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Zheng Z, Xu L, Gao Y, Dou H, Zhou Y, Feng X, He X, Tian Z, Song L, Mo G, Hu J, Zhao H, Wei H, Church GM, Yang L. Testing multiplexed anti-ASFV CRISPR-Cas9 in reducing African swine fever virus. Microbiol Spectr 2024:e0216423. [PMID: 38563791 DOI: 10.1128/spectrum.02164-23] [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: 05/24/2023] [Accepted: 01/20/2024] [Indexed: 04/04/2024] Open
Abstract
African swine fever (ASF) is a highly fatal viral disease that poses a significant threat to domestic pigs and wild boars globally. In our study, we aimed to explore the potential of a multiplexed CRISPR-Cas system in suppressing ASFV replication and infection. By engineering CRISPR-Cas systems to target nine specific loci within the ASFV genome, we observed a substantial reduction in viral replication in vitro. This reduction was achieved through the concerted action of both Type II and Type III RNA polymerase-guided gRNA expression. To further evaluate its anti-viral function in vivo, we developed a pig strain expressing the multiplexable CRISPR-Cas-gRNA via germline genome editing. These transgenic pigs exhibited normal health with continuous expression of the CRISPR-Cas-gRNA system, and a subset displayed latent viral replication and delayed infection. However, the CRISPR-Cas9-engineered pigs did not exhibit a survival advantage upon exposure to ASFV. To our knowledge, this study represents the first instance of a living organism engineered via germline editing to assess resistance to ASFV infection using a CRISPR-Cas system. Our findings contribute valuable insights to guide the future design of enhanced viral immunity strategies. IMPORTANCE ASFV is currently a devastating disease with no effective vaccine or treatment available. Our study introduces a multiplexed CRISPR-Cas system targeting nine specific loci in the ASFV genome. This innovative approach successfully inhibits ASFV replication in vitro, and we have successfully engineered pig strains to express this anti-ASFV CRISPR-Cas system constitutively. Despite not observing survival advantages in these transgenic pigs upon ASFV challenges, we did note a delay in infection in some cases. To the best of our knowledge, this study constitutes the first example of a germline-edited animal with an anti-virus CRISPR-Cas system. These findings contribute to the advancement of future anti-viral strategies and the optimization of viral immunity technologies.
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Affiliation(s)
- Zezhong Zheng
- South China Agricultural University, Guangzhou, China
| | - Lei Xu
- Qihan Biotechnology, Hangzhou, China
| | | | | | | | - Xu Feng
- Qihan Biotechnology, Hangzhou, China
| | | | - Zhen Tian
- Qihan Biotechnology, Hangzhou, China
| | | | | | - Jiapan Hu
- Qihan Biotechnology, Hangzhou, China
| | - Hongye Zhao
- Yunan Agriculture University, Kunming, China
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Cho KH, Hong SK, Kim DY, Jang MK, Kim JH, Lee H, Kim EM, Park JH, Suh TY, Choi JG, Yoo DS, Kang HE, Kim YH. Pathogenicity and Pathological Characteristics of African Swine Fever Virus Strains from Pig Farms in South Korea from 2022 to January 2023. Pathogens 2023; 12:1158. [PMID: 37764966 PMCID: PMC10534632 DOI: 10.3390/pathogens12091158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Since the first African swine fever (ASF) outbreak occurred at a pig farm in South Korea in September 2019, as of 31 January 2023, 31 ASF cases have occurred at pig farms, while 2799 ASF virus (ASFV)-infected wild boars have been identified. The circulation of ASFV in wild boar populations poses a high risk of spillover to pig farms in the country. However, information on the changes in the pathogenicity of Korean ASFV strains from wild boars is not available. Investigating the pathogenicity of ASFV strains from pig farms is the only way to predict their alterations. In a previous study, no changes in the pathogenicity of ASFV strains circulating during 2019-2021 were identified through animal experiments. In this study, we chose two ASFV strains with potentially reduced pathogenicity among ten viruses obtained from pig premises from 2022 to January 2023 and estimated their pathogenicities and pathological characteristics. All the inoculated pigs died 8-10 days post-inoculation after showing pyrexia, depression, anorexia, and recumbency together with the common pathological lesions of enlarged hemorrhagic lymph nodes and splenomegaly with infarction. These results support that the pathogenicity among ASFV isolates in South Korea still remained unchanged during the study period.
