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Alotaibi BS, Wu CH, Khan M, Nawaz M, Chen CC, Ali A. African swine fever; insights into genomic aspects, reservoirs and transmission patterns of virus. Front Vet Sci 2024; 11:1413237. [PMID: 39193370 PMCID: PMC11347335 DOI: 10.3389/fvets.2024.1413237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 06/19/2024] [Indexed: 08/29/2024] Open
Abstract
African swine fever is a hemorrhagic disease of pigs with high mortality rates. Since its first characterization in 1921, there has been sufficient information about African swine fever virus (ASFV) and related diseases. The virus has been found and maintained in the sylvatic cycle involving ticks and domestic and wild boars in affected regions. The ASFV is spread through direct and indirect contact with infected pigs, their products and carrier vectors especially Ornithodoros ticks. Severe economic losses and a decline in pig production have been observed in ASFV affected countries, particularly in sub-Saharan Africa and Europe. At the end of 2018, the ASFV adversely affected China, the world's leading pork-producer. Control strategies for the disease remained challenging due to the unavailability of effective vaccines and the lack of successful therapeutic measures. However, considerable efforts have been made in recent years to understand the biology of the virus, surveillance and effective control measures. This review emphasizes and summarizes the current state of information regarding the knowledge of etiology, epidemiology, transmission, and vaccine-based control measures against ASFV.
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Affiliation(s)
- Bader S. Alotaibi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Shaqra University, Riyadh, Saudi Arabia
| | - Chia-Hung Wu
- Division of General Surgery, Department of Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Majid Khan
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Mohsin Nawaz
- Faculty of Veterinary and Animal Sciences, University of Poonch Rawalakot Azad Kashmir, Rawalakot, Pakistan
| | - Chien-Chin Chen
- Department of Pathology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
- Department of Cosmetic Science, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
- Ph.D. Program in Translational Medicine and Rong Hsing Translational Medicine Research Center, National Chung Hsing University, Taichung, Taiwan
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Abid Ali
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
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Sánchez-Cordón PJ, Lean FZX, Batten C, Steinbach F, Neimanis A, Le Potier MF, Wikström-Lassa E, Wynne F, Strong R, McCleary S, Crooke H, Gavier-Widén D, Núñez A. Comparative evaluation of disease dynamics in wild boar and domestic pigs experimentally inoculated intranasally with the European highly virulent African swine fever virus genotype II strain "Armenia 2007". Vet Res 2024; 55:89. [PMID: 39010163 PMCID: PMC11247888 DOI: 10.1186/s13567-024-01343-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/21/2024] [Indexed: 07/17/2024] Open
Abstract
Since the reintroduction of African swine fever virus (ASFV) in Europe in 2007 and its subsequent spread to Asia, wild boar has played a crucial role in maintaining and disseminating the virus. There are significant gaps in the knowledge regarding infection dynamics and disease pathogenesis in domestic pigs and wild boar, particularly at the early infection stage. We aimed to compare domestic pigs and wild boar infected intranasally to mimic natural infection with one of the original highly virulent genotype II ASFV isolates (Armenia 2007). The study involved euthanising three domestic pigs and three wild boar on days 1, 2, 3, and 5 post-infection, while four domestic pigs and four wild boar were monitored until they reached a humane endpoint. The parameters assessed included clinical signs, macroscopic lesions, viremia levels, tissue viral load, and virus shedding in nasal and rectal swabs from day 1 post-infection. Compared with domestic pigs, wild boar were more susceptible to ASFV, with a shorter incubation period and earlier onset of clinical signs. While wild boar reached a humane endpoint earlier than domestic pigs did, the macroscopic lesions were comparatively less severe. In addition, wild boar had earlier viremia, and the virus was also detected earlier in tissues. The medial retropharyngeal lymph nodes were identified as key portals for ASFV infection in both subspecies. No viral genome was detected in nasal or rectal swabs until shortly before reaching the humane endpoint in both domestic pigs and wild boar, suggesting limited virus shedding in acute infections.
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Affiliation(s)
- Pedro J Sánchez-Cordón
- Department of Pathology and Animal Sciences, Animal and Plant Health Agency (APHA-Weybridge), New Haw, Addlestone, UK.
- Department of Infectious Diseases and Global Health, Centro de Investigación en Sanidad Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas, Valdeolmos, Madrid, Spain.
| | - Fabian Z X Lean
- Department of Pathology and Animal Sciences, Animal and Plant Health Agency (APHA-Weybridge), New Haw, Addlestone, UK
- Department of Pathobiology & Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, AL9 7TA, UK
| | | | - Falko Steinbach
- Department of Virology, Animal and Plant Health Agency, (APHA-Weybridge), New Haw, Addlestone, UK
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Aleksija Neimanis
- Department of Pathology and Wildlife Diseases, Swedish Veterinary Agency (SVA), Uppsala, Sweden
| | - Marie-Frédérique Le Potier
- ANSES, Laboratoire de Ploufragan/Plouzané/Niort, Unité Virologie Immunologie Porcines, Anses, 22440, Ploufragan, France
| | - Emil Wikström-Lassa
- Department of Pathology and Wildlife Diseases, Swedish Veterinary Agency (SVA), Uppsala, Sweden
| | - Felicity Wynne
- Department of Virology, Animal and Plant Health Agency, (APHA-Weybridge), New Haw, Addlestone, UK
| | - Rebecca Strong
- Department of Virology, Animal and Plant Health Agency, (APHA-Weybridge), New Haw, Addlestone, UK
| | - Stephen McCleary
- Department of Virology, Animal and Plant Health Agency, (APHA-Weybridge), New Haw, Addlestone, UK
| | - Helen Crooke
- Department of Virology, Animal and Plant Health Agency, (APHA-Weybridge), New Haw, Addlestone, UK
| | - Dolores Gavier-Widén
- Department of Pathology and Wildlife Diseases, Swedish Veterinary Agency (SVA), Uppsala, Sweden.
| | - Alejandro Núñez
- Department of Pathology and Animal Sciences, Animal and Plant Health Agency (APHA-Weybridge), New Haw, Addlestone, UK.
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Li X, Hu Z, Tian X, Fan M, Liu Q, Wang X. A suitable sampling strategy for the detection of African swine fever virus in living and deceased pigs in the field: a retrospective study. Front Vet Sci 2024; 11:1419083. [PMID: 38988987 PMCID: PMC11234165 DOI: 10.3389/fvets.2024.1419083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 06/12/2024] [Indexed: 07/12/2024] Open
Abstract
African swine fever (ASF) is a fatal disease that threatens the health status of the swine population and thus can impact the economic outcome of the global pig industry. Monitoring the ASF virus (ASFV) is of utmost concern to prevent and control its distribution. This study aims to identify a suitable sampling strategy for ASFV detection in living and deceased pigs under field conditions. A range of samples, comprising tissues obtained from deceased pigs, as well as serum and tonsil swab samples from live pigs, were gathered and subjected to detection using the qPCR method. The findings revealed that the mandibular lymph nodes demonstrated the highest viral loads among superficial tissues, thereby indicating their potential suitability for detecting ASFV in deceased pigs. Additionally, the correlations between virus loads in various tissues have demonstrated that tonsil swab samples are a viable specimen for monitoring live pigs, given the strong associations observed with other tissues. These findings indicated two dependable sample types for the detection of ASFV: mandibular lymph nodes for deceased pigs and tonsil swabs for live pigs, which supply some references for the development of efficacious preventive measures against ASFV.
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Affiliation(s)
- Xiaowen Li
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Shandong Engineering Laboratory of Pig and Poultry Healthy Breeding and Disease Diagnosis Technology, Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
- China Agriculture Research System-Yangling Comprehensive Test Station, Xianyang, China
| | - Zhiqiang Hu
- Shandong Engineering Laboratory of Pig and Poultry Healthy Breeding and Disease Diagnosis Technology, Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
- College of Animal Science, Xichang University, Xichang, China
| | - Xiaogang Tian
- Shandong Engineering Laboratory of Pig and Poultry Healthy Breeding and Disease Diagnosis Technology, Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
| | - Mingyu Fan
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Shandong Engineering Laboratory of Pig and Poultry Healthy Breeding and Disease Diagnosis Technology, Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
| | - Qingyuan Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Shandong Engineering Laboratory of Pig and Poultry Healthy Breeding and Disease Diagnosis Technology, Xiajin New Hope Liuhe Agriculture and Animal Husbandry Co., Ltd., Dezhou, China
| | - Xinglong Wang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
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Cho KH, Hong SK, Kim DY, Sohn HJ, Yoo DS, Kang HE, Kim YH. Disease Course of Korean African Swine Fever Virus in Domestic Pigs Exposed Intraorally, Intranasally, Intramuscularly, and by Direct Contact with Infected Pigs. Viruses 2024; 16:433. [PMID: 38543798 PMCID: PMC10974542 DOI: 10.3390/v16030433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/06/2024] [Accepted: 03/10/2024] [Indexed: 05/23/2024] Open
Abstract
African swine fever (ASF) is a fatal contagious disease affecting swine. The first Korean ASF virus (ASFV) isolate (Korea/Pig/Paju1/2019) was used to compare the disease course of ASFV in pigs inoculated via the four routes. In the challenge experiment, domestic pigs were infected via the intraoral (IO) and intranasal (IN) routes with a 106 50% hemadsorbing dose (HAD50) and an intramuscular (IM) injection of 103 HAD50. In the direct contact (DC) group, five naïve pigs were brought into direct contact with two IM-ASFV-infected pigs. IO-, IN-, and IM-inoculated pigs showed similar disease courses, whereas DC pigs had comparable ASF syndrome after a 7-day latent period. The disease course in the DC route, one of the most common routes of infection, was not significantly different from that in the IO and IN routes. IM and DC groups differed in terms of the severity of fever and hemorrhagic lesions in the lymph nodes and spleen, indicating that the IM route, suitable for early vaccine development trials, is not appropriate for studying the ASFV infection mechanism, including early stage of infection, and IO and IN challenges with a designated dose can be alternatives in trials for assessing ASFV pathogenicity and vaccine efficacy investigations.
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Affiliation(s)
- Ki-Hyun Cho
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
| | - Seong-Keun Hong
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
| | - Da-Young Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
| | - Hyun-Joo Sohn
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
| | - Dae-Sung Yoo
- College of Veterinary Medicine, Chonnam National University, Gwangju 61168, Republic of Korea;
| | - Hae-Eun Kang
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
| | - Yeon-Hee Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (H.-J.S.); (H.-E.K.)
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Avagyan H, Hakobyan S, Baghdasaryan B, Arzumanyan H, Poghosyan A, Bayramyan N, Semerjyan A, Sargsyan M, Voskanyan H, Vardanyan T, Karalyan N, Hakobyan L, Abroyan L, Avetisyan A, Karalova E, Semerjyan Z, Karalyan Z. Pathology and Clinics of Naturally Occurring Low-Virulence Variants of African Swine Fever Emerged in Domestic Pigs in the South Caucasus. Pathogens 2024; 13:130. [PMID: 38392868 PMCID: PMC10893001 DOI: 10.3390/pathogens13020130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
Shortly after the establishment of African swine fever virus (ASFV) genotype II in 2007, cases of acute fatal infection were observed. However, after several years of circulation in the Eurasian region, the clinical signs of the disease changed. Currently, this disease can occur acutely, subclinically, chronically, or asymptomatically. Cases of the complete recovery of infected pigs, and the disappearance of ASFV from their tissues and secretions have been described. This form of the disease first appeared in Armenia at the end of 2011. This virus was described and identified as the Dilijan2011IMB strain. The goal of our research was to study the main features of clinical, pathological, immunological, virological, and genetic parameters involved in the development of new forms of African swine fever (ASF). Chronic ASF was characterized with low titers of the virus and a decrease in the intensity of hemadsorption. Additionally, a reduced intensity in clinical symptoms and pathoanatomical results was noted. The absolute, but not the relative number of immune cells changes; the neutropenia (in bone marrow and spleen), lymphopenia (in bone marrow), lymphocytosis (only in spleen), lymphoid cell depletion (in bone marrow), and pancytopenia (in bone marrow) observed in the chronic form of ASF were less pronounced compared to in the acute form. When comparing the late stage of chronic ASF to the acute form, the key cytological indicators in the spleen, lymph nodes, and blood were less severe in the chronic stage. Bone marrow failure in the chronic form, expressed in a pronounced decrease in all cell types, generally coincided with the data in the acute form of ASF. The same data were obtained after assessing serum TNF-alpha levels. Thus, we can conclude that the chronic form of ASF occurs due to a less pronounced immune response, as well as a decrease in virus titers in the blood and tissues of infected pigs.
