Pathobiological analysis of african swine fever virus contact-exposed pigs and estimation of the basic reproduction number of the virus in Vietnam

Porcine Health Management

Research

Yoon Jung Do¹  Tai-Young Hur¹  Young-Hun Jung¹  Eunju Kim¹  Ara Cho¹  Han Gyu Lee¹  Eun-Yeong Bok¹  Sang-Ik Oh²  Hu Suk Lee³  Duy Tung Dao⁴  Vuong Nghia Bui⁴  Ngoc Anh Bui⁴ 

[1] Division of Animal Diseases & Health, Rural Development Administration, National Institute of Animal Science, 55365, Wanju, Republic of Korea;Division of Animal Diseases & Health, Rural Development Administration, National Institute of Animal Science, 55365, Wanju, Republic of Korea;Bio-Safety Research Institute and Laboratory of Veterinary Pathology, College of Veterinary Medicine, Jeonbuk National University, 54596, Iksan, Republic of Korea;International Livestock Research Institute, Hanoi, Vietnam;College of Veterinary Medicine, Chungnam National University, 34134, Daejeon, Republic of Korea;Virology Department, National Institute of Veterinary Research, Hanoi, Vietnam;

关键词: African swine fever;    African swine fever virus;    Basic reproduction number (R);    Pathobiology;    Transmission rate (β);    Vietnam;   

DOI  :  10.1186/s40813-023-00330-0

 received in 2023-02-17, accepted in 2023-06-26,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundAfrican 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 (R0) in Vietnam. Fifteen pigs were randomly divided into two groups: experimental (n = 10) and negative control (n = 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).ResultsThe 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 R0. The R0 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]: 0.379–1.765) for EG and 1.004 (95% CI: 0.283–2.450) for ML.ConclusionsThis 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.

【 授权许可】

CC BY   
© The Author(s) 2023

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