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Affiliation(s)
- Ki-Hyun Cho
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Seong-Keun Hong
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Da-Young Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Min-Kyung Jang
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Jong-Ho Kim
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Hyunkyoung Lee
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Eun-Mi Kim
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (J.-H.K.); (H.L.); (E.-M.K.)
| | - Ji-Hoon Park
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Tae-Young Suh
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Jun-Gu Choi
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Dae-Sung Yoo
- College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Hae-Eun Kang
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
| | - Yeon-Hee Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (K.-H.C.); (S.-K.H.); (D.-Y.K.); (M.-K.J.); (J.-H.P.); (T.-Y.S.); (J.-G.C.); (H.-E.K.)
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Salman M, Lin H, Suntisukwattana R, Watcharavongtip P, Jermsutjarit P, Tantituvanont A, Nilubol D. Intradermal needle-free injection prevents African Swine Fever transmission, while intramuscular needle injection does not. Sci Rep 2023; 13:4600. [PMID: 36944725 PMCID: PMC10028754 DOI: 10.1038/s41598-023-31199-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/08/2023] [Indexed: 03/23/2023] Open
Abstract
Shared needles are a possible iatrogenic and hematogenous inanimate vector of African Swine Fever virus (ASFV) in farm conditions. To evaluate that possible transmission, sixty, 4-week-old pigs were procured from an ASF free herd free. Upon arrival, pigs were randomly divided into two sets. Set 1 served as seeder pigs, and were randomly allocated to 4 groups. The other pigs were divided into 8 groups, and served as sentinels. Seeder pigs were oronasally challenged with ASFV at high (108 copy numbers/mL), moderate (106 copy numbers/mL) or low (101 copy numbers/mL) challenge titer, except a subgroup that remained unchallenged (negative control). At 7 days post challenge (peak viremia), all four seeder groups were intradermally and intramuscularly (IM) injected with a vaccine adjuvant (Diluvac Forte, MSD Animal Health, The Netherlands) using a needle-free device (IDAL 3G, MSD Animal Health, The Netherlands) and conventional needles, respectively. The same needle or needle-free device was then used to inject the same volume of adjuvant into set 2 (n = 48) pigs. All pigs were observed for clinical disease daily and assayed for the presence of ASFV DNA by quantitative PCR. All seeder groups developed viremia (except the control pigs). ASFV viremia was detected in all sentinel groups injected via the intramuscular route. Transmission rate from the IM route via conventional needles was positively correlated with virus titer in blood circulation of seeders. Sentinels intramuscularly exposed to needles from high titer challenged seeders displayed more severe and acute clinical disease compared to that of exposed to low titer challenged seeders. No viremia nor clinical signs were observed in the sentinel groups injected via the intradermal route. This study confirmed the hematogenous transmission of ASFV between pigs through needle-sharing.
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Affiliation(s)
- Muhammad Salman
- Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Hongyao Lin
- MSD Animal Health Innovation Pte Ltd, Singapore, 718847, Singapore
| | - Roypim Suntisukwattana
- Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Parin Watcharavongtip
- Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Patumporn Jermsutjarit
- Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Angkana Tantituvanont
- Department of Pharmaceutic and Industrial Pharmacies, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Dachrit Nilubol
- Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
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Innovative Research Offers New Hope for Managing African Swine Fever Better in Resource-Limited Smallholder Farming Settings: A Timely Update. Pathogens 2023; 12:pathogens12020355. [PMID: 36839627 PMCID: PMC9963711 DOI: 10.3390/pathogens12020355] [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: 02/01/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 02/23/2023] Open
Abstract
African swine fever (ASF) in domestic pigs has, since its discovery in Africa more than a century ago, been associated with subsistence pig keeping with low levels of biosecurity. Likewise, smallholder and backyard pig farming in resource-limited settings have been notably affected during the ongoing epidemic in Eastern Europe, Asia, the Pacific, and Caribbean regions. Many challenges to managing ASF in such settings have been identified in the ongoing as well as previous epidemics. Consistent implementation of biosecurity at all nodes in the value chain remains most important for controlling and preventing ASF. Recent research from Asia, Africa, and Europe has provided science-based information that can be of value in overcoming some of the hurdles faced for implementing biosecurity in resource-limited contexts. In this narrative review we examine a selection of these studies elucidating innovative solutions such as shorter boiling times for inactivating ASF virus in swill, participatory planning of interventions for risk mitigation for ASF, better understanding of smallholder pig-keeper perceptions and constraints, modified culling, and safe alternatives for disposal of carcasses of pigs that have died of ASF. The aim of the review is to increase acceptance and implementation of science-based approaches that increase the feasibility of managing, and the possibility to prevent, ASF in resource-limited settings. This could contribute to protecting hundreds of thousands of livelihoods that depend upon pigs and enable small-scale pig production to reach its full potential for poverty alleviation and food security.