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Affiliation(s)
- Hranush Avagyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
- Experimental Laboratory, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia
| | - Sona Hakobyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Bagrat Baghdasaryan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Hranush Arzumanyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Arpine Poghosyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Nane Bayramyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Anna Semerjyan
- Department of Medical Biology and Genetics, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia;
| | - Mariam Sargsyan
- Department of Epizootiology and Parasitology, Armenian National Agrarian University, Yerevan 0009, Armenia;
| | - Henry Voskanyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Tigranuhi Vardanyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Naira Karalyan
- Department of Pathological Anatomy and Clinical Morphology, Yerevan State Medical University after M. Heratsi, Yerevan 0025, Armenia;
| | - Lina Hakobyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Liana Abroyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
| | - Aida Avetisyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
- Experimental Laboratory, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia
| | - Elena Karalova
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
- Experimental Laboratory, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia
| | - Zara Semerjyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
- Experimental Laboratory, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia
| | - Zaven Karalyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan 0014, Armenia; (H.A.); (S.H.); (B.B.); (H.A.); (A.P.); (N.B.); (H.V.); (T.V.); (L.H.); (L.A.); (A.A.); (E.K.); (Z.S.)
- Department of Medical Biology and Genetics, Yerevan State Medical University after M. Heratsy, Yerevan 0025, Armenia;
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Urbano AC, Ferreira N, Jordão N, Boinas F, Martins C, Ferreira F. Targeted mutagenesis of the β-strand DNA binding region of African swine fever virus histone-like protein (pA104R) impairs DNA-binding activity and antibody recognition. Antiviral Res 2024; 221:105784. [PMID: 38103699 DOI: 10.1016/j.antiviral.2023.105784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/19/2023]
Abstract
African Swine Fever (ASF) is a highly contagious disease caused by a double-stranded DNA virus (ASFV). Despite significant advances made over the last decade, issues such as residual virulence and absence of differentiating infected from vaccinated animals (DIVA) capacity remain an obstacle in the development of live attenuated vaccines (LAVs) against ASFV. It is, therefore, necessary to identify novel strategies to improve vaccine safety, by rational mutagenesis of virulence associated genes and generation of DIVA markers. ASFV encodes a HU (histone-like protein from E. coli strain U93) homolog protein, pA104R, which is involved in viral genome assembly and host immune recognition. A phylogenetic analysis revealed that pA104R is highly conserved among ASFV isolates, suggesting that it can be a good target for vaccine design. Thus, we selectively mutated the β-strand DNA binding region (BDR) of pA104R to attenuate its enzymatic activity, and identified and mutated several B-cell epitopes present in pA104R to generate a negative marker. Residues K64, K66, and R69 in the BDR were identified as relevant for pA104R activity, with double mutation of the first two showing additive attenuation. pA104R-reactive IgM and IgG epitopes were also identified in the bottom of the BDR, with selective mutagenesis drastically reducing antibody recognition and, when combined with mutations in the arm of the BDR, leading to a further reduction of DNA-binding activity. Interestingly, the immunodominant pA104R-reactive IgG epitope was mainly recognized by IgG1 suggesting that pA104R induces a dominant Th2 response. In sum, the rational mutagenesis can reduce pA104R-DNA binding activity and immune reactivity, providing a rationale for the development of an ASFV pA104R-based DIVA vaccine.
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Affiliation(s)
- Ana Catarina Urbano
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Nicolas Ferreira
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Nuno Jordão
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Fernando Boinas
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Carlos Martins
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Fernando Ferreira
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal.
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Glišić D, Milićević V, Krnjaić D, Toplak I, Prodanović R, Gallardo C, Radojičić S. Genetic analysis reveals multiple intergenic region and central variable region in the African swine fever virus variants circulating in Serbia. Vet Res Commun 2023; 47:1925-1936. [PMID: 37256519 DOI: 10.1007/s11259-023-10145-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/22/2023] [Indexed: 06/01/2023]
Abstract
This study provides the first comprehensive report on the molecular characteristics of African swine fever virus (ASFV) variants in Serbia between 2019 and 2022. Since its first observation in July 2019, the disease has been found in wild boar and domestic swine. The study involved the analysis of 95 ASFV-positive samples collected from 12 infected administrative districts in Serbia. Partial four genomic regions were genetically characterized, including B646L, E183L, B602L, and the intergenic region (IGR) between the I73R-I329L genes. The results of the study suggest that multiple ASFV strains belonging to genotype II are circulating in Serbia, as evidenced by the analysis of the IGR between I73R-I329L genes that showed the most differences. Furthermore, the phylogenetic analysis of the B602L gene showed three different clades within the CVR I group of ASFV strains. Regarding the IGR, 98.4% were grouped into IGR II, with only one positive sample grouped into the IGR III group. These findings provide essential insights into the molecular characteristics of ASFV variants in Serbia and contribute to the knowledge of circulating strains of ASFV in Europe. However, further research is necessary to gain a better understanding of ASFV spread and evolution.
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Affiliation(s)
- Dimitrije Glišić
- Department of Virology, Institute of Veterinary Medicine of Serbia, 11000, Belgrade, Serbia.
| | - Vesna Milićević
- Department of Virology, Institute of Veterinary Medicine of Serbia, 11000, Belgrade, Serbia
| | - Dejan Krnjaić
- Department of Microbiology and Immunology, University of Belgrade Faculty of Veterinary Medicine, 11000, Belgrade, Serbia
| | - Ivan Toplak
- Institute of Microbiology and Parasitology, Laboratory for Virology, Veterinary Faculty, 1000, Ljubljana, Slovenia
| | - Radiša Prodanović
- Department of Ruminants and Swine Diseases, University of Belgrade Faculty of Veterinary Medicine, 11000, Belgrade, Serbia
| | - Carmina Gallardo
- European Union Reference Laboratory for ASF (EURL-ASF): Centro de Investigación en Sanidad Animal (CISA-INIA, CSIC), Valdeolmos, Madrid, Spain
| | - Sonja Radojičić
- Department of Infectious Animals Diseases and Diseases of Bees, University of Belgrade Faculty of Veterinary Medicine, 11000, Belgrade, Serbia
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Huang C, Cao C, Xu Z, Lin Y, Wu J, Weng Q, Liu Z, Jin Y, Chen P, Hua Q. A blocking ELISA based on virus-like nanoparticles chimerized with an antigenic epitope of ASFV P54 for detecting ASFV antibodies. Sci Rep 2023; 13:19928. [PMID: 37968284 PMCID: PMC10651890 DOI: 10.1038/s41598-023-47068-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023] Open
Abstract
African swine fever virus (ASFV) is a highly lethal pathogen of domestic and wild pigs. Due to no vaccines or drugs available, early accurate diagnosis and eradication of infected animals are the most important measures for ASFV prevention and control. Bluetongue virus (BTV) core-like particles (CLPs) are non-infectious hollow nanoparticles assembled from the BTV VP3 and VP7 proteins, which could be used as a platform for presenting foreign epitopes. In this study, the secondary structure of BTV VP7 protein was analyzed and predicted using the IEDB Analysis resource. Based on the prediction results of the VP7 protein, the chimeric CLPs with an ASFV P54 epitope were successfully prepared through the BAC-to-BAC baculovirus expression system and sucrose gradient centrifugation. Based on the chimeric CLPs and mAb 2E4 against AFSV P54 epitope, a blocking ELISA for detecting AFSV antibodies was established, and its reaction conditions were optimized. Through comprehensive evaluation of the method, the results showed the chimeric CLPs-based blocking ELISA displayed the best detection performance, with an AUC of 0.9961, a sensitivity of 97.65%, and a specificity of 95.24% in ROC analysis. Compared with western blot and a commercial c-ELISA for detecting anti-ASFV antibodies, this method had an excellent agreement of 96.35% (kappa value = 0.911) and 97.76% (kappa value = 0.946) with the other tests, respectively. This ELISA also had high repeatability, with CV < 10%, and no cross-reaction with the serum antibodies against other swine viruses or Orbivirus. In brief, this was the first report on developing a blocking ELISA based on virus-like nanoparticles chimerized with an antigenic epitope of ASFV P54 for serological diagnosis of ASFV.
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Affiliation(s)
- Chaohua Huang
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China
| | - Chenfu Cao
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China
| | - Zhichao Xu
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
| | - Yanxing Lin
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China
| | - Jiang Wu
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China
| | - Qiaoyu Weng
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China
| | - Zheng Liu
- Kobilka Institute of Innovative Drug Discovery, School of Medicine, Chinese University of Hong Kong, Shenzhen, 518172, People's Republic of China
| | - Ye Jin
- Hu Nan Project Bioscience LTD, Changsha, 410137, People's Republic of China
| | - Peng Chen
- Shenzhen Biolove Technology CO., LTD., Shenzhen, 518110, People's Republic of China
| | - Qunyi Hua
- Animal and Plant Inspection and Quarantine Center of Shenzhen Customs, Shenzhen, 518045, People's Republic of China.
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9
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Cho KH, Hong SK, Kim DY, Jang MK, Kim JH, Lee H, Kim EM, Park JH, Suh TY, Choi JG, Yoo DS, Kang HE, Kim YH. Pathogenicity and Pathological Characteristics of African Swine Fever Virus Strains from Pig Farms in South Korea from 2022 to January 2023. Pathogens 2023; 12:1158. [PMID: 37764966 PMCID: PMC10534632 DOI: 10.3390/pathogens12091158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Since the first African swine fever (ASF) outbreak occurred at a pig farm in South Korea in September 2019, as of 31 January 2023, 31 ASF cases have occurred at pig farms, while 2799 ASF virus (ASFV)-infected wild boars have been identified. The circulation of ASFV in wild boar populations poses a high risk of spillover to pig farms in the country. However, information on the changes in the pathogenicity of Korean ASFV strains from wild boars is not available. Investigating the pathogenicity of ASFV strains from pig farms is the only way to predict their alterations. In a previous study, no changes in the pathogenicity of ASFV strains circulating during 2019-2021 were identified through animal experiments. In this study, we chose two ASFV strains with potentially reduced pathogenicity among ten viruses obtained from pig premises from 2022 to January 2023 and estimated their pathogenicities and pathological characteristics. All the inoculated pigs died 8-10 days post-inoculation after showing pyrexia, depression, anorexia, and recumbency together with the common pathological lesions of enlarged hemorrhagic lymph nodes and splenomegaly with infarction. These results support that the pathogenicity among ASFV isolates in South Korea still remained unchanged during the study period.
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Affiliation(s)
- Ki-Hyun Cho
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Seong-Keun Hong
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Da-Young Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Min-Kyung Jang
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Jong-Ho Kim
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Hyunkyoung Lee
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Eun-Mi Kim
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Ji-Hoon Park
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Tae-Young Suh
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Jun-Gu Choi
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Dae-Sung Yoo
- College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Hae-Eun Kang
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Yeon-Hee Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
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10
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Martínez Avilés M, Bosch J, Ivorra B, Ramos ÁM, Ito S, Barasona JÁ, Sánchez-Vizcaíno JM. Epidemiological impacts of attenuated African swine fever virus circulating in wild boar populations. Res Vet Sci 2023; 162:104964. [PMID: 37531717 DOI: 10.1016/j.rvsc.2023.104964] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/20/2023] [Accepted: 07/22/2023] [Indexed: 08/04/2023]
Abstract
African swine fever virus (ASFV) genotype II has been present in wild boar in the European Union since 2014. Control measures have reduced the incidence of the ASF, but highly virulent as well as attenuated ASFV strains continue to circulate. We present the intraherd epidemiological parameters of low and highly virulent ASFV in wild boar from experimental data, and for the first time, evaluate the impact of attenuated strain circulation through unique deterministic compartmental model simulations under various potential scenarios and hypotheses. Using an estimated PCR infectious threshold of TPCR = 36.4, we obtained several transmission parameters, like an Rx (experimental intraherd R0) value of 4.5. We also introduce two novel epidemiological parameters: infectious power and resistance power, which indicate the ability of animals to transmit the infection and the reduction in infectiousness after successive exposures to varying virulence strains, respectively. The presence of ASFV attenuated strains results in 4-17% of animals either remaining in a carrier state or becoming susceptible again when exposed to highly virulent ASFV for more than two years. The timing between exposures to viruses of different virulence also influences the percentage of animals that die or remain susceptible. The findings of this study can be utilized in epidemiological modelling and provide insight into important risk situations that should be considered for surveillance and future potential ASF vaccination strategies in wild boar.
