OVERVIEWFeline immunodeficiency virus (FIV) is a viral infection that attacks the immune system of cats. The immunodeficiency can promote a variety of symptoms including: infections caused by a poorly functioning immune system, anemia and low blood-cell counts, infections of the gums and mouth, cancer or neurologic disease.
FIV is a retrovirus similar to Human Immunodeficiency Virus, and a syndrome similar to AIDS occurs in cats. FIV is not contagious to people; it is an infectious disease spread from cat to cat, primarily by biting. FIV has been found in the mother's milk and can be transmitted from mother to kitten. Transmission among household cats through normal contact is thought to be unlikely. Outdoor and male cats are predisposed.
FIV has three stages of infection. They include an acute phase associated with various symptoms, which includes infections, fever and lymph node (gland) enlargement. The second phase is called the subclinical phase, which lasts from months to years, during which time many cats appear healthy. The third phase is chronic infection, which is associated with deterioration of the immune function and that predisposes cats to a variety of infections.
Infection is thought to involve between one and 14 percent of the cat population. Co-infection with feline leukemia virus (FeLV) can occur. DIAGNOSISVeterinary care should include diagnostic tests and subsequent treatments. Diagnostic tests are needed to recognize FIV and exclude other diseases. Tests may include:
Complete medical history and physical examination
Blood test called the ELISA or IFA test should be done. Results can be difficult to interpret in cats less than six months of age. These tests will also be positive if the cat has been vaccinated for FIV. For this reason, only unvaccinated cats should be tested and every cat should be tested before the first FIV vaccination. TREATMENTThere has been no proven effective treatment for FIV infection, but supportive care and symptomatic therapy is important, including:
Antibiotics for bacterial infections Nutritional support Parasite control Keeping the cat indoors and isolated from other cats Biopsy and removal of tumors HOME CAREAdminister prescribed medications and monitor your cat's general activity level, body weight, appetite and attitude. Provide quality nutrition and schedule veterinary visits to monitor the condition.
Keep all FIV infected cats indoors to decrease exposure to other cats. Isolate FIV infected cats from negative cats. PREVENTATIVE CAREFeline immunodeficiency virus is an infectious disease can can be prevented primarily by eliminating interactions with infected cats. Prevent fighting, neuter males and isolate, test and treat infected cats.
Preventative health care and dental care with antibiotic coverage prior to the procedure is often recommended in infected cats. Recently, a vaccine has been developed that can help reduce the risk of acquiring FIV in at-risk cats. Vaccination for other diseases should be discussed with your veterinarian. If yearly vaccinations are given, only killed vaccines, which are vaccines made up of killed virus, as opposed to other types where live virus may have been modified, should be utilized to protect a potentially inadequate immune system in infected cats. INFORMATION IN-DEPTHOther medical problems can lead to symptoms similar to those encountered in feline immunodeficiency virus. It is important to exclude these conditions before establishing a diagnosis of FIV infection:
Anemia
Ehrlichiosis, an infectious disease caused by unusual bacteria called rickettsia that live inside of white blood cells or platelets
Rocky mountain spotted fever, an infectious disease caused by another rickettsial agent
Feline leukemia virus (FeLV) infection
Feline infectious peritonitis (FIP), a viral disease of cats
Fungal infections such as cryptococcosis, histoplasmosis, blastomycosis and coccidioidomycosis
Toxoplasmosis, an infectious disease caused by a protozoa that completes its life cycle in cats
Hemobartonella felis, an infectious disease caused by a bacterial parasite that lives in red blood cells
Leukemia, cancer of blood-forming tissues with spread of cancer cells through the bloodstream
Lymphoma, solid tumor of the lymphoid tissues that produce lymphocytes
Multiple myeloma, a tumor of the antibody-producing B-type lymphocytes
Myeloproliferative disease, cancer of the white blood cell producing bone marrow tissue
Other forms of cancer
Sepsis, body wide infection caused by spread of bacteria or their toxins in the bloodstream
Systemic lupus erythematosus, a disease in which the body’s immune system mistakenly recognizes certain body tissue components as foreign and attacks them. VETERINARY CARE IN-DEPTHVeterinary care should include diagnostic tests and subsequent treatments. DIAGNOSIS IN-DEPTHDiagnostic tests must be performed to confirm the diagnosis of feline immunodeficiency virus and exclude other diseases that may cause similar symptoms. Some of the following diagnostic tests may be recommended:
A complete medical history and a thorough physical examination. Special attention is paid to mucous membrane color and lymph node size.
Blood test for feline immunodeficiency virus. If positive, confirmation of FIV status can be obtained through serology. The western blot test is considered to be definitive for FIV. If the initial screening test is positive but the western blot is negative, the cat is considered negative for FIV. Testing is difficult on cats that have been previously vaccinated so only unvaccinated cats should be tested.