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Duck plague virus infection alter the microbiota composition and intestinal functional activity in Muscovy ducks. Poult Sci 2022; 102:102365. [PMID: 36610104 PMCID: PMC9829712 DOI: 10.1016/j.psj.2022.102365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/24/2022] [Accepted: 11/27/2022] [Indexed: 12/15/2022] Open
Abstract
Intestinal damage from the duck plague virus (DPV) infection affects intestinal inflammation factors expression and barrier dysfunction. Here we report findings from the pathogenicity of the intestinal tract, intestinal morphological, intestinal permeability, inflammatory cytokines, and tight junction gene expression in 72 two-wk-old Muscovy ducks exposed to DPV. The characterization of intestinal metabolites and their classification were examined using 16-sequencing technology. The primary outcomes of the study evaluated the correlation between intestinal microbiota characteristics and the degree of infected tissue. The secondary outcomes were to determine whether the biosignatures that defined the microbiota were positively or negatively correlated with viral infection. The tissue was infected accompanied a mild damage of liver and spleen, and severe intestinal bleeding. Two inoculation routes were constructed with susceptible animals to assess the pathogenicity of the DPV in order to enrich the status of infection in Muscovy ducks. High levels of virus titer from Muscovy ducks were found being in the intestine. The expression of INF-α and IL-β with viral infection increased at 4, and 6 dpi, respectively, after detecting of the inflammatory factor and barrier function genes. At 4 and 6 dpi, barrier function gene of ZO-1 and Occludin reduced. The severity of viral infection was significantly correlated with the characteristics of the intestinal microbiota. Ducks infected with the DPV had an increase in the phylum Firmicutes, a decrease in the phylum Actinobacteriota, and differential enrichment with the genus Bacteroides, Tyzzerella, Enterococcus, and Escherchia-Shigella, while the genus Rothia, Streptococcus, and Ralstonia were differentially enriched in the control group. The findings from the current study demonstrated that DPV infection leads to an imbalance of the intestinal microbiota and disruption of the microbial homeostasis in the intestinal tissue in ducks, which might be one of the mechanisms whereby DPV infection might be established in Muscovy ducks. Na+/K+-ATPase and Ca2+/Mg2+-ATPase activity monitoring also showed that viral infection reduced these activities. These findings imply that changes in intestinal microbiota, intestinal barrier gene expression, and inflammatory factor are related to viral infection. When taken as a whole, this work provides fresh perspectives on the characteristics of intestinal microbiota and the infection damage caused by the DPV.
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Comparison of the Virulence of Korean African Swine Fever Isolates from Pig Farms during 2019-2021. Viruses 2022; 14:v14112512. [PMID: 36423121 PMCID: PMC9696264 DOI: 10.3390/v14112512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) was first reported in South Korea in September 2019, and as of 31 December 2021, a total of 21 cases in domestic pig farms and 1875 ASFV-infected wild boars have been confirmed in the country. With the continued circulation of ASF in wild boars, and subsequent outbreaks in domestic pigs, concerns were raised about the possible changes in virulence occurring among African swine fever viruses (ASFV) circulating in South Korea. In this study, four Korean ASFV strains isolated from domestic pig farms at different time points between 2019 and 2021 were chosen, and used to experimentally infect domestic pigs by intramuscular inoculation to compare their virulence. All challenged pigs died at 4-9 days post-inoculation, with many showing clinical symptoms of fever, depression, loss of appetite, and recumbency. Gross lesions observed at necropsy included enlargement and hemorrhage of the lymph nodes and hydropericardium. The study showed that all four Korean ASFV isolates caused acute forms of illness, which supports the view that virulence among the circulating ASFV isolates in South Korea remained unchanged and highly virulent during this period.
