a State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute , Chinese Academy of Agricultural Sciences , Harbin , People's Republic of China.
b National High Containment Laboratory for Animal Diseases Control and Prevention , Harbin , People's Republic of China.
Emerg Microbes Infect. 2019;8(1):438-447. doi: 10.1080/22221751.2019.1590128.
African swine fever (ASF) entered China in August 2018 and rapidly spread across the entire country, severely threatening the Chinese domestic pig population, which accounts for more than 50% of the pig population worldwide. In this study, an ASFV isolate, Pig/Heilongjiang/2018 (Pig/HLJ/18), was isolated in primary porcine alveolar macrophages (PAMs) from a pig sample from an ASF outbreak farm. The isolate was characterized by using the haemadsorption (HAD) test, Western blotting and immunofluorescence, and electronic microscopy. Phylogenetic analysis of the viral p72 gene revealed that Pig/HLJ/18 belongs to Genotype II. Infectious titres of virus propagated in primary PAMs and pig marrow macrophages were as high as 10 HAD/ml. Specific-pathogen-free pigs intramuscularly inoculated with different virus dosages at 10-10 HAD showed acute disease with fever and haemorrhagic signs. The incubation periods were 3-5 days for virus-inoculated pigs and 9 days for contact pigs. All virus-inoculated pigs died between 6-9 days post-inoculation (p.i.), and the contact pigs died between 13-14 days post-contact (p.c.). Viremia started on day 2 p.i. in inoculated pigs and on day 9 p.c. in contact pigs. Viral genomic DNA started to be detected from oral and rectal swab samples on 2-5 days p.i. in virus-inoculated pigs, and 6-10 days p.c. in contact pigs. These results indicate that Pig/HLJ/18 is highly virulent and transmissible in domestic pigs. Our study demonstrates the threat of ASFV and emphasizes the need to control and eradicate ASF in China.
非洲猪瘟（ASF）于 2018 年 8 月传入中国，并迅速蔓延至全国，严重威胁着中国国内的生猪存栏量，占全球生猪存栏量的 50%以上。在本研究中，从 ASF 暴发场的猪样本中，在原代猪肺泡巨噬细胞（PAMs）中分离到一株 ASFV 分离株，命名为 Pig/Heilongjiang/2018（Pig/HLJ/18）。该分离株通过红细胞吸附（HAD）试验、Western blot 和免疫荧光以及电子显微镜进行了鉴定。病毒 p72 基因的系统进化分析表明，Pig/HLJ/18 属于基因型 II。在原代 PAMs 和猪骨髓巨噬细胞中增殖的病毒滴度高达 10 HAD/ml。用不同剂量的病毒对特定病原体猪进行肌肉接种，在 10-10 HAD 时，猪表现出发热和出血症状的急性疾病。接种病毒的猪潜伏期为 3-5 天，接触猪为 9 天。所有接种病毒的猪在接种后 6-9 天死亡，接触猪在接触后 13-14 天死亡。接种病毒的猪在接种后第 2 天开始出现病毒血症，接触猪在接触后第 9 天出现病毒血症。在接种病毒的猪中，从接种后第 2-5 天开始，从口腔和直肠拭子样本中检测到病毒基因组 DNA，在接触猪中，从接触后第 6-10 天开始检测到病毒基因组 DNA。这些结果表明，Pig/HLJ/18 在国内猪中具有高度的毒力和传染性。我们的研究表明了 ASFV 的威胁，并强调了在中国控制和根除 ASF 的必要性。
