Cats infected with FIV or FeLV often show no symptoms for years, which may make it hard to detect infected cats and increases transmission. Both viruses do cause a weakened immune system; consequently, they will often develop symptoms of other illness, such as respiratory infections.
Feline Leukemia Virus usually causes very few symptoms, if any, in the early stages of the disease. Over the course of 1-3 years, recurrent infections of other diseases begin. In later stages, cats may show a variety of symptoms, depending on how the virus attacks the body. These include, but are not limited to, recurrent respiratory, eye, mouth, or skin infections. Cats may have poor appetite or persistent diarrhea. In later stages, cancers like lymphoma may develop.
Testing for FIV/FeLV is recommended for all new cats adopted and routinely for cats that are outdoor at increased risk. A screening test is generally done by your veterinarian collecting a small blood sample; most will know results in about 20 minutes. If the initial test is positive, a blood sample may be sent to a laboratory for confirmation. Testing is reliable and, in most cases, accurate. With FIV, young kittens may occasionally be a false positive, so retesting in 6 weeks may be recommended.
There is no cure for FIV or FeLV once a cat is infected. Secondary illness may be treated, but the cat will always be infected with the viruses and suffer from a weakened immune system.
FIV and FeLV are both contagious to other cats (they are not contagious to humans or dogs). FIV is transmitted almost exclusively through bites. So it is easier to manage an FIV positive cat in a household with other cats, if the cats are not aggressive with each other.
Feline Leukemia Virus, on the other hand, may be spread by bite wounds, sharing food or water bowls, sharing litter boxes, or mutual grooming. This does make this virus more contagious, and infected cats should be kept completely separate from healthy cats.
Testing cats and vaccines for those at high risk is the best way to prevent cats from being infected. All newly acquired cats should be tested before bringing into your home, or kept in quarantine away from other cats until testing has come back negative. Preventing exposure to the virus is much easier for indoor cats as their surroundings are controlled. Outdoor cats are at more of a risk because of the likelihood of a “stray,” feral or neighbor’s cat exposing them to the virus.
A vaccine is available for FeLV. It is not considered core for all cats but is highly recommended for any cats that will be going outdoors or may potentially be exposed to cats that could be infected.
In the case of Feline Immunodeficiency Virus, the vaccine is not effective against all strains. After a cat has been vaccinated it will test positive, so the vaccine for FIV is only recommended for cats that are in the highest risk categories.
Feline leukemia is shed in all body fluids, including saliva, urine, and feces. Positive cats should always be kept separate from non-infected cats, with no comingling or socializing at all. Water/food bowls should not be shared and litter boxes should not be interchanged between the infected and non-infected.
Feline Immunodeficiency Virus is also shed in saliva and almost primarily spread by bite wounds. It is less likely to be transmitted by simply sharing water bowls or litter boxes, so in houses where the cats are not aggressive with each other they may share common areas. But if the cats do fight, the potential is there for the disease to spread.