Cats with FIP do not appear to be very contagious to cats that they come in contact with. Although this has been based mainly on clinical observations, it has also been confirmed by laboratory studies. Contact transmission has not been observed in experimental settings. Furthermore, cat-to-cat transmission implies that every FIPV isolated from a group outbreak of FIP will be genetically identical. UC Davis researchers have yet to observe this. However, researchers now know that FIPV is present in the feces of some cats with FIP, so horizontal transmission is theoretically possible, and may explain the uncommon epizootics of FIP where a number of cats in the same environment develop FIP within a days or weeks of each other.