Limit the number of new cats and isolate each for at least one month,
preferably two. I know it sounds like a long period of time, but
consider the alternatives! You could lose every cat in your household.
During the one month’s time period, make sure you watch carefully for
signs of illness. You should give the coronavirus titer test at the
beginning and the end of the quarantine period, and the titer should
decrease over that time period.

Scoop the litter box daily, discard the rest of the litter weekly and
disinfect the boxes with a 1:32 solution of bleach. The area around the
boxes should be swept and disinfected, there should be at least one box
for every two cats in the household. Again, weekly discarding of the
scoopable litter may seem like a waste, but so far the ONLY thing the
sources agree upon with regard to transmission is that it is definitely
transmitted through the feces, if nothing else. In the words of one
breeder: “It cost me approximately $3,000 in veterinary and laboratory
services to diagnose the incidence of FIP in my cattery, test and
retest (and retest) all of my cats. Believe me it is FAR less expensive
to discard the litter” (Polli, p. 81). If your cats have long hair and
fecal matter tends to stick to the britches, this hair should be kept
clipped short.

Change food and water daily, disinfect the bowls weekly. Do not mix the
bowls all around the house, keep the same set of bowls with the same
cats, and keep the same set of litter boxes with the same cats.