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Obanda V, Akinyi M, King'ori E, Nyakundi R, Ochola G, Oreng P, Mugambi K, Waiguchu GM, Chege M, Rosenbaum W, Ylitalo EB, Bäck AT, Pettersson L, Mukunzi OS, Agwanda B, Stenberg-Lewerin S, Lwande OW. Epidemiology and ecology of the sylvatic cycle of African Swine Fever Virus in Kenya. Virus Res 2024; 348:199434. [PMID: 39004284 DOI: 10.1016/j.virusres.2024.199434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/07/2024] [Accepted: 07/07/2024] [Indexed: 07/16/2024]
Abstract
African Swine Fever (ASF) is caused by a DNA virus (AFSV) maintained and transmitted by the Argasid ticks. The re-emergence of the disease in Africa coupled with its rapid spread globally is a threat to the pig industry, food security and livelihoods. The ecology and epidemiology of the ASFV sylvatic cycle, especially in the face of changing land use and land cover, further compounds the menace and impacts of this disease in Kenya. The study aimed to determine the occurrence and distribution of ASFV seroprevalence in warthog populations, the tick vectors and extent of tick infestation of warthog burrows, and the genotypes of ASFV in soft ticks in Kenya. Warthogs from different parts of Kenya were captured and venous blood was centrifuged to harvest sera. Warthog burrows were examined for their conditions and to extract ticks. Sera were analyzed for antibodies against ASFV using a commercial ELISA kit coated with p32 ASFV recombinant protein. Ticks were pooled, DNA extracted and the p72 gene of the ASFV was amplified by qPCR and conventional PCR. The overall seroprevalence of ASFV in warthogs was 87.5 %. A total of 228 warthog burrows were examined and 2154 argasid ticks were extracted from the burrows. Tick pools from Kigio Farm and Lewa Wildlife Conservancies were ASFV-positive by qPCR and conventional PCR. ASFV was further confirmed by the Twist Comprehensive Viral Research Panel (TCVRP), which also identified the argasid ticks as Ornithodoros porcinus. The ticks were infected with virus genotype IX, and their occurrence overlaps with regions of previous ASF outbreaks in domestic pigs. Further, Viruses that could be tick endosymbionts/commensals or due to bloodmeal were detected in ticks by TCVRP; Porcine type-C oncovirus; Pandoravirus neocaledonia; Choristoneura fumiferana granulovirus; Enterobacteria phage p7; Leporid herpesvirus 4 isolate; 5; Human Lymphotropic virus; Human herpesvirus 5. In conclusion, our results suggest that infected Ornithodoros spp. seems to have a rich virome, which has not been explored but could be exploited to inform ASF control in Kenya. Further, the ecology of Ornithodoros spp. and burrow-use dynamics are complex and more studies are needed to understand these dynamics, specifically in the spread of ASFV at the interface of wild and domestic pigs. Further, our results provide evidence of genotype IX ASFV sylvatic cycle which through O. porcinus tick transmission has resulted in high exposure of adult common warthogs. Finally, the co-circulation of ASFV genotype IX in the same location with past ASF outbreaks in domestic pigs and presently in ticks brings to focus the role of the interface and ticks on virus transmission to pigs and warthogs.
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Affiliation(s)
- Vincent Obanda
- Veterinary Science and Laboratories Department, Wildlife Research and Training Institute, P.O Box 842-20117, Naivasha, Kenya
| | - Mercy Akinyi
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - Edward King'ori
- Veterinary Services Department, Kenya Wildlife Service, P.O. Box 54582 00200, Nairobi, Kenya
| | - Ruth Nyakundi
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - Griphin Ochola
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - Purity Oreng
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - Kevin Mugambi
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - Grace Mwihaki Waiguchu
- Center for Savannah, Arid and Semi-Arid Ecosystems, Wildlife Research and Training Institute, Tsavo, P.O Box 842-20117, Naivasha, Kenya
| | - Mary Chege
- Institute of Primate Research, P.O. Box 24481 Karen 00502, Nairobi, Kenya
| | - William Rosenbaum
- Department of Medical Biosciences, Clinical Genomics, 901 87, Umeå University, Umeå, Sweden
| | | | | | - Lisa Pettersson
- Department of Clinical Microbiology, Umeå University, 901 85, Umeå, Sweden
| | - Opanda Silvanos Mukunzi
- Centre for Virus Research, Kenya Medical Research Training Institute, P.O. BOX 54628-00200, Nairobi, Kenya
| | - Bernard Agwanda
- Zoology Department, National Museums of Kenya, P.O. BOX 40658- 00100, Nairobi, Kenya
| | - Susanna Stenberg-Lewerin
- Department of Animal Biosciences, Swedish University of Agricultural Sciences, P.O Box 7023 75007, Uppsala, Sweden
| | - Olivia Wesula Lwande
- Department of Clinical Microbiology, Umeå University, 901 85, Umeå, Sweden; Umeå Centre for Microbiology Research, Umeå University, 901 87, Umeå, Sweden.
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Penrith ML, van Emmenes J, Hakizimana JN, Heath L, Kabuuka T, Misinzo G, Odoom T, Wade A, Zerbo HL, Luka PD. African Swine Fever Diagnosis in Africa: Challenges and Opportunities. Pathogens 2024; 13:296. [PMID: 38668251 PMCID: PMC11054189 DOI: 10.3390/pathogens13040296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/18/2024] [Accepted: 03/29/2024] [Indexed: 04/29/2024] Open
Abstract
The global spread of African swine fever (ASF) in recent decades has led to the need for technological advances in sampling and diagnostic techniques. The impetus for these has been the need to enable sampling by lay persons and to obtain at least a preliminary diagnosis in the field for early control measures to be put in place before final laboratory confirmation. In rural Africa, rapid diagnosis is hampered by challenges that include lack of infrastructure as well as human and financial resources. Lack of animal health personnel, access to affordable means to transport field samples to a laboratory, and lack of laboratories with the capacity to make the diagnosis result in severe under-reporting of ASF, especially in endemic areas. This review summarizes the challenges identified in gap analyses relevant to low- and middle-income countries, with a focus on Africa, and explore the opportunities provided by recent research to improve field diagnosis and quality of diagnostic samples used. Sampling techniques include invasive sampling techniques requiring trained personnel and non-invasive sampling requiring minimal training, sampling of decomposed carcass material, and preservation of samples in situations where cold chain maintenance cannot be guaranteed. Availability and efficacy of point-of-care (POC) tests for ASF has improved considerably in recent years and their application, as well as advantages and limitations, are discussed. The adequacy of existing laboratory diagnostic capacity is evaluated and opportunities for networking amongst reference and other laboratories offering diagnostic services are discussed. Maintaining laboratory diagnostic efficiency in the absence of samples during periods of quiescence is another issue that requires attention, and the role of improved laboratory networking is emphasized. Early diagnosis of ASF is key to managing the disease spread. Therefore, the establishment of the Africa Chapter of the Global African Swine Fever Research Alliance (GARA) increases opportunities for collaboration and networking among the veterinary diagnostic laboratories in the region.
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Affiliation(s)
- Mary-Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria 0110, South Africa
| | - Juanita van Emmenes
- Transboundary Animal Diseases, Onderstepoort Veterinary Institute, Agricultural Research Council, Pretoria 0110, South Africa; (J.v.E.); (L.H.)
| | - Jean N. Hakizimana
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro P.O. Box 3297, Tanzania; (J.N.H.); (G.M.)
| | - Livio Heath
- Transboundary Animal Diseases, Onderstepoort Veterinary Institute, Agricultural Research Council, Pretoria 0110, South Africa; (J.v.E.); (L.H.)
| | - Tonny Kabuuka
- National Livestock Resources Research Institute, National Agricultural Research Organization, Entebbe P.O. Box 295, Uganda;
| | - Gerald Misinzo
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro P.O. Box 3297, Tanzania; (J.N.H.); (G.M.)
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro P.O. Box 3019, Tanzania
| | - Theophilus Odoom
- Veterinary Services Directorate, Accra Veterinary Laboratory, Accra P.O. Box M161, Ghana;
| | - Abel Wade
- National Veterinary Laboratory (LANAVET), Garoua P.O. Box 503, Cameroon;
| | - Habibata L. Zerbo
- Ministry of Agriculture, Animal and Fisheries Resources, Ouagadougou 03 BP 907, Burkina Faso;
| | - Pam D. Luka
- Biotechnology Centre, National Veterinary Research Institute, PMB 1, Vom 930103, Nigeria
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Goatley LC, Freimanis G, Tennakoon C, Foster TJ, Quershi M, Dixon LK, Batten C, Forth JH, Wade A, Netherton C. Full genome sequence analysis of African swine fever virus isolates from Cameroon. PLoS One 2024; 19:e0293049. [PMID: 38512923 PMCID: PMC10956809 DOI: 10.1371/journal.pone.0293049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 03/06/2024] [Indexed: 03/23/2024] Open
Abstract
African swine fever (ASF) is a devastating disease of domestic pigs that has spread across the globe since its introduction into Georgia in 2007. The etiological agent is a large double-stranded DNA virus with a genome of 170 to 180 kb in length depending on the isolate. Much of the differences in genome length between isolates are due to variations in the copy number of five different multigene families that are encoded in repetitive regions that are towards the termini of the covalently closed ends of the genome. Molecular epidemiology of African swine fever virus (ASFV) is primarily based on Sanger sequencing of a few conserved and variable regions, but due to the stability of the dsDNA genome changes in the variable regions occur relatively slowly. Observations in Europe and Asia have shown that changes in other genetic loci can occur and that this could be useful in molecular tracking. ASFV has been circulating in Western Africa for at least forty years. It is therefore reasonable to assume that changes may have accumulated in regions of the genome other than the standard targets over the years. At present only one full genome sequence is available for an isolate from Western Africa, that of a highly virulent isolate collected from Benin during an outbreak in 1997. In Cameroon, ASFV was first reported in 1981 and outbreaks have been reported to the present day and is considered endemic. Here we report three full genome sequences from Cameroon isolates of 1982, 1994 and 2018 outbreaks and identify novel single nucleotide polymorphisms and insertion-deletions that may prove useful for molecular epidemiology studies in Western Africa and beyond.
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Affiliation(s)
- Lynnette C. Goatley
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Graham Freimanis
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Chandana Tennakoon
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Thomas J. Foster
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Mehnaz Quershi
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Linda K. Dixon
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Carrie Batten
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom
| | - Jan Hendrik Forth
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Abel Wade
- National Veterinary Laboratory (LANAVET), Garoua, Cameroon
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Rodarte KA, Fair JM, Bett BK, Kerfua SD, Fasina FO, Bartlow AW. A scoping review of zoonotic parasites and pathogens associated with abattoirs in Eastern Africa and recommendations for abattoirs as disease surveillance sites. Front Public Health 2023; 11:1194964. [PMID: 37529427 PMCID: PMC10387540 DOI: 10.3389/fpubh.2023.1194964] [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: 03/27/2023] [Accepted: 06/26/2023] [Indexed: 08/03/2023] Open
Abstract
Abattoirs are facilities where livestock are slaughtered and are an important aspect in the food production chain. There are several types of abattoirs, which differ in infrastructure and facilities, sanitation and PPE practices, and adherence to regulations. In each abattoir facility, worker exposure to animals and animal products increases their risk of infection from zoonotic pathogens. Backyard abattoirs and slaughter slabs have the highest risk of pathogen transmission because of substandard hygiene practices and minimal infrastructure. These abattoir conditions can often contribute to environmental contamination and may play a significant role in disease outbreaks within communities. To assess further the risk of disease, we conducted a scoping review of parasites and pathogens among livestock and human workers in abattoirs across 13 Eastern African countries, which are hotspots for zoonoses. Our search results (n = 104 articles) showed the presence of bacteria, viruses, fungi, and macroparasites (nematodes, cestodes, etc.) in cattle, goats, sheep, pigs, camels, and poultry. Most articles reported results from cattle, and the most frequent pathogen detected was Mycobacterium bovis, which causes bovine tuberculosis. Some articles included worker survey and questionnaires that suggested how the use of PPE along with proper worker training and safe animal handling practices could reduce disease risk. Based on these findings, we discuss ways to improve abattoir biosafety and increase biosurveillance for disease control and mitigation. Abattoirs are a 'catch all' for pathogens, and by surveying animals at abattoirs, health officials can determine which diseases are prevalent in different regions and which pathogens are most likely transmitted from wildlife to livestock. We suggest a regional approach to biosurveillance, which will improve testing and data gathering for enhanced disease risk mapping and forecasting. Next generation sequencing will be key in identifying a wide range of pathogens, rather than a targeted approach.
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Affiliation(s)
- Katie A. Rodarte
- Genomics and Bioanalytics, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Jeanne M. Fair
- Genomics and Bioanalytics, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Bernard K. Bett
- International Livestock Research Institute and ILRI/BMZ One Health Research, Education, Outreach and Awareness Centre, Nairobi, Kenya
| | - Susan D. Kerfua
- National Livestock Resources Research Institute, National Agricultural Research Organization, Kampala, Uganda
| | - Folorunso O. Fasina
- Emergency Centre for Transboundary Animal Diseases, Food and Agriculture Organization of the United Nations, Nairobi, Kenya
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South Africa
| | - Andrew W. Bartlow
- Genomics and Bioanalytics, Los Alamos National Laboratory, Los Alamos, NM, United States
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Okwasiimire R, Flint JF, Kayaga EB, Lakin S, Pierce J, Barrette RW, Faburay B, Ndoboli D, Ekakoro JE, Wampande EM, Havas KA. Whole Genome Sequencing Shows that African Swine Fever Virus Genotype IX Is Still Circulating in Domestic Pigs in All Regions of Uganda. Pathogens 2023; 12:912. [PMID: 37513759 PMCID: PMC10386283 DOI: 10.3390/pathogens12070912] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 07/30/2023] Open
Abstract
Blood samples were collected from pigs at six abattoirs in the Kampala, Uganda metropolitan area from May 2021 through June 2022, and tested for African swine fever virus. Thirty-one samples with cycle threshold values < 26 from pigs with different geographic origins, clinical and pathologic signs, and Ornithodoros moubata exposure underwent whole genome sequencing. The p72 gene was used to genotype the isolates, and all were found to be genotype IX; whole genome sequences to previous genotype IX isolates confirmed their similarity. Six of the isolates had enough coverage to evaluate single nucleotide polymorphisms (SNPs). Five of the isolates differed from historic regional isolates, but had similar SNPs to one another, and the sixth isolate also differed from historic regional isolates, but also differed from the other five isolates, even though they are all genotype IX. Whole genome sequencing data provide additional detail on viral evolution that can be useful for molecular epidemiology, and understanding the impact of changes in genes to disease phenotypes, and may be needed for vaccine targeting should a commercial vaccine become available. More sequencing of African swine fever virus isolates is needed in Uganda to understand how and when the virus is changing.
