Infectious diseases

An infectious disease is caused by the presence of pathogenic organisms such as viruses, bacteria, fungi, or parasites (either animalian or protozoan). Most of these diseases can spread from cat to cat via airborne pathogens or through direct or indirect contact, while others require a vector such as a tick or mosquito. Certain infectious diseases are a concern from a public health standpoint because they are a Feline zoonosis and transmittable to human.

Genetic diseases

A cat displaying heterochromia

Domestic cats are affected by over 250 naturally occurring hereditary disorders, many of which are similar to those in humans, such as diabetes, hemophilia and Tay–Sachs disease.^[3][5] For example, Abyssinian cat's pedigree contains a genetic mutation that causes retinitis pigmentosa, which also affects humans.^[3]

• Familial renal disease is inherited in Abyssinians and Persians
• Feline hypertrophic cardiomyopathy
• Heart valve dysplasia
• Heterochromia
• Luxating patella
• Portosystemic shunt. Found in Persians and Himalayans.
• Flat-chested kitten syndrome

Skin disorders

Skin disorders are among the most common health problems in cats and have many causes. The condition of a cat's skin and coat can be an important indicator of its general health.

• Cheyletiellosis is a mild dermatitis caused by mites of the genus Cheyletiella. It is also known as walking dandruff due to skin scales being carried by the mites.
• Feline acne
• Feline eosinophilic granuloma
• Flea allergy dermatitis
• Miliary dermatitis (feline eczema)
• Mange
• Nutritional skin disorders

Tumors and cancer

• Bladder cancer
• Bone cancer
• Intestinal cancer
• Liver cancer
• Lymphoma in animals
• Mammary tumor
• Mast cell tumor
• Nose cancer
• Skin cancer
• Soft tissue sarcoma
• Stomach cancer

Other diseases

• Anal sacs impaction
• Cerebellar hypoplasia is a disorder found in cats and dogs in which the cerebellum is not completely mature at birth. Cerebellar hypoplasia causes jerky movements, tremors and generally uncoordinated motion. The animal often falls down and has trouble walking. Tremors increase when the animal is excited and subside when at ease.
• A corneal ulcer is an inflammatory condition of the cornea involving loss of its outer layer. It is very common in dogs and is sometimes seen in cats.
• Diabetes
• Feline hyperaldosteronism
• Feline hyperthyroidism
• Epilepsy is characterized by recurrent unprovoked seizures. Epilepsy in cats is rare likely because there is no hereditary component to epilepsy in cats.
• Feline asthma
• Feline hepatic lipidosis also known as Feline Fatty Liver Syndrome, is one of the most common forms of liver disease of cats.^[6] The disease begins when the cat stops eating from a loss of appetite, forcing the liver to convert body fat into usable energy.
• Feline lower urinary tract disease is a term that is used to cover many problems of the feline urinary tract, including stones and cystitis. The term feline urologic syndrome is an older term which is still sometimes used for this condition. It is a common disease in adult cats, though it can strike in young cats too. It may present as any of a variety of urinary tract problems, and can lead to a complete blockage of the urinary system, which if left untreated is fatal.
• Feline odontoclastic resorptive lesion
• Feline spongiform encephalopathy
• Polyneuropathy
• Pyometra
• Uterine unicornis a condition in which the female cat is missing a uterine horn. A rare discovery by veterinarians, the condition can be detected by x-ray or ultrasound prior to spaying if the patient has a family history of the medical condition. There is no known scientific study to prove that uterine unicornis is a hereditary genetic disorder. In some cases, the patient may also be missing a kidney on the same side as its missing uterine horn. This phenomenon is also called unilateral renal agenesis.

Zoonosis

Researchers at the University of Cornell Feline Health Center believe that "most zoonotic diseases pose minimal threat" to humans. However some humans are particularly at risk. These are people "with immature or weakened immune systems" (infants, the elderly, people undergoing cancer therapy, and individuals with acquired immunodeficiency syndrome).

Some common and preventable forms of zoonosis^[7] are as follows:

• Toxoplasmosis
• Giardia
• Cat-scratch disease
• Rabies
• Ringworm

Vaccinations

Vaccinations are an important preventive animal health measure. The specific vaccinations recommended for cats varies depending on geographic location, environment, travel history, and the activities the animal frequently engages in. In the United States, regardless of any of these factors, it is usually highly recommended that cats be vaccinated against rabies, feline herpesvirus 1 (FHV-1), feline calicivirus (FCV), and feline panleukopenia virus (FPV). The decision on whether to vaccinate against other diseases should be made between an owner and a veterinarian, taking into account factors specific to the cat.

Detection of diseases

Feline diseases such as FeLV, FIV, and feline heartworm can be detected during a routine visit to a veterinarian. A variety of tests exist that can detect feline illnesses, and with early detection most diseases can be managed effectively.

