Potential infectious risk from the pets carrying SARS-CoV-2.

Dear Editor,

Since December 2019, novel coronavirus (SARS-CoV-2)-infected pneumonia (COVID-19) occurred in Wuhan, and rapidly spread worldwide. Despite the commonly assumption that SARS-CoV-2 originated from wild animals, the transmission capacity of SARS-CoV-2 from domestic animals to humans is inconclusive. Recently, one preliminary study (albeit not peer-reviewed) suggested that cats could be infected with SARS-CoV-2 [1]. In addition, Hong Kong Department of Agriculture, Fisheries and Conservation also reported a SARS-CoV-2-carrying pet dog from a COVID-19 patient family. Samples from the dog's mouth, nasal cavity, and anus were tested for the virus nucleic acid, and showed weakly positive in oral and nasal samples [2].

These aroused our great concern on the pets, mainly mammals, such as cats and dogs, which may be potential carriers of SARS-CoV-2. In the previous SARS-CoV infection, Martina et al. found an asymptomatic infection of SARS-CoV in cats and their transmission to healthy cats [3]. Mechanically, Yan et al. recently reported the three-dimensional structure of the SARS-CoV-2 surface S protein receptor binding domain and the cell surface receptor angiotensin-converting enzyme 2 (ACE2) full-length protein complex [4]. The findings greatly promoted our understanding of the infectious mechanism of SARS-CoV-2 on human cells. Paralleling this, ACE2 was also expressed in the kidney and myocardial tissues of cats and dogs [5]. Sequencing of domestic cat lung tissues further revealed 85% similarity in the amino acid between cat and ACE2. More importantly, three ACE2 domains associated with SARS-CoV in the cat have the highest homology with human ACE2, suggesting that cats may be involved in SARS-CoV-2 interspecies infection [6].

To prevent pets from transmitting SARS-CoV-2 to humans, surveillance and isolation should be emphasized. First, during the COVID-19 outbreak, the pet owners should not take their pets out to those high-risk areas, even if they do, the pets should be tested. Second, for diagnosed COVID-19 patients, their pets need a surveillance and isolation to rule out the possibility of infection. Finally, for the recovered owners, their pets should be also tested and kept in quarantine. These recovered patients might be re-infected when they lived with the SARS-CoV-2-carrying pets again after discharge. Recently, some previously recovered COVID-19 patients had a positive virus detection. It was not clear whether it derived from the residual viruses in the body or the viruses in the environment from infected pets.

Funding source

None.

Declaration of competing interest

No competing interest.