Feline Immune Deficiency Viruses
What are feline immune deficiency viruses?
Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) belong to a family of viruses know as retroviruses. The most infamous retrovirus is HIV, which causes acquired immunodeficiency syndrome (AIDS) in people. The major characteristic of retroviruses is that they decrease the ability of the immune system to fight infections.
Humans and dogs cannot catch FIV or FeLV or develop AIDS through exposure to FIV-positive or FeLV-positive cats. Only cats are susceptible to these diseases.
How do cats get FIV or FeLV?
Most cats become infected with FIV when they are bitten while fighting with an infected cat. The virus, present in the saliva of infected cats, passes beneath the skin of the victim when he is bitten. FIV is not spread by casual contact between cats (by sharing food and water bowls or litter pans, by airborne germs or by mutual grooming) it is unusual for cats in the same household to spread the disease to each other unless they fight.
FeLV is spread through contact with saliva, urine, or blood. Also, an infected mother cat can pass the virus to her kittens before they are born or through her milk while nursing.
Most FIV-positive cats have a history of cat fights and bite-wound abscesses. Considering that bites are the primary mode of transmission, it is not surprising that cats at greatest risk of FIV infection are outdoor, adult males who are most likely to engage in aggressive fights over territory.
Sexual transmission of FIV is theoretically possible. However, the actual incidence of sexual transmission is unknown. This possibility can be greatly reduced by early neutering/spaying.
How do I know if my cat has FIV?
In most cases, there is no way to know whether your cat has FIV without a blood test. All kittens and cats should be tested to determine if they are infected, even if they show no physical signs of disease.
FIV infection progresses slowly, with a long interval between initial exposure and the onset of signs of the disease. Cats diagnosed with FIV infection may remain free of symptoms for years. Because their immune systems are compromised, FIV-positive cats often develop illnesses that are unrelated to the virus itself. It is the onset of these illnesses that may be the first indication a cat is immunosuppressed, thus raising suspicions of an underlying retroviral infection.
Common health problems reported in cats in the chronic stage of FIV infection include:
- Oral-cavity infections
- Upper-respiratory infections
- Weight loss
- Skin infections
- Ear infections
- Fever of unknown origin
- Enlarged lymph nodes
- Low red- or white-blood-cell counts
- Kidney disease
- Eye disease
- Reproductive failure, such as spontaneous abortions or stillbirths
- Neurologic disease, such as personality changes, tremors, or seizures
How do I know if my cat has FeLV?
Cats can carry FeLV disease without showing any physical signs. The only way to know for certain whether your cat has FeLV is to have your veterinarian test his blood for the presence of the FeLV virus. All cats and kittens should be tested, even if they show no physical signs of disease.
Like cats with FIV, cats with FeLV often develop illnesses that are unrelated to the virus itself be-cause their immune systems are compromised. Health problems associated with FeLV include:
- Anemia, which causes a lack of pink or red color in the gums
- Weight loss
- Recurring or chronic illness
- Fading Kitten Syndrome, during which a kitten becomes progressively weaker
- A syndrome similar to distemper, with lethargy, fever, and diarrhea
- Persistent or recurring fevers or infections
- Rapid breathing or difficulty with breathing
- Jaundice, which causes a yellow color in the mouth and/or the whites of the eyes
- Eye infections and disease
- Certain types of cancer
Is there any treatment for FIV or FeLV?
To date, there is no cure for FIV or FeLV infection. FIV-positive cats are considered to be infected for life. Some cats infected with FeLV may revert to a FeLV-negative status, but others remain infected for life. Your veterinarian can provide supportive care for your cat and can treat some of the secondary illnesses that develop as a result of the disease.
Diagnostic tests, such as blood profiles, fecal exams, urinalyses, and radiographs (x-rays), are frequently required before your veterinarian can begin treatment. Care may include providing fluids, B-vitamins, appetite stimulants, and antidiarrheal medications. Though there are no drugs or therapeutic agents licensed for treatment of feline retroviral infections at this time, cats may benefit from certain prescription medication. Other forms of therapy, such as homeopathy, botanical medicine, and nutritional supplementation, are also gaining popularity. However, there is no scientific evidence to prove that these less conventional forms of therapy are effective.
The prognosis for FIV-positive or FeLV-postive cats depends on 1) the stage of infection; 2) the nature and severity of any coexisting infections; and 3) how promptly and aggressively the infection is treated. Cats can live long and relatively healthy lives despite retroviral infection. This is because some related disorders, including secondary infections, respond well if they are diagnosed early and treated aggressively.
How can these diseases be prevented?
First, it is important to vaccinate your cat against FeLV if it comes into contact with other cats. Your veterinarian can discuss your cats potential exposure to and risk of developing FeLV infection. Currently, there are no vaccines to protect cats against FIV infection.
Second, make sure your cat is never exposed to an FIV-positive or FeLV-positive cat. This means keeping your cat indoors and separated from all cats of unknown FeLV and FIV status. Unsupervised outdoor activity puts cats at risk. There is no way to ensure that cats allowed to roam freely outdoors will not be exposed to other cats that have an immune deficiency disease. Most cats currently infected with FIV or FeLV were first exposed to the disease through this kind of contact.
Third, have all of your cats tested for FIV and FeLV on a regular basis. In particular, testing is recommended for:
- Any newly acquired kitten or adult cat before it joins a multiple-cat household and prior to the first FeLV vaccine
- Any cat used for breeding
- Any cat with known FIV or FeLV exposure (if the first test is negative, retest every three to six months for one year)
- Any sick cat with symptoms that suggest FIV or FeLV infection