Experimental infection of domestic dogs and cats with SARS-CoV-2: Pathogenesis, transmission, and response to reexposure in cats

Angela M. Bosco-Lauth; Airn E. Hartwig; Stephanie M. Porter; Paul W. Gordy; Mary Nehring; Alex D. Byas; Sue VandeWoude; Izabela K. Ragan; Rachel M. Maison; Richard A. Bowen

doi:10.1073/pnas.2013102117

New Research In

Edited by Peter Palese, Icahn School of Medicine at Mount Sinai, New York, NY, and approved August 27, 2020 (received for review June 24, 2020)

Significance

SARS-CoV-2 is an emerging pathogen that has already had catastrophic consequences on the health and well-being of people worldwide. As a zoonotic virus, the implications for animal populations are largely unknown. This manuscript describes a pilot study in which domestic cats and dogs were assessed for their susceptibility to infection. While neither species developed clinical disease in this study, cats shed infectious virus for up to 5 d and infected naive cats via direct contact, while dogs do not appear to shed virus. Cats that were reinfected with SARS-CoV-2 mounted an effective immune response and did not become reinfected. These studies have important implications for animal health and suggest that cats may be a good model for vaccine development.

Abstract

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached nearly every country in the world with extraordinary person-to-person transmission. The most likely original source of the virus was spillover from an animal reservoir and subsequent adaptation to humans sometime during the winter of 2019 in Wuhan Province, China. Because of its genetic similarity to SARS-CoV-1, it is probable that this novel virus has a similar host range and receptor specificity. Due to concern for human–pet transmission, we investigated the susceptibility of domestic cats and dogs to infection and potential for infected cats to transmit to naive cats. We report that cats are highly susceptible to infection, with a prolonged period of oral and nasal viral shedding that is not accompanied by clinical signs, and are capable of direct contact transmission to other cats. These studies confirm that cats are susceptible to productive SARS-CoV-2 infection, but are unlikely to develop clinical disease. Further, we document that cats developed a robust neutralizing antibody response that prevented reinfection following a second viral challenge. Conversely, we found that dogs do not shed virus following infection but do seroconvert and mount an antiviral neutralizing antibody response. There is currently no evidence that cats or dogs play a significant role in human infection; however, reverse zoonosis is possible if infected owners expose their domestic pets to the virus during acute infection. Resistance to reinfection holds promise that a vaccine strategy may protect cats and, by extension, humans.

Footnotes

↵¹A.M.B.-L., A.E.H., and S.M.P. contributed equally to this work.
↵²To whom correspondence may be addressed. Email: angela.bosco-lauth{at}colostate.edu.

Author contributions: A.M.B.-L., A.E.H., S.M.P., and R.A.B. designed research; A.M.B.-L., A.E.H., S.M.P., P.W.G., A.D.B., and R.A.B. performed research; P.W.G., M.N., and S.V. contributed new reagents/analytic tools; A.M.B.-L., A.E.H., S.M.P., M.N., A.D.B., I.K.R., and R.M.M. analyzed data; and A.M.B.-L. and S.V. wrote the paper.
The authors declare no competing interest.
This article is a PNAS Direct Submission.