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Affiliation(s)
- Marta Martínez Avilés
- Centro de Investigación en Sanidad Animal (Animal Health Research Centre), CISA-INIA, CSIC. Madrid, 28130, Spain.
| | - Jaime Bosch
- Animal Health Health Surveillance Centre (VISAVET) and Animal Health Department, Veterinary School Complutense University of Madrid (UCM), 28040, Spain
| | - Benjamin Ivorra
- Interdisciplinary Mathematics Institute (IMI), Complutense University of Madrid (UCM), 28040, Spain
| | - Ángel Manuel Ramos
- Interdisciplinary Mathematics Institute (IMI), Complutense University of Madrid (UCM), 28040, Spain
| | - Satoshi Ito
- Animal Health Health Surveillance Centre (VISAVET) and Animal Health Department, Veterinary School Complutense University of Madrid (UCM), 28040, Spain
| | - José Ángel Barasona
- Animal Health Health Surveillance Centre (VISAVET) and Animal Health Department, Veterinary School Complutense University of Madrid (UCM), 28040, Spain
| | - José Manuel Sánchez-Vizcaíno
- Animal Health Health Surveillance Centre (VISAVET) and Animal Health Department, Veterinary School Complutense University of Madrid (UCM), 28040, Spain
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11
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Yamaguchi E, Takagi M, Osaki M, Hayama Y, Yamamoto T. Sex-based differences in the distribution of Aujeszky's disease-seropositive Japanese wild boar. Porcine Health Manag 2023; 9:28. [PMID: 37312154 DOI: 10.1186/s40813-023-00323-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/31/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Aujeszky's disease virus (ADV) primarily infects domestic pigs and wild boars, causing the abortion and death of young piglets due to central nervous system disorders. In Japan, the national eradication program for ADV in domestic pigs has been successful in most prefectures; however, concern has been raised regarding ADV-infected wild boars as a source of transmission to domestic pigs. RESULTS We assessed the nationwide seroprevalence of ADV among wild boars (Sus scrofa) in Japan. Moreover, we determined the sex-based differences in the spatial clustering of seropositive animals. Serum samples were obtained from a total of 1383 wild boars acquired by hunting in 41 prefectures in three fiscal years (April-March in 2014, 2015, and 2017). Seropositivity tests for ADV using enzyme-linked immunosorbent assay, the latex agglutination and neutralization tests showed 29 boars seropositive for ADV (29/1383, 2.1% [95% confidence interval, CI: 1.4-3.0%]), with 28 of these boars originating from three prefectures in the Kii Peninsula (28/121, 23.1% [95% CI: 16.0-31.7%]). The degree of spatial clustering of these ADV-seropositive adult boars in the Kii Peninsula was evaluated using the K-function and data from sera samples of 46 (14 seropositive) male and 54 (12 seropositive) female boars. The degree of clustering among females was significantly higher in seropositive animals than in tested animals; however, such a difference was not observed for seropositive males. CONCLUSIONS The spatial dynamics of ADV among adult wild boars may be characterized based on sex, and is likely due to sex-based differences in behavioral patterns including dispersal among wild boars.
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Affiliation(s)
- Emi Yamaguchi
- Epidemiology Unit, Division of Transboundary Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Kannondai 3-1-5, Tsukuba, 305-0856, Ibaraki, Japan
| | - Michihiro Takagi
- Biologicals Production Office, Department of Animal Disease Control and Prevention, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Japan
- Virus Group, Division of Infectious Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Makoto Osaki
- Strategic Planning Headquarters, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Yoko Hayama
- Epidemiology Unit, Division of Transboundary Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Kannondai 3-1-5, Tsukuba, 305-0856, Ibaraki, Japan
| | - Takehisa Yamamoto
- Epidemiology Unit, Division of Transboundary Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Kannondai 3-1-5, Tsukuba, 305-0856, Ibaraki, Japan.
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12
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Vilem A, Nurmoja I, Tummeleht L, Viltrop A. Differentiation of African Swine Fever Virus Strains Isolated in Estonia by Multiple Genetic Markers. Pathogens 2023; 12:pathogens12050720. [PMID: 37242390 DOI: 10.3390/pathogens12050720] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/08/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
The African swine fever virus (ASFV) was first detected in Estonia, in September 2014. In the subsequent three years, the virus spread explosively all over the country. Only one county, the island of Hiiumaa, remained free of the disease. Due to the drastic decrease in the wild boar population in the period of 2015-2018, the number of ASFV-positive cases among wild boar decreased substantially. From the beginning of 2019 to the autumn of 2020, no ASFV-positive wild boar or domestic pigs were detected in Estonia. A new occurrence of ASFV was detected in August 2020, and by the end of 2022, ASFV had been confirmed in seven counties in Estonia. Investigations into proven molecular markers, such as IGR I73R/I329L, MGF505-5R, K145R, O174L, and B602L, were performed with the aim of clarifying whether these cases of ASFV were new entries or remnants of previous epidemics. The sequences from the period of 2014-2022 were compared to the Georgia 2007/1 reference sequence and the variant strains present in Europe. The results indicated that not all the molecular markers of the virus successfully used in other geographical regions were suitable for tracing the spread of ASFV in Estonia. Only the B602L-gene analysis enabled us to place the ASFV isolates spreading in 2020-2022 into two epidemiologically different clusters.
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Affiliation(s)
- Annika Vilem
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
- The National Centre for Laboratory Research and Risk Assessment, LABRIS, 51006 Tartu, Estonia
| | - Imbi Nurmoja
- The National Centre for Laboratory Research and Risk Assessment, LABRIS, 51006 Tartu, Estonia
| | - Lea Tummeleht
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
| | - Arvo Viltrop
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
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13
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Oberin M, Hillman A, Ward MP, Holley C, Firestone S, Cowled B. The Potential Role of Wild Suids in African Swine Fever Spread in Asia and the Pacific Region. Viruses 2022; 15:61. [PMID: 36680101 PMCID: PMC9867030 DOI: 10.3390/v15010061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/28/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
African swine fever (ASF) in Asia and the Pacific is currently dominated by ASF virus transmission within and between domestic pig populations. The contribution made by wild suids is currently not well understood; their distribution, density and susceptibility to the virus has raised concerns that their role in the epidemiology of ASF in the region might be underestimated. Whilst in the Republic of Korea wild suids are considered important in the spread and maintenance of ASF virus, there is an apparent underreporting to official sources of the disease in wild suids from other countires and regions. A review of the current literature, an analysis of the official reporting resources and a survey of the World Organisation of Animal Health Member delegates in Asia and the Pacific were used to assess the potential role of wild suids in ASF outbreaks, and also to gain insight into what ASF management or control strategies are currently implemented for wild suids. Applying appropriate population control and management strategies can be increased in some areas, especially to assist in the conservation of endangered endemic wild suids in this region.
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Affiliation(s)
- Madalene Oberin
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Ausvet, Canberra, ACT 2617, Australia
| | - Alison Hillman
- Ausvet, Canberra, ACT 2617, Australia
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Michael P. Ward
- Sydney School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
| | - Caitlin Holley
- The World Organisation for Animal Health, Tokyo 113-8657, Japan
| | - Simon Firestone
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Brendan Cowled
- Ausvet, Canberra, ACT 2617, Australia
- Sydney School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
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14
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Comparison of the Virulence of Korean African Swine Fever Isolates from Pig Farms during 2019-2021. Viruses 2022; 14:v14112512. [PMID: 36423121 PMCID: PMC9696264 DOI: 10.3390/v14112512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) was first reported in South Korea in September 2019, and as of 31 December 2021, a total of 21 cases in domestic pig farms and 1875 ASFV-infected wild boars have been confirmed in the country. With the continued circulation of ASF in wild boars, and subsequent outbreaks in domestic pigs, concerns were raised about the possible changes in virulence occurring among African swine fever viruses (ASFV) circulating in South Korea. In this study, four Korean ASFV strains isolated from domestic pig farms at different time points between 2019 and 2021 were chosen, and used to experimentally infect domestic pigs by intramuscular inoculation to compare their virulence. All challenged pigs died at 4-9 days post-inoculation, with many showing clinical symptoms of fever, depression, loss of appetite, and recumbency. Gross lesions observed at necropsy included enlargement and hemorrhage of the lymph nodes and hydropericardium. The study showed that all four Korean ASFV isolates caused acute forms of illness, which supports the view that virulence among the circulating ASFV isolates in South Korea remained unchanged and highly virulent during this period.
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15
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Ruiz-Saenz J, Diaz A, Bonilla-Aldana DK, Rodríguez-Morales AJ, Martinez-Gutierrez M, Aguilar PV. African swine fever virus: A re-emerging threat to the swine industry and food security in the Americas. Front Microbiol 2022; 13:1011891. [PMID: 36274746 PMCID: PMC9581234 DOI: 10.3389/fmicb.2022.1011891] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/16/2022] [Indexed: 12/15/2022] Open
Affiliation(s)
- Julian Ruiz-Saenz
- Grupo de Investigación en Ciencias Animales—GRICA, Universidad Cooperativa de Colombia, Bucaramanga, Colombia,*Correspondence: Julian Ruiz-Saenz ;
| | - Andres Diaz
- PIC—Pig Improvement Company, Querétaro, Mexico
| | - D. Katterine Bonilla-Aldana
- Grupo de Investigación Biomedicina, Faculty of Medicine, Fundación Universitaria Autónoma de las Américas, Pereira, Colombia
| | - Alfonso J. Rodríguez-Morales
- Grupo de Investigación Biomedicina, Faculty of Medicine, Fundación Universitaria Autónoma de las Américas, Pereira, Colombia,Faculty of Health Sciences, Universidad Cientifica del Sur, Lima, Peru
| | - Marlen Martinez-Gutierrez
- Grupo de Investigación en Microbiología Veterinaria, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Patricia V. Aguilar
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States,Center for Tropical Diseases, Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, United States
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16
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Wang Q, Tian Z, Yang J, Gao S, Du J, Zhang H, Zhang Z, Guan G, Niu Q, Yin H. An improved luciferase immunosorbent assay for ultrasensitive detection of antibodies against African swine fever virus. Front Microbiol 2022; 13:1013678. [PMID: 36246209 PMCID: PMC9557169 DOI: 10.3389/fmicb.2022.1013678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 09/16/2022] [Indexed: 11/20/2022] Open
Abstract
African swine fever (ASF), caused by African swine fever virus (ASFV), is a fatal infectious disease of pigs and causes great socioeconomic losses globally. The reliable diagnostic method is critical for prevention and control of the disease. In this study, an improved Luciferase immunosorbent assay (LISA) for detecting ASF was developed using the cell lysates containing ASFV p35 protein fused with a reporter Nano-luciferase (p35-Luc protein). The improved method avoids the complicate procedures of immobilizing the serum samples with protein G in the normal LISA method, and replaced by directly coating the serum samples with carbonate buffer, therefore reduces the productive cost and simplifies the operation procedures. The p35-Luc LISA exhibited high specificity for anti-ASFV sera while no cross-reactions with the sera against other swine viruses. The detection limit of the p35-Luc LISA was shown to be at least four times higher than that of the p35 based indirect ELISA established in our lab. The receiver operating characteristic (ROC) analysis showed the 96.36% relative specificity and 96.97% relative sensitivity of the p35-Luc LISA with the cutoff values of 3.55 as compared to the commercial Ingezim p72-ELISA kit. Furthermore, a total of 248 serum samples were tested by both the p35-Luc LISA and commercial Ingezim p72-ELISA kit, and there was a high degree of agreement (97.6%, kappa = 0.9753) in the performance of the two assays. Collectively, the improved LISA based on the p35-Luc protein could be used as a rapid, ultrasensitive, cost-effective and reliable diagnostic tool for serological survey of ASF in pig farms.
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Affiliation(s)
- Qiongjie Wang
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Zhancheng Tian
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- *Correspondence: Zhancheng Tian,
| | - Jifei Yang
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Shandian Gao
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Junzheng Du
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hongge Zhang
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Zhonghui Zhang
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Guiquan Guan
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Qingli Niu
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hong Yin
- African Swine Fever Regional Laboratory of China (Lanzhou), State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, State Key Laboratory of Veterinary Etiological Biology Project, Yangzhou, China
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17
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Shotin AR, Mazloum A, Igolkin AS, Shevchenko IV, Elsukova AA, Aronova EV, Vlasova NN. [Alternative approaches to the diagnosis of African swine fever in the Russian Federation in 2017-2021]. Vopr Virusol 2022; 67:290-303. [PMID: 36097710 DOI: 10.36233/0507-4088-112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
INTRODUCTION Prevention and control of African swine fever (ASF) transmission on the territory of the Russian Federation requires monitoring based on testing of samples from pigs and wild boars. Specific anti-ASFV antibodies are rarely detected in samples during routine serological diagnostics. Although, ASF isolates with weakened virulence were confirmed in Russia and neighboring countries.The aim of this work was to determine the possibility of using alternative samples for ASF diagnosis and evaluate the effectiveness of the diagnostic methods used on the territory of Russia. MATERIALS AND METHODS Biological materials obtained from experimentally infected animals and samples collected in the "field" conditions were used in this study. RESULTS Complex testing (RT-PCR and ELISA) is a more effective approach to diagnose chronic and asymptomatic forms of ASF compared to the separate use of these techniques. The possibility and efficiency of using alternative samples in diagnostics are demonstrated. It was confirmed that IPT method overcomes ELISA by high diagnostic sensitivity and detection of antibodies on earlier stages in extended range of samples. Anti-ASFV antibodies were detected in domestic and wild pigs in five regions of Russia. Samples from infected pigs that are negative in RT-PCR can be positive for anti-ASFV antibodies. The detection of antibodies in samples from shot wild boars (negative or uncertain in RT-PCR test) suggests the existence of animals surviving ASF infection. CONCLUSION The data obtained suggest a revision of the ASF surveillance strategy, by introducing complex diagnostic methods aimed at detection of both the virus genome and anti-ASFV antibodies simultaneously.
