extralimital animals have flourished to become an invasive species. Since 2016, there have been outbreaks of ASF in pigs outside the controlled area that cannot be linked to transfer of infected animals or products from the north. An investigation in 2008–2012 revealed that the presence of Ornithodoros ticks and ASFV in warthog burrows extended marginally across the boundary of the controlled area. We found serological evidence of ASFV circulation in extralimital warthogs further south in the central part of the country.

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 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.

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