cats can spread coronavirus and must be kept indoors while their owners self-isolate, scientists say.Moggies are "highly susceptible" to catching the virus and can pass it on for the next five days.Dogs can also catch the bug but don't pose any risk of infecting others with Covid-19, a US pilot study found.There are now hopes that felines' immune systems could hold the key for new coronavirus vaccines as the virus's global death toll topped one million.The Colorado State University researchers said: "Infected pet cats should not be allowed to roam freely outdoors to prevent potential risk of spreading infection to other outdoor cats or wildlife."While neither species developed clinical disease in this study, cats shed infectious virus for.