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Affiliation(s)
- Rodney Okwasiimire
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala P.O. Box 7062, Uganda
| | - Joseph F Flint
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Edrine B Kayaga
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala P.O. Box 7062, Uganda
| | - Steven Lakin
- Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Services, United States Department of Agriculture, Greenport, NY 11957, USA
| | - Jim Pierce
- Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Services, United States Department of Agriculture, Greenport, NY 11957, USA
| | - Roger W Barrette
- Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Services, United States Department of Agriculture, Greenport, NY 11957, USA
| | - Bonto Faburay
- Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Services, United States Department of Agriculture, Greenport, NY 11957, USA
| | - Dickson Ndoboli
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala P.O. Box 7062, Uganda
| | - John E Ekakoro
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Eddie M Wampande
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala P.O. Box 7062, Uganda
| | - Karyn A Havas
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Koutsoumanis K, Allende A, Alvarez Ordoñez A, Bolton D, Bover‐Cid S, Chemaly M, Herman L, Hilbert F, Lindqvist R, Nauta M, Nonno R, Peixe L, Skandamis P, Suffredini E, Fernandez Escamez P, Gonzales‐Barron U, Roberts H, Ru G, Simmons M, Cruz RB, Lourenço Martins J, Messens W, Ortiz‐Pelaez A, Simon AC, De Cesare A. Assessment on the efficacy of methods 2 to 5 and method 7 set out in Commission Regulation (EU) No 142/2011 to inactivate relevant pathogens when producing processed animal protein of porcine origin intended to feed poultry and aquaculture animals. EFSA J 2023; 21:e08093. [PMID: 37416785 PMCID: PMC10320699 DOI: 10.2903/j.efsa.2023.8093] [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] [Indexed: 07/08/2023] Open
Abstract
An assessment was conducted on the level of inactivation of relevant pathogens that could be present in processed animal protein of porcine origin intended to feed poultry and aquaculture animals when methods 2 to 5 and method 7, as detailed in Regulation (EU) No 142/2011, are applied. Five approved scenarios were selected for method 7. Salmonella Senftenberg, Enterococcus faecalis, spores of Clostridium perfringens and parvoviruses were shortlisted as target indicators. Inactivation parameters for these indicators were extracted from extensive literature search and a recent EFSA scientific opinion. An adapted Bigelow model was fitted to retrieved data to estimate the probability that methods 2 to 5, in coincidental and consecutive modes, and the five scenarios of method 7 are able to achieve a 5 log10 and a 3 log10 reduction of bacterial indicators and parvoviruses, respectively. Spores of C. perfringens were the indicator with the lowest probability of achieving the target reduction by methods 2 to 5, in coincidental and consecutive mode, and by the five considered scenarios of method 7. An expert knowledge elicitation was conducted to estimate the certainty of achieving a 5 log10 reduction of spores of C. perfringens considering the results of the model and additional evidence. A 5 log10 reduction of C. perfringens spores was judged: 99-100% certain for methods 2 and 3 in coincidental mode; 98-100% certain for method 7 scenario 3; 80-99% certain for method 5 in coincidental mode; 66-100% certain for method 4 in coincidental mode and for method 7 scenarios 4 and 5; 25-75% certain for method 7 scenario 2; and 0-5% certain for method 7 scenario 1. Higher certainty is expected for methods 2 to 5 in consecutive mode compared to coincidental mode.
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Hakizimana JN, Yona C, Makange MR, Kasisi EA, Netherton CL, Nauwynck H, Misinzo G. Complete genome analysis of African swine fever virus genotypes II, IX and XV from domestic pigs in Tanzania. Sci Rep 2023; 13:5318. [PMID: 37002287 PMCID: PMC10066019 DOI: 10.1038/s41598-023-32625-1] [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: 01/23/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023] Open
Abstract
African swine fever (ASF) caused by ASF virus (ASFV) is an infectious transboundary animal disease notifiable to the World Organization for Animal Health causing high mortality in domestic pigs and wild boars threatening the global domestic pig industry. To date, twenty-four ASFV genotypes have been described and currently genotypes II, IX, X, XV and XVI are known to be circulating in Tanzania. Despite the endemic status of ASF in Tanzania, only one complete genome of ASFV from the country has been described. This study describes the first complete genome sequence of ASFV genotype XV. In addition, the first Tanzanian complete genome of ASFV genotype IX and three ASFV strains belonging to genotype II collected during ASF outbreaks in domestic pigs in Tanzania were determined in this study using Illumina sequencing and comparative genomics analysis. The generated ASFV complete genome sequences ranged from 171,004 to 184,521 base pairs in length with an average GC content of 38.53% and encoded 152 to 187 open reading frames. The results of this study provide insights into the genomic structure of ASFV and can be used to monitor changes within the ASFV genome and improve our understanding of ASF transmission dynamics.
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Affiliation(s)
- Jean N Hakizimana
- OR Tambo Africa Research Chair for Viral Epidemics, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania
| | - Clara Yona
- OR Tambo Africa Research Chair for Viral Epidemics, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania
- Department of Biosciences, Solomon Mahlangu College of Natural and Applied Sciences, Sokoine University of Agriculture, PO Box 3038, Morogoro, Tanzania
| | - Mariam R Makange
- OR Tambo Africa Research Chair for Viral Epidemics, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania
| | - Ester A Kasisi
- OR Tambo Africa Research Chair for Viral Epidemics, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania
| | - Christopher L Netherton
- African Swine Fever Vaccinology Group, The Pirbright Institute, Ash Road, Pirbright, Woking, GU24 0NF, Surrey, UK
| | - Hans Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Gerald Misinzo
- OR Tambo Africa Research Chair for Viral Epidemics, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania.
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, PO Box 3297, Morogoro, Tanzania.
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, PO Box 3019, Morogoro, Tanzania.
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An Updated Review of Ornithodoros Ticks as Reservoirs of African Swine Fever in Sub-Saharan Africa and Madagascar. Pathogens 2023; 12:pathogens12030469. [PMID: 36986391 PMCID: PMC10059854 DOI: 10.3390/pathogens12030469] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
This updated review provides an overview of the available information on Ornithodoros ticks as reservoirs and biological vectors of the ASF virus in Africa and Indian Ocean islands in order to update the current knowledge in this field, inclusive of an overview of available methods to investigate the presence of ticks in the natural environment and in domestic pig premises. In addition, it highlights the major areas of research that require attention in order to guide future investigations and fill knowledge gaps. The available information suggests that current knowledge is clearly insufficient to develop risk-based control and prevention strategies, which should be based on a sound understanding of genotype distribution and the potential for spillover from the source population. Studies on tick biology in the natural and domestic cycle, including genetics and systematics, represent another important knowledge gap. Considering the rapidly changing dynamics affecting the African continent (demographic growth, agricultural expansion, habitat transformation), anthropogenic factors influencing tick population distribution and ASF virus (ASFV) evolution in Africa are anticipated and have been recorded in southern Africa. This dynamic context, together with the current global trends of ASFV dissemination, highlights the need to prioritize further investigation on the acarological aspects linked with ASF ecology and evolution.
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9
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Okwasiimire R, Nassali A, Ndoboli D, Ekakoro JE, Faburay B, Wampande E, Havas KA. Comparison of diaphragm meat juice and muscle swab samples to spleen and spleen swab samples for the detection of African swine fever viral nucleic acid. J Vet Diagn Invest 2023; 35:145-152. [PMID: 36694917 PMCID: PMC9999393 DOI: 10.1177/10406387231151663] [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] [Indexed: 01/26/2023] Open
Abstract
Use of meat juice and muscle swabs at slaughterhouses may provide an easy-to-collect sample for African swine fever (ASF) surveillance. Meat juice has been experimentally shown to be a reliable sample for the detection of ASF virus (ASFV). We compared the detection of ASFV nucleic acid from diaphragm meat juice, diaphragm muscle swab, spleen, and spleen swabs from pigs with signs of ASFV infection at slaughterhouses around Kampala, Uganda. Pigs with ≥2 clinical or pathology signs at the time of slaughter had a spleen sample, spleen swab, diaphragm muscle sample, and diaphragm muscle swab collected. Meat juice was collected from muscle samples through a freeze-thaw cycle. Each sample was tested individually, and 72 spleen, meat juice, and muscle swab sample pools of 4 negative and 1 positive sample were tested, as well. Standard operating procedures from the USDA-Foreign Animal Disease Diagnostic Laboratory for viral DNA extraction and real-time PCR (rtPCR) were used. Of the 493 pigs evaluated, we classified as positive 357 (72.4%) diaphragm meat juice samples, 218 (44.2%) diaphragm muscle swabs, 247 (50.1%) spleen samples, and 241 (48.9%) spleen swabs. All spleen sample pools were positive (72 of 72; 100%), as were 71 of 72 (98.6%) meat juice pools and 67 of 72 (93.1%) muscle swab pools. Meat juice samples provided a reliable sample type for the detection by rtPCR of ASFV in pigs with natural infections.
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Affiliation(s)
- Rodney Okwasiimire
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Aisha Nassali
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Dickson Ndoboli
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - John E. Ekakoro
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Bonto Faburay
- Foreign Animal Disease Diagnostic Laboratory, Veterinary Services, Animal and Plant Health Inspection Services, U.S. Department of Agriculture, Greenport, NY, USA
| | - Edward Wampande
- Central Diagnostic Laboratory, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Karyn A. Havas
- Pipestone Research, Pipestone Holdings, Pipestone, MN, USA
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Giammarioli M, Alessandro D, Cammà C, Masoero L, Torresi C, Marcacci M, Zoppi S, Curini V, Rinaldi A, Rossi E, Casciari C, Pela M, Pellegrini C, Iscaro C, Feliziani F. Molecular Characterization of the First African Swine Fever Virus Genotype II Strains Identified from Mainland Italy, 2022. Pathogens 2023; 12:pathogens12030372. [PMID: 36986294 PMCID: PMC10055901 DOI: 10.3390/pathogens12030372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 03/30/2023] Open
Abstract
African swine fever (ASF) is responsible for important socio-economic effects in the global pig industry, especially for countries with large-scale piggery sectors. In January 2022, the African swine fever virus (ASFV) genotype II was identified in a wild boar population in mainland Italy (Piedmont region). This study describes the molecular characterization, by Sanger and next-generation sequencing (NGS), of the first index case 632/AL/2022 and of another isolate (2802/AL/2022) reported in the same month, in close proximity to the first, following multiple ASF outbreaks. Phylogenetic analysis based on the B646L gene and NGS clustered the isolates 632/AL/2022 and 2802/AL/2022 within the wide and most homogeneous p72 genotype II that includes viruses from European and Asian countries. The consensus sequence obtained from the ASFV 2802/AL/2022 isolate was 190,598 nucleotides in length and had a mean GC content of 38.38%. At the whole-genome level, ASF isolate 2802/AL/2022 showed a close genetic correlation with the other representative ASFV genotype II strains isolated between April 2007 and January 2022 from wild and domestic pigs in Eastern/Central European (EU) and Asian countries. CVR subtyping clustered the two Italian ASFV strains within the major CVR variant circulating since the first virus introduction in Georgia in 2007. Intergenic region I73R-I329L subtyping placed the Italian ASFV isolates within the variant identical to the strains frequently identified among wild boars and domestic pigs. Presently, given the high sequence similarity, it is impossible to trace the precise geographic origin of the virus at a country level. Moreover, the full-length sequences available in the NCBI are not completely representative of all affected territories.
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Affiliation(s)
- Monica Giammarioli
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Dondo Alessandro
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, 10154 Torino, Italy
| | - Cesare Cammà
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Campo Boario, 64100 Teramo, Italy
| | - Loretta Masoero
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, 10154 Torino, Italy
| | - Claudia Torresi
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Maurilia Marcacci
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Campo Boario, 64100 Teramo, Italy
| | - Simona Zoppi
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, 10154 Torino, Italy
| | - Valentina Curini
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Campo Boario, 64100 Teramo, Italy
| | - Antonio Rinaldi
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Campo Boario, 64100 Teramo, Italy
| | - Elisabetta Rossi
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Cristina Casciari
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Michela Pela
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Claudia Pellegrini
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Carmen Iscaro
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
| | - Francesco Feliziani
- Istituto Zooprofilattico Sperimentale Umbria e Marche "Togo Rosati", 06126 Perugia, Italy
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11
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Gallardo C, Casado N, Soler A, Djadjovski I, Krivko L, Madueño E, Nieto R, Perez C, Simon A, Ivanova E, Donescu D, Milicevik V, Chondrokouki E, Nurmoja I, Frant M, Feliziani F, Václavek P, Pileviciene S, Marisa A. A multi gene-approach genotyping method identifies 24 genetic clusters within the genotype II-European African swine fever viruses circulating from 2007 to 2022. Front Vet Sci 2023; 10:1112850. [PMID: 36761884 PMCID: PMC9905734 DOI: 10.3389/fvets.2023.1112850] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/06/2023] [Indexed: 01/26/2023] Open
Abstract
Introduction African swine fever (ASF) is a contagious viral disease of pigs and wild boar that poses a major threat to the global swine industry. The genotype II African swine fever virus (ASFV) entered the European Union (EU) in 2014 and since then fourteen countries have been affected, Italy and North Macedonia being the last in 2022. While whole genome sequencing remains the gold standard for the identification of new genetic markers, sequencing of multiple loci with significant variations could be used as a rapid and cost-effective alternative to track outbreaks and study disease evolution in endemic areas. Materials and methods To further our understanding of the epidemiology and spread of ASFV in Europe, 382 isolates collected during 2007 to 2022 were sequenced. The study was initially performed by sequencing the central variable region (CVR), the intergenic region (IGR) between the I73R and I329L genes and the O174L and K145R genes. For further discrimination, two new PCRs were designed to amplify the IGR between the 9R and 10R genes of the multigene family 505 (MGF505) and the IGR between the I329L and I215L genes. The sequences obtained were compared with genotype II isolates from Europe and Asia. Results The combination of the results obtained by sequencing these variable regions allowed to differentiate the European II-ASFV genotypes into 24 different groups. In addition, the SNP identified in the IGR I329L-I215L region, not previously described, grouped the viruses from North Macedonia that caused the 2022 outbreaks with viruses from Romania, Bulgaria, Serbia and Greece, differentiating from other genotype II isolates present in Europe and Asia. Furthermore, tandem repeat sequence (TRS) within the 9R-10R genes of the multigene family 505 (MGF505) revealed eight different variants circulating. Discussion These findings describe a new multi-gene approach sequencing method that can be used in routine genotyping to determine the origin of new introductions in ASF-free areas and track infection dynamics in endemic areas.