Parasite medication

Once-a-month topical products or ingestible pills are the most commonly used products to kill and prevent future parasite infestations.

Food allergy

Food allergy is a non-seasonal disease with skin and/or gastrointestinal disorders. The main complaint is pruritus. The exact prevalence of food allergy in cats remains unknown. There is no breed, sex or age predilection, although some breeds are commonly affected. Before the onset of clinical signs, the animals have been fed the offending food components for at least two years, although some animals are less than a year old. In 20 to 30% of the cases, cats have concurrent allergic diseases (atopy / flea-allergic dermatitis). A reliable diagnosis can only be made with an elimination diet. Challenge–dechallenge–rechallenge is necessary for the identification of the causative food component(s). Therapy consists of avoiding the offending food component(s).^[10] Cats with food allergies may present with red, hairless, and scabby skin. Hair loss usually occurs on the face and/or anus. Depending on the severity of the reaction, it may take two weeks to three months for a cat to recover once the offending allergen is removed.

Food dangerous to cats

A number of common human foods and household ingestibles are toxic to cats, including chocolate solids, onion, garlic, avocados, grapes, raisins, coffee, tomato and tomato leaves, and milk.

Phenolic compounds such as those in TCP are harmful to cats.^[11]

Malnutrition

Malnutrition in cats is currently uncommon due to complete and balanced diets being formulated and fed.^[12] Yet it can still occur if the cat's food intake decreases beyond what the food can provide, if interactions occur between ingredients or nutrients, if mistakes are made during formulation or manufacturing, and if the food is stored for a lengthy amount of time.^[12] If a cat becomes malnourished, a deficiency of energy, protein, taurine, essential fatty acids, minerals (calcium, phosphorus, magnesium, sodium, potassium), vitamins (A, D, E, thiamine, niacin, biotin), and trace elements (iron, copper, zinc, iodine, selenium) can occur, causing a multitude of deficiency symptoms.^[13]

For information about a correct cat diet, see Cat food.

Obesity

Neutering and overfeeding have contributed to increased obesity in domestic cats, especially in developed countries. Obesity in cats has similar effects as in humans, and will increase the risk of heart disease, diabetes mellitus, etc., thereby shortening the cat's lifespan.

Toxic substances

The ASPCA lists some common sources of toxins^[18] that pets encounter, including: plants,^[19] human medications and cosmetics,^[20] cleaning products,^[21] and even foods.^[22]

Some houseplants are harmful to cats. For example, the leaves of the Easter Lily can cause permanent and life-threatening kidney damage to cats, and Philodendron are also poisonous to cats. The Cat Fanciers' Association has a full list of plants harmful to cats.^[23]

Paracetamol or acetaminophen (trade name Panadol and Tylenol) is extremely toxic to cats, and should not be given to them under any circumstances. Cats lack the necessary glucuronyl transferase enzymes to safely break paracetamol down and minute portions of a normal tablet for humans may prove fatal.^[24] Initial symptoms include vomiting, salivation and discolouration of the tongue and gums. After around two days, liver damage is evident, typically giving rise to jaundice. Unlike an overdose in humans, it is rarely liver damage that is the cause of death; instead, methaemoglobin formation and the production of Heinz bodies in red blood cells inhibit oxygen transport by the blood, causing asphyxiation. Effective treatment is occasionally possible for small doses, but must be extremely rapid.

Even aspirin, which is sometimes used to treat arthritis in cats, can be toxic and must be administered cautiously.^[25] Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidentally or by well-meaning owners attempting to counter loss of fur, has sometimes proved fatal.^[26][27]

In addition to such obvious dangers as insecticides and weed killers, other common household substances that should be used with caution in areas where cats may be exposed include mothballs and other naphthalene products,^[25] as well as phenol-based products often used for cleaning and disinfecting near cats' feeding areas or litter boxes, such as Pine-Sol, Dettol (Lysol), hexachlorophene, etc.^[25] which, although they are widely used without problem, have been sometimes seen to be fatal.^[28] Essential oils are toxic to cats and there have been reported cases of serious illnesses caused by tea tree oil and tea tree oil-based flea treatments and shampoos.^[29][30][31]

Many human foods are somewhat toxic to cats; theobromine in chocolate can cause theobromine poisoning, for instance, although few cats will eat chocolate. Toxicity in cats ingesting relatively large amounts of onions or garlic has also been reported.^[25]

Cats may be poisoned by many chemicals usually considered safe by their human guardians,^[25] because their livers are less effective at some forms of detoxification.^[32][33] Some of the most common causes of poisoning in cats are antifreeze and rodent baits.^[34] Cats may be particularly sensitive to environmental pollutants.^[25][35]