Upper respiratory infection is very common among the cats and is also known as kitty cold by their owners. The symptoms are very similar to the cold of the humans, accompanied by sneezing and running nose. Even though it seems to be alike, the infections caused in the cats are very different as one species get infected by the other species. But, it can be contagious among the cats. The upper respiratory tract infection can lead to loss of appetite and can affect them from days to weeks. The cats must be made to eat, which can be encouraged by warming their foods and applying a warm, moist cloth to keep the cat's nose and eyes free from any kind of discharge. If the loss of appetite persists and if the discharge becomes yellowish green in color and thicker, they have to be taken to the veterinarian immediately as it will be a serious problem.

Feline Chlamydia is a kind of bacteria which affects the cats, usually infesting the eye, causing conjunctivitis. The symptoms of feline Chlamydia are anorexia, cough, breathing problem, pneumonia, fever, sneezing, running nose, watery eyes etc. It is best treated with the help of antibiotics. This is also one of the common cat diseases.

Panleukopenia is a cat disease that makes the cat's white blood cell count to drop drastically. As white blood cells are very important for the cat's immunity, this condition makes the cats susceptible to many deadly infections. This virus is transmitted through body secretions, mainly via feces and can be carried by water or shoes.

Feline leukemia virus can cause many cat diseases. One among them is leukemia otherwise known as the cancer of the white blood cells. There is no known treatment for this disease and might lead to death after months or years after the incidence of this disease. It is usually transmitted during cat fights. Other reasons for transmission may be through foods shared among them, through water bowls, from mother to the kittens in the womb etc.

Parasites are organisms which feed on other living being for their own survival. Cats are affected by parasites, which feed on their blood. External parasites such as ear mites, fleas etc can be seen on the skin or fur of the cats and in their ears. Internal parasites detection may be bit difficult, but can be known through sighting small rice like debris lingering to the cat's anus or in the cat's bedding. Some of the internal parasites are ring worms, hook worms, tape worms etc.

Coccidia is a microscopic parasite which lives in the lining cells of the intestines. The symptom associated with this parasite is diarrhea which if left untreated, can lead to dehydration and even death. Ear mites usually take up residence in the cat's ear canals causing severe itching.