Department of Veterinary Medicine, Zhejiang University, Hangzhou, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.
Transbound Emerg Dis. 2022 Sep;69(5):e2006-e2019. doi: 10.1111/tbed.14535. Epub 2022 Apr 5.
A novel swine enteric alphacoronavirus, swine acute diarrhoea syndrome coronavirus (SADS-CoV), related to Rhinolophus bat CoV HKU2 in the subgenus Rhinacovirus emerged in southern China in 2017, causing diarrhoea in newborn piglets, and critical questions remain about the pathogenicity, cross-species transmission and potential animal reservoirs. Our laboratory's previous research has shown that SADS-CoV can replicate in various cell types from different species, including chickens. Here, we systematically explore the susceptibility of chickens to a cell-adapted SADS-CoV strain both in vitro and in vivo. First, evidence of SADS-CoV replication in primary chicken cells, including cytopathic effects, immunofluorescence staining, growth curves and structural protein expression, was proven. Furthermore, we observed that SADS-CoV replicated in chicken embryos without causing gross lesions and that experimental infection of chicks resulted in mild respiratory symptoms. More importantly, SADS-CoV shedding and viral distribution in the lungs, spleens, small intestines and large intestines of infected chickens were confirmed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The genomic sequence of the original SADS-CoV from the pig source sample in 2017 was determined to have nine nucleotide differences compared to the cell-adapted strain used; among these were three nonsynonymous mutations in the spike gene. These results collectively demonstrate that chickens are susceptible to SADS-CoV infection, suggesting that they are a potential animal reservoir. To our knowledge, this study provides the first experimental evidence of cross-species infection in which a mammalian alphacoronavirus is able to infect an avian species.
一种新型猪肠道α冠状病毒，猪急性腹泻综合征冠状病毒（SADS-CoV），与亚属 Rhinacovirus 中的菊头蝠冠状病毒 HKU2 相关，于 2017 年在中国南方出现，导致新生仔猪腹泻，但其致病性、跨种传播和潜在动物宿主等关键问题仍未解决。我们实验室之前的研究表明，SADS-CoV 可以在不同物种的各种细胞类型中复制，包括鸡。在这里，我们系统地研究了 SADS-CoV 对细胞适应株的易感性，包括体外和体内研究。首先，证明了 SADS-CoV 在原代鸡细胞中的复制，包括细胞病变效应、免疫荧光染色、生长曲线和结构蛋白表达。此外，我们观察到 SADS-CoV 在鸡胚中复制而不引起明显病变，实验感染雏鸡引起轻微的呼吸道症状。更重要的是，通过定量逆转录聚合酶链反应和免疫组织化学证实了感染鸡的 SADS-CoV 脱落和病毒在肺部、脾脏、小肠和大肠中的分布。与用于细胞适应的毒株相比，2017 年猪源样本中原始 SADS-CoV 的基因组序列有 9 个核苷酸差异；其中尖峰基因中有 3 个非同义突变。这些结果共同表明，鸡易感染 SADS-CoV，提示其可能是一种潜在的动物宿主。据我们所知，这项研究首次提供了哺乳动物α冠状病毒能够感染禽类的种间感染实验证据。