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Affiliation(s)
- Carmina Gallardo
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain,*Correspondence: Carmina Gallardo ✉
| | - Nadia Casado
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Alejandro Soler
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Igor Djadjovski
- 2Faculty of Veterinary Medicine, University Ss. Cyril and Methodius in Skopje, Skopje, North Macedonia
| | - Laura Krivko
- 3Latvia NRL: Laboratory of Microbiology and Pathology, Institute of Food Safety, Animal Health and Enviroment, BIOR, Riga, Latvia
| | - Encarnación Madueño
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Raquel Nieto
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Covadonga Perez
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Alicia Simon
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
| | - Emiliya Ivanova
- 4Bulgaria NRL: National Diagnostic and Research Veterinary Medical Institute (NDVRI), Sofia, Bulgaria
| | - Daniel Donescu
- 5Romania NRL: Institute for Diagnostic and Animal Health, Bucharest, Romania
| | - Vesna Milicevik
- 6Republic of Serbia NRL: Institute of Veterinary Medicine of Serbia, Belgrade, Serbia
| | - Eleni Chondrokouki
- 7Greece NRL: Greek Ministry of Rural Development and Food FMD, Virological, Rickettsial & Exotic Diseases, Athens, Greece
| | - Imbi Nurmoja
- 8Estonian NRL: National Centre for Laboratory Research and Risk Assessment (LABRIS), Tartu, Estonia
| | - Maciej Frant
- 9Poland NRL: National Veterinary Research Institute, Puławy, Poland
| | - Francesco Feliziani
- 10Italy NRL: Istituto Zooprofilattico Sperimentale (IZS) dell'Umbria e delle Marche, Perugia, Italy
| | - Petr Václavek
- 11Czech Republic NRL: State Veterinary Institute Jihlava, Jihlava, Czechia
| | - Simona Pileviciene
- 12Lithuania NRL: National Food and Veterinary Risk Assessment Institute (NFVRAI), Vilnius, Lithuania
| | - Arias Marisa
- 1European Union Reference Laboratory for ASF (EURL-ASF): Centro De investigación en Sanidad Animal (CISA-INIA, CSIC), Madrid, Spain
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12
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Evidence indicating transmission of porcine parvovirus 1 between warthogs and domestic pigs in Namibia. Vet Res Commun 2022; 47:981-985. [DOI: 10.1007/s11259-022-10038-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/10/2022] [Indexed: 12/14/2022]
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13
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Omelchenko H, Avramenko NO, Petrenko MO, Wojciechowski J, Pejsak Z, Woźniakowski G. Ten Years of African Swine Fever in Ukraine: An Endemic Form of the Disease in the Wild Boar Population as a Threat to Domestic Pig Production. Pathogens 2022; 11:pathogens11121459. [PMID: 36558794 PMCID: PMC9788585 DOI: 10.3390/pathogens11121459] [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: 11/04/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
(1) Background: African swine fever (ASF) has been present in Ukraine for more than ten years (2012-2022). The purpose of our study was to perform a retrospective analysis of the spread of ASF to assess the role of wild boar in the epizootic expansion in Ukraine. (2) Methods: Statistical materials were collected and the epizootic situation of ASF from 2012 to 2022 was examined. The potential sources of the African swine fever virus (ASFV) and transmission factors were analysed. The main factors exerting negative impacts on domestic pig production were also analysed. (3) Results: Consequently, from the results of the retrospective analysis of ASF outbreaks in Ukraine, the probability ratio of ASF outbreaks in the wild boar and domestic pig populations was determined. The data show a direct relationship between ASF outbreaks among wild boar and domestic pigs with the observed decay of wild boar outbreaks across the entire territory of Ukraine. At the same time, an increase in the number of wild boars has been observed in the Mykolaiv region, with a parallel spillover of outbreaks in domestic pigs. (4) Conclusions: The epidemiological situation observed for ASF in the wild boar population may suggest an endemic form of the disease. This may further complicate eradication programs and the protection of domestic pig farms from ASF outbreaks. An additional and major reason to control the ASF epizootic is the continuing military Russian offensive in Ukraine.
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Affiliation(s)
- Hanna Omelchenko
- Department of Normal and Pathological Anatomy and Physiology of Animals, Poltava State Agrarian University, 36-0036 Poltava, Ukraine
| | - Natalia O. Avramenko
- Department of Normal and Pathological Anatomy and Physiology of Animals, Poltava State Agrarian University, 36-0036 Poltava, Ukraine
| | - Maksym O. Petrenko
- Department of Normal and Pathological Anatomy and Physiology of Animals, Poltava State Agrarian University, 36-0036 Poltava, Ukraine
| | | | - Zygmunt Pejsak
- Department of Infectious and Parasitic Diseases, The University Centre of Veterinary Medicine JU-AU, 31-120 Krakow, Poland
| | - Grzegorz Woźniakowski
- Department of Infectious and Invasive Diseases and Veterinary Administration, Institute of Veterinary Medicine, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, 87-100 Toruń, Poland
- Correspondence:
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14
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Penrith ML, Van Heerden J, Heath L, Abworo EO, Bastos ADS. Review of the Pig-Adapted African Swine Fever Viruses in and Outside Africa. Pathogens 2022; 11:pathogens11101190. [PMID: 36297247 PMCID: PMC9609104 DOI: 10.3390/pathogens11101190] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/08/2022] [Accepted: 10/11/2022] [Indexed: 12/04/2022] Open
Abstract
The region in eastern, central and southern Africa (ECSA) where African swine fever (ASF) originated in a sylvatic cycle is home to all the p72 genotypes of ASF virus identified so far. While 20 of the 24 genotypes have been isolated from outbreaks in domestic pigs in the region, only five of the genotypes (I, II, VIII, IX, X) have an extended field presence associated with domestic pigs. Of the genotypes that appear to be strongly adapted to domestic pigs, two have spread beyond the African continent and have been the focus of efforts to develop vaccines against ASF. Most of the experimental ASF vaccines described do not protect against a wider spectrum of viruses and may be less useful in the event of incursions of different strains or where multiple genotypes co-exist. The other three pig-adapted strains that are currently restricted to the ECSA region might spread, and priority should be given to understanding not only the genetic and antigenic characteristics of these viruses but also their history. We review historic and current knowledge of the distribution of these five virus genotypes, and note that as was the case for genotype II, some pig-associated viruses have the propensity for geographical range expansion. These features are valuable for prioritizing vaccine-development efforts to ensure a swift response to virus escape. However, whilst ASF vaccines are critical for high-production systems, global food security relies on parallel efforts to improve biosecurity and pig production in Africa and on continued ASFV surveillance and characterisation in the ECSA region.
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Affiliation(s)
- Mary-Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria 0110, South Africa
- Correspondence: or
| | - Juanita Van Heerden
- Transboundary Animal Diseases, Onderstepoort Veterinary Research, Agricultural Research Council, Pretoria 0110, South Africa
| | - Livio Heath
- Transboundary Animal Diseases, Onderstepoort Veterinary Research, Agricultural Research Council, Pretoria 0110, South Africa
| | - Edward Okoth Abworo
- Biosciences, Animal and Human Health Program, International Livestock Research Institute (ILRI), Nairobi 00100, Kenya
| | - Armanda D. S. Bastos
- Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0028, South Africa
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15
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Molini U, Franzo G, Settypalli TBK, Hemberger MY, Khaiseb S, Cattoli G, Dundon WG, Lamien CE. Viral Co-Infections of Warthogs in Namibia with African Swine Fever Virus and Porcine Parvovirus 1. Animals (Basel) 2022; 12:ani12131697. [PMID: 35804594 PMCID: PMC9265065 DOI: 10.3390/ani12131697] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Wild animals can transmit diseases to domestic animals. In Africa, warthogs are known to be carriers of pathogens that can infect pigs; consequently, it is important to identify these pathogens in order to protect pigs from infection. In this study, two important swine pathogens i.e., African swine fever virus (ASFV) and porcine parvovirus 1 (PPV1) were identified in warthogs in Namibia and characterized genetically. The results will be of interest to those working in swine disease management and control in Namibia. Abstract Understanding virus circulation in wild animals, particularly those that have contact with domestic animals, is crucial for disease management and control. In Africa, warthogs are known to be asymptomatic carriers of porcine pathogens; a recent study in Namibia has shown them to be positive for Porcine circovirus-2 (PCV-2). In this study, the same samples used for the PCV-2 investigation in Namibia were further screened for the presence of African swine fever virus (ASFV) and porcine parvovirus 1 (PPV1) by PCR. Of the 42 animals tested, 2 (4.8%) and 13 (31%) were positive for AFSV and PPV1, respectively. The two AFSV were also co-infected with PPV1. Combing the results of this study with the results of the previous PCV-2 investigation, four warthogs were shown to be co-infected with both PPV1 and PCV-2. Sequence and phylogenetic analysis revealed that the AFSV belonged to genotype (Ib) but were from different serogroups. Unexpectedly, the ASFVs from the warthogs were genetically distinct to those observed in an outbreak in the same region of Namibia that occurred less than fifteen months prior to the sampling of the warthogs. In fact, a stronger genetic relationship was observed between the warthog viruses and historical Namibian and South African ASFVs identified in 1980, 2004 and 2008. For the PPV1s, the closest relative to the Namibian PPV1 were viruses identified in wild boar in Romania in 2011. This study confirms that warthogs are carriers of porcine pathogens and the data should encourage further studies on larger populations of wild and domestic swine to more fully understand the epidemiology and transmission of viral pathogens from these species.
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Affiliation(s)
- Umberto Molini
- School of Veterinary Medicine, Faculty of Health Sciences and Veterinary Medicine, University of Namibia, Neudamm Campus, Private Bag 13301, Windhoek 9000, Namibia; (U.M.); (M.Y.H.)
- Central Veterinary Laboratory (CVL), 24 Goethe Street, Private Bag 18137, Windhoek 9000, Namibia;
| | - Giovanni Franzo
- Department of Animal Medicine, Production and Health, University of Padova, Viale dell’Università 16, 35020 Legnaro, Italy;
| | - Tirumala B. K. Settypalli
- Animal Production and Health Laboratory, Animal Production and Health Section, Joint FAO/IAEA Division, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, P.O. Box 100, 1400 Vienna, Austria; (T.B.K.S.); (G.C.); (C.E.L.)
| | - Maria Y. Hemberger
- School of Veterinary Medicine, Faculty of Health Sciences and Veterinary Medicine, University of Namibia, Neudamm Campus, Private Bag 13301, Windhoek 9000, Namibia; (U.M.); (M.Y.H.)
| | - Siegfried Khaiseb
- Central Veterinary Laboratory (CVL), 24 Goethe Street, Private Bag 18137, Windhoek 9000, Namibia;
| | - Giovanni Cattoli
- Animal Production and Health Laboratory, Animal Production and Health Section, Joint FAO/IAEA Division, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, P.O. Box 100, 1400 Vienna, Austria; (T.B.K.S.); (G.C.); (C.E.L.)
| | - William G. Dundon
- Animal Production and Health Laboratory, Animal Production and Health Section, Joint FAO/IAEA Division, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, P.O. Box 100, 1400 Vienna, Austria; (T.B.K.S.); (G.C.); (C.E.L.)
- Correspondence:
| | - Charles E. Lamien
- Animal Production and Health Laboratory, Animal Production and Health Section, Joint FAO/IAEA Division, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, P.O. Box 100, 1400 Vienna, Austria; (T.B.K.S.); (G.C.); (C.E.L.)
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16
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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: 5] [Impact Index Per Article: 1.7] [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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Rajkhowa TK, Kiran J, Hauhnar L, Zodinpui D, Paul A, Sagolsem S. Molecular detection and characterization of African swine fever virus from field outbreaks in domestic pigs, Mizoram, India. Transbound Emerg Dis 2021; 69:e1028-e1036. [PMID: 34743424 DOI: 10.1111/tbed.14384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/28/2021] [Accepted: 11/02/2021] [Indexed: 11/28/2022]
Abstract
African swine fever (ASF) is a devastating haemorrhagic disease of domestic pigs, which can cause mortality up to 100%. Sudden mortality in pigs following an acute course of systemic disease was investigated in Mizoram state of India and confirmed the outbreak as ASF. Affected pigs suffered from severe depression, high fever, bloody diarrhoea, cutaneous haemorrhages and showed haemorrhagic lesions in visceral organs. The outbreak was confirmed by detection of p72, p54 and the central variable region of B602L genes by PCR in representative tissue samples collected from dead pigs. The nucleotide and phylogenetic analyses of p72, p54 and B602L characterized the ASFV as genotype II. Interestingly, the analysis of B602L gene has revealed that the ASFV from Mizoram state of India is more closely linked to the Eurasian ASFV strains isolated prior to 2014 and discriminated the Indian strains in two separate groups indicating that the source of origin for the Mizoram outbreak could be different from that of the other states of India.
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Affiliation(s)
- Tridib Kumar Rajkhowa
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - J Kiran
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - Lalthapui Hauhnar
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - Doris Zodinpui
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - Amitava Paul
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - Sheityabati Sagolsem
- Department of Veterinary Pathology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
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18
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Machuka EM, Muigai AWT, Amimo JO, Domelevo Entfellner JB, Lekolool I, Abworo EO, Pelle R. Comparative Analysis of SLA-1, SLA-2, and DQB1 Genetic Diversity in Locally-Adapted Kenyan Pigs and Their Wild Relatives, Warthogs. Vet Sci 2021; 8:180. [PMID: 34564574 PMCID: PMC8473215 DOI: 10.3390/vetsci8090180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/25/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022] Open
Abstract
Swine leukocyte antigen (SLA) plays a central role in controlling the immune response by discriminating self and foreign antigens and initiating an immune response. Studies on SLA polymorphism have demonstrated associations between SLA allelic variants, immune response, and disease resistance. The SLA polymorphism is due to host-pathogen co-evolution resulting in improved adaptation to diverse environments making SLA a crucial genomic region for comparative diversity studies. Although locally-adapted African pigs have small body sizes, they possess increased resilience under harsh environmental conditions and robust immune systems with reported tolerance to some diseases, including African swine fever. However, data on the SLA diversity in these pigs are not available. We characterized the SLA of unrelated locally-adapted domestic pigs from Homa Bay, Kenya, alongside exotic pigs and warthogs. We undertook SLA comparative diversity of the functionally expressed SLA class I (SLA-1, SLA-2) and II (DQB1) repertoires in these three suids using the reverse transcription polymerase chain reaction (RT-PCR) sequence-based typing (SBT) method. Our data revealed higher genetic diversity in the locally-adapted pigs and warthogs compared to the exotic pigs. The nucleotide substitution rates were higher in the peptide-binding regions of the SLA-1, SLA-2, and DQB1 loci, indicative of adaptive evolution. We obtained high allele frequencies in the three SLA loci, including some breed-specific private alleles, which could guide breeders to increase their frequency through selection if confirmed to be associated with enhanced resilience. Our study contributes to the growing body of knowledge on genetic diversity in free-ranging animal populations in their natural environment, availing the first DQB1 gene data from locally-adapted Kenyan pigs.
