These carrier cats shed viruses either continuously or intermittently for long periods of time perhaps for life and serve as a major source of infection to other cats. Protection induced by the currently available vaccines minimizes the severity of disease, but does not prevent disease in all cats. Nonetheless, vaccination is recommended for all cats. Rabies is an increasing threat to cats. At present, the number of reported feline rabies cases in the United States far exceeds that of dogs and all other domestic animals.
Rabies is routinely fatal and is a major public health concern.
Because of the potential for human exposure, rabies vaccination is recommended for all cats and is required by law in many parts of the country. Disease caused by FeLV is very serious, and it is estimated that fewer than 20 percent of infected cats will survive more than three years after being infected. Cats living in households with FeLV-infected cats or with cats of unknown infection status are also at risk. Kittens younger than 4 months of age appear to be much more susceptible to infection than are adult cats. Indoor-only adult cats with little chance of exposure to potentially infected cats are not likely to be exposed or infected.