While researching appropriate medicine for humans infected with severe acute respiratory syndrome (SARS), scientists discovered that cats and ferrets can get SARS from humans, at least in a laboratory. Previously, only wildlife was known to have the virus. What is still unknown for certain is whether or not people can get SARS from infected cats and ferrets, and what role pets play in this disease. That uncertainty could change as research continues, but for now, there is no evidence that pets can give SARS to humans. According to the World Health Organization (WHO), several studies are being undertaken in this area.

Scientists gave the coronavirus to six cats and six ferrets. The cats had no signs other than a mild pneumonia. Half of the ferrets, however, became lethargic and one of them died four days later. The animals transmitted the virus to other animals. All of the animals clearly had respiratory disease. The remaining animals all produced antibodies in 28 days. The research was reported in the October 30, 2003, issue of the scientific journal Nature.

In their Consensus Document on the Epidemiology of Severe Acute Respiratory Syndrome (SARS) paper, WHO states, “Much more research is needed before any firm conclusions can be reached as to the role of these and other animals in the transmission of SARS to human populations and as animal reservoirs of SARS-CoV. At present, no evidence exists to suggest that these species play a significant role in the epidemiology of SARS outbreaks. However, it cannot be ruled out that these animals might have been a source of human infection.”

SARS was first recognized in China, where some animals (raccoon dogs [Nyctereutes procyonoides], ferret badgers [Melogale moschata], and masked palm civets [Paguma larvata]) had a similar virus. According to WHO, rats, mice, poultry, pigs, and rabbits are resistant to infection, but antibody levels are undetermined. In Severe acute respiratory syndrome coronavirus as an agent of emerging and reemerging infection (Cheng VC, Lau SK, Woo PC, Yuen KY; Clin Microbiol Rev. 2007 Oct;20(4):660-94), the authors say that horseshoe bats are the natural reservoir for SARS-CoV-like virus and civets are the amplification host.

In Isolation And Characterization Of A Bat SARS-Like Coronavirus That Uses The ACE2 Receptor, the authors report whole-genome sequences of two novel bat coronaviruses from Chinese horseshoe bats (family: Rhinolophidae). The authors also say: "We report the first recorded isolation of a live SL-CoV (bat SL-CoV-WIV1) from bat faecal samples in Vero E6 cells, which has typical coronavirus morphology, 99.9% sequence identity to Rs3367 and uses ACE2 from humans, civets, and Chinese horseshoe bats for cell entry. Preliminary in vitro testing indicates that WIV1 also has a broad species tropism. Our results provide the strongest evidence to date that Chinese horseshoe bats are natural reservoirs of SARS-CoV, and that intermediate hosts may not be necessary for direct human infection by some bat SL-CoVs."

In Severe acute respiratory syndrome vaccine efficacy in ferrets: whole killed virus and adenovirus-vectored vaccines (See RH, Petric M, Lawrence DJ, Mok CP, Rowe T, Zitzow LA, Karunakaran KP, Voss TG, Brunham RC, Gauldie J, Finlay BB, Roper R; J Gen Virol. 2008 Sep;89(Pt 9):2136-46), the authors say: The ferret may be a good model for SARS-CoV infection because it is the only model that replicates the fever seen in human patients, as well as replicating other SARS disease features including infection by the respiratory route, clinical signs, viral replication in upper and lower respiratory tract and lung damage.

The big SARS outbreak ended in 2003, but several smaller outbreaks were reported in 2004, and public health officials expected further outbreaks in the future. However, as of November, 2017, the WHO and the CDC both indicate that there have not been any more cases of SARS reported anywhere in the world.