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Affiliation(s)
| | - A Mazloum
- FGBI "Federal Centre for Animal Health"
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Li Z, Chen W, Qiu Z, Li Y, Fan J, Wu K, Li X, Zhao M, Ding H, Fan S, Chen J. African Swine Fever Virus: A Review. Life (Basel) 2022; 12:1255. [PMID: 36013434 PMCID: PMC9409812 DOI: 10.3390/life12081255] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) is a viral disease with a high fatality rate in both domestic pigs and wild boars. ASF has greatly challenged pig-raising countries and also negatively impacted regional and national trade of pork products. To date, ASF has spread throughout Africa, Europe, and Asia. The development of safe and effective ASF vaccines is urgently required for the control of ASF outbreaks. The ASF virus (ASFV), the causative agent of ASF, has a large genome and a complex structure. The functions of nearly half of its viral genes still remain to be explored. Knowledge on the structure and function of ASFV proteins, the mechanism underlying ASFV infection and immunity, and the identification of major immunogenicity genes will contribute to the development of an ASF vaccine. In this context, this paper reviews the available knowledge on the structure, replication, protein function, virulence genes, immune evasion, inactivation, vaccines, control, and diagnosis of ASFV.
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Affiliation(s)
- Zhaoyao Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Wenxian Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Zilong Qiu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yuwan Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Jindai Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Keke Wu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Xiaowen Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Hongxing Ding
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; (Z.L.); (W.C.); (Z.Q.); (Y.L.); (J.F.); (K.W.); (X.L.); (M.Z.); (H.D.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou 510642, China
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Walczak M, Szczotka-Bochniarz A, Żmudzki J, Juszkiewicz M, Szymankiewicz K, Niemczuk K, Pérez-Núñez D, Liu L, Revilla Y. Non-Invasive Sampling in the Aspect of African Swine Fever Detection-A Risk to Accurate Diagnosis. Viruses 2022; 14:1756. [PMID: 36016380 PMCID: PMC9416727 DOI: 10.3390/v14081756] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
African swine fever remains one of the most economically important and dangerous diseases of the Suidae family. Until now, neither a safe vaccine nor a treatment against ASF has been available, which is why prevention of the disease involves biosecurity measures and early recognition based on accurate diagnosis. Nowadays, different strategies for ASF detection are discussed to reduce both animal suffering and the costs of ASF surveillance. This article aims to indicate the risk, with regard to non-invasive sampling, for the detection of ASFV. In this study, we analyzed data from three independent animal trials, in the framework of the detection of positive samples in different matrices (blood, sera, oral and rectal swabs) collected from nineteen domestic pigs infected with similar doses but under different scenarios, including different ASFV strains or routes of infection. Genetic material of ASFV was found in all matrices, but detection occurred earlier in the blood samples than in the oral and the rectal swabs. Furthermore, analyses revealed that at relevant sampling timepoints, PCR-positive blood samples were detected more frequently and reached higher percentages (up to 100% during fever) than oral and rectal swabs. Moreover, mean Ct values in blood samples collected from animals infected with virulent strains were significantly lower than in oral and rectal swabs, ensuring a higher probability of ASFV detection. High Ct values and occasional shedding in all tested matrices, in the cases of animals infected by an attenuated ASFV-strain, showed that blood sampling may be necessary to confirm the presence of anti-ASFV antibodies in sera. This study showed that during veterinary surveillance, blood sampling (for both PCR and serological analyses) is essential for the accurate diagnosis of ASF and provides the highest probability of detection of the disease.
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Affiliation(s)
- Marek Walczak
- National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100 Pulawy, Poland
| | | | - Jacek Żmudzki
- National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100 Pulawy, Poland
| | | | | | - Krzysztof Niemczuk
- National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100 Pulawy, Poland
| | - Daniel Pérez-Núñez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Microbes in Health and Welfare Department, c/Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Lihong Liu
- National Veterinary Institute, SE-756 51 Uppsala, Sweden
| | - Yolanda Revilla
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Microbes in Health and Welfare Department, c/Nicolás Cabrera 1, 28049 Madrid, Spain
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Pepin KM, Brown VR, Yang A, Beasley JC, Boughton R, VerCauteren KC, Miller RS, Bevins SN. Optimizing response to an introduction of African swine fever in wild pigs. Transbound Emerg Dis 2022; 69:e3111-e3127. [PMID: 35881004 DOI: 10.1111/tbed.14668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 11/28/2022]
Abstract
African swine fever virus (ASFv) is a virulent pathogen that threatens domestic swine industries globally and persists in wild boar populations in some countries. Persistence in wild boar can challenge elimination and prevent disease-free status, making it necessary to address wild swine in proactive response plans. In the U.S., invasive wild pigs are abundant and found across a wide range of ecological conditions that could drive different epidemiological dynamics among populations. Information on size of control areas required to rapidly eliminate ASFv in wild pigs and how this area should change with management constraints and local ecology are needed to optimize response planning. We developed a spatially-explicit disease transmission model contrasting wild pig movement and contact ecology in two ecosystems in southeastern U.S. We simulated ASFv spread and determined optimal response area (reported as radius of a circle) for eliminating ASFv rapidly over a range of detection times (when ASFv is detected relative to true date of introduction), culling capacities (proportion of wild pigs in the culling zone removed weekly), and wild pig densities. Large radii for response areas (14 km) were needed under most conditions but could be shortened with early detection (≤ 8 weeks) and high culling capacities (≥ 15% weekly). Under most conditions ASFv was eliminated in less than 22 weeks using optimal control radii, although ecological conditions with high rates of wild pig movement required higher culling capacities (≥ 10% weekly) for elimination within one year. Results highlight the importance of adjusting response plans based on local ecology and show wild pig movement is a better predictor of optimal response area than numbers of ASFv cases early in the outbreak trajectory. Our framework provides a tool for determining optimal control plans in different areas, guiding expectations of response impacts, and planning resources needed for rapid elimination. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kim M Pepin
- National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 Laporte Ave., Fort Collins, CO, 80526
| | - Vienna R Brown
- United States Department of Agriculture, Animal and Plant Health Inspection Services, Wildlife Services, National Feral Swine Damage Management Program, Fort Collins, CO
| | - Anni Yang
- National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 Laporte Ave., Fort Collins, CO, 80526.,Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, 80523, US
| | - James C Beasley
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, PO Drawer E, Aiken, South Carolina, 29802, US
| | - Raoul Boughton
- Archbold Biological Station's Buck Island Ranch, 300 Buck Island Ranch Road, Lake Placid, FL, 33852, US
| | - Kurt C VerCauteren
- National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 Laporte Ave., Fort Collins, CO, 80526
| | - Ryan S Miller
- Centers for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 2150 Center Ave., Fort Collins, CO, 80526
| | - Sarah N Bevins
- National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 Laporte Ave., Fort Collins, CO, 80526
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African Swine Fever (ASF) Trend Analysis in Wild Boar in Poland (2014–2020). Animals (Basel) 2022; 12:ani12091170. [PMID: 35565596 PMCID: PMC9105269 DOI: 10.3390/ani12091170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 12/10/2022] Open
Abstract
Simple Summary African swine fever (ASF) has been present in Poland since 2014. The article describes and explains the changes in the ASF epidemic in the wild boar population in the period 2014–2020. In that relatively short time, the disease has spread to about half of the territory of Poland, affecting eastern and western provinces. Most ASF-positive animals were molecular/virus-positive, however, the observation of the increase of serologically positive animals (potential survivors) in successive years of the epidemic, especially in areas where the virus has been present for a longer time, may indicate the potential beginning of ASF endemicity in Poland. Abstract African swine fever (ASF) is a lethal hemorrhagic disease of Suidae, i.e., domestic pigs and wild boars. The disease was introduced to Poland in 2014 and is now present in the wild boar population. Appropriate ASF prevention requires further research for answers to fundamental questions about the importance of vectors in virus transmission, the impact of environmental factors on the presence of ASFV in wild boar habitats, and the role of survivors as potential virus carriers and their part in the potential endemicity of ASF. In order to analyze the changes in the molecular and serological prevalence of ASFV in wild boar population in Poland, real-time PCR and ELISA/IPT tests were conducted. In the analyzed period (2014–2020), most of the ASF-positive wild boars were molecular/virus-positive, however, over the years the percentage and the number of seropositive animals has increased. At the beginning of the epidemic, the disease was limited to a small area of the country. Since then, it has spread to new provinces of Poland. From the beginning and until today, most notifications of ASF-positive wild boars were for carcasses (passive surveillance), however, the number of serologically positive animals is still increasing. Despite the fact that notifications of ASF outbreaks are still being received near the eastern border of Poland, the old ASF area seems to be limited mainly to ASF serologically positive animals, which may indicate the beginning of ASF endemicity in Poland.
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22
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African swine fever virus: A raised global upsurge and a continuous threaten to pig husbandry. Microb Pathog 2022; 167:105561. [DOI: 10.1016/j.micpath.2022.105561] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/01/2022] [Accepted: 04/27/2022] [Indexed: 11/21/2022]
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Amado MEV, Carmo LP, Berezowski J, Fischer C, Santos MJ, Grütter G. Towards risk-based surveillance of African Swine Fever in Switzerland. Prev Vet Med 2022; 204:105661. [DOI: 10.1016/j.prevetmed.2022.105661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 03/14/2022] [Accepted: 04/24/2022] [Indexed: 10/18/2022]
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Malladi S, Ssematimba A, Bonney PJ, St Charles KM, Boyer T, Goldsmith T, Walz E, Cardona CJ, Culhane MR. Predicting the time to detect moderately virulent African swine fever virus in finisher swine herds using a stochastic disease transmission model. BMC Vet Res 2022; 18:84. [PMID: 35236347 PMCID: PMC8889644 DOI: 10.1186/s12917-022-03188-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/24/2022] [Indexed: 11/10/2022] Open
Abstract
Background African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Using an approximate Bayesian computation algorithm in conjunction with Monte Carlo simulation, we have estimated the adequate contact rate for moderately virulent ASFV strains and determined the statistical distributions for the durations of mild and severe clinical signs using individual, pig-level data. A discrete individual based disease transmission model was then used to estimate the time to detect ASF infection based on increased mild clinical signs, severe clinical signs, or daily mortality. Results Our results indicate that it may take two weeks or longer to detect ASF in a finisher swine herd via mild clinical signs or increased mortality beyond levels expected in routine production. A key factor contributing to the extended time to detect ASF in a herd is the fairly long latently infected period for an individual pig (mean 4.5, 95% P.I., 2.4 - 7.2 days). Conclusion These transmission model parameter estimates and estimated time to detection via clinical signs provide valuable information that can be used not only to support emergency preparedness but also to inform other simulation models of evaluating regional disease spread.
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Affiliation(s)
- Sasidhar Malladi
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Amos Ssematimba
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA. .,Department of Mathematics, Faculty of Science, Gulu University, Gulu, Uganda.
| | - Peter J Bonney
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
| | | | - Timothy Boyer
- Center for Epidemiology and Animal Health, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, Fort Collins, Colorado, USA
| | - Timothy Goldsmith
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Emily Walz
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Carol J Cardona
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Marie R Culhane
- Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA
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Development of a one-step multiplex qRT–PCR assay for the detection of African swine fever virus, classical swine fever virus and atypical porcine pestivirus. BMC Vet Res 2022; 18:43. [PMID: 35042532 PMCID: PMC8764768 DOI: 10.1186/s12917-022-03144-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 01/06/2022] [Indexed: 12/02/2022] Open
Abstract
Background African swine fever virus (ASFV), classical swine fever virus (CSFV) and atypical porcine pestivirus (APPV) have caused great economic losses to the swine industry in China. Since coinfections of ASFV, CSFV and APPV occur in certain pig herds, it is necessary to accurately and differentially detect these pathogens in field-collected samples. In this study, a one-step multiplex real-time quantitative reverse transcription-polymerase chain reaction (multiplex qRT–PCR) was developed for the simultaneous and differential detection of ASFV, CSFV and APPV. Results The one-step multiplex qRT–PCR presented here was able to simultaneously detect ASFV, CSFV and APPV but could not amplify other viruses, including porcine circovirus type 2 (PCV2), pseudorabies virus (PRV), porcine reproductive and respiratory syndrome virus (PRRSV), foot-and-mouth disease virus (FMDV), porcine parvovirus (PPV), porcine epidemic diarrhoea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine rotavirus (PRoV), porcine deltacoronavirus (PDCoV), border disease virus (BDV), bovine viral diarrhoea virus type 1 (BVDV-1), BVDV-2, etc. The limit of detection (LOD) of the assay was 2.52 × 101 copies/μL for ASFV, CSFV and APPV. A repeatability test using standard recombinant plasmids showed that the intra- and interassay coefficients of variation (CVs) were less than 2%. An assay of 509 clinical samples collected in Guangxi Province, southern China, from October 2018 to December 2020 showed that the positive rates of ASFV, CSFV and APPV were 45.58, 12.57 and 3.54%, respectively, while the coinfection rates of ASFV and CSFV, ASFV and APPV, CSFV and APPV were 4.91, 1.38, 0.98%, respectively. Phylogenetic analysis based on the nucleotide sequences of the partial ASFV p72 gene showed that all ASFV strains from Guangxi Province belonged to genotypes I and II. Conclusion A one-step multiplex qRT–PCR with high specificity, sensitivity and repeatability was successfully developed for the simultaneous and differential detection of ASFV, CSFV and APPV.