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Affiliation(s)
- Eunice Magoma Machuka
- Biosciences Eastern and Central Africa, International Livestock Research Institute (BecA-ILRI) Hub, Nairobi P.O. Box 30709-00100, Kenya;
- Institute for Basic Sciences Technology and Innovation (PAUSTI), Pan African University, Nairobi P.O. Box 62000-00200, Kenya
| | - Anne W. Thairu Muigai
- Botany Department, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya;
| | - Joshua Oluoch Amimo
- Center for Food Animal Health, Department of Animal Sciences, 1680 Madison Avenue, The Ohio State University, Wooster, OH 44691, USA;
| | - Jean-Baka Domelevo Entfellner
- Biosciences Eastern and Central Africa, International Livestock Research Institute (BecA-ILRI) Hub, Nairobi P.O. Box 30709-00100, Kenya;
| | - Isaac Lekolool
- Kenya Wildlife Services, Nairobi P.O. Box 40241-00100, Kenya;
| | - Edward Okoth Abworo
- Animal and Human Health Program, International Livestock Research Institute, Nairobi P.O. Box 30709-00100, Kenya;
| | - Roger Pelle
- Biosciences Eastern and Central Africa, International Livestock Research Institute (BecA-ILRI) Hub, Nairobi P.O. Box 30709-00100, Kenya;
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19
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ANTIBODY PREVALENCE TO AFRICAN SWINE FEVER VIRUS, MYCOBACTERIUM BOVIS, FOOT-AND-MOUTH DISEASE VIRUS, RIFT VALLEY FEVER VIRUS, INFLUENZA A VIRUS, AND BRUCELLA AND LEPTOSPIRA SPP. IN FREE-RANGING WARTHOG (PHACOCHOERUS AFRICANUS) POPULATIONS IN SOUTH AFRICA. J Wildl Dis 2021; 57:60-70. [PMID: 33635986 DOI: 10.7589/jwd-d-20-00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/28/2020] [Indexed: 11/20/2022]
Abstract
The warthog (Phacochoerus africanus) can be used as a model for investigating disease transmission at the human, wildlife, and livestock interface. An omnivore and scavenger, a warthog moves freely between natural ecotypes, farmland, and human communities and is susceptible to diseases of zoonotic, agricultural, and conservation concern. A retrospective study using 100 individual serum samples collected from May 1999 to August 2016 was performed to determine antibody prevalence to seven pathogens in warthogs from five locations in northeastern South Africa. Higher prevalence of antibodies to African swine fever virus and Mycobacterium bovis were detected in warthogs from the Greater Kruger National Park ecosystem in comparison to lower prevalence of antibodies to M. bovis and no antibodies to African swine fever virus in warthogs from uMhkuze Game Reserve. Low prevalence of antibodies to foot-and-mouth disease virus, Rift Valley fever virus, and influenza A virus was detected in all locations, and no antibodies against Brucella and Leptospira spp. were detected. No statistically significant difference in antibody prevalence was found between sexes for any disease. At the univariate analysis, M. bovis seropositivity was significantly different among age categories, with 49% (35/71) of adults found positive versus 29% (4/14) of juveniles and 9% (1/11) of sub-adults (Fisher's exact test, P=0.020), and between the sampling locations (Fisher's exact test, P=0.001). The multivariate model results indicated that juvenile warthogs had lower odds of testing positive to M. bovis antibodies than adults (juveniles' odds ratio [OR]=0.17, 95% confidence interval [CI]: 0.02-1.0), although this result was not statistically significant at the 5% level (P=0.052). For warthogs sampled at Satara Buffalo Camp, the odds (OR=0.22, 95% CI: 0.035-0.96) of being M. bovis antibody positive were significantly lower (P=0.043) than for warthogs sampled at Skukuza. Of particular interest in this study was the detection of warthogs seropositive for influenza A virus.
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20
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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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21
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Wang F, Zhang H, Hou L, Yang C, Wen Y. Advance of African swine fever virus in recent years. Res Vet Sci 2021; 136:535-539. [PMID: 33882382 DOI: 10.1016/j.rvsc.2021.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022]
Abstract
African swine fever (ASF) is one of the most devastating hemorrhagic infectious diseases that affect pigs and wild suids due to the lack of a vaccine or an effective treatment. The large dsDNA genome of African swine fever virus (ASFV) contains up to 167 ORFs that are predicted to encode proteins. Since its introduction to China in 2018, this genome has aroused the enthusiasm of researchers throughout the world. Here, we review the research progress on ASFV in recent years. Given the importance of this disease, this review will highlight recent discoveries in basic virology, focusing mainly on epidemiology, virulence, pathogenic mechanisms, diagnosis, vaccine development, and treatment; this will help in understanding virus-host interactions and disease prevention regarding ASFV.
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Affiliation(s)
- Fengxue Wang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China.
| | - He Zhang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Lina Hou
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Chao Yang
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
| | - Yongjun Wen
- College of Veterinary Medicine, Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases at the Ministry of Agriculture, Inner Mongolia Agricultural University, Inner Mongolia Autonomous Region, Huhhot 010018, People's Republic of China
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22
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Bisimwa PN, Ishara LK, Wasso DS, Bantuzeko F, Tonui R, Bwihangane AB. Detection and genetic characterization of African swine fever virus (ASFV) in clinically infected pigs in two districts in South Kivu province, Democratic Republic Congo. Heliyon 2021; 7:e06419. [PMID: 33732937 PMCID: PMC7938247 DOI: 10.1016/j.heliyon.2021.e06419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/05/2021] [Accepted: 03/01/2021] [Indexed: 11/13/2022] Open
Abstract
African swine fever (ASF) is a notifiable contagious disease caused by the African swine fever virus (ASFV), leading to a serious socio-economic impact, constraining pig industry, and affecting food security worldwide. This study aimed to detect and characterize ASFV strains from suspected infected domestic pigs in two South-Kivu province districts of the Democratic Republic of the Congo (DRC). A total of 155 pig samples were screened for viral DNA and sequencing at multiple loci. An infection rate of 5.2% (8/155) was recorded from a total of 155 blood samples with the highest ASFV infection rate of 8% for Uvira (6/75) and mostly in female pigs 5 (7.6%). Most ASF associated clinical signs were redness on the skin and snout at 49% (95% CI: 21–34), followed by the unwillingness of pigs to stand at 29 % (95%, CI: 19–35). Phylogenetic analysis of partial B646L (p72) and the full-length E183 (p54) gene sequences revealed the circulation of genotypes IX and X, which clustered with previously reported viruses in the same region, Uganda, Kenya, and Tanzania. Intragenotypic resolution of the CVR region clustered the viruses into two subgroups: the genotype X strain subgroup (10 repeats, AAAABNAABA) and the genotype IX strain subgroup (11 repeats, AAAAAAAAAAF). This finding provides additional evidence that genetically similar ASFV strains may be circulating within South Kivu province and highlights the need for improved coordination to prevent the spread of the disease in non-infected areas.
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Affiliation(s)
- Patrick N. Bisimwa
- Université Evangélique en Afrique, Department of Animal Science and Production, Biosciences Unit, Bukavu, Democratic Republic of the Congo
- Pan African University Institute of Basic Sciences, Technology and Innovation, Department of Molecular Biology and Biotechnology, Nairobi, Kenya
- Corresponding author.
| | - Lionel K. Ishara
- Université Evangélique en Afrique, Department of Animal Science and Production, Biosciences Unit, Bukavu, Democratic Republic of the Congo
| | - Dieudonné S. Wasso
- Université Evangélique en Afrique, Department of Animal Science and Production, Biosciences Unit, Bukavu, Democratic Republic of the Congo
| | - Fabrice Bantuzeko
- Université Evangélique en Afrique, Department of Animal Science and Production, Biosciences Unit, Bukavu, Democratic Republic of the Congo
| | - Ronald Tonui
- Pan African University Institute of Basic Sciences, Technology and Innovation, Department of Molecular Biology and Biotechnology, Nairobi, Kenya
| | - Ahadi B. Bwihangane
- Université Evangélique en Afrique, Department of Animal Science and Production, Biosciences Unit, Bukavu, Democratic Republic of the Congo
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23
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Hakizimana JN, Yona C, Kamana O, Nauwynck H, Misinzo G. African Swine Fever Virus Circulation between Tanzania and Neighboring Countries: A Systematic Review and Meta-Analysis. Viruses 2021; 13:v13020306. [PMID: 33672090 PMCID: PMC7919636 DOI: 10.3390/v13020306] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
For over 100 years after the description of the first case of African swine fever (ASF) in Kenya, ASF virus (ASFV) cross-border spread in eastern and southern Africa has not been fully investigated. In this manuscript, we reviewed systematically the available literature on molecular epidemiology of ASF in Tanzania and its eight neighboring countries in order to establish the transmission dynamics of ASFV between these countries. Data were retrieved from World Animal Health Information System (WAHIS), Google Scholar, PubMed, Scopus, and CrossRef databases, using the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and reviewed to document ASF outbreaks and ASFV genotypes distribution. Using phylogeographic approach applied to ASFV p72 sequence dataset, the evolutionary history and the dispersal pattern of the ASFV strains were assessed. From 2005 to 2019, a total of 1588 ASF outbreaks affecting 341,742 cases that led to 302,739 domestic pig deaths were reported. The case fatality rates (CFR) varied from 15.41% to 98.95% with an overall CFR of 88.58%. Fifteen different p72 ASFV genotypes were reported and the time to the most recent common ancestor (TMRCA) for ASFV strains dated back to 1652.233 (1626.473, 1667.735) with an evolutionary rate of 4.805 × 10−5 (2.5857 × 10−5, 9.7789 × 10−5). Phylogeographic dispersal analysis revealed several transboundary spread events of ASFV strains between these countries. These results suggest persistent circulation of ASFV in these countries and advocate for more research to improve our understanding of the transmission dynamics of the virus and for a regional approach to mitigate the spread of ASFV.
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Affiliation(s)
- Jean N. Hakizimana
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania;
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania
- Correspondence: (J.N.H.); (G.M.)
| | - Clara Yona
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania;
- Department of Biosciences, Solomon Mahlangu College of Science and Education, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania
| | - Olivier Kamana
- Department of Applied Research and Development and Foresight Incubation, National Industrial Research and Development Agency, P.O. Box 273 Kigali, Rwanda;
| | - Hans Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium;
| | - Gerald Misinzo
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania;
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019 Morogoro, Tanzania
- Correspondence: (J.N.H.); (G.M.)
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24
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Brookes VJ, Barrett TE, Ward MP, Roby JA, Hernandez-Jover M, Cross EM, Donnelly CM, Barnes TS, Wilson CS, Khalfan S. A scoping review of African swine fever virus spread between domestic and free-living pigs. Transbound Emerg Dis 2021; 68:2643-2656. [PMID: 33455062 DOI: 10.1111/tbed.13993] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/31/2022]
Abstract
Since 2007, African swine fever virus (ASFV) has spread to countries in Europe, Asia and Oceania and has caused devastating impacts on pigs and the pork industry. Transmission can be direct or indirect, and epidemiologic scenarios have been described in which spread occurs between free-living and domestic pigs. The purpose of this scoping review was to identify primary research in which authors made statements to support ASFV transmission between free-living and domestic pigs and assess the circumstances in which transmission events occurred. A search was conducted in five bibliographic databases and the grey literature. Two reviewers (from a team of ten) independently screened each record and charted data (demographics of the pig populations, their husbandry [domestic pigs] and habitat [free-living pigs], the spatial and temporal distribution of ASF, the occurrence or burden of ASF in the populations, and whether ticks were present in the geographic range of the pig populations). Data synthesis included statistics and a narrative summary. From 1,349 records screened, data were charted from 46 individual studies published from 1985 to 2020. Outbreak investigations revealed that whilst poor biosecurity of domestic pig operations was often reported, direct contact resulting in transmission between free-living and domestic pigs was rarely reported. Studies in which quantitative associations were made generally found that spread within populations was more important than spread between populations, although this was not always the case, particularly when domestic pigs were free-ranging. We conclude that there is limited evidence that transmission of ASFV between free-living and domestic pigs is an important feature of ASF epidemiology, especially in the current ASF epidemic in Europe and the Russian Federation. If ASFV elimination cannot be achieved in free-living pigs, compartmentalization of domestic pig populations from free-living populations via biosecurity strategies could be used to support trade of domestic pigs.
