Transmission of SARS-CoV-2 from humans to cats
Susceptibility to SARS-CoV-2 infection has been demonstrated in a wide range of mammals under laboratory conditions, with cats and ferrets being the most permissive hosts. Although the transmission of SARS-CoV-2 is mainly between humans, there have been reports of probable human-to-cat transmission, including transmission from infected owners of pet cats.
On 8 May 2020, the Institute of Agrifood Research and Technology (IRTA) reported the case of the first cat infected with SARS-CoV-2 in Spain. It was a 4-year-old cat, who lived with a family affected by COVID-19, with one case of death. Coinciding with these facts, the animal presented severe respiratory difficulties and was taken to a veterinary hospital. The RT-PCR test confirmed that the animal had become infected with SARS-CoV-2, but with a very low and residual viral load.
To date there have been few cases of feline SARS-CoV-2 infection worldwide, which is why the IRTA-CReSA coronavirus research team, alongside researchers from IrsiCaixa, the Barcelona Supercomputing Center (BSC) and veterinarians from a veterinary hospital near Barcelona have deepened the case study and published it recently in the journal Proceedings of the National Academy of Sciences (PNAS). They performed serological tests on the cat and another cat that also lived in the same home, which did not show any signs of disease. The tests, showed that the two cats had developed antibodies against SARS-CoV-2.
Experimental studies currently being conducted show that cats, in addition to becoming infected with SARS-CoV-2, can transmit it to other nearby cats, but without any clinical signs. However, the first suspicions of researchers were that both cats had been infected by their owners because they had not had contact with other cats.
Library preparation kits for sequencing SARS-CoV-2
Using Swift Bioscience’s Swift Amplicon® SARS-CoV-2 panel, this group was able to:
- Perform whole-genome sequencing of the viruses from the infected cat and its owner and confirm their close genetic relationship (99.9% nucleotide identity).
- Detect mutations in the cat’s sequence that have not been previously detected in pets and the larger number of mutations observed in the owner’s sequence may have been due to a longer time of infection in humans and/or less efficient viral replication in cats.
- Confirm previous observations of asymptomatic or mildly symptomatic SARS-CoV2 infection in cats, although it cannot be excluded that it may lead to severe disease
In conclusion, these findings should encourage COVID-19-positive cat owners to avoid close contact with their pets in order to prevent virus transmission. The World Organization for Animal Health (OIE) recommends that domestic cats in COVID-19 positive households should quarantine like their owners, mainly for their well-being and not due to public health concerns.
Reference: Joaquim Segalés, Mariona Puig, Jordi Rodon, Carlos Avila-Nieto, Jorge Carrillo, Guillermo Cantero, Maria Teresa Terrón, Sílvia Cruz, Mariona Parera, Marc Noguera-Julián, Nuria Izquierdo-Useros, Víctor Guallar, Enric Vidal, Alfonso Valencia, Ignacio Blanco, Julià Blanco, Bonaventura Clotet, Júlia Vergara-Alert. Detection of SARS-CoV-2 in a cat owned by a COVID-19−affected patient in Spain. Proceedings of the National Academy of Sciences. PNAS first published September 18, 2020. 202010817; DOI: 10.1073/pnas.2010817117