SARS-CoV-2 in fruit bats, ferrets, pigs, and chickens: an experimental transmission study
SARS-CoV-2 in fruit bats, ferrets, pigs, and chickens: an experimental transmission study
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DOI：
10.1016/s2666-5247(20)30089-6
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发表时间：
2020-09-01
期刊：
影响因子：
38.2
通讯作者：
Beer, Martin
中科院分区：
文献类型：
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作者：
Schlottau, Kore;Rissmann, Melanie;Beer, Martin
背景2019年12月，中国出现了一种新型人畜共患严重急性呼吸综合征相关冠状病毒。新型严重急性呼吸综合征冠状病毒2（SARS-CoV-2）在数周内成为大流行，人类感染和重症病例的数量正在增加。我们的目的是调查潜在的动物宿主的易感性和人畜共患病的溢出infecties.Methods的风险，我们鼻内接种9只果蝠（Rousetus aegyptiacus），雪貂（Mustela putorius），猪（猪），和17只鸡（原鸡）与10（5）TCID 50的SARS-CoV-2分离株每只动物。在接种后24 h纳入直接接触动物（n=3），以检测病毒传播。在感染后第2、4、8、12、16和21天，通过定量RT-PCR（RT-qPCR）从鼻洗液和直肠拭子（雪貂）、口腔拭子和合并粪便样品（果蝠）、鼻拭子和直肠拭子（猪）或口咽拭子和泄殖腔拭子（鸡）中提取核酸，监测动物的临床体征和病毒脱落。在第4、8和12天，对每种属的两只接种动物（或在鸡的情况下为三只）实施安乐死，并在第21天对所有剩余动物（包括接触动物）实施安乐死。对所有动物进行尸检，并收集各种组织，通过RT-qPCR、组织病理学免疫组织化学和原位杂交进行病毒检测。SARS-CoV-2反应性抗体的存在进行了测试，通过间接免疫荧光试验和病毒中和试验在接种前收集的样品，并在尸检。所有拭子、器官样本和接触动物的病毒RNA均为阴性，猪或鸡均未发生血清转化。九只果蝠中有七只（78%）有短暂感染，通过RT-qPCR、免疫组织化学和鼻腔原位杂交可检测到病毒，与鼻炎相关。在第4天处死的两只动物的气管、肺和肺相关淋巴组织中也发现了病毒RNA。三分之一的接触蝙蝠被感染。在雪貂中观察到更有效的病毒复制，但未观察到临床体征，并传播给所有三只直接接触动物。轻度鼻炎与呼吸道和嗅觉上皮中的病毒抗原检测有关。在果蝠和雪貂的上呼吸道中检测到0- 10（4）个病毒基因组拷贝/mL的显著病毒RNA载量，并且两个物种在21天后产生SARS-CoV-2反应性抗体，中和滴度高达1/1024.Interpretation猪和鸡不能被SARS-CoV-2鼻内感染，而果蝠显示出储存宿主的特征。病毒在雪貂中的复制类似于亚临床的人类感染，并具有有效的传播。雪貂可以作为进一步研究的有用模型，例如，测试疫苗或抗病毒药。
Background In December, 2019, a novel zoonotic severe acute respiratory syndrome-related coronavirus emerged in China. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became pandemic within weeks and the number of human infections and severe cases is increasing. We aimed to investigate the susceptibilty of potential animal hosts and the risk of anthropozoonotic spill-over infections.Methods We intranasally inoculated nine fruit bats (Rousettus aegyptiacus), ferrets (Mustela putorius), pigs (Sus scrofa domesticus), and 17 chickens (Gallus gallus domesticus) with 10(5) TCID50 of a SARS-CoV-2 isolate per animal. Direct contact animals (n=3) were included 24 h after inoculation to test viral transmission. Animals were monitored for clinical signs and for virus shedding by nucleic acid extraction from nasal washes and rectal swabs (ferrets), oral swabs and pooled faeces samples (fruit bats), nasal and rectal swabs (pigs), or oropharyngeal and cloacal swabs (chickens) on days 2, 4, 8, 12, 16, and 21 after infection by quantitative RT-PCR (RT-qPCR). On days 4, 8, and 12, two inoculated animals (or three in the case of chickens) of each species were euthanised, and all remaining animals, including the contacts, were euthanised at day 21. All animals were subjected to autopsy and various tissues were collected for virus detection by RT-qPCR, histopathology immunohistochemistry, and in situ hybridisation. Presence of SARS-CoV-2 reactive antibodies was tested by indirect immunofluorescence assay and virus neutralisation test in samples collected before inoculation and at autopsy.Findings Pigs and chickens were not susceptible to SARS-CoV-2. All swabs, organ samples, and contact animals were negative for viral RNA, and none of the pigs or chickens seroconverted. Seven (78%) of nine fruit bats had a transient infection, with virus detectable by RT-qPCR, immunohistochemistry, and in situ hybridisation in the nasal cavity, associated with rhinitis. Viral RNA was also identified in the trachea, lung, and lung-associated lymphatic tissue in two animals euthanised at day 4. One of three contact bats became infected. More efficient virus replication but no clinical signs were observed in ferrets, with transmission to all three direct contact animals. Mild rhinitis was associated with viral antigen detection in the respiratory and olfactory epithelium. Prominent viral RNA loads of 0- 10(4) viral genome copies per mL were detected in the upper respiratory tract of fruit bats and ferrets, and both species developed SARS-CoV-2-reactive antibodies reaching neutralising titres of up to 1/1024 after 21 days.Interpretation Pigs and chickens could not be infected intranasally by SARS-CoV-2, whereas fruit bats showed characteristics of a reservoir host. Virus replication in ferrets resembled a subclinical human infection with efficient spread. Ferrets might serve as a useful model for further studies-eg, testing vaccines or antivirals.