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African Swine Fever Virus and host response - transcriptome profiling of the Georgia 2007/1 strain and porcine macrophages. J Virol 2022; 96:e0193921. [PMID: 35019713 PMCID: PMC8906413 DOI: 10.1128/jvi.01939-21] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
African swine fever virus (ASFV) has a major global economic impact. With a case fatality in domestic pigs approaching 100%, it currently presents the largest threat to animal farming. Although genomic differences between attenuated and highly virulent ASFV strains have been identified, the molecular determinants for virulence at the level of gene expression have remained opaque. Here, we characterize the transcriptome of ASFV genotype II Georgia 2007/1 (GRG) during infection of the physiologically relevant host cells, porcine macrophages. In this study, we applied cap analysis gene expression sequencing (CAGE-seq) to map th0e 5′ ends of viral mRNAs at 5 and 16 h postinfection. A bioinformatics analysis of the sequence context surrounding the transcription start sites (TSSs) enabled us to characterize the global early and late promoter landscape of GRG. We compared transcriptome maps of the GRG isolate and the lab-attenuated BA71V strain that highlighted GRG virulence-specific transcripts belonging to multigene families, including two predicted MGF 100 genes, I7L and I8L. In parallel, we monitored transcriptome changes in the infected host macrophage cells. Of the 9,384 macrophage genes studied, transcripts for 652 host genes were differentially regulated between 5 and 16 h postinfection compared with only 25 between uninfected cells and 5 h postinfection. NF-κB activated genes and lysosome components such as S100 were upregulated, and chemokines such as CCL24, CXCL2, CXCL5, and CXCL8 were downregulated. IMPORTANCE African swine fever virus (ASFV) causes hemorrhagic fever in domestic pigs, with case fatality rates approaching 100% and no approved vaccines or antivirals. The highly virulent ASFV Georgia 2007/1 strain (GRG) was the first isolated when ASFV spread from Africa to the Caucasus region in 2007, then spreading through Eastern Europe and, more recently, across Asia. We used an RNA-based next-generation sequencing technique called CAGE-seq to map the starts of viral genes across the GRG DNA genome. This has allowed us to investigate which viral genes are expressed during early or late stages of infection and how this is controlled, comparing their expression to the nonvirulent ASFV-BA71V strain to identify key genes that play a role in virulence. In parallel, we investigated how host cells respond to infection, which revealed how the ASFV suppresses components of the host immune response to ultimately win the arms race against its porcine host.
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Njau EP, Machuka EM, Cleaveland S, Shirima GM, Kusiluka LJ, Okoth EA, Pelle R. African Swine Fever Virus (ASFV): Biology, Genomics and Genotypes Circulating in Sub-Saharan Africa. Viruses 2021; 13:2285. [PMID: 34835091 PMCID: PMC8623397 DOI: 10.3390/v13112285] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/17/2021] [Accepted: 11/03/2021] [Indexed: 12/22/2022] Open
Abstract
African swine fever (ASF) is a highly infectious and fatal haemorrhagic disease of pigs that is caused by a complex DNA virus of the genus Asfivirus and Asfarviridae African suids family. The disease is among the most devastating pig diseases worldwide including Africa. Although the disease was first reported in the 19th century, it has continued to spread in Africa and other parts of the world. Globally, the rising demand for pork and concomitant increase in transboundary movements of pigs and pork products is likely to increase the risk of transmission and spread of ASF and pose a major challenge to the pig industry. Different genotypes of the ASF virus (ASFV) with varying virulence have been associated with different outbreaks in several countries in sub-Saharan Africa (SSA) and worldwide, and understanding genotype circulation will be important for ASF prevention and control strategies. ASFV genotypes unique to Africa have also been reported in SSA. This review briefly recounts the biology, genomics and genotyping of ASFV and provides an account of the different genotypes circulating in SSA. The review also highlights prevention, control and progress on vaccine development and identifies gaps in knowledge of ASFV genotype circulation in SSA that need to be addressed.
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Affiliation(s)
- Emma P. Njau
- Biosciences Eastern and Central Africa—International Livestock Research Institute Hub, P.O. Box 30709, Nairobi 00100, Kenya; (E.M.M.); (E.A.O.); (R.P.)
- Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania; (S.C.); (G.M.S.); (L.J.K.)
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Chuo Kikuu, Morogoro P.O. Box 3015, Tanzania
| | - Eunice M. Machuka
- Biosciences Eastern and Central Africa—International Livestock Research Institute Hub, P.O. Box 30709, Nairobi 00100, Kenya; (E.M.M.); (E.A.O.); (R.P.)
| | - Sarah Cleaveland
- Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania; (S.C.); (G.M.S.); (L.J.K.)
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Gabriel M. Shirima
- Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania; (S.C.); (G.M.S.); (L.J.K.)
| | - Lughano J. Kusiluka
- Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania; (S.C.); (G.M.S.); (L.J.K.)
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Chuo Kikuu, Morogoro P.O. Box 3015, Tanzania
- Mzumbe University, Morogoro P.O. Box 1, Tanzania
| | - Edward A. Okoth
- Biosciences Eastern and Central Africa—International Livestock Research Institute Hub, P.O. Box 30709, Nairobi 00100, Kenya; (E.M.M.); (E.A.O.); (R.P.)
| | - Roger Pelle
- Biosciences Eastern and Central Africa—International Livestock Research Institute Hub, P.O. Box 30709, Nairobi 00100, Kenya; (E.M.M.); (E.A.O.); (R.P.)
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Liu X, Ao D, Jiang S, Xia N, Xu Y, Shao Q, Luo J, Wang H, Zheng W, Chen N, Meurens F, Zhu J. African Swine Fever Virus A528R Inhibits TLR8 Mediated NF-κB Activity by Targeting p65 Activation and Nuclear Translocation. Viruses 2021; 13:v13102046. [PMID: 34696476 PMCID: PMC8539517 DOI: 10.3390/v13102046] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 12/23/2022] Open
Abstract
African swine fever (ASF) is mainly an acute hemorrhagic disease which is highly contagious and lethal to domestic pigs and wild boars. The global pig industry has suffered significant economic losses due to the lack of an effective vaccine and treatment. The African swine fever virus (ASFV) has a large genome of 170–190 kb, encoding more than 150 proteins. During infection, ASFV evades host innate immunity via multiple viral proteins. A528R is a very important member of the polygene family of ASFV, which was shown to inhibit IFN-β production by targeting NF-κB, but its mechanism is not clear. This study has shown that A528R can suppress the TLR8-NF-κB signaling pathway, including the inhibition of downstream promoter activity, NF-κB p65 phosphorylation and nuclear translocation, and the antiviral and antibacterial activity. Further, we found the cellular co-localization and interaction between A528R and p65, and ANK repeat domains of A528R and RHD of p65 are involved in their interaction and the inhibition of p65 activity. Therefore, we conclude that A528R inhibits TLR8-NF-κB signaling by targeting p65 activation and nuclear translocation.
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Affiliation(s)
- Xueliang Liu
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Da Ao
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Sen Jiang
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Nengwen Xia
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Yulin Xu
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Qi Shao
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Jia Luo
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Heng Wang
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Wanglong Zheng
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Nanhua Chen
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - François Meurens
- BIOEPAR, INRAE, Oniris, 44307 Nantes, France;
- Department of Veterinary Microbiology and Immunology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - Jianzhong Zhu
- College Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (X.L.); (D.A.); (S.J.); (N.X.); (Y.X.); (Q.S.); (J.L.); (H.W.); (W.Z.); (N.C.)
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
- Correspondence:
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Dynamic Variations in Infrared Skin Temperature of Weaned Pigs Experimentally Inoculated with the African Swine Fever Virus: A Pilot Study. Vet Sci 2021; 8:vetsci8100223. [PMID: 34679053 PMCID: PMC8541399 DOI: 10.3390/vetsci8100223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 09/30/2021] [Accepted: 10/06/2021] [Indexed: 11/17/2022] Open
Abstract
African swine fever (ASF) is a devastating viral disease in pigs and is therefore economically important for the swine industry. ASF is characterized by a short incubation period and immediate death, making the early identification of ASF-infected pigs essential. This pilot-scale study evaluates whether the infrared thermography (IRT) technique can be used as a diagnostic tool to detect changes in skin temperature (Tsk) during the early stages of disease development in experimentally ASF-infected pigs. Clinical symptoms and rectal temperatures (Tcore) were recorded daily, and IRT readings during the experimental ASF infection were analyzed. All infected pigs died at 5–8 days post inoculation (dpi), and the incubation period was approximately 4 dpi. The average Tcore increased from 0 dpi (38.9 ± 0.3 °C) to 7 dpi (41.0 ± 0.5 °C) and decreased by 8 dpi (39.8 ± 0 °C). The maximum Tsk of ASF-infected pigs increased from 2 (35.0 °C) to 3 dpi (38.5 °C). The mean maximum Tsk observed from three regions on the skin (ear, inguinal, and neck) significantly increased from 2 to 3 dpi. This study presents a non-contact method for the early detection of ASF in infected pigs using thermal imaging at 3 days after ASF infection.
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Machado G, Farthing TS, Andraud M, Lopes FPN, Lanzas C. Modelling the role of mortality-based response triggers on the effectiveness of African swine fever control strategies. Transbound Emerg Dis 2021; 69:e532-e546. [PMID: 34590433 DOI: 10.1111/tbed.14334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 01/26/2023]
Abstract
African swine fever (ASF) is considered the most impactful transboundary swine disease. In the absence of effective vaccines, control strategies are heavily dependent on mass depopulation and shipment restrictions. Here, we developed a nested multiscale model for the transmission of ASF, combining a spatially explicit network model of animal shipments with a deterministic compartmental model for the dynamics of two ASF strains within 3 km × 3 km pixels in one Brazilian state. The model outcomes are epidemic duration, number of secondary infected farms and pigs, and distance of ASF spread. The model also shows the spatial distribution of ASF epidemics. We analyzed quarantine-based control interventions in the context of mortality trigger thresholds for the deployment of control strategies. The mean epidemic duration of a moderately virulent strain was 11.2 days, assuming the first infection is detected (best-case scenario), and 15.9 days when detection is triggered at 10% mortality. For a highly virulent strain, the epidemic duration was 6.5 days and 13.1 days, respectively. The distance from the source to infected locations and the spatial distribution was not dependent on strain virulence. Under the best-case scenario, we projected an average number of infected farms of 23.77 farms and 18.8 farms for the moderate and highly virulent strains, respectively. At 10% mortality-trigger, the predicted number of infected farms was on average 46.27 farms and 42.96 farms, respectively. We also demonstrated that the establishment of ring quarantine zones regardless of size (i.e. 5 km, 15 km) was outperformed by backward animal movement tracking. The proposed modelling framework provides an evaluation of ASF epidemic potential, providing a ranking of quarantine-based control strategies that could assist animal health authorities in planning the national preparedness and response plan.
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Affiliation(s)
- Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Trevor S Farthing
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Mathieu Andraud
- Anses, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare Research Unit, Ploufragan, France
| | - Francisco Paulo Nunes Lopes
- Departamento de Defesa Agropecuária, Secretaria da Agricultura, Pecuária e Desenvolvimento Rural, Porto Alegre, Brazil
| | - Cristina Lanzas
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
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Sauter-Louis C, Conraths FJ, Probst C, Blohm U, Schulz K, Sehl J, Fischer M, Forth JH, Zani L, Depner K, Mettenleiter TC, Beer M, Blome S. African Swine Fever in Wild Boar in Europe-A Review. Viruses 2021; 13:1717. [PMID: 34578300 PMCID: PMC8472013 DOI: 10.3390/v13091717] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
The introduction of genotype II African swine fever (ASF) virus, presumably from Africa into Georgia in 2007, and its continuous spread through Europe and Asia as a panzootic disease of suids, continues to have a huge socio-economic impact. ASF is characterized by hemorrhagic fever leading to a high case/fatality ratio in pigs. In Europe, wild boar are especially affected. This review summarizes the currently available knowledge on ASF in wild boar in Europe. The current ASF panzootic is characterized by self-sustaining cycles of infection in the wild boar population. Spill-over and spill-back events occur from wild boar to domestic pigs and vice versa. The social structure of wild boar populations and the spatial behavior of the animals, a variety of ASF virus (ASFV) transmission mechanisms and persistence in the environment complicate the modeling of the disease. Control measures focus on the detection and removal of wild boar carcasses, in which ASFV can remain infectious for months. Further measures include the reduction in wild boar density and the limitation of wild boar movements through fences. Using these measures, the Czech Republic and Belgium succeeded in eliminating ASF in their territories, while the disease spread in others. So far, no vaccine is available to protect wild boar or domestic pigs reliably against ASF.
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Affiliation(s)
- Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Franz J. Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Carolina Probst
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Ulrike Blohm
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Immunology, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (F.J.C.); (C.P.); (K.S.)
| | - Julia Sehl
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Melina Fischer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Jan Hendrik Forth
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Laura Zani
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of International Animal Health/One Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (L.Z.); (K.D.)
| | - Klaus Depner
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of International Animal Health/One Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (L.Z.); (K.D.)
| | - Thomas C. Mettenleiter
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Martin Beer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (M.F.); (J.H.F.); (M.B.); (S.B.)