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Oh SI, Nguyen TTH, Yang MS, Nga BTT, Bui VN, Le VP, Yi SW, Kim E, Hur TY, Lee HS, Kim B. Blood parameters and pathological lesions in pigs experimentally infected with Vietnam's first isolated African swine fever virus. Front Vet Sci 2022; 9:978398. [PMID: 36157181 PMCID: PMC9495444 DOI: 10.3389/fvets.2022.978398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/01/2022] [Indexed: 11/28/2022] Open
Abstract
African swine fever virus (ASFV) is a notable virus and one of the most serious global threats to the pig industry. Improving awareness about host–virus interactions could facilitate the understanding of the disease pathogenesis. Therefore, we investigated changes in blood parameters, viral loads, and pathological changes in ASFV-inoculated pigs according to the time of death after the onset of viremia. For the analyses, the ASFV-infected pigs (n = 10) were divided into two groups (five pigs/group) according to their time of death after the onset of viremia. The blood cell count dynamics and serum biochemistry profiles were similar between the groups; however, viral load distribution was different. A comparison of the histopathological changes and immunohistochemistry results between the two groups indicated that the lymphoid system, particularly the spleen, was more damaged in the early stage of the disease than in the last stage. Additionally, the virus-induced lesions in other organs (liver and kidney) were more severe in the late stage than in the early stage. Our findings provide invaluable information on the characteristics of blood parameters and pathological lesions in pigs infected with the Asia-epidemic ASFV strain and the course of ASF, targeting internal organs in pigs. Overall, this study characterizes the host-pathogen interaction in ASFV infection, offering insight for the establishment of ASF control strategies.
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Affiliation(s)
- Sang-Ik Oh
- National Institute of Animal Science, Rural Development Administration, Wanju, South Korea
- College of Veterinary Medicine, Jeonbuk National University, Iksan, South Korea
- Sang-Ik Oh
| | - Thi Thu Huyen Nguyen
- Bac Giang Agriculture and Forestry University, Hanoi, Vietnam
- College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Myeon-Sik Yang
- College of Veterinary Medicine, Jeonbuk National University, Iksan, South Korea
| | - Bui Thi To Nga
- College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Vuong Nghia Bui
- Virology Department, National Institute of Veterinary Research, Hanoi, Vietnam
| | - Van Phan Le
- College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Seung-Won Yi
- National Institute of Animal Science, Rural Development Administration, Wanju, South Korea
| | - Eunju Kim
- National Institute of Animal Science, Rural Development Administration, Wanju, South Korea
| | - Tai-Young Hur
- National Institute of Animal Science, Rural Development Administration, Wanju, South Korea
| | - Hu Suk Lee
- International Livestock Research Institute, Hanoi, Vietnam
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
- Hu Suk Lee
| | - Bumseok Kim
- College of Veterinary Medicine, Jeonbuk National University, Iksan, South Korea
- *Correspondence: Bumseok Kim
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Establishment of a Direct PCR Assay for Simultaneous Differential Diagnosis of African Swine Fever and Classical Swine Fever Using Crude Tissue Samples. Viruses 2022; 14:v14030498. [PMID: 35336904 PMCID: PMC8948687 DOI: 10.3390/v14030498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/17/2022] [Accepted: 02/25/2022] [Indexed: 12/04/2022] Open
Abstract
African swine fever (ASF) and classical swine fever (CSF) are contagious swine diseases that are clinically indistinguishable from each other; hence, reliable test methods for accurate diagnosis and differentiation are highly demanded. By employing a buffer system suitable for crude extraction of nucleic acids together with an impurity-tolerant enzyme, we established a multiplex assay of real-time reverse-transcription polymerase chain reaction (rRT-PCR) for simultaneous detection of ASF virus (ASFV), CSF virus (CSFV) and swine internal control derived genes in a sample without the need for prior purification of viral nucleic acids. We applied this method to test serum and tissue samples of infected pigs and wild boars and compared the statistical sensitivities and specificities with those of standard molecular diagnostic methods. When a serum was used as a test material, the newly established assay showed 94.4% sensitivity for both and 97.9 and 91.9% specificity for ASFV and CSFV detection, respectively. In contrast, the results were 100% identical with those obtained by the standard methods when a crude tissue homogenate was used as a test material. The present data indicate that this new assay offers a practical, quick, and reliable technique for differential diagnosis of ASF and CSF where geographical occurrences are increasingly overlapping.
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