Date Received: 04-06-2025
Date Accepted: 31-07-2025
Date Published: 31-07-2025
##submissions.doi##: https://doi.org/10.31817/tckhnnvn.2025.23.7.04
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Virulence Assessment of the African Swine Fever Virus Strain VNUA/HY-ASF1 Through Contact Transmission Between Healthy Pigs and Experimentally Infected Pigs via Intranasal Route
Keywords
African swine fever (ASF), genotype II, natural transmission, clinical signs, pathological lesions
Abstract
This study assessed the infectivity and disease progression of African swine fever virus (ASFV) through a natural transmission model between pigs directly inoculated via intranasal instillation and contact pigs. The results showed that inoculated pigs exhibited clinical signs from 3–4 days post-inoculation (dpi), including high fever (>40°C), lethargy, anorexia, and mortality between 6–9 dpi. Contact pigs developed symptoms from 8 dpi, with two pigs dying at 14 dpi, while the remaining pig exhibited severe clinical signs, including a critically high fever (41.9°C). Real-time PCR testing detected ASFV in blood as early as 4 dpi in inoculated pigs and 6 dpi in contact pigs, with viral loads increasing over time and peaking before death. ASFV was also detected in natural orifices (nasal, oral, and rectal secretions) with varying levels of viral shedding. Gross pathological assessment revealed that the spleen was the most severely affected organ, characterized by enlargement, congestion, and softening, while the lungs, liver, kidneys, and lymph nodes exhibited lesions ranging from mild to severe. The overall severity of organ lesions increased from inoculated to contact pigs, reflecting the disease's progression. These findings provide critical insights into ASFV transmission dynamics, viral shedding, and pathological outcomes in a natural infection model, contributing to a better understanding of ASFV spread in pig populations
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