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Gallardo C, Soler A, Nurmoja I, Cano-Gómez C, Cvetkova S, Frant M, Woźniakowski G, Simón A, Pérez C, Nieto R, Arias M. Dynamics of African swine fever virus (ASFV) infection in domestic pigs infected with virulent, moderate virulent and attenuated genotype II ASFV European isolates. Transbound Emerg Dis 2021; 68:2826-2841. [PMID: 34273247 DOI: 10.1111/tbed.14222] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 06/28/2021] [Accepted: 07/04/2021] [Indexed: 01/15/2023]
Abstract
This study aimed to compare the infection dynamics of three genotype II African swine fever viruses (ASFV) circulating in Europe. Eighteen domestic pigs divided into three groups were infected intramuscularly or by direct contact with two haemadsorbent ASFVs (HAD) from Poland (Pol16/DP/ OUT21) and Estonia (Est16/WB/Viru8), and with the Latvian non-HAD ASFV (Lv17/WB/Rie1). Parameters, such as symptoms, pathogenicity, and distribution of the virus in tissues, humoral immune response, and dissemination of the virus by blood, oropharyngeal and rectal routes, were investigated. The Polish ASFV caused a case of rapidly developing fatal acute disease, while the Estonian ASFV caused acute to sub-acute infections and two animals survived. In contrast, animals infected with the ASFV from Latvia developed a more subtle, mild, or even subclinical disease. Oral excretion was sporadic or even absent in the attenuated group, whereas in animals that developed an acute or sub-acute form of ASF, oral excretion began at the same time the ASFV was detected in the blood, or even 3 days earlier, and persisted up to 22 days. Regardless of virulence, blood was the main route of transmission of ASFV and infectious virus was isolated from persistently infected animals for at least 19 days in the attenuated group and up to 44 days in the group of moderate virulence. Rectal excretion was limited to the acute phase of infection. In terms of diagnostics, the ASFV genome was detected in contact pigs from oropharyngeal samples earlier than in blood, independently of virulence. Together with blood, both samples could allow to detect ASFV infection for a longer period. The results presented here provide quantitative data on the spread and excretion of ASFV strains of different virulence among domestic pigs that can help to better focus surveillance activities and, thus, increase the ability to detect ASF introductions earlier.
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Affiliation(s)
- Carmina Gallardo
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Alejandro Soler
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Imbi Nurmoja
- Estonian Veterinary and Food Laboratory, Estonian ASF-National reference laboratory (NRL), Kreutzwaldi, Tartu, Estonia
| | - Cristina Cano-Gómez
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Svetlana Cvetkova
- Laboratory of Microbiology and Pathology Institute of Food Safety, Animal Health and Enviroment, BIOR, Latvian ASF-National reference laboratory, Lejupes, Riga, Latvia
| | - Maciej Frant
- National Veterinary Research Institute, Poland ASF-National reference laboratory, Partyzantow, Pulawy, Poland
| | - Grzegorz Woźniakowski
- National Veterinary Research Institute, Poland ASF-National reference laboratory, Partyzantow, Pulawy, Poland.,Department of Diagnostics and Clinical Sciences, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska, Toruń, Poland
| | - Alicia Simón
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Covadonga Pérez
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Raquel Nieto
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
| | - Marisa Arias
- Centro de Investigación en Sanidad Animal, CISA, INIA-CSIC, European Union Reference Laboratory for African Swine Fever (EURL), Valdeolmos, Madrid, Spain
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Schulz K, Masiulis M, Staubach C, Malakauskas A, Pridotkas G, Conraths FJ, Sauter-Louis C. African Swine Fever and Its Epidemiological Course in Lithuanian Wild Boar. Viruses 2021; 13:1276. [PMID: 34208894 PMCID: PMC8310040 DOI: 10.3390/v13071276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/31/2022] Open
Abstract
African swine fever (ASF) has been present in Lithuania since 2014. It is mainly the wild boar population that is affected. Currently, little is known about the epidemiological course of ASF in Lithuania. In the present study, ASF surveillance data from 2016-2021 were analyzed. The numbers of samples taken from hunted wild boar and wild boar found dead per year and month were recorded and the prevalence was estimated for each study month and administrative unit. A Bayesian space-time model was used to calculate the temporal trend of the prevalence estimates. In addition, population data were analyzed on a yearly basis. Most samples were investigated in 2016 and 2017 and originated from hunted animals. Prevalence estimates of ASF virus-positive wild boar decreased from May 2019 onwards. Seroprevalence estimates showed a slight decrease at the same time, but they increased again at the end of the study period. A significant decrease in the population density was observed over time. The results of the study show that ASF is still present in the Lithuanian wild boar population. A joint interdisciplinary effort is needed to identify weaknesses in the control of ASF in Lithuania and to combat the disease more successfully.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Marius Masiulis
- Emergency Response Division, State Food and Veterinary Service, Siesiku 19, LT-07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Dr. L. Kriauceliunas Small Animal Clinic, Veterinary Academy, Lithuanian University of Health Sciences, Tilzes Street 18, LT-47181 Kaunas, Lithuania
- National Food and Veterinary Risk Assessment Institute, J. Kairiūkščio Street 10, LT-08409 Vilnius, Lithuania;
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Alvydas Malakauskas
- Emergency Response Division, State Food and Veterinary Service, Siesiku 19, LT-07170 Vilnius, Lithuania; (M.M.); (A.M.)
- Department of Veterinary Pathobiology, Veterinary Academy, Lithuanian University of Health Sciences, Tilzes Street 18, LT-47181 Kaunas, Lithuania
| | - Gediminas Pridotkas
- National Food and Veterinary Risk Assessment Institute, J. Kairiūkščio Street 10, LT-08409 Vilnius, Lithuania;
| | - Franz J. Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
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34
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Njau EP, Domelevo Entfellner JB, Machuka EM, Bochere EN, Cleaveland S, Shirima GM, Kusiluka LJ, Upton C, Bishop RP, Pelle R, Okoth EA. The first genotype II African swine fever virus isolated in Africa provides insight into the current Eurasian pandemic. Sci Rep 2021; 11:13081. [PMID: 34158551 PMCID: PMC8219699 DOI: 10.1038/s41598-021-92593-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 05/24/2021] [Indexed: 02/05/2023] Open
Abstract
African swine fever (ASF) caused by the African swine fever virus (ASFV) is ranked by OIE as the most important source of mortality in domestic pigs globally and is indigenous to African wild suids and soft ticks. Despite two ASFV genotypes causing economically devastating epidemics outside the continent since 1961, there have been no genome-level analyses of virus evolution in Africa. The virus was recently transported from south-eastern Africa to Georgia in 2007 and has subsequently spread to Russia, eastern Europe, China, and south-east Asia with devastating socioeconomic consequences. To date, two of the 24 currently described ASFV genotypes defined by sequencing of the p72 gene, namely genotype I and II, have been reported outside Africa, with genotype II being responsible for the ongoing pig pandemic. Multiple complete genotype II genome sequences have been reported from European, Russian and Chinese virus isolates but no complete genome sequences have yet been reported from Africa. We report herein the complete genome of a Tanzanian genotype II isolate, Tanzania/Rukwa/2017/1, collected in 2017 and determined using an Illumina short read strategy. The Tanzania/Rukwa/2017/1 sequence is 183,186 bp in length (in a single contig) and contains 188 open reading frames. Considering only un-gapped sites in the pairwise alignments, the new sequence has 99.961% identity with the updated Georgia 2007/1 reference isolate (FR682468.2), 99.960% identity with Polish isolate Pol16_29413_o23 (MG939586) and 99.957% identity with Chinese isolate ASFV-wbBS01 (MK645909.1). This represents 73 single nucleotide polymorphisms (SNPs) relative to the Polish isolate and 78 SNPs with the Chinese genome. Phylogenetic analysis indicated that Tanzania/Rukwa/2017/1 clusters most closely with Georgia 2007/1. The majority of the differences between Tanzania/Rukwa/2017/1 and Georgia 2007/1 genotype II genomes are insertions/deletions (indels) as is typical for ASFV. The indels included differences in the length and copy number of the terminal multicopy gene families, MGF 360 and 110. The Rukwa2017/1 sequence is the first complete genotype II genome from a precisely mapped locality in Africa, since the exact origin of Georgia2007/1 is unknown. It therefore provides baseline information for future analyses of the diversity and phylogeography of this globally important genetic sub-group of ASF viruses.
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Affiliation(s)
- Emma P Njau
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya.
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
- Sokoine University of Agriculture, P. O. Box 3019, Morogoro, Tanzania.
| | | | - Eunice M Machuka
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya
| | - Edwina N Bochere
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya
| | - Sarah Cleaveland
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Gabriel M Shirima
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Lughano J Kusiluka
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
- Mzumbe University, Morogoro, Tanzania
| | - Chris Upton
- Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada
| | - Richard P Bishop
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya
| | - Roger Pelle
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya
| | - Edward A Okoth
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, Nairobi, Kenya
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Evaluation of Lesions and Viral Antigen Distribution in Domestic Pigs Inoculated Intranasally with African Swine Fever Virus Ken05/Tk1 (Genotype X). Pathogens 2021; 10:pathogens10060768. [PMID: 34207265 PMCID: PMC8234863 DOI: 10.3390/pathogens10060768] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 12/13/2022] Open
Abstract
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.
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Lee HS, Bui VN, Dao DT, Bui NA, Le TD, Kieu MA, Nguyen QH, Tran LH, Roh JH, So KM, Hur TY, Oh SI. Pathogenicity of an African swine fever virus strain isolated in Vietnam and alternative diagnostic specimens for early detection of viral infection. Porcine Health Manag 2021; 7:36. [PMID: 33934707 PMCID: PMC8091783 DOI: 10.1186/s40813-021-00215-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/21/2021] [Indexed: 11/17/2022] Open
Abstract
Background African swine fever (ASF), caused by the ASF virus (ASFV), was first reported in Vietnam in 2019 and spread rapidly thereafter. Better insights into ASFV characteristics and early detection by surveillance could help control its spread. However, the pathogenicity and methods for early detection of ASFV isolates from Vietnam have not been established. Therefore, we investigated the pathogenicity of ASFV and explored alternative sampling methods for early detection. Results Ten pigs were intramuscularly inoculated with an ASFV strain from Vietnam (titer, 103.5 HAD50/mL), and their temperature, clinical signs, and virus excretion patterns were recorded. In addition, herd and environmental samples were collected daily. The pigs died 5–8 days-post-inoculation (dpi), and the incubation period was 3.7 ± 0.5 dpi. ASFV genome was first detected in the blood (2.2 ± 0.8) and then in rectal (3.1 ± 0.7), nasal (3.2 ± 0.4), and oral (3.6 ± 0.7 dpi) swab samples. ASFV was detected in oral fluid samples collected using a chewed rope from 3 dpi. The liver showed the highest viral loads, and ear tissue also exhibited high viral loads among 11 tissues obtained from dead pigs. Overall, ASFV from Vietnam was classified as peracute to acute form. The rope-based oral fluid collection method could be useful for early ASFV detection and allows successful ASF surveillance in large pig farms. Furthermore, ear tissue samples might be a simple alternative specimen for diagnosing ASF infection in dead pigs. Conclusions Our data provide valuable insights into the characteristics of a typical ASFV strain isolated in Vietnam and suggest an alternative, non-invasive specimen collection strategy for early detection.
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Affiliation(s)
- Hu Suk Lee
- International Livestock Research Institute (ILRI), Hanoi, Vietnam
| | - Vuong Nghia Bui
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Duy Tung Dao
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Ngoc Anh Bui
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Thanh Duy Le
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Minh Anh Kieu
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Quang Huy Nguyen
- International Livestock Research Institute (ILRI), Hanoi, Vietnam.,Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Long Hoang Tran
- Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
| | - Jae-Hee Roh
- Division of Animal Disease & Health, National Institute of Animal Science, Rural Development Administration, 55365, Wanju, Republic of Korea
| | - Kyoung-Min So
- Division of Animal Disease & Health, National Institute of Animal Science, Rural Development Administration, 55365, Wanju, Republic of Korea
| | - Tai-Young Hur
- Division of Animal Disease & Health, National Institute of Animal Science, Rural Development Administration, 55365, Wanju, Republic of Korea
| | - Sang-Ik Oh
- Division of Animal Disease & Health, National Institute of Animal Science, Rural Development Administration, 55365, Wanju, Republic of Korea.
