Cat health
The health of domestic cats is a well studied area in veterinary medicine. Topics include infectious and genetic diseases, diet and nutrition and non-therapeutic surgical procedures such as neutering and declawing. Diseases. 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. Viral. Viral diseases in cats can be serious, especially in catteries and kennels. Timely vaccination can reduce the risk and severity of an infection. The most commonly recommended viruses to vaccinate cats against are: Viruses for which there are no vaccines: See: Global spread of H5N1#Felidae (cats) Parasites. Veterinary parasitology studies both external and internal parasites in animals. External parasites, such as fleas, mites, ticks and mosquitoes can cause skin irritation, and are also often carriers of other diseases or of internal parasites. Genetic diseases. 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. For example, Abyssinian cat's pedigree contains a genetic mutation that causes retinitis pigmentosa, which also affects humans. 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. 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 are as follows: Preventive medicine. 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