The illness factor usually takes the form of infectious diseases like panleucopenia (distemper the cat), salmonellosis, the worm, protozoa and the fungus that caused enteritis.
Because of that the complete vaccination and giving of medicine the routine worm very important.
If doing the replacement of food, did in stages
Mix old and new food by changing the amount comparison in stages every day so as food has for a long time been completely lost from his daily menu.