Niels Pedersen, DVM, PhD, professor emeritus, University of California, Davis School of Veterinary Medicine, explains what in feline enteric coronavirus is and just how prevalent it is in feline communities.
"Feline enteric coronavirus is the ubiquitous parent form of FIPs and viruses, and so enteric coronaviruses exists all over the world and they exist in any place where there's a large number of cats that are congregated together, that share litter pans, or have people exposure, or fecal exposure to each other. So, virtually every cattery, every shelter, every kitten foster rescue, every dense feral cat population has in it enzootic or endemic feline coronavirus infection. And
most kittens are exposed naturally when they're around 9 weeks of age through exposure to virus being shed by up to 40 to 60% of the normal healthy cats in the environment.
And so, what happens is that during that initial infection with enteric coronavirus, some of that virus can mutate into a new form, and instead of that virus infecting the intestinal tract, that mutant virus then will go into the lymph nodes, and abdomen, and that, and infect what we call macrophages, and then create an entirely different type of disease. Although the mutations are very slight, there are only 3 spots in the viral genome that are mutated, the mutations are very slight, but the repercussions in terms of disease are huge."