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Affiliation(s)
- Victoria J Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Tamille E Barrett
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Michael P Ward
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW, Australia
| | - Justin A Roby
- Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia.,School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Marta Hernandez-Jover
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Emily M Cross
- School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Camilla M Donnelly
- School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, Qld, Australia.,The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Gatton, Qld, Australia
| | - Cara S Wilson
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Shahid Khalfan
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
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25
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Bisimwa PN, Ongus JR, Steinaa L, Bisimwa EB, Bochere E, Machuka EM, Entfellner JBD, Okoth E, Pelle R. The first complete genome sequence of the African swine fever virus genotype X and serogroup 7 isolated in domestic pigs from the Democratic Republic of Congo. Virol J 2021; 18:23. [PMID: 33478547 PMCID: PMC7819171 DOI: 10.1186/s12985-021-01497-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/12/2021] [Indexed: 11/25/2022] Open
Abstract
Background African swine fever (ASF), a highly contagious hemorrhagic disease, affects domestic pigs in the Democratic Republic of Congo (DRC) where regular outbreaks are reported leading to high mortality rates approaching 100% in the affected regions. No study on the characteristics of the complete genome of strains responsible for ASF outbreaks in the South Kivu province of DRC is available, limited a better understanding of molecular evolution and spread of this virus within the country. The present study aimed at determining the complete genome sequence of ASFV strains genotype X involved in 2018–2019 ASF disease outbreaks in South Kivu province of DRC. Materials and methods Genomic DNA of a spleen sample from an ASFV genotype X-positive domestic pig in Uvira, during the 2018–2019 outbreaks in South Kivu, was sequenced using the Illumina HiSeq X platform. Obtained trimmed reads using Geneious Prime 2020.0.4 were blasted against a pig reference genome then contigs were generated from the unmapped reads enriched in ASFV DNA using Spades implemented in Geneious 2020.0.4. The assembly of the complete genome sequence of ASFV was achieved from the longest overlapping contigs. The new genome was annotated with the genome annotation transfer utility (GATU) software and the CLC Genomics Workbench 8 software was further used to search for any ORFs that failed to be identified by GATU. Subsequent analyses of the newly determined Uvira ASFV genotype X genome were done using BLAST for databases search, CLUSTAL W for multiple sequences alignments and MEGA X for phylogeny. Results 42 Gbp paired-end reads of 150 bp long were obtained containing about 0.1% of ASFV DNA. The assembled Uvira ASFV genome, termed Uvira B53, was 180,916 bp long that could be assembled in 2 contigs. The Uvira B53genome had a GC content of 38.5%, encoded 168 open reading frames (ORFs) and had 98.8% nucleotide identity with the reference ASFV genotype X Kenya 1950. The phylogenetic relationship with selected representative genomes clustered the Uvira B53 strain together with ASFV genotype X reported to date (Kenya 1950 and Ken05/Tk1). Multiple genome sequences comparison with the two reference ASFV genotype X strains showed that 130 of the 168 ORFs were fully conserved in the Uvira B53. The other 38 ORFs were divergent mainly due to SNPs and indels (deletions and insertions). Most of 46 multigene family (MGF) genes identified were affected by various genetic variations. However, 8 MGF ORFs present in Kenya 1950 and Ken05/Tk1 were absent from the Uvira B53 genome including three members of MGF 360, four of MGF 110 and one of MGF 100 while one MGF ORF (MGF 360-1L) at the left end of the genome was truncated in Uvira B53. Moreover, ORFs DP96R and p285L were also absent in the Uvira B53 genome. In contrast, the ORF MGF 110-5L present in Uvira B53 and Ken05/Tk1 was missing in Kenya 1950. The analysis of the intergenic region between the I73R and I329L genes also revealed sequence variations between the three genotype X strains mainly characterized by a deletion of 69 bp in Uvira B53 and 36 bp in Kenya 1950, compared to Ken05/Tk1. Assessment of the CD2v (EP402R) antigen unveiled the presence of SNPs and indels particularly in the PPPKPY tandem repeat region between selected variants representing the eight serogroups reported to date. Uvira B53 had identical CD2v variable region to the Uganda (KM609361) strain, the only other ASFV serogroup 7 reported to date. Conclusion We report the first complete genome sequence of an African swine fever virus (ASFV) p72 genotype X and CD2v serogroup 7, termed Uvira B53. This study provides additional insights on genetic characteristics and evolution of ASFV useful for tracing the geographical spread of ASF and essential for improved design of control and management strategies against ASF.
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Affiliation(s)
- Patrick N Bisimwa
- Institute of Basic Sciences, Technology and Innovation, Department of Molecular Biology and Biotechnology, Pan African University, Nairobi, Kenya. .,Department of Animal Science and Production, Université Evangélique en Afrique, P.O. Box 3323, Bukavu, Democratic Republic of Congo.
| | - Juliette R Ongus
- Institute of Basic Sciences, Technology and Innovation, Department of Molecular Biology and Biotechnology, Pan African University, Nairobi, Kenya.,Department of Medical Laboratory Sciences, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Lucilla Steinaa
- International Livestock Research Institute, Animal and Human Health, Nairobi, Kenya
| | - Espoir B Bisimwa
- Department of Animal Science and Production, Université Evangélique en Afrique, P.O. Box 3323, Bukavu, Democratic Republic of Congo
| | - Edwina Bochere
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100, 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
| | - Jean-Baka Domelevo Entfellner
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100, Kenya
| | - Edward Okoth
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, Naivasha Road, P.O. Box 30709, Nairobi, 00100, 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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26
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Hakizimana JN, Nyabongo L, Ntirandekura JB, Yona C, Ntakirutimana D, Kamana O, Nauwynck H, Misinzo G. Genetic Analysis of African Swine Fever Virus From the 2018 Outbreak in South-Eastern Burundi. Front Vet Sci 2020; 7:578474. [PMID: 33251264 PMCID: PMC7674587 DOI: 10.3389/fvets.2020.578474] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/01/2020] [Indexed: 11/24/2022] Open
Abstract
African swine fever (ASF) is a contagious viral disease that causes high mortality, approaching 100%, in domestic pigs and wild boars. The disease has neither a cure nor a vaccine, and it is caused by an ASF virus (ASFV), the only member of the family Asfarviridae, genus Asfivirus, and the only known DNA arbovirus. Twenty-four genotypes of ASFV have been described to date, and all of them have been described in Africa. ASF is endemic in Burundi, and several outbreaks have been reported in the country; the disease continues to economically impact on small-scale farmers. This study aimed at genetic characterization of ASFV that caused an ASF outbreak in the Rutana region, Burundi, in the year 2018. Tissue samples from domestic pigs that died as a result of a severe hemorrhagic disease were collected in order to confirm the disease using polymerase chain reaction (PCR) and to conduct partial genome sequencing. Nucleotide sequences were obtained for the B646L (p72) gene, the intergenic fragment between the I73R and I329L genes, and the central variable region (CVR) of the B602L gene. Phylogenetic analysis of the Burundian 2018 ASFV grouped the virus within B646L (p72) genotype X and clustered together with those reported during the 1984 and 1990 outbreaks in Burundi with high nucleotide identity to some ASFV strains previously reported in neighboring East African countries, indicating a regional distribution of this ASFV genotype. Analysis of the intergenic fragment between I73R and I329L genes showed that the Burundian 2018 ASFV described in this study lacked a 32–base pair (bp) fragment present in the reference genotype X strain, Kenya 1950. In addition, the strain described in this study had the signature AAABNAABA at the CVR (B602L) gene and showed 100% amino acid sequence identity to viruses responsible for recent ASF outbreaks in the region. The virus described in this study showed high genetic similarities with ASFV strains previously described in domestic pigs, wild suids, and soft ticks in East African countries, indicating a possible common wild source and continuous circulation in domestic pigs in the region.
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Affiliation(s)
- Jean N Hakizimana
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Lionel Nyabongo
- National Veterinary Laboratory of Burundi, Bujumbura, Burundi
| | - Jean B Ntirandekura
- Department of Animal Health and Productions, University of Burundi, Bujumbura, Burundi
| | - Clara Yona
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Biosciences, Solomon Mahlangu College of Science and Education, Sokoine University of Agriculture, Morogoro, Tanzania
| | | | - Olivier Kamana
- Department of Food Science and Technology, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Busogo, Rwanda.,Department of Applied Research and Development and Foresight Incubation, National Industrial Research and Development Agency, Kigali, Rwanda
| | - Hans Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Gerald Misinzo
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
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Wang T, Sun Y, Huang S, Qiu HJ. Multifaceted Immune Responses to African Swine Fever Virus: Implications for Vaccine Development. Vet Microbiol 2020; 249:108832. [PMID: 32932135 DOI: 10.1016/j.vetmic.2020.108832] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/23/2020] [Indexed: 12/13/2022]
Abstract
African swine fever (ASF) is a highly contagious, often fatal viral disease caused by African swine fever virus (ASFV), leading to high fever, severe hemorrhages with high lethality in domestic pigs and wild boar. In 2007, ASF was reintroduced into Europe. Since then, ASF has spread to many European and Asian countries and now becomes a major concern to the swine industry worldwide. There have been various vaccine attempts, but no commercial ASF vaccines are available so far. A key hurdle in developing a safe and efficacious ASF vaccine is the limited understanding of innate and adaptive immune responses elicited by ASFV infection. Though several promising vaccine candidates have been described, more key scientific challenges remain unsolved. Here, we provide an overview of the current knowledge in innate and adaptive immune responses elicited by ASFV infection and different kinds of vaccine candidates. Additionally, the applications and prospects of vaccine candidates are discussed. Finally, we highlight the implications of these mechanisms for rational design of ASF vaccines.
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Affiliation(s)
- Tao Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Yuan Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Shujian Huang
- School of Life Engineering, Foshan University, Foshan 528231, China
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; School of Life Engineering, Foshan University, Foshan 528231, China.
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28
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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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Hakizimana JN, Kamwendo G, Chulu JLC, Kamana O, Nauwynck HJ, Misinzo G. Genetic profile of African swine fever virus responsible for the 2019 outbreak in northern Malawi. BMC Vet Res 2020; 16:316. [PMID: 32859205 PMCID: PMC7455991 DOI: 10.1186/s12917-020-02536-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/23/2020] [Indexed: 11/10/2022] Open
Abstract
Background African swine fever (ASF) is an infectious transboundary animal disease which causes high mortality, approaching 100% in domestic pigs and it is currently considered as the most serious constraint to domestic pig industry and food security globally. Despite regular ASF outbreaks within Malawi, few studies have genetically characterized the causative ASF virus (ASFV). This study aimed at genetic characterization of ASFV responsible for the 2019 outbreak in northern Malawi. The disease confirmation was done by polymerase chain reaction (PCR) followed by molecular characterization of the causative ASFV by partial genome sequencing and phylogenetic reconstruction of the B646L (p72) gene, nucleotide alignment of the intergenic region (IGR) between I73R and I329L genes and translation of the central variable region (CVR) coded by B602L gene. Results All thirteen samples collected during this study in Karonga district in September 2019 were ASFV-positive and after partial genome sequencing and phylogenetic reconstruction of the B646L (p72) gene, the viruses clustered into ASFV p72 genotype II. The viruses characterized in this study lacked a GAATATATAG fragment between the I173R and the I329L genes and were classified as IGR I variants. Furthermore, the tetrameric amino acid repeats within the CVR of the B602L gene of the 2019 Malawian ASFV reported in this study had the signature BNDBNDBNAA, 100% similar to ASFV responsible for the 2013 and 2017 ASF outbreaks in Zambia and Tanzania, respectively. Conclusions The results of this study confirm an ASF outbreak in Karonga district in northern Malawi in September 2019. The virus was closely related to other p72 genotype II ASFV that caused outbreaks in neighboring eastern and southern African countries, emphasizing the possible regional transboundary transmission of this ASFV genotype. These findings call for a concerted regional and international effort to control the spread of ASF in order to improve nutritional and food security.
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Affiliation(s)
- J N Hakizimana
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - G Kamwendo
- Department of Animal Health and Livestock Development, Ministry of Agriculture, Irrigation and Water Development, Lilongwe, Malawi
| | - J L C Chulu
- Department of Animal Health and Livestock Development, Ministry of Agriculture, Irrigation and Water Development, Lilongwe, Malawi
| | - O Kamana
- Department of Food Science and Technology, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Busogo, Rwanda.,Department of Applied Research and Development and Foresight Incubation, National Industrial Research and Development Agency, Kigali, Rwanda
| | - H J Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - G Misinzo
- SACIDS Africa Centre of Excellence for Infectious Diseases, SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania. .,Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania.
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30
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Peter E, Machuka E, Githae D, Okoth E, Cleaveland S, Shirima G, Kusiluka L, Pelle R. Detection of African swine fever virus genotype XV in a sylvatic cycle in Saadani National Park, Tanzania. Transbound Emerg Dis 2020; 68:813-823. [PMID: 32696552 PMCID: PMC8246581 DOI: 10.1111/tbed.13747] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 07/08/2020] [Accepted: 07/16/2020] [Indexed: 11/28/2022]
Abstract
African swine fever (ASF) is a severe haemorrhagic disease of domestic pigs caused by ASF virus (ASFV). ASFV is transmitted by soft ticks (Ornithodoros moubata complex group) and by direct transmission. In Africa, ASF is maintained in transmission cycles of asymptomatic infection involving wild suids, mainly warthogs (Phacochoerus africanus). ASF outbreaks have been reported in many parts of Tanzania; however, active surveillance has been limited to pig farms in a few geographical locations. There is an information gap on whether and where the sylvatic cycle may occur independently of domestic pigs. To explore the existence of a sylvatic cycle in Saadani National Park in Tanzania, blood and serum samples were collected from 19 warthogs selected using convenience sampling along vehicle-accessible transects within the national park. The ticks were sampled from warthog burrows. Blood samples and ticks were subjected to ASFV molecular diagnosis (PCR) and genotyping, and warthog sera were subjected to serological (indirect ELISA) testing for ASFV antibody detection. All warthog blood samples were PCR-negative, but 16/19 (84%) of the warthog sera were seropositive by ELISA confirming exposure of warthogs to ASFV. Of the ticks sampled, 20/111 (18%) were positive for ASFV by conventional PCR. Sequencing of the p72 virus gene fragments showed that ASF viruses detected in ticks belonged to genotype XV. The results confirm the existence of a sylvatic cycle of ASFV in Saadani National Park, Tanzania, that involves ticks and warthogs independent of domestic pigs. Our findings suggest that genotype XV previously reported in 2008 in Tanzania is likely to be widely distributed and involved in both wild and domestic infection cycles. Whole-genome sequencing and analysis of the ASFV genotype XV circulating in Tanzania is recommended to determine the phylogeny of the viruses.
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Affiliation(s)
- Emma Peter
- 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, Morogoro, Tanzania
| | - Eunice Machuka
- Biosciences eastern and central Africa - International Livestock Research Institute Hub, Nairobi, Kenya
| | - Dedan Githae
- Biosciences eastern and central Africa - International Livestock Research Institute Hub, Nairobi, Kenya
| | - Edward Okoth
- 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 Shirima
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Lughano Kusiluka
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.,Sokoine University of Agriculture, Morogoro, Tanzania
| | - Roger Pelle
- Biosciences eastern and central Africa - International Livestock Research Institute Hub, Nairobi, Kenya
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Abstract
Abstract
Until July 30th, 2019 when the first case of African swine fever (ASF) was confirmed, Serbia was a country free from ASF. After the owner reported atypical illness and death of a sow, the local veterinarian submitted the organ samples to the National Reference Laboratory for Classical Swine Fever (CSF) and African Swine Fever within the Institute of Veterinary Medicine of Serbia in Belgrade. Observed gross lesions included splenomegaly, serous edema of the wall of the gallbladder and hemorrhages in the enlarged portal lymph nodes, petechial hemorrhages on the kidney and epicardium, and petechial and echymotic hemorrhages on the mucosa of the urinary bladder. Results of real-time PCR confirmed that the cause of illness and death of the swine was African swine fever virus. The samples were sent for confirmation to the EU Reference Laboratory where it was confirmed that Serbian domestic pig virus isolates based on p72 belong to genotype II. In total, 270 pigs from 18 affected holdings were killed in the infected zones. According to the on-record data, mortality was 6.89%, whereas lethality reached 64.5%. Currently, an extensive surveillance program is being conducted, aiming to force passive surveillance. ASF in wild boar has not been confirmed so far.
