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Susceptibility of ferrets, cats, dogs, and other domesticated animals to SARS–coronavirus 2

2020/4/19 16:45:17      点击:

Jianzhong Shi1*, Zhiyuan Wen1*, Gongxun Zhong1*, Huanliang Yang1*, Chong Wang1*, Baoying Huang2*, Renqiang Liu1, Xijun He3, Lei Shuai1, Ziruo Sun1, Yubo Zhao1, Peipei Liu2, Libin Liang1, Pengfei Cui1, Jinliang Wang1, Xianfeng Zhang3, Yuntao Guan3, Wenjie Tan2, Guizhen Wu2†, Hualan Chen1†, Zhigao Bu1,3† 


1State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, People’s Republic of China. 2National Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, People’s Republic of China. 3National High Containment Laboratory for Animal Diseases Control and Prevention, Harbin 150069, People’s Republic of China. *These authors contributed equally to this work. 


†Corresponding author. Email: [email protected] (Z.B.); [email protected] (H.C.); [email protected] (G.W.) Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the infectious disease COVID-19, which was first reported in Wuhan, China in December, 2019. Despite the tremendous efforts to control the disease, COVID-19 has now spread to over 100 countries and caused a global pandemic. SARS-CoV-2 is thought to have originated in bats; however, the intermediate animal sources of the virus are completely unknown. Here, we investigated the susceptibility of ferrets and animals in close contact with humans to SARS-CoV-2. We found that SARS-CoV-2 replicates poorly in dogs, pigs, chickens, and ducks, but ferrets and cats are permissive to infection. We found experimentally that cats are susceptible to airborne infection. Our study provides important insights into the animal models for SARS-CoV-2 and animal management for COVID-19 control.


In late December 2019, an unusual pneumonia emerged in humans in Wuhan, China, and rapidly spread internationally, raising global public health concerns. The causative pathogen was identified as a novel coronavirus (1–16 ) that was named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on the basis of a phylogenetic analysis of related coro-naviruses by the Coronavirus Study Group of the Interna-tional Committee on Virus Taxonomy (17 ); the  disease it causes was subsequently designated COVID-19 by the World Health Organization (WHO). Despite tremendous efforts to control the COVID-19 outbreak, the disease is still spreading. As of March 11, 2020, SARS-CoV-2 infections have been re-ported in more than 100 countries, and 118,326 human cases have been confirmed, with 4,292 fatalities (18 ). COVID-19 has now been announced as a pandemic by WHO. 


Although SARS-CoV-2 shares 96.2% identity at the nucle-otide level with the coronavirus RaTG13, which was detected in horseshoe bats (R h in olo ph u s  spp) in Yunnan province in 2013 (3 ), it has not previously been detected in humans or other animals. The emerging situation raises many urgent questions. Could the widely disseminated viruses transmit to other animal species, which then become reservoirs of infec-tion? The SARS-CoV-2 infection has a wide clinical spectrum in humans, from mild infection to death, but how does the virus behave in other animals? As efforts are made for vaccine and antiviral drug development, which animal(s) can be used most precisely to model the efficacy of such control measures in humans? To address these questions, we evaluated the sus-ceptibility of different model laboratory animals, as well as companion and domestic animals to SARS-CoV-2. 


All experiments with infectious SARS-CoV-2 were per-formed in the biosafety level 4 and animal biosafety level 4 facilities in the Harbin Veterinary Research Institute (HVRI) of the Chinese Academy of Agricultural Sciences (CAAS), which was approved for such use by the Ministry of Agricul-ture and Rural Affairs of China. Details of the biosafety and biosecurity measures taken are provided in the supplemen-tary materials (19 ). The protocols for animal study and ani-mal welfare were reviewed and approved by the Committee on the Ethics of Animal Experiments of the HVRI of CAAS (approval number 2020-01-01JiPi). 

Ferrets are commonly used as an animal model for respir-atory viruses that infected humans (20–26 ). We therefore tested the susceptibility of SARS-CoV-2 in ferrets. Two viruses [SARS-CoV-2/F13/environment/2020/Wuhan, isolated from an environmental sample collected in the Huanan Seafood Market in Wuhan (F13-E), and SARS-CoV-2/CTan/human/2020/Wuhan (CTan-H), isolated from a hu-man patient] were used in this study. Pairs of ferrets were inoculated intranasally with 105
 plaque forming unit (PFU) of F13-E or CTan-H, respectively, and euthanized on day 4 post-inoculation (p.i.). The nasal turbinate, soft palate, tonsils, trachea, lung, heart, liver, spleen, kidneys, pancreas, small in-testine, and brain from each ferret were collected for viral RNA quantification by qPCR and virus titration in Vero E6 cells. Viral RNA (Fig. 1, A and B) and infectious virus were detected in the nasal turbinate, soft palate, and tonsils of all four ferrets inoculated with these two viruses, but was not detected in any other organs tested (Fig. 1, C and D). These results indicate that SARS-CoV-2 can replicate in the upper respiratory tract of ferrets, but its replication in other organs is undetectable. 


To investigate the replication dynamics of these viruses in ferrets, groups of three animals were inoculated intranasally with 105 PFU of F13-E or CTan-H, and then placed in three separate cages within an isolator. Nasal washes and rectal swabs were collected on days 2, 4, 6, 8, and 10 p.i. from the ferrets for viral RNA detection and virus titration. Body tem-peratures and signs of disease were monitored for two weeks. As shown in Fig. 1, viral RNA was detected in the nasal washes on days 2, 4, 6, and 8 p.i. in all six ferrets inoculated with the two viruses (Fig. 1, E and F). Viral RNA was also de-tected in some of the rectal swabs of the virus-inoculated fer-rets although the copy numbers were notably lower than those in the nasal washes of these ferrets (fig. S1, A and C). Infectious virus was detected from the nasal washes of all fer-rets (Fig. 1, G and H), but not from the rectal swabs of any ferrets (fig. S1, B and D). 


One ferret from each virus-inoculated group developed fe-ver and loss of appetite on days 10 and 12 p.i., respectively. To investigate whether these symptoms were caused by virus replication in the lower respiratory tract, we euthanized the two ferrets on day 13 p.i., and collected their organs for viral RNA detection. However, viral RNA was not detected in any other tissues or organs of either ferret, except for a low copy number (105.4  copies/g) in the turbinate of the ferret inocu-lated with CTan-H (fig. S2). Pathological studies revealed se-vere lymphoplasmacytic perivasculitis and vasculitis, increased numbers of type II pneumocytes, macrophages, and neutrophils in the alveolar septa and alveolar lumen, and mild peribronchitis in the lungs of the two ferrets euthanized on day 13 p.i. (fig. S3). Antibodies against SARS-CoV-2 were detected in all of the ferrets by an ELISA and a neutralization assay, although the antibody titers of the two ferrets that were euthanized on day 13 p.i. were notably lower than those of the ferrets euthanized on day 20 p.i. (Fig. 1, I to L).