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Arzumanyan H, Hakobyan S, Avagyan H, Izmailyan R, Nersisyan N, Karalyan Z. Possibility of long-term survival of African swine fever virus in natural conditions. Vet World 2021; 14:854-859. [PMID: 34083931 PMCID: PMC8167539 DOI: 10.14202/vetworld.2021.854-859] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/22/2021] [Indexed: 11/16/2022] Open
Abstract
Background and Aim: In modern scientific literature presents an understanding that African swine fever (ASF) ASF virus (ASFV) is remarkably stable in the environment, and carcasses of the pigs which were died after ASF, play a key role as ASFV reservoir. The aim of this study was to evaluate the possibility of the ASFV (different isolates) survival in bodies of dead animals, bones, remnants of bone marrow, residual organ matrix in natural conditions. Materials and Methods: Skeletons of ASFV infected pigs which were died and left/abandoned in forests or buried in Armenia at diverse time points and locations had been excavated and examined for the presence of ASFV genome by real-time polymerase chain reaction (PCR) assay and for infection abilities through in vitro (hemadsorption test and infection in porcine lung macrophages) as well as by intramuscular infection in healthy pigs. Results: Current exploration showed that in several samples (with different times of exposure) of excavated skeletons had been detected the presence of the virus gene (p72) using real-time PCR. However, in none of these porcine samples, infectious ASFV could be isolated. Data obtained by real-time PCR at frequent intervals indicated the presence of the virus gene (p72), especially within the case of the acute form of the disease. This can be explained by the highest levels of the virus during the latter case mentioned above. Conclusion: ASFV seems to be very sensitive to environmental temperature. The best place for ASFV long-term survival in the natural environment is bone marrow from intact big tubular bones (like femur or tibia) of buried carcasses. In artificial “graves,” complete bones with not destructed bone marrow can preserve the virus gene (p72) for a very long time (more than 2 years). Infectious particles in underground conditions survive not so long: In complete bones with not affected bone marrow, possible presence of the virus for several months.
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Affiliation(s)
- Hranush Arzumanyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan, Armenia
| | - Sona Hakobyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan, Armenia
| | - Hranush Avagyan
- Experimental Laboratory, Yerevan State Medical University, Yerevan, Armenia
| | - Roza Izmailyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan, Armenia
| | - Narek Nersisyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan, Armenia
| | - Zaven Karalyan
- Laboratory of Cell Biology and Virology, Institute of Molecular Biology of NAS RA, Yerevan, Armenia
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High Doses of Inactivated African Swine Fever Virus Are Safe, but Do Not Confer Protection against a Virulent Challenge. Vaccines (Basel) 2021; 9:vaccines9030242. [PMID: 33802021 PMCID: PMC7999564 DOI: 10.3390/vaccines9030242] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 12/29/2022] Open
Abstract
African swine fever (ASF) is currently the major concern of the global swine industry, as a consequence of which a reconsideration of the containment and prevention measures taken to date is urgently required. A great interest in developing an effective and safe vaccine against ASF virus (ASFV) infection has, therefore, recently appeared. The objective of the present study is to test an inactivated ASFV preparation under a vaccination strategy that has not previously been tested in order to improve its protective effect. The following have been considered: (i) virus inactivation by using a low binary ethyleneimine (BEI) concentration at a low temperature, (ii) the use of new and strong adjuvants; (iii) the use of very high doses (6 × 109 haemadsorption in 50% of infected cultures (HAD50)), and (iv) simultaneous double inoculation by two different routes of administration: intradermal and intramuscular. Five groups of pigs were, therefore, inoculated with BEI- Pol16/DP/OUT21 in different adjuvant formulations, twice with a 4-week interval. Six weeks later, all groups were intramuscularly challenged with 10 HAD50 of the virulent Pol16/DP/OUT21 ASFV isolate. All the animals had clinical signs and pathological findings consistent with ASF. This lack of effectiveness supports the claim that an inactivated virus strategy may not be a viable vaccine option with which to fight ASF.
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Cho KH, Kim HJ, Kim DY, Yoo D, Nah JJ, Kim YJ, Kang HE. Surveillance of ASF-infected pig farms from September to October 2019 in South Korea. J Vet Sci 2021; 22:e26. [PMID: 33774941 PMCID: PMC8007448 DOI: 10.4142/jvs.2021.22.e26] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 11/22/2022] Open
Abstract
Fourteen African swine fever (ASF) outbreaks occurred in the pig farms in the northwestern region of South Korea, near the border with North Korea, from September 16, 2019 to October 9, 2019. Active and passive surveillance on the ASF-infected farms indicated that the infection was limited only to pigsties where the infected pigs were detected on the farm for the first time before further transmission to other pigsties and farms. This early detection could be one of the pivotal factors for the prompt eradication of ASF in domestic pig farms within 1 month in the northwestern region of South Korea.
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Affiliation(s)
- Ki Hyun Cho
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
| | - Hyun Joo Kim
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
| | - Da Young Kim
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
| | - Daesung Yoo
- Department of Public Health, Graduate School, Korea University, Seoul 02841, Korea
| | - Jin Ju Nah
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
| | - Yong Joo Kim
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
| | - Hae Eun Kang
- Animal and Plant Quarantine Agency, Gimcheon 39660, Korea.
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Gortazar Schmidt C, Herskin M, Michel V, Miranda Chueca MÁ, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Stahl K, Velarde A, Winckler C, Abrahantes JC, Dhollander S, Ivanciu C, Papanikolaou A, Van der Stede Y, Blome S, Guberti V, Loi F, More S, Olsevskis E, Thulke HH, Viltrop A. ASF Exit Strategy: Providing cumulative evidence of the absence of African swine fever virus circulation in wild boar populations using standard surveillance measures. EFSA J 2021; 19:e06419. [PMID: 33717352 PMCID: PMC7926520 DOI: 10.2903/j.efsa.2021.6419] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
EFSA assessed the role of seropositive wild boar in African swine fever (ASF) persistence. Surveillance data from Estonia and Latvia investigated with a generalised equation method demonstrated a significantly slower decline in seroprevalence in adult animals compared with subadults. The seroprevalence in adults, taking more than 24 months to approach zero after the last detection of ASFV circulation, would be a poor indicator to demonstrate the absence of virus circulation. A narrative literature review updated the knowledge on the mortality rate, the duration of protective immunity and maternal antibodies and transmission parameters. In addition, parameters potentially leading to prolonged virus circulation (persistence) in wild boar populations were reviewed. A stochastic explicit model was used to evaluate the dynamics of virus prevalence, seroprevalence and the number of carcasses attributed to ASF. Secondly, the impact of four scenarios on the duration of ASF virus (ASFV) persistence was evaluated with the model, namely a: (1) prolonged, lifelong infectious period, (2) reduction in the case-fatality rate and prolonged transient infectiousness; (3) change in duration of protective immunity and (4) change in the duration of protection from maternal antibodies. Only the lifelong infectious period scenario had an important prolonging effect on the persistence of ASF. Finally, the model tested the performance of different proposed surveillance strategies to provide evidence of the absence of virus circulation (Exit Strategy). A two-phase approach (Screening Phase, Confirmation Phase) was suggested for the Exit Strategy. The accuracy of the Exit Strategy increases with increasing numbers of carcasses collected and tested. The inclusion of active surveillance based on hunting has limited impact on the performance of the Exit Strategy compared with lengthening of the monitoring period. This performance improvement should be reasonably balanced against an unnecessary prolonged 'time free' with only a marginal gain in performance. Recommendations are provided for minimum monitoring periods leading to minimal failure rates of the Exit Strategy. The proposed Exit Strategy would fail with the presence of lifelong infectious wild boar. That said, it should be emphasised that the existence of such animals is speculative, based on current knowledge.
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Gortázar Schmidt C, Herskin M, Michel V, Miranda Chueca MÁ, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Ståhl K, Velarde A, Viltrop A, Winckler C, De Clercq K, Klement E, Stegeman JA, Gubbins S, Antoniou S, Broglia A, Van der Stede Y, Zancanaro G, Aznar I. Scientific Opinion on the assessment of the control measures of the category A diseases of Animal Health Law: African Swine Fever. EFSA J 2021; 19:e06402. [PMID: 33552298 PMCID: PMC7848183 DOI: 10.2903/j.efsa.2021.6402] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for African Swine Fever (ASF). In this opinion, EFSA and the AHAW Panel of experts reviewed the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period and (iii) the minimum radius of the protection and surveillance zone, and the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere; nonetheless, specific details of the model used for the assessment of the laboratory sampling procedures for ASF are presented here. Here, also, the transmission kernels used for the assessment of the minimum radius of the protection and surveillance zones are shown. Several scenarios for which these control measures had to be assessed were designed and agreed prior to the start of the assessment. In summary, several sampling procedures as described in the diagnostic manual for ASF were considered ineffective and a suggestion to exclude, or to substitute with more effective procedures was made. The monitoring period was assessed as non-effective for several scenarios and a longer monitoring period was suggested to ensure detection of potentially infected herds. It was demonstrated that the surveillance zone comprises 95% of the infections from an affected establishment, and therefore is considered effective. Recommendations provided for each of the scenarios assessed aim to support the European Commission in the drafting of further pieces of legislation, as well as for plausible ad hoc requests in relation to ASF.
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Abstract
African swine fever is a devastating disease that can result in death in almost all infected pigs. The continuing spread of African swine fever from Africa to Europe and recently to the high-pig production countries of China and others in Southeast Asia threatens global pork production and food security. The African swine fever virus is an unusual complex DNA virus and is not related to other viruses. This has presented challenges for vaccine development, and currently none is available. The virus is extremely well adapted to replicate in its hosts in the sylvatic cycle in East and South Africa. Its spread to other regions, with different wildlife hosts, climatic conditions, and pig production systems, has revealed unexpected epidemiological scenarios and different challenges for control. Here we review the epidemiology of African swine fever in these different scenarios and methods used for control. We also discuss progress toward vaccine development and research priorities to better understand this complex disease and improve control.
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Affiliation(s)
- Linda K Dixon
- The Pirbright Institute, Woking, Surrey GU24 0NF, United Kingdom;
| | - Karl Stahl
- Department of Disease Control and Epidemiology, National Veterinary Institute, SE-751 89 Uppsala, Sweden;
| | - Ferran Jori
- UMR CIRAD-INRA ASTRE (Animal, Health, Territories, Risks and Ecosystems) Department BIOS, Campus International de Baillarguet, 34398 Montpellier, Cedex 5, France; ,
| | - Laurence Vial
- UMR CIRAD-INRA ASTRE (Animal, Health, Territories, Risks and Ecosystems) Department BIOS, Campus International de Baillarguet, 34398 Montpellier, Cedex 5, France; ,
| | - Dirk U Pfeiffer
- Centre for Applied One Health Research and Policy Advice, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, PR China;
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Feng Z, Chen J, Liang W, Chen W, Li Z, Chen Q, Cai S. The recombinant pseudorabies virus expressing African swine fever virus CD2v protein is safe and effective in mice. Virol J 2020; 17:180. [PMID: 33198749 PMCID: PMC7668019 DOI: 10.1186/s12985-020-01450-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Background African swine fever (ASF) leads to high mortality in domestic pigs and wild boar and is caused by the African swine fever virus (ASFV). Currently, no vaccine is commercially available for prevention, and the epidemic is still spreading. Here, we constructed a recombinant pseudorabies virus (PRV) (PRV-ΔgE/ΔgI/ΔTK-(CD2v)) that expresses the CD2v protein of ASFV and evaluated its effectiveness and safety as a vaccine candidate in mice. Methods A homologous recombination fragment containing ASFV CD2v was synthesized and co-transfected into HEK 293 T cells, a knockout vector targeting the PRV TK gene. The transfected cells were infected with PRV-ΔgE/ΔgI, and the recombinant strain (PRV-ΔgE/ΔgI/ΔTK-(CD2v)) was obtained by plaque purification in Vero cells. The expression of ASFV CD2v in the recombinant virus was confirmed by sequencing, Western blotting, and immunofluorescence analysis, and the genetic stability was tested in Vero cells over 20 passages. The virulence, immunogenicity and protective ability of the recombinant virus were further tested in a mouse model. Results The PRV-ΔgE/ΔgI/ΔTK-(CD2v) recombinant strain is stable in Vero cells, and the processing of CD2v does not depend on ASFV infection. The vaccination of PRV-ΔgE/ΔgI/ΔTK-(CD2v) causes neither pruritus, not a systemic infection and inflammation (with the high expression of interleukin-6 (IL6)). Besides, the virus vaccination can produce anti-CD2v specific antibody and activate a specific cellular immune response, and 100% protect mice from the challenge of the virulent strain (PRV-Fa). The detoxification occurs much earlier upon the recombinant virus vaccination and the amount of detoxification is much lower as well. Conclusions The PRV-ΔgE/ΔgI/ΔTK-(CD2v) recombinant strain has strong immunogenicity, is safe and effective, and maybe a potential vaccine candidate for the prevention of ASF and Pseudorabies.
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Affiliation(s)
- Zhihua Feng
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Jianghua Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Wangwang Liang
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Wenzhi Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Zhaolong Li
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China. .,Institute of Animal Husbandry and Veterinary Medicine, Fujian Province, Fujian Academy of Agricultural Sciences, Pudang, Jin-an District, Fuzhou, 350117, People's Republic of China.
| | - Qi Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China.
| | - Shaoli Cai
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China.