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32
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Mutua F, Lindahl J, Randolph D. Possibilities of establishing a smallholder pig identification and traceability system in Kenya. Trop Anim Health Prod 2019; 52:859-870. [PMID: 31529303 PMCID: PMC7039844 DOI: 10.1007/s11250-019-02077-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/06/2019] [Indexed: 11/07/2022]
Abstract
Consumers have a right to safer foods, and traceability is one approach to meeting their expectations. Kenya does not have an operational animal traceability system, and while a few initiatives have been piloted, these have only focused on the beef value chain. In this paper, we begin a discussion on traceability in the pig value chain, with an initial focus on smallholder systems of Western Kenya. First, a background to local pig production is given, and a description of animal identification and traceability options applicable to these systems is explained. Based on this, a “butcher-to-farm” traceability system, with health, production and food safety as objectives, is discussed. Requirements for establishing such a system (including actor incentives) are additionally discussed. The proposed approach can be piloted in the field and findings used to inform the design of a larger pilot and possibly pave way for implementation of a national traceability system, in line with the guidelines provided by the World Organization for Animal Health (OIE). Organized systems in the area (including commercial producer and trader groups) would offer a useful starting point.
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Affiliation(s)
- Florence Mutua
- International Livestock Research Institute, P. O. Box 30709, Nairobi, 00100, Kenya.
| | - Johanna Lindahl
- International Livestock Research Institute, P. O. Box 30709, Nairobi, 00100, Kenya.,Zoonoses Science Centre, Uppsala University, P. O. Box 70790, SE-750 07, Uppsala, Sweden.,Department of Clinical Sciences, Swedish University of Agricultural Sciences, P. O. Box 70790, SE-750 07, Uppsala, Sweden
| | - Delia Randolph
- International Livestock Research Institute, P. O. Box 30709, Nairobi, 00100, Kenya
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33
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Lack of evidence for long term carriers of African swine fever virus - a systematic review. Virus Res 2019; 272:197725. [PMID: 31430503 DOI: 10.1016/j.virusres.2019.197725] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 11/23/2022]
Abstract
African swine fever (ASF) was first described in 1921 as a highly fatal and contagious disease which caused severe outbreaks among settlers' pigs in British East Africa. Since then the disease has expanded its geographical distribution and is currently present in large parts of Africa, Europe and Asia and considered a global threat. Although ASF is typically associated with very high case fatality rates, a certain proportion of infected animals will recover from the infection and survive. Early on it was speculated that such survivors may act as carriers of the virus, and the importance of such carries for disease persistence and spread has since then almost become an established truth. However, the scientific basis for such a role of carriers may be questioned. With this in mind, the objective of this study was to review the available literature in a systematic way and to evaluate the available scientific evidence. The selection of publications for the review was based on a database search, followed by a stepwise screening process in order to exclude duplicates and non-relevant publications based on pre-defined exclusion criteria. By this process the number of publications finally included was reduced from the 3664 hits identified in the initial database search to 39 publications, from which data was then extracted and analysed. Based on this it was clear that a definition of an ASF virus carrier is lacking, and that in general any survivor or seropositive animal has been referred to as carrier. It was also clear that evidence of any significant role of such a carrier is absent. Two types of "survivors" could be defined: 1) pigs that do not die but develop a persistent infection, characterised by periodic viraemia and often but not always accompanied by some signs of subacute to chronic disease, and 2) pigs which clear the infection independently of virulence of the virus, and which are not persistently infected and will not present with prolonged virus excretion. There is no evidence that suggests that any of these categories of survivors can be considered as "healthy" carriers, i.e. pigs that show no sign of disease but can transmit the virus to in-contact pigs. However, localized virus persistence in lymphoid tissues may occur to some extent in any of the categories of survivors, which in theory may cause infection after oral uptake. To what extent this is relevant in reality, however, can be questioned given the virus dose generally needed for oral infection.
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Chang'a JS, Mayenga C, Settypalli TBK, Achenbach JE, Mwanandota JJ, Magidanga B, Cattoli G, Jeremiah M, Kamigwe A, Guo S, Kalabi D, Mramba F, Lamien CE. Symptomatic and asymptomatic cases of African swine fever in Tanzania. Transbound Emerg Dis 2019; 66:2402-2410. [PMID: 31325213 DOI: 10.1111/tbed.13298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 11/27/2022]
Abstract
African swine fever (ASF) is an acute, highly contagious and deadly viral haemorrhagic disease of domestic pigs caused by African swine fever virus (ASFV). In ASF endemic countries, there are an increasing number of reports on circulating ASFV strains with different levels of virulence causing a broad range of clinical symptoms in susceptible animals. Tanzania, where ASFV is endemic since 2001, recorded several outbreaks including symptomatic and asymptomatic cases between 2015 and 2017. We collected 35 clinical samples from four outbreaks for diagnostic confirmation and sequenced the partial B646L (p72), the full E183L (p54) gene, the central variable region of the B602L gene and the intergenic region between the I73R and I329L genes to characterize molecularly the new ASFV isolates and analyse their relatedness with previously reported Tanzanian and foreign isolates. We detected ASFV in 21 samples, 15 from symptomatic and six from asymptomatic pigs. Phylogenetic analyses based on the partial p72 gene and the complete p54 (E183L) genes revealed that the ASFVs in samples from symptomatic pigs belonged to genotypes II and those in samples from asymptomatic pigs belonged to genotype IX. The CVR profiles of the p72 genotype II and genotype IX isolates differed between each other and from previously published Tanzanian sequences. The sequence analysis of the intergenic region between the I73R and I329L for the 2017 genotype II isolates showed the absence of one GGAATATATA motif in those isolates. This study showed the simultaneous circulation of two different ASFV genotypes with different levels of pathogenicity in Tanzania. Since the existence of sub-clinically infected pigs may contribute to the persistence of the virus, our findings suggest continuous surveillance and characterization of ASFV isolates in disease-endemic regions.
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Affiliation(s)
- Jelly S Chang'a
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Charles Mayenga
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Tirumala Bharani K Settypalli
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | | | - Julius J Mwanandota
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Bishop Magidanga
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Giovanni Cattoli
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Mashaka Jeremiah
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Aloyce Kamigwe
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Shukuru Guo
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Denis Kalabi
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Furaha Mramba
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Charles E Lamien
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
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Mulumba-Mfumu LK, Saegerman C, Dixon LK, Madimba KC, Kazadi E, Mukalakata NT, Oura CAL, Chenais E, Masembe C, Ståhl K, Thiry E, Penrith ML. African swine fever: Update on Eastern, Central and Southern Africa. Transbound Emerg Dis 2019; 66:1462-1480. [PMID: 30920725 DOI: 10.1111/tbed.13187] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/21/2019] [Accepted: 03/24/2019] [Indexed: 11/28/2022]
Abstract
Control of African swine fever (ASF) in countries in Eastern, Central and Southern Africa (ECSA) is particularly complex owing to the presence of all three known epidemiological cycles of maintenance of the virus, namely an ancient sylvatic cycle involving the natural hosts and vectors of the disease as well as domestic cycles with and without involvement of natural vectors. While the situation is well documented in some of the countries, for others very little information is available. In spite of the unfavourable ASF situation, the pig population in the sub-region has grown exponentially in recent decades and is likely to continue to grow in response to rapid urban growth resulting in increasing demand for animal protein by populations that are no longer engaged in livestock production. Better management of ASF will be essential to permit the pig sector to reach its full potential as a supplier of high quality protein and a source of income to improve livelihoods and create wealth. No vaccine is currently available and it is likely that, in the near future, the sub-region will continue to rely on the implementation of preventive measures, based on the epidemiology of the disease, to avoid both the devastating losses that outbreaks can cause and the risk the sub-region poses to other parts of Africa and the world. The current situation in the ECSA sub-region is reviewed and gaps in knowledge are identified in order to support ongoing strategy development for managing ASF in endemic areas.
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Affiliation(s)
- Léopold K Mulumba-Mfumu
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.,Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR- ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Claude Saegerman
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR- ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | | | - Kapanga C Madimba
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Eric Kazadi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Ndeji T Mukalakata
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Chris A L Oura
- School of Veterinary Medicine, Faculty of Medical Sciences, University of the West Indies, Champ Fleurs, Trinidad and Tobago
| | - Erika Chenais
- Department of Disease Control and Epidemiology, SVA, Uppsala, Sweden
| | - Charles Masembe
- College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Karl Ståhl
- Department of Disease Control and Epidemiology, SVA, Uppsala, Sweden
| | - Etienne Thiry
- Veterinary Virology and Animal Viral Diseases, Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Mary Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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Penrith ML, Bastos AD, Etter EMC, Beltrán-Alcrudo D. Epidemiology of African swine fever in Africa today: Sylvatic cycle versus socio-economic imperatives. Transbound Emerg Dis 2019; 66:672-686. [PMID: 30633851 DOI: 10.1111/tbed.13117] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 11/29/2022]
Abstract
African swine fever (ASF) is believed to have evolved in eastern and southern Africa in a sylvatic cycle between common warthogs (Phacochoerus africanus) and argasid ticks of the Ornithodoros moubata complex that live in their burrows. The involvement of warthogs and possibly other wild suids in the maintenance of ASF virus means that the infection cannot be eradicated from Africa, but only prevented and controlled in domestic pig populations. Historically, outbreaks of ASF in domestic pigs in Africa were almost invariably linked to the presence of warthogs, but subsequent investigations of the disease in pigs revealed the presence of another cycle involving domestic pigs and ticks, with a third cycle becoming apparent when the disease expanded into West Africa where the sylvatic cycle is not present. The increase in ASF outbreaks that has accompanied the exponential growth of the African pig population over the last three decades has heralded a shift in the epidemiology of ASF in Africa, and the growing importance of the pig husbandry and trade in the maintenance and spread of ASF. This review, which focuses on the ASF situation between 1989 and 2017, suggests a minor role for wild suids compared with the domestic cycle, driven by socio-economic factors that determine the ability of producers to implement the control measures needed for better management of ASF in Africa.
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Affiliation(s)
- Mary-Louise Penrith
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Armanda Duarte Bastos
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Eric M C Etter
- Department of Production Animal Studies, University of Pretoria, Pretoria, South Africa.,CIRAD, UMR Animal Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ. Montpellier, CIRAD, INRA, Montpellier, France
| | - Daniel Beltrán-Alcrudo
- Regional Office for Europe and Central Asia, Food and Agriculture Organization of the United Nations, Budapest, Hungary
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Freitas TRP, Lyra TMDP. Molecular studies on African swine fever virus from Brazilian isolates. ARQUIVOS DO INSTITUTO BIOLÓGICO 2018. [DOI: 10.1590/1808-1657000712016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ABSTRACT: African swine fever (ASF) is a devastating viral infirmity that affects domestic and wild swine caused by the ASF virus (ASFV) that belongs to the family Asfaviridae in the Asfavirus genus. Studies for genotypic and antigenic determination of ASFV including samples from Brazilian outbreaks were carried out outside Brazil. Here, we have reviewed studies on the molecular aspects of Brazilian isolates from 1978 and 1979. Results obtained from restriction fragment analysis, cloning and gene sequencing display the genotypic variation of viral samples. Viral genotyping based on sequences of the 3’ region of the p72 gene included in genotype I Brazilian samples, reinforcing the suggestion of the European origin for the virus that infected Brazilian herds and having low virulence potential. Corroborating those findings, at the American station PIADC, the infection of healthy pigs with the Brazilian strain induced ASF sub acute disease with low mortality and a low-virulence. Those results were similar with epidemiological vigilance forms of Brazilian swineherd in good health conditions having at least one ASFV isolation, and the ASF pioneer’s studies on the low mortality in the Brazilian herds affected by ASF. The ASFV spreading in Eastern Europe and Russia triggered a greater concern with intensifying the risk of viral dissemination from country to country. The low virulence ASF strains can increase the problem because of hidden viral reservoirs - which further reinforces the need for safety and preventive measures in virus-free countries. Finally, the problem is further compounded by the lack of vaccines and other immunological resources.
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Quembo CJ, Jori F, Vosloo W, Heath L. Genetic characterization of African swine fever virus isolates from soft ticks at the wildlife/domestic interface in Mozambique and identification of a novel genotype. Transbound Emerg Dis 2018; 65:420-431. [PMID: 28921895 PMCID: PMC5873395 DOI: 10.1111/tbed.12700] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 11/27/2022]
Abstract
African swine fever virus (ASFV) is one of the most threatening infectious diseases of pigs. There are not sufficient data to indicate the importance of the sylvatic cycle in the spread and maintenance of the disease locally and potentially, globally. To assess the capacity to maintain ASF in the environment, we investigated the presence of soft tickreservoirs of ASFV in Gorongosa National Park (GNP) and its surrounding villages. A total of 1,658 soft ticks were recovered from warthog burrows and pig pens at the wildlife/livestock interface of the GNP and viral DNA was confirmed by nested PCR in 19% of Ornithodoros porcinus porcinus and 15% of O. p. domesticus. However, isolation of ASFV was only achieved in approximately 50% of the PCR-positive samples with nineteen haemadsorbing virus isolates recovered. These were genotyped using a combination of partial sequencing of the B646L gene (p72) and analysis of the central variable region (CVR) of the B602L gene. Eleven isolates were classified as belonging to genotype II and homologous to contemporary isolates from southern Africa, the Indian Ocean and eastern Europe. Three isolates grouped within genotype V and were similar to previous isolates from Mozambique and Malawi. The remaining five isolates constituted a new, previously unidentified genotype, designated genotype XXIV. This work confirms for the first time that the virus currently circulating in eastern Europe is likely to have a wildlife origin, and that the large diversity of ASFV maintained in wildlife areas can act as a permanent sources of different strains for the domestic pig value chain in Mozambique and beyond its boundaries. Their genetic similarity to ASFV strains currently spreading across Europe justifies the need to continue studying the sylvatic cycle in this African country and other parts of southern Africa in order to identify potential hot spots of ASF emergence and target surveillance and control efforts.
