Research out of Kansas State University (K-State) has found cats can be asymptomatic carriers of SARS-CoV-2, the coronavirus responsible for COVID-19. Specifically, domestic cats without obvious clinical signs of the virus can still shed SARS-CoV-2 through their nasal, oral, and rectal cavities, and are capable of spreading it efficiently to other cats within two days, researchers say.
Additional studies are needed to determine whether domestic cats can spread the virus to other animals and humans.
Conversely, pigs are unlikely to be significant carriers of the virus, K-State says.
“Other research has shown COVID-19-infected human patients are transmitting SARS-CoV-2 to cats; this includes domestic cats and even large cats, such as lions and tigers,” says Jürgen A. Richt, DVM, PhD, the Regents distinguished professor at K-State’s College of Veterinary Medicine (CVM). “Our findings are important because of the close association between humans and companion animals.”
There are about 95 million house cats in the U.S. and between 60 million and 100 million feral cats, according to Dr. Richt, who is also the director of the university’s Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD) and the Center on Emerging and Zoonotic Infectious Diseases (CEZID).
“This efficient transmission between domestic cats indicates a significant animal and public health need to investigate a potential human-cat-human transmission chain,” he says.
Meanwhile, regarding the porcine study, researchers determined SARS-CoV-2-infected pigs are not susceptible to the coronavirus infection and do not appear to transmit it to contact animals.
“Pigs play an important role in U.S. agriculture, which made it important to determine the potential SARS-CoV-2 susceptibility in pigs,” Richt says. “Our results show pigs are unlikely to be significant carriers of SARS-CoV-2.”
Researchers are planning additional studies to further understand SARS-CoV-2 transmission in cats and pigs. Specifically, Richt says, they intend to explore whether cats are immune to SARS-CoV-2 reinfection after they have recovered from a primary SARS-CoV-2 infection.
“This research is important for risk assessment, implementing mitigation strategies, addressing animal welfare issues, and to develop preclinical animal models for evaluating drug and vaccine candidates for COVID-19,” he says.
Richt is the senior author on two recent collaborative publications featured in the journal Emerging Microbes & Infections: “SARS-CoV-2 infection, disease and transmission in domestic cats” and “Susceptibility of swine cells and domestic pigs to SARS-CoV-2.”