Comparison of Genotype II African Swine Fever Virus Strain SY18 Challenge Models
Author:
Zhou Xintao123ORCID, Fan Jiaqi123, Guo Xiaopan23, Chen Teng23, Yang Jinjin23, Zhang Yanyan23, Mi Lijuan23, Zhang Fei23, Miao Faming23, Li Min1, Hu Rongliang123ORCID
Affiliation:
1. College of Life Sciences, Ningxia University, Yinchuan 750021, China 2. Key Laboratory of Prevention & Control for African Swine Fever and Other Major Pig Diseases, Ministry of Agriculture and Rural Affairs, Changchun 130122, China 3. Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130122, China
Abstract
African swine fever (ASF) is a viral haemorrhagic disease found in domestic and wild boars caused by the African swine fever virus (ASFV). A highly virulent strain was used to evaluate the efficacy of newly developed vaccine candidates. The ASFV strain SY18 was isolated from the first ASF case in China and is virulent in pigs of all ages. To evaluate the pathogenesis of ASFV SY18 following intraoral (IO) and intranasal (IN) infections, a challenge trial was conducted in landrace pigs, with intramuscular (IM) injection as a control. The results showed that the incubation period of IN administration with 40–1000 50 % tissue culture infective dose (TCID50) was 5–8 days, which was not significantly different from that of IM inoculation with 200 TCID50. A significantly longer incubation period, 11–15 days, was observed in IO administration with 40–5000 TCID50. Clinical features were similar among all infected animals. Symptoms, including high fever (≥40.5 °C), anorexia, depression, and recumbency, were observed. No significant differences were detected in the duration of viral shedding during fever. There was no significant difference in disease outcome, and all animals succumbed to death. This trial showed that IN and IO infections could be used for the efficacy evaluation of an ASF vaccine. The IO infection model, similar to that of natural infection, is highly recommended, especially for the primary screening of candidate vaccine strains or vaccines with relatively weak immune efficacy, such as live vector vaccines and subunit vaccines.
Funder
National Key Research and Development Program of China
Subject
Virology,Infectious Diseases
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