Pathobiological characterization and estimation of the basic reproduction number of a recombinant african swine fever virus in contact-exposed pigs in Vietnam.
| Title: | Pathobiological characterization and estimation of the basic reproduction number of a recombinant african swine fever virus in contact-exposed pigs in Vietnam. |
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| Authors: | Nguyen TVH; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Vu ND; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Nguyen VD; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Than TT; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Dang TN; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Nguyen HT; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Tran TCG; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Nguyen HT; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Nguyen PA; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam.; Cho KH; Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea.; Hong SK; Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea.; Ambagala A; Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB R3E 3R2, Canada.; Kim YH; Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea. Electronic address: vetyh@korea.kr.; Le VP; College of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam; Laboratory of Viral Infectious Diseases, Center for Research Excellence and Innovation, Vietnam National University of Agriculture, Hanoi 100000, Vietnam. Electronic address: letranphan@vnua.edu.vn. |
| Source: | Veterinary microbiology [Vet Microbiol] 2026 May; Vol. 316, pp. 110961. Date of Electronic Publication: 2026 Feb 27. |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: Elsevier Scientific Pub. Co Country of Publication: Netherlands NLM ID: 7705469 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-2542 (Electronic) Linking ISSN: 03781135 NLM ISO Abbreviation: Vet Microbiol Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: Amsterdam, Elsevier Scientific Pub. Co. |
| MeSH Terms: | African Swine Fever*/virology ; African Swine Fever*/transmission ; African Swine Fever*/pathology ; African Swine Fever*/epidemiology ; African Swine Fever Virus*/genetics ; African Swine Fever Virus*/pathogenicity ; African Swine Fever Virus*/physiology ; Basic Reproduction Number*/veterinary; Vietnam/epidemiology ; Viral Load/veterinary ; Antibodies, Viral/blood ; Viremia/veterinary ; Animals ; Swine ; Virus Replication ; Genotype ; Virulence |
| Abstract: | African swine fever virus (ASFV) causes a highly lethal disease in domestic pigs, resulting in severe economic losses. This study examined the clinical course, viral dynamics, immune response, and pathological changes in pigs infected with a recombinant ASFV strain of p72 genotypes I/II (rASFV I/II) via direct inoculation or natural contact. The directly infected pig developed persistent fever (> 40 °C), anorexia, lethargy, and respiratory distress soon after the onset of viremia, and died six days post-inoculation (dpi). Contact-exposed pigs showed similar clinical signs and died between 12 and 21 days post-exposure (dpe). Real-time PCR revealed rapid viral replication in blood and secretions, with peak viral loads detected at or just before death. No detectable antibody response was observed in either group, indicating acute disease progression and high virulence. Gross pathological examination revealed severe lesions in the spleen, lymph nodes, gastrointestinal tract, and lungs. Epidemiological analysis using the susceptible-infectious-removed (SIR) model estimated the generation time (mean ± SD) as 1.101 ± 0.507 days. The basic reproduction number (R₀) was 1.201 (95% CI: 0.628-2.302) using the exponential growth method and 1.248 (95% CI: 0.310-3.236) using the maximum likelihood method. These findings demonstrate the high virulence and transmission potential of the rASFV I/II strain, highlighting the need for early detection and rapid containment measures.; (Copyright © 2026 Elsevier B.V. All rights reserved.) |
| Competing Interests: | Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. |
| Contributed Indexing: | Keywords: Pathogenicity; Pig; Recombinant African swine fever virus; R₀; rASFV I/II |
| Substance Nomenclature: | 0 (Antibodies, Viral) |
| Entry Date(s): | Date Created: 20260307 Date Completed: 20260418 Latest Revision: 20260418 |
| Update Code: | 20260420 |
| DOI: | 10.1016/j.vetmic.2026.110961 |
| PMID: | 41793983 |
| Database: | MEDLINE |
Journal Article