책임운영기관 농촌진흥청 국립축산과학원 (로고)

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>African swine fever (ASF), caused by African swine fever virus (ASFV), is a fatal disease affecting wild and domestic pigs. Since China reported the first ASF outbreak in August 2018, ASFV has swept over the neighbouring Asian countries. However, studies involving experimental pig-to-pig ASFV transmission in Vietnam are lacking. The main objective of this experimental study was to demonstrate the pathobiological characteristics of ASFV contact-exposed pigs and estimate their basic reproduction number (R<jats:sub>0</jats:sub>) in Vietnam. Fifteen pigs were randomly divided into two groups: experimental (n&#8201;=&#8201;10) and negative control (n&#8201;=&#8201;5) groups. One pig in the experimental group was intramuscularly inoculated with ASFV strain from Vietnam in 2020 and housed with the uninoculated pigs during the study period (28 days).</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The inoculated pig died 6 days post-inoculation, and the final survival rate was 90.0%. We started observing viremia and excretion of ASFV 10 days post-exposure in contact-exposed pigs. Unlike the surviving and negative control pigs, all necropsied pigs showed severe congestive splenomegaly and moderate-to-severe haemorrhagic lesions in the lymph nodes. The surviving pig presented with mild haemorrhagic lesions in the spleen and kidneys. We used Susceptible-Infectious-Removed models for estimating R<jats:sub>0</jats:sub>. The R<jats:sub>0</jats:sub> values for exponential growth (EG) and maximum likelihood (ML) were calculated to be 2.916 and 4.015, respectively. In addition, the transmission rates (β) were estimated to be 0.729 (95% confidence interval [CI]: 0.379&#8211;1.765) for EG and 1.004 (95% CI: 0.283&#8211;2.450) for ML.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>This study revealed pathobiological and epidemiological information in about pig-to-pig ASFV transmission. Our findings suggested that culling infected herds within a brief period of time may mitigate the spread of ASF outbreaks.</jats:p> </jats:sec>