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Affiliation(s)
- C. J. Quembo
- Transboundary Animal Disease ProgramOnderstepoort Veterinary InstitutePretoriaSouth Africa
- Department of Veterinary Tropical DiseasesFaculty of Veterinary SciencesUniversity of PretoriaPretoriaSouth Africa
- Laboratório Regional de Veterinária em ChimoioCentro Zonal de Investigação Agrária da Zona CentroInstituto de Investigação Agrária de MoçambiqueChimoioMozambique
| | - F. Jori
- UMR ASTRECIRADMontpellierFrance
- Department of Zoology & EntomologyMammal Research InstituteUniversity of PretoriaPretoriaSouth Africa
| | - W. Vosloo
- Transboundary Animal Disease ProgramOnderstepoort Veterinary InstitutePretoriaSouth Africa
- Department of Veterinary Tropical DiseasesFaculty of Veterinary SciencesUniversity of PretoriaPretoriaSouth Africa
- Australian Animal Health LaboratoryGeelongVic.Australia
| | - L. Heath
- Transboundary Animal Disease ProgramOnderstepoort Veterinary InstitutePretoriaSouth Africa
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Brown VR, Bevins SN. A Review of African Swine Fever and the Potential for Introduction into the United States and the Possibility of Subsequent Establishment in Feral Swine and Native Ticks. Front Vet Sci 2018; 5:11. [PMID: 29468165 PMCID: PMC5808196 DOI: 10.3389/fvets.2018.00011] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/19/2018] [Indexed: 11/26/2022] Open
Abstract
African swine fever (ASF) is caused by African swine fever virus (ASFV), which can cause substantial morbidity and mortality events in swine. The virus can be transmitted via direct and indirect contacts with infected swine, their products, or competent vector species, especially Ornithodoros ticks. Africa and much of Eastern Europe are endemic for ASF; a viral introduction to countries that are currently ASF free could have severe economic consequences due to the loss of production from infected animals and the trade restrictions that would likely be imposed as a result of an outbreak. We identified vulnerabilities that could lead to ASFV introduction or persistence in the United States or other ASF-free regions. Both legal and illegal movements of live animals, as well as the importation of animal products, byproducts, and animal feed, pose a risk of virus introduction. Each route is described, and current regulations designed to prevent ASFV and other pathogens from entering the United States are outlined. Furthermore, existing ASFV research gaps are highlighted. Laboratory experiments to evaluate multiple species of Ornithodoros ticks that have yet to be characterized would be useful to understand vector competence, host preferences, and distribution of competent soft tick vectors in relation to high pig production areas as well as regions with high feral swine (wild boar or similar) densities. Knowledge relative to antigenic viral proteins that contribute to host response and determination of immune mechanisms that lead to protection are foundational in the quest for a vaccine. Finally, sampling of illegally imported and confiscated wild suid products for ASFV could shed light on the types of products being imported and provide a more informed perspective relative to the risk of ASFV importation.
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Affiliation(s)
- Vienna R. Brown
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, United States
| | - Sarah N. Bevins
- Wildlife Services, National Wildlife Research Center (NWRC), Animal and Plant Health Inspection Service, United States Department of Agriculture (USDA), Fort Collins, CO, United States
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40
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Onzere CK, Bastos AD, Okoth EA, Lichoti JK, Bochere EN, Owido MG, Ndambuki G, Bronsvoort M, Bishop RP. Multi-locus sequence typing of African swine fever viruses from endemic regions of Kenya and Eastern Uganda (2011-2013) reveals rapid B602L central variable region evolution. Virus Genes 2018; 54:111-123. [PMID: 29143187 PMCID: PMC5847163 DOI: 10.1007/s11262-017-1521-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 11/07/2017] [Indexed: 11/28/2022]
Abstract
The central variable region (CVR) within the B602L gene of the African swine fever virus (ASFV) is highly polymorphic within the 23 ASFV genotypes defined by sequencing of the C-terminal end of the p72 locus. Sequencing the p54 gene further discriminates ASFV genotypes that are conserved at the p72 locus. Variation in the thymidine kinase locus is a novel additional tool for ASFV genotyping whose application for this purpose is described for the first time herein. We evaluated genetic variation at these four polymorphic loci in 39 ASFV isolates obtained from outbreaks in Kenya and a region of Eastern Uganda between 2011 and 2013. Analysis of the p72 and p54 loci revealed high genetic conservation among these isolates; all clustered within p72 genotype IX and were similar to isolates associated with earlier outbreaks in East Africa. The thymidine kinase gene of the Kenyan isolates in this study were distinct relative to Southern African isolates and synonymous substitutions were observed among viruses from central Kenya. Analysis of the CVR within the B602L gene revealed two previously unknown polymorphisms that were restricted to Western Kenya and Eastern Uganda. A novel variant was revealed within CVR subgroup XXIV and a novel CVR subgroup XXIVa that contains tetrameric repeat F which has previously only been associated with p72 genotype I, was also identified for the first time in East Africa. Phylogeographic analysis of isolates based on CVR polymorphisms revealed rapid evolution and dissemination of variants present within ASFV genotype IX in East Africa.
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Affiliation(s)
- C. K. Onzere
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
- College of Medicine and Veterinary Medicine, University of Edinburgh, The Chancellor’s Building, 49 Little France Crescent, Edinburgh, EH16 4S Scotland, UK
| | - A. D. Bastos
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag 20, Hatfield, 0028 South Africa
| | - E. A. Okoth
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
| | - J. K. Lichoti
- State Department of Veterinary Services, Ministry of Agriculture, Livestock and Fisheries, Private Bag-00625, Nairobi, Kenya
| | - E. N. Bochere
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
| | - M. G. Owido
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
| | - G. Ndambuki
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
| | - M. Bronsvoort
- College of Medicine and Veterinary Medicine, University of Edinburgh, The Chancellor’s Building, 49 Little France Crescent, Edinburgh, EH16 4S Scotland, UK
| | - R. P. Bishop
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100 Kenya
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41
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Abstract
African swine fever (ASF) is an acute and often fatal disease affecting domestic pigs and wild boar, with severe economic consequences for affected countries. ASF is endemic in sub-Saharan Africa and the island of Sardinia, Italy. Since 2007, the virus emerged in the republic of Georgia, and since then spread throughout the Caucasus region and Russia. Outbreaks have also been reported in Belarus, Ukraine, Lithuania, Latvia, Estonia, Romania, Moldova, Czech Republic, and Poland, threatening neighboring West European countries. The causative agent, the African swine fever virus (ASFV), is a large, enveloped, double-stranded DNA virus that enters the cell by macropinocytosis and a clathrin-dependent mechanism. African Swine Fever Virus is able to interfere with various cellular signaling pathways resulting in immunomodulation, thus making the development of an efficacious vaccine very challenging. Inactivated preparations of African Swine Fever Virus do not confer protection, and the role of antibodies in protection remains unclear. The use of live-attenuated vaccines, although rendering suitable levels of protection, presents difficulties due to safety and side effects in the vaccinated animals. Several African Swine Fever Virus proteins have been reported to induce neutralizing antibodies in immunized pigs, and vaccination strategies based on DNA vaccines and recombinant proteins have also been explored, however, without being very successful. The complexity of the virus particle and the ability of the virus to modulate host immune responses are most likely the reason for this failure. Furthermore, no permanent cell lines able to sustain productive virus infection by both virulent and naturally attenuated African Swine Fever Virus strains exist so far, thus impairing basic research and the commercial production of attenuated vaccine candidates.
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Abworo EO, Onzere C, Oluoch Amimo J, Riitho V, Mwangi W, Davies J, Blome S, Peter Bishop R. Detection of African swine fever virus in the tissues of asymptomatic pigs in smallholder farming systems along the Kenya-Uganda border: implications for transmission in endemic areas and ASF surveillance in East Africa. J Gen Virol 2017; 98:1806-1814. [PMID: 28721858 DOI: 10.1099/jgv.0.000848] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The persistence of African swine fever virus (ASFV) in endemic areas, with small-scale but regular outbreaks in domestic pigs, is not well understood. ASFV has not been detected using conventional diagnosis in these pigs or adjacent populations of resistant African wild pigs, that could act as potential carriers during the outbreaks. However, such data are crucial for the design of evidence-based control strategies. We conducted cross-sectional (1107 pigs) and longitudinal (100 pigs) monitoring of ASFV prevalence in local pigs in Kenya and Uganda. The horizontal survey revealed no evidence of ASFV in the serum or blood using either conventional or real-time PCR. One pig consistently tested positive using ELISA, but negative using PCR assays on blood. Interestingly, the isotype of the antibodies from this animal were strongly IgA biased relative to control domestic pigs and warthogs, suggesting a role for mucosal immunity. The tissues from this pig were positive by PCR following post-mortem. Internal organ tissues of 44 healthy pigs (28 sentinel pigs and 16 pigs from slaughter slabs) were tested with four different PCR assays; 15.9 % were positive for ASFV suggesting that healthy pigs carrying ASFV exist in the swine population in the study area. P72 and p54 genotyping of ASFV revealed very limited diversity: all were classified in genotype IX at both loci, as were virtually all viruses causing recent ASF outbreaks in the region. Our study suggests that carrier pigs may play a role in ASF disease outbreaks, although the triggers for outbreaks remain unclear and require further investigation. This study significantly increases scientific knowledge of the epidemiology of ASF in the field in Africa, which will contribute to the design of effective surveillance and control strategies.
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Affiliation(s)
- Edward Okoth Abworo
- International Livestock Research Institute (ILRI), P.O. Box 30709, GPO 00100, Nairobi, Kenya
| | - Cynthia Onzere
- International Livestock Research Institute (ILRI), P.O. Box 30709, GPO 00100, Nairobi, Kenya
| | - Joshua Oluoch Amimo
- The University of Nairobi, Faculty of Veterinary Medicine, P.O Box 29053 00625, Nairobi, Kenya
| | - Victor Riitho
- International Livestock Research Institute (ILRI), P.O. Box 30709, GPO 00100, Nairobi, Kenya
| | - Waithaka Mwangi
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Jocelyn Davies
- Land and Water, The Commonwealth Scientific and Industrial Research Organisation (CSIRO), Alice Springs, Australia.,The Northern Institute, Charles Darwin University, Grevillea River, Alice Springs, Australia
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Bundesforschungsinstitut für Tiergesundheit, Federal Research Institute for Animal Health, Südufer 10 , D-17493 Greifswald-Insel Riems, Germany
| | - Richard Peter Bishop
- International Livestock Research Institute (ILRI), P.O. Box 30709, GPO 00100, Nairobi, Kenya
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Thomas LF, Bishop RP, Onzere C, Mcintosh MT, Lemire KA, de Glanville WA, Cook EAJ, Fèvre EM. Evidence for the presence of African swine fever virus in an endemic region of Western Kenya in the absence of any reported outbreak. BMC Vet Res 2016; 12:192. [PMID: 27608711 PMCID: PMC5016997 DOI: 10.1186/s12917-016-0830-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 09/06/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African swine fever (ASF), caused by African swine fever virus (ASFV), is a severe haemorrhagic disease of pigs, outbreaks of which can have a devastating impact upon commercial and small-holder pig production. Pig production in western Kenya is characterised by low-input, free-range systems practised by poor farmers keeping between two and ten pigs. These farmers are particularly vulnerable to the catastrophic loss of livestock assets experienced in an ASF outbreak. This study wished to expand our understanding of ASFV epidemiology during a period when no outbreaks were reported. RESULTS Two hundred and seventy six whole blood samples were analysed using two independent conventional and real time PCR assays to detect ASFV. Despite no recorded outbreak of clinical ASF during this time, virus was detected in 90/277 samples analysed by conventional PCR and 142/209 samples analysed by qPCR. Genotyping of a sub-set of these samples indicated that the viruses associated with the positive samples were classified within genotype IX and that these strains were therefore genetically similar to the virus associated with the 2006/2007 ASF outbreaks in Kenya. CONCLUSION The detection of ASFV viral DNA in a relatively high number of pigs delivered for slaughter during a period with no reported outbreaks provides support for two hypotheses, which are not mutually exclusive: (1) that virus prevalence may be over-estimated by slaughter-slab sampling, relative to that prevailing in the wider pig population; (2) that sub-clinical, chronically infected or recovered pigs may be responsible for persistence of the virus in endemic areas.
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Affiliation(s)
- Lian F Thomas
- Centre for Infection Immunity, and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Labs, West Mains Rd, Edinburgh, EH9 3JT, UK.,International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya
| | - Richard P Bishop
- International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya
| | - Cynthia Onzere
- International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya
| | - Michael T Mcintosh
- United States Department of Agriculture, Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Animal and Plant Health Inspection Services, PO Box 848, Greenport, NY, 1944, USA
| | - Karissa A Lemire
- United States Department of Agriculture, Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, Animal and Plant Health Inspection Services, PO Box 848, Greenport, NY, 1944, USA
| | - William A de Glanville
- Centre for Infection Immunity, and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Labs, West Mains Rd, Edinburgh, EH9 3JT, UK.,International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya
| | - E Anne J Cook
- Centre for Infection Immunity, and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Labs, West Mains Rd, Edinburgh, EH9 3JT, UK.,International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya
| | - Eric M Fèvre
- International Livestock Research Institute, PO Box 30709, Nairobi, 00100, Kenya. .,Institute for Infection and Global Health, University of Liverpool, Leahurst Campus, Chester High Road, Neston, CH64 7TE, UK.
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Barongo MB, Bishop RP, Fèvre EM, Knobel DL, Ssematimba A. A Mathematical Model that Simulates Control Options for African Swine Fever Virus (ASFV). PLoS One 2016; 11:e0158658. [PMID: 27391689 PMCID: PMC4938631 DOI: 10.1371/journal.pone.0158658] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/20/2016] [Indexed: 01/27/2023] Open
Abstract
A stochastic model designed to simulate transmission dynamics of African swine fever virus (ASFV) in a free-ranging pig population under various intervention scenarios is presented. The model was used to assess the relative impact of the timing of the implementation of different control strategies on disease-related mortality. The implementation of biosecurity measures was simulated through incorporation of a decay function on the transmission rate. The model predicts that biosecurity measures implemented within 14 days of the onset of an epidemic can avert up to 74% of pig deaths due to ASF while hypothetical vaccines that confer 70% immunity when deployed prior to day 14 of the epidemic could avert 65% of pig deaths. When the two control measures are combined, the model predicts that 91% of the pigs that would have otherwise succumbed to the disease if no intervention was implemented would be saved. However, if the combined interventions are delayed (defined as implementation from > 60 days) only 30% of ASF-related deaths would be averted. In the absence of vaccines against ASF, we recommend early implementation of enhanced biosecurity measures. Active surveillance and use of pen-side diagnostic assays, preferably linked to rapid dissemination of this data to veterinary authorities through mobile phone technology platforms are essential for rapid detection and confirmation of ASF outbreaks. This prediction, although it may seem intuitive, rationally confirms the importance of early intervention in managing ASF epidemics. The modelling approach is particularly valuable in that it determines an optimal timing for implementation of interventions in controlling ASF outbreaks.