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Bisimwa PN, Ongus JR, Tiambo CK, Machuka EM, Bisimwa EB, Steinaa L, Pelle R. First detection of African swine fever (ASF) virus genotype X and serogroup 7 in symptomatic pigs in the Democratic Republic of Congo. Virol J 2020; 17:135. [PMID: 32883295 PMCID: PMC7468181 DOI: 10.1186/s12985-020-01398-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/14/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND African swine fever (ASF) is a highly contagious and severe hemorrhagic viral disease of domestic pigs. The analysis of variable regions of African swine fever virus (ASFV) genome led to more genotypic and serotypic information about circulating strains. The present study aimed at investigating the genetic diversity of ASFV strains in symptomatic pigs in South Kivu province of the Democratic Republic of Congo (DRC). MATERIALS AND METHODS Blood samples collected from 391 ASF symptomatic domestic pigs in 6 of 8 districts in South Kivu were screened for the presence of ASFV, using a VP73 gene-specific polymerase chain reaction (PCR) with the universal primer set PPA1-PPA2. To genotype the strains, we sequenced and compared the nucleotide sequences of PPA-positive samples at three loci: the C-terminus of B646L gene encoding the p72 protein, the E183L gene encoding the p54 protein, and the central hypervariable region (CVR) of the B602L gene encoding the J9L protein. In addition, to serotype and discriminate between closely related strains, the EP402L (CD2v) gene and the intergenic region between the I73R and I329L genes were analyzed. RESULTS ASFV was confirmed in 26 of 391 pigs tested. However, only 19 and 15 PPA-positive samples, respectively, were successfully sequenced and phylogenetically analyzed for p72 (B646L) and p54 (E183L). All the ASFV studied were of genotype X. The CVR tetrameric repeat clustered the ASFV strains in two subgroups: the Uvira subgroup (10 TRS repeats, AAAABNAABA) and another subgroup from all other strains (8 TRS repeats, AABNAABA). The phylogenetic analysis of the EP402L gene clustered all the strains into CD2v serogroup 7. Analyzing the intergenic region between I73R and I329L genes revealed that the strains were identical but contained a deletion of a 33-nucleotide internal repeat sequence compared to ASFV strain Kenya 1950. CONCLUSION ASFV genotype X and serogroup 7 was identified in the ASF disease outbreaks in South Kivu province of DRC in 2018-2019. This represents the first report of ASFV genotype X in DRC. CVR tetrameric repeat sequences clustered the ASFV strains studied in two subgroups. Our finding emphasizes the need for improved coordination of the control of ASF.
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Affiliation(s)
- Patrick N. Bisimwa
- Department of Molecular Biology and Biotechnology, Pan African University, Institute of Basic Sciences, Technology and Innovation, Nairobi, Kenya
- Department of Animal Science and Production, Université Evangélique en Afrique, Bukavu, Democratic Republic of the Congo
| | - Juliette R. Ongus
- Department of Molecular Biology and Biotechnology, Pan African University, Institute of Basic Sciences, Technology and Innovation, Nairobi, Kenya
- Department of Medical Laboratory Sciences, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Christian K. Tiambo
- Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100 Kenya
- Centre for Tropical Livestock Genetics and Health (CTLGH), International Livestock Research Institute, Nairobi, Kenya
| | - Eunice M. Machuka
- Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Espoir B. Bisimwa
- Department of Animal Science and Production, Université Evangélique en Afrique, Bukavu, Democratic Republic of the Congo
| | - Lucilla Steinaa
- International Livestock Research Institute, Animal and Human Health, Nairobi, Kenya
| | - Roger Pelle
- Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100 Kenya
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Epidemiological analysis of the 2015–2017 African swine fever outbreaks in Estonia. Prev Vet Med 2020; 181:104556. [DOI: 10.1016/j.prevetmed.2018.10.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/01/2018] [Indexed: 11/21/2022]
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Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014-2019. Pathogens 2020; 9:pathogens9070582. [PMID: 32709020 PMCID: PMC7400522 DOI: 10.3390/pathogens9070582] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/28/2022] Open
Abstract
After the extensive spread of the African swine fever virus (ASFV) genotype II in Eastern Europe, the first case of African swine fever (ASF) in Estonia was diagnosed in September 2014. By the end of 2019, 3971 ASFV-positive wild boars were found, and 27 domestic pig outbreaks were reported. A selection of ASFV isolates from wild boar and domestic pigs (during the period of September 2014–2019) was molecularly characterized using standardized genotyping procedures. One of the proven markers to characterize this virus is the central variable region (CVR) within the B602L gene. In summer 2015, a new ASFV genotype II CVR variant 2 (GII-CVR2) was confirmed in Estonia. The results suggest that the GII-CVR2 variant was only confirmed in wild boar from a limited area in southern Estonia in 2015 and 2016. In addition to GII-CVR2, a single nucleotide polymorphism (SNP) that resulted in amino acid change was identified within the genotype II CVR variant 1 (GII-CVR1). The GII-CVR1/SNP1 strain was isolated in Estonia in November 2016. Additional GII-CVR1/SNP1 cases were confirmed in two neighbouring counties, as well as in one outbreak farm in June 2017. Based on the available data, no GII-CVR2 and GII-CVR1/SNP1 have been reported by other affected European countries. The spread of variant strains in Estonia has been limited over time, and restricted to a relatively small area.
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Schulz K, Staubach C, Blome S, Nurmoja I, Viltrop A, Conraths FJ, Kristian M, Sauter-Louis C. How to Demonstrate Freedom from African Swine Fever in Wild Boar-Estonia as an Example. Vaccines (Basel) 2020; 8:E336. [PMID: 32630595 PMCID: PMC7350251 DOI: 10.3390/vaccines8020336] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 11/24/2022] Open
Abstract
Estonia has been combatting African swine fever (ASF) for six years now. Since October 2017, the disease has only been detected in the wild boar population, but trade restrictions had to remain in place due to international regulations. Yet, the epidemiological course of the disease has changed within the last few years. The prevalence of ASF virus (ASFV)-positive wild boar decreased steadily towards 0%. In February 2019, the last ASFV-positive wild boar was detected. Since then, positive wild boar samples have exclusively been positive for ASFV-specific antibodies, suggesting the possible absence of circulating ASFV in the Estonian wild boar population. However, as the role of seropositive animals is controversially discussed and the presence of antibody-carriers is regarded as an indication of virus circulation at EU and OIE level, Estonia remains under trade restrictions. To make the disease status of a country reliable for trading partners and to facilitate the process of declaration of disease freedom, we suggest to monitor the prevalence of seropositive wild boar in absence of ASFV-positive animals. The possibility to include ASF in the list of diseases, for which an official pathway for recognition of disease status is defined by the OIE should be evaluated.
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Affiliation(s)
- Katja Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Christoph Staubach
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany;
| | - Imbi Nurmoja
- Estonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006 Tartu, Estonia;
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014 Tartu, Estonia;
| | - Arvo Viltrop
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014 Tartu, Estonia;
| | - Franz J. Conraths
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
| | - Maarja Kristian
- Veterinary and Food Board, Väike-Paala 3, 11415 Tallinn, Estonia;
| | - Carola Sauter-Louis
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Insel Riems, Germany; (C.S.); (F.J.C.); (C.S.-L.)
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Danzetta ML, Marenzoni ML, Iannetti S, Tizzani P, Calistri P, Feliziani F. African Swine Fever: Lessons to Learn From Past Eradication Experiences. A Systematic Review. Front Vet Sci 2020; 7:296. [PMID: 32582778 PMCID: PMC7296109 DOI: 10.3389/fvets.2020.00296] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/30/2020] [Indexed: 11/13/2022] Open
Abstract
Prevention, early detection, prompt reaction, and communication play a crucial role in African swine fever (ASF) control. Appropriate surveillance capable of early detection of the disease in both domestic and wild animals, and the implementation of consolidated contingency plans, are currently considered the best means of controlling this disease. The purpose of this study was to understand the lessons to be learned through the global disease eradication history. To establish which strategies were successful for prevention, control, and eradication of ASF, and which errors should not be repeated, we conducted a systematic review. A query was defined to search for surveillance and control strategies applied by countries worldwide for ASF eradication in the past. Inclusion and exclusion criteria were defined. Decisions on study eligibility and data extraction were performed by two independent reviewers and the differences were resolved by consensus or by a third reviewer. From 1,980 papers, 23 were selected and included in the qualitative analysis. Reports from Belgium, Brazil, Cuba, the Dominican Republic and Haiti, France, mainland Italy, Malta, Portugal, and Spain were included. Despite the economic resources allocated and the efforts made, eradication was possible in only eight countries, between the 50s and 90s in the twentieth century, in different epidemiological and cultural contexts, in some instances within <1 year, and in others in about 40 years. Classical surveillance strategies, such as active and passive surveillance, both at farm and slaughterhouse levels, targeted surveillance, together with conventional biosafety and sanitary measures, led to eradication even in countries in which the tick's epidemiological role was demonstrated. Historical surveillance data analysis indicated that eradication was possible even when technological tools either were not available or were used less than they are currently. This emphasizes that data on surveillance and on animal population are crucial for planning effective surveillance, and targeting proper control and intervention strategies. This paper demonstrates that some strategies applied in the past were effective; these could be implemented and improved to confront the current epidemiological wave. This offers encouragement for the efforts made particularly in Europe during the recent epidemics.
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Affiliation(s)
- Maria Luisa Danzetta
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | | | - Simona Iannetti
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
| | - Paolo Tizzani
- World Animal Health Information and Analysis Department (WAHIAD), World Organisation for Animal Health, OIE, Paris, France
| | - Paolo Calistri
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
| | - Francesco Feliziani
- National Reference Laboratory for Swine Fevers, Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche “Togo Rosati”, Perugia, Italy
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Oļševskis E, Schulz K, Staubach C, Seržants M, Lamberga K, Pūle D, Ozoliņš J, Conraths FJ, Sauter-Louis C. African swine fever in Latvian wild boar-A step closer to elimination. Transbound Emerg Dis 2020; 67:2615-2629. [PMID: 32372476 DOI: 10.1111/tbed.13611] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 11/29/2022]
Abstract
In 2014, African swine fever (ASF) emerged in Latvia for the first time. The majority of cases appeared in wild boar, but the presence of ASF in these animals constitutes a permanent threat to domestic pig holdings. Recent studies have shown an increase in serologically positive and a decrease in PCR-positive ASF cases in wild boar, possibly indicating a decline of ASF incidence. We aimed to investigate the course of the ASF epidemic in wild boar in Latvia, thus attaining further insights into the ASF epidemiology in this country with the goal of assessing the stage of the epidemic. Latvian ASF surveillance data of wild boar were utilized to estimate the seroprevalence and ASF virus (ASFV) prevalence in the wild boar population. Prevalence estimates were obtained for both the eastern and western part of the country and in addition for the 2014/2015 to 2018/2019 hunting seasons. Moreover, prevalence estimates for three different age classes were calculated. An increase in serologically positive yet PCR-negative wild boar samples from active surveillance was identified over time. When comparing the age groups, wild boar younger than one year displayed the ASFV prevalence to be higher than the seroprevalence, whereas older animals shared higher seroprevalence estimates. These findings support the assumption that only a small proportion of affected animals survive an infection, leading to an accumulation of their numbers over time. As a result, ASF elimination in a country with an infected wild boar population could possibly be achieved, if effective wild boar population management and surveillance is maintained and combined with the detection and removal of wild boar carcasses to reduce the viral load in the environment. In addition, the wild boar population should be kept as small as possible to break the ASFV infection cycle.
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Affiliation(s)
- Edvīns Oļševskis
- Food and Veterinary Service, Riga, Latvia.,Institute of Food Safety, Animal Health and Environment-'BIOR', Riga, Latvia
| | - Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | | | - Kristīne Lamberga
- Food and Veterinary Service, Riga, Latvia.,Latvia University of Life Sciences and Technologies, Jelgava, Latvia
| | - Daina Pūle
- Institute of Food Safety, Animal Health and Environment-'BIOR', Riga, Latvia
| | - Jānis Ozoliņš
- Latvian State Forest Research Institute 'Silava', Salaspils, Latvia
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany
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Salguero FJ. Comparative Pathology and Pathogenesis of African Swine Fever Infection in Swine. Front Vet Sci 2020; 7:282. [PMID: 32509811 PMCID: PMC7248413 DOI: 10.3389/fvets.2020.00282] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/27/2020] [Indexed: 01/23/2023] Open
Abstract
African Swine Fever (ASF) is a viral disease that affects animals of the Suidae family, and soft ticks from the genus Ornithodoros can also be infected by the ASF virus (ASFV). The disease was first described in Africa at the beginning of the twentieth century as an acute disease characterized by high mortality and fatal hemorrhages. ASF has caused outbreaks in numerous countries and it continues to be devastating nowadays for the porcine sector in those countries affected, and a massive threat for those free of the disease. ASF can follow clinical courses from peracute to chronic in domestic pigs (Sus scrofa) depending on a variety of factors, including the immune status of the animals and the virulence of the ASFV strain. The key features of the pathogenesis of the disease in domestic swine are a) a severe lymphoid depletion including lymphopenia and a state of immunodeficiency, and b) hemorrhages. However, African wild swine like bushpigs (Potamochoerus larvatus), red river hogs (Potamochoerus porcus), and warthogs (Phacochoerus africanus) can be infected by ASFV showing no clinical signs of disease and acting as natural reservoir hosts. In this article we review the key features of the gross and microscopic pathology together with a description of the pathogenesis of ASFV infection in domestic pigs following the different clinical courses. The pathogenesis of ASF in wild and domestic swine is also described, what can provide important information for the design of control strategies, such as vaccines.
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