If you have more then one cat they can catch diseases from each other if the sick cat is not not quarantined. They can catch a disease from another cat that is sick that is sneezing, coughing, or sharing the same litter box that they are using also. When you bring a new cat into your household put it in quarantine for at least seven days before you let it loose with your other cats and also take the new comer to your Vet for a complete checkup from head to tail.
Cats with a respiratory infection can pass on that infection to all of your cats. Even though the cat may have recovered completely it always remains a carrier of the feline respiratory virus even though they present no symptoms anymore.
Distemper in cats can be very deadly as they become dehydrated quickly. Cats sneeze, cough, have runny eyes and constant diarrhea. Your cats fur will look scruffy and they will be very lethargic. Cats can recover in five days if they have an excellent immune system. The very young and old cats may succumb to the disease. I always make sure my cats distemper shots are up to date.
Cats can get worms from each other and by eating small mammals and birds. Worms will cause weight loss, diarrhea, vomiting and inflection around the anus. Cats may slid their derriere across your floor. You may see small fragments of worms in your cats litter box or in their stool. Remember give you cat worm medicine to prevent this problem.
Cats can get fleas and they will itch miserably. A good flea medicine will prevent that problem for you and your cat. Cats can get feline leukemia which is a blood cancer, feline aids, renal failure, feline influenza, Toxoplasmosis and a few cats have gotten COVID -19 virus. Do not let your cats outdoors and always wash your hands before you touch your house cats to avoid giving them COVID -19 virus. If your cat is sick always take them to your vet as soon as possible as it may be a matter of life or death. Hope you and your cat stay well and you have many happy years together. God bless you and all of your feline friends.