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Affiliation(s)
- Mike B. Barongo
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Richard P Bishop
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Eric M Fèvre
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
- Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, United Kingdom
| | - Darryn L Knobel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Amos Ssematimba
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
- Department of Mathematics, Faculty of Science, Gulu University, P.O. Box 166, Gulu, Uganda
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45
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Achenbach JE, Gallardo C, Nieto-Pelegrín E, Rivera-Arroyo B, Degefa-Negi T, Arias M, Jenberie S, Mulisa DD, Gizaw D, Gelaye E, Chibssa TR, Belaye A, Loitsch A, Forsa M, Yami M, Diallo A, Soler A, Lamien CE, Sánchez-Vizcaíno JM. Identification of a New Genotype of African Swine Fever Virus in Domestic Pigs from Ethiopia. Transbound Emerg Dis 2016; 64:1393-1404. [PMID: 27211823 DOI: 10.1111/tbed.12511] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 11/29/2022]
Abstract
African swine fever (ASF) is an important emerging transboundary animal disease (TAD), which currently has an impact on many countries in Africa, Eastern Europe, the Caucasus and the Russian Federation. The current situation in Europe shows the ability of the virus to rapidly spread, which stands to threaten the global swine industry. At present, there is no viable vaccine to minimize spread of the disease and stamping out is the main source of control. In February 2011, Ethiopia had reported its first suspected outbreaks of ASF. Genomic analyses of the collected ASF virus (ASFV) strains were undertaken using 23 tissue samples collected from domestic swine in Ethiopia from 2011 to 2014. The analysis of Ethiopian ASFVs partial p72 gene sequence showed the identification of a new genotype, genotype XXIII, that shares a common ancestor with genotypes IX and X, which comprise isolates circulating in Eastern African countries and the Republic of Congo. Analysis of the p54 gene also followed the p72 pattern and the deduced amino acid sequence of the central variable region (CVR) of the B602L gene showed novel tetramer repeats not previously characterized.
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Affiliation(s)
- J E Achenbach
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - C Gallardo
- European Union Reference Laboratory for ASF: Centro de Investigación en Sanidad Animal, INIA, Madrid, Spain
| | - E Nieto-Pelegrín
- OIE Reference Laboratory for ASF: VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
| | - B Rivera-Arroyo
- OIE Reference Laboratory for ASF: VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
| | | | - M Arias
- European Union Reference Laboratory for ASF: Centro de Investigación en Sanidad Animal, INIA, Madrid, Spain
| | - S Jenberie
- National Veterinary Institute, Debre Ziet, Ethiopia
| | - D D Mulisa
- National Animal Health Diagnostic and Investigation Center (NAHDIC), Sebeta, Ethiopia
| | - D Gizaw
- National Animal Health Diagnostic and Investigation Center (NAHDIC), Sebeta, Ethiopia
| | - E Gelaye
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria.,National Veterinary Institute, Debre Ziet, Ethiopia
| | - T R Chibssa
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria.,National Animal Health Diagnostic and Investigation Center (NAHDIC), Sebeta, Ethiopia
| | - A Belaye
- National Veterinary Institute, Debre Ziet, Ethiopia
| | - A Loitsch
- Institute for Veterinary Disease Control, Austrian Agency for Health and Food Safety, Mödling, Austria
| | - M Forsa
- National Animal Health Diagnostic and Investigation Center (NAHDIC), Sebeta, Ethiopia
| | - M Yami
- National Veterinary Institute, Debre Ziet, Ethiopia
| | - A Diallo
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - A Soler
- European Union Reference Laboratory for ASF: Centro de Investigación en Sanidad Animal, INIA, Madrid, Spain
| | - C E Lamien
- Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - J M Sánchez-Vizcaíno
- OIE Reference Laboratory for ASF: VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
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46
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Gallardo MC, Reoyo ADLT, Fernández-Pinero J, Iglesias I, Muñoz MJ, Arias ML. African swine fever: a global view of the current challenge. Porcine Health Manag 2015; 1:21. [PMID: 28405426 PMCID: PMC5382474 DOI: 10.1186/s40813-015-0013-y] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/12/2015] [Indexed: 11/25/2022] Open
Abstract
African Swine Fever (ASF) is an important contagious haemorrhagic viral disease affecting swine whose notification is mandatory due to its high mortality rates and the great sanitary and socioeconomic impact it has on international trade in animal and swine products. This disease only affects porcine species, both wild and domestic, and produces a variety of clinical signs such as fever and functional disorders of the digestive and respiratory systems. Lesions are mainly characterized by congestive-haemorrhagic alterations. ASF epidemiology varies significantly between countries, regions and continents, since it depends on the characteristics of the virus in circulation, the presence of wild hosts and reservoirs, environmental conditions and human social behaviour. Furthermore, a specific host will not necessarily always play the same active role in the spread and maintenance of ASF in a particular area. Currently, ASF is endemic in most sub-Saharan African countries where wild hosts and tick vectors (Ornithodoros) play an important role acting as biological reservoirs for the virus. In Europe, the disease has been endemic since 1978 on the island of Sardinia (Italy) and since 2007, when it was first reported in Georgia, in a number of Eastern European countries. It is also endemic in certain regions of the Russia Federation, where domestic pig and wild boar populations are widely affected. By contrast, in the affected eastern European Union (EU) countries where ASF is currently as epidemic, the on-going spread of the disease affects mainly wild boar populations located in restricted areas and, to a much less extent, domestic pigs. Unlike most livestock diseases, no vaccine or specific treatment is currently available for ASF. Therefore, disease control is mainly based on early detection and the application of strict sanitary and biosecurity measures. Epidemiology of ASF is very complex by the existence of different virus circulating, reservoirs and a number of scenarios, and the on-going spread of the disease through Africa and Europe. Survivor pigs can remain persistently infected for months which may contribute to virus transmission and thus the spread and maintenance of the disease, thereby complicating attempts to control it.
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Affiliation(s)
- Ma Carmen Gallardo
- European Union Reference Laboratory (EURL) for African swine fever, INIA-CISA, 28130 Valdeolmos, Madrid Spain.,FAO Reference Centre for African swine fever, INIA-CISA, Valdeolmos, 28130 Madrid Spain
| | - Ana de la Torre Reoyo
- FAO Reference Centre for African swine fever, INIA-CISA, Valdeolmos, 28130 Madrid Spain.,Epidemiology Department, National Institute for Agricultural and Food Research and Technology, Animal Health Research Centre, INIA-CISA, 28130 Valdeolmos, Madrid Spain
| | - Jovita Fernández-Pinero
- European Union Reference Laboratory (EURL) for African swine fever, INIA-CISA, 28130 Valdeolmos, Madrid Spain.,FAO Reference Centre for African swine fever, INIA-CISA, Valdeolmos, 28130 Madrid Spain
| | - Irene Iglesias
- Epidemiology Department, National Institute for Agricultural and Food Research and Technology, Animal Health Research Centre, INIA-CISA, 28130 Valdeolmos, Madrid Spain
| | - Ma Jesús Muñoz
- FAO Reference Centre for African swine fever, INIA-CISA, Valdeolmos, 28130 Madrid Spain.,Epidemiology Department, National Institute for Agricultural and Food Research and Technology, Animal Health Research Centre, INIA-CISA, 28130 Valdeolmos, Madrid Spain
| | - Ma Luisa Arias
- European Union Reference Laboratory (EURL) for African swine fever, INIA-CISA, 28130 Valdeolmos, Madrid Spain.,FAO Reference Centre for African swine fever, INIA-CISA, Valdeolmos, 28130 Madrid Spain
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47
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Nieto-Pelegrín E, Rivera-Arroyo B, Sánchez-Vizcaíno JM. First Detection of Antibodies Against African Swine Fever Virus in Faeces Samples. Transbound Emerg Dis 2015; 62:594-602. [PMID: 26431943 DOI: 10.1111/tbed.12429] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/30/2022]
Abstract
African swine fever (ASF) is a viral, highly lethal haemorrhagic disease of swine with no available vaccine or effective treatment. Introduction of ASF into a country triggers immediate restriction measures that cause significant economic losses and threatens spread to neighbouring countries. Wild boar populations have been recently assigned an essential role in the spread of African swine fever virus (ASFV) to European countries. Therefore, effective surveillance and monitoring of wild boar populations is required, but sampling wild boar is logistically challenging and expensive. This study assessed the feasibility of detecting antibodies against ASFV in faeces for later implementation in surveillance and control programmes. Two groups of pigs were experimentally infected with an attenuated ASFV isolate Ken05, and blood, oral fluid and faecal samples were tested for the presence of viral DNA using quantitative real-time polymerase chain reaction (qPCR) to monitor infection progress. Faecal samples were analysed using two indirect enzyme-linked immunosorbent assays (ELISAs) based on semipurified viral protein (vp) 72 or purified recombinant vp30 expressed in mammalian cells. Faecal samples from 9 of 10 pigs with non-haemorrhagic diarrhoea tested positive for antibodies against ASFV using the two ELISA tests that showed a positive correlation. The serum sample results from the two indirect ELISAs were compared against results from the reference ELISA technique and the immunoperoxidase test. Our findings indicate the feasibility of faecal sampling for detecting anti-ASFV antibodies, which may provide a practical non-invasive alternative for sampling wild boar populations. In conclusion, the application of these ELISA tests to faecal field samples could be particularly useful to screen for the presence of ASF in field conditions.
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Affiliation(s)
- E Nieto-Pelegrín
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
| | - B Rivera-Arroyo
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
| | - J M Sánchez-Vizcaíno
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Animal Health Department, Universidad Complutense Madrid, Madrid, Spain
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48
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Gallardo C, Fernández-Pinero J, Pelayo V, Gazaev I, Markowska-Daniel I, Pridotkas G, Nieto R, Fernández-Pacheco P, Bokhan S, Nevolko O, Drozhzhe Z, Pérez C, Soler A, Kolvasov D, Arias M. Genetic variation among African swine fever genotype II viruses, eastern and central Europe. Emerg Infect Dis 2015; 20:1544-7. [PMID: 25148518 PMCID: PMC4178389 DOI: 10.3201/eid2009.140554] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
African swine fever virus (ASFV) was first reported in eastern Europe/Eurasia in 2007. Continued spread of ASFV has placed central European countries at risk, and in 2014, ASFV was detected in Lithuania and Poland. Sequencing showed the isolates are identical to a 2013 ASFV from Belarus but differ from ASFV isolated in Georgia in 2007.
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49
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Muhangi D, Masembe C, Emanuelson U, Boqvist S, Mayega L, Ademun RO, Bishop RP, Ocaido M, Berg M, Ståhl K. A longitudinal survey of African swine fever in Uganda reveals high apparent disease incidence rates in domestic pigs, but absence of detectable persistent virus infections in blood and serum. BMC Vet Res 2015; 11:106. [PMID: 25967670 PMCID: PMC4432512 DOI: 10.1186/s12917-015-0426-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 05/05/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND African swine fever (ASF) is a fatal, haemorrhagic disease of domestic pigs, that poses a serious threat to pig farmers and is currently endemic in domestic pigs in most of sub-Saharan Africa. To obtain insight into the factors related to ASF outbreaks at the farm-level, a longitudinal study was performed in one of the major pig producing areas in central Uganda. Potential risk factors associated with outbreaks of ASF were investigated including the possible presence of apparently healthy ASF-virus (ASFV) infected pigs, which could act as long-term carriers of the virus. Blood and serum were sampled from 715 pigs (241 farms) and 649 pigs (233 farms) to investigate presence of ASFV and antibodies, during the periods of June-October 2010 and March-June 2011, respectively. To determine the potential contribution of different risks to ASF spread, a questionnaire-based survey was administered to farmers to assess the association between ASF outbreaks during the study period and the risk factors. RESULTS Fifty-one (21 %) and 13 (5.6 %) farms reported an ASF outbreak on their farms in the previous one to two years and during the study period, respectively. The incidence rate for ASF prior to the study period was estimated at 14.1 per 100 pig farm-years and 5.6 per 100 pig farm-years during the study. Three pigs tested positive for ASFV using real-time PCR, but none tested positive for ASFV specific antibodies using two different commercial ELISA tests. CONCLUSIONS There was no evidence for existence of pigs that were long-term carriers for the virus based on the analysis of blood and serum as there were no seropositive pigs and the only three ASFV DNA positive pigs were acutely infected and were linked to outbreaks reported by farmers during the study. Potential ASF risk factors were present on both small and medium-scale pig farms, although small scale farms exhibited a higher proportion with multiple potential risk factors (like borrowing boars for sows mating, buying replacement from neighboring farms without ascertaining health status, etc) and did not implement any biosecurity measures. However, no risk factors were significantly associated with ASF reports during the study.
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Affiliation(s)
- Denis Muhangi
- Department of Wildlife and Aquatic Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Charles Masembe
- Department of Biological Sciences, College of Natural Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Ulf Emanuelson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, P. O. Box 7054, SE-750 07, Uppsala, Sweden.
| | - Sofia Boqvist
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P. O. Box 7028, SE-750 07, Uppsala, Sweden.
| | - Lawrence Mayega
- District Veterinary Office, under the Ministry of Agriculture, Animal Industry and Fisheries, Masaka, Uganda.
| | - Rose Okurut Ademun
- Ministry of Agriculture, Animal Industry and Fisheries, P. O. Box 102, Entebbe, Uganda.
| | - Richard P Bishop
- International Livestock Research Institute (ILRI), P.O. Box 30709, GPO 00100, Nairobi, Kenya.
| | - Michael Ocaido
- Department of Wildlife and Aquatic Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Mikael Berg
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P. O. Box 7028, SE-750 07, Uppsala, Sweden.
| | - Karl Ståhl
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P. O. Box 7028, SE-750 07, Uppsala, Sweden.
- Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), SE-751 89, Uppsala, Sweden.
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50
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Comparative analysis of the complete genome sequences of Kenyan African swine fever virus isolates within p72 genotypes IX and X. Virus Genes 2015; 50:303-9. [PMID: 25645905 DOI: 10.1007/s11262-014-1156-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
Abstract
Twelve complete African swine fever virus (ASFV) genome sequences are currently publicly available and these include only one sequence from East Africa. We describe genome sequencing and annotation of a recent pig-derived p72 genotype IX, and a tick-derived genotype X isolate from Kenya using the Illumina platform and comparison with the Kenya 1950 isolate. The three genomes constitute a cluster that was phylogenetically distinct from other ASFV genomes, but 98-99 % conserved within the group. Vector-based compositional analysis of the complete genomes produced a similar topology. Of the 125 previously identified 'core' ASFV genes, two ORFs of unassigned function were absent from the genotype IX sequence which was 184 kb in size as compared to 191 kb for the genotype X. There were multiple differences among East African genomes in the 360 and 110 multicopy gene families. The gene corresponding to 360-19R has transposed to the 5' variable region in both genotype X isolates. Additionally, there is a 110 ORF in the tick-derived genotype X isolate formed by fusion of 13L and 14L that is unique among ASFV genomes. In future, functional analysis based on the variations in the multicopy families may reveal whether they contribute to the observed differences in virulence between genotpye IX and X viruses.
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