Blood test for feline leukemia virus (FeLV), because FeLV infection can cause similar signs to FIV infection
Blood test for feline infectious peritonitis (FIP)
Serum tests for toxoplasmosis and ehrlichiosis
A complete blood count (CBC) to evaluate your cat for anemia, signs of inflammation and blood platelet numbers
A biopsy or fine needle aspirate, which is a sample collected by aspirating cells through a syringe and needle, of any solid tumors may be performed for microscopic analysis and diagnosis.
Your veterinarian may recommend additional diagnostic tests to exclude or diagnose other conditions and to better understand the impact of FIV infection. These tests ensure optimal medical care and are selected on a case-by-case basis and may include:
Serum biochemistry tests to evaluate the general health of your cat and to determine the impact of FIV infection on other body systems such as the kidneys and liver. Serum biochemistry tests often are normal in cats with FIV infection.
Urinalysis to evaluate kidney function and identify protein loss in the urine or urinary tract infection. Urinalysis usually is normal in cats with FIV infection, but occasionally unless urinary tract infection may be present.
Thoracocentesis refers to the aspiration of accumulated fluid from the chest cavity using a needle and syringe. The fluid obtained is submitted for microscopic analysis to identify other diseases such as lymphosarcoma, pyothorax (bacterial infection in the chest cavity) or feline infectious peritonitis.
Abdominal paracentesis refers to the aspiration of accumulated fluid from the abdominal cavity using a needle and syringe. The fluid obtained is submitted for microscopic analysis to identify other diseases such as FIP and spread of cancer to the peritoneal cavity.
Chest X-rays may be taken if your cat has difficulty breathing or abnormalities are found on listening to the chest with a stethoscope. Chest X-rays may show evidence of secondary bacterial pneumonia in some cats with FIV infection.
Bone marrow aspiration and microscopic analysis may be recommended in some FIV-infected cats with some combination of low white cell count, anemia, and low platelet count.
Cerebrospinal fluid (CSF) analysis may be recommended in FIV-infected cats with clinical signs of nervous system disease. The CSF fluid also can be analyzed for the presence of antibodies against FIV, abnormally high numbers of inflammatory cells and high CSF protein concentration. TREATMENT IN-DEPTHTreatment of FIV infection must be individualized based on the severity of the condition and other factors that must be analyzed by your veterinarian. If your cat has no clinical signs, no treatment may be necessary. In this situation, regular follow-up visits to your veterinarian are important to ensure the condition does not progress. If immunodeficiency and secondary infection have developed, additional treatment will be necessary. Supportive care and symptomatic therapy are important and include:
Antibiotics for secondary bacterial infections
Nutritional support
Fluid therapy in dehydrated cats
Parasite control
Isolation from other cats
Biopsy and removal of tumors
Several drugs that are used to treat people with human immunodeficiency virus (HIV) infection have been used in cats with FIV infection. Drugs used may include the following:
Alpha interferon (Roferon®) may reduce viral replication in some infected cats. It is not licensed for use in cats, but some clinical studies found increased activity, increased appetite, improvement of blood abnormalities, increased clearance of virus and prolonged survival in treated cats.
Immunomodulators could be beneficial in cats with FIV infection by restoring immune function. Examples include Propionbacterium acnes (Immunoregulin®) and Acemannan (Carrisyn®).
Azothiouridine (AZT®) is an antiviral drug (a nucleoside analog) commonly used in human patients with AIDS that also has been used in FIV-infected cats. Treatment with AZT may result in clinical improvement, immune function, and quality of life. AZT has some potentially serious adverse effects and should be administered to FIV-infected cats under the supervision of a veterinarian experienced with its use.
3TC (lamivudine) is another nucleoside analog used in human patients with AIDS that also has been used in some cats with FIV infection. Like AZT, its use is associated with potentially serious adverse effects and it should be administered to FIV-infected cats under the supervision of a veterinarian experienced with its use.
9-(2-phosphonylmethoxylethyl) adenine (PMEA) is another drug that has been used in FIV-infected cats and has been reported to reduce the severity of chronic mouth infections in affected cats.
Bone marrow transplantation has been performed in a limited number of FIV-infected cats and is successful in restoring white blood cell counts in some instances. Infected cats, however, remain infected with FIV. This procedure is only available at a limited number of referral research institutions. FOLLOW-UPOptimal treatment for your cat requires a combination of home and professional veterinary care. Follow-up is crucial. Follow-up veterinary care for FIV often includes the following recommendations:
Administer any medications by your veterinarian as directed.
Contact your veterinarian promptly if you are having trouble treating your cat.
Contact your veterinarian if your cat develops any new symptoms or if existing symptoms worsen.
Carefully observe your cat’s appetite and general activity level. These are quality of life issues important to you and your cat.
Examine and monitor your cat’s gum color, urination, defection, and lymph node size. Your veterinarian can show you where the superficial lymph nodes are located and how to palpate them.
Use the “Test and Remove” program, which is a method to eliminate FIV-infected cats in a cattery or a multiple-cat household. The principles of this program are as follows:
Do not bring any new cats into the household.
Remove all FIV-positive, sick cats from the household.
Quarantine all FIV-positive cats to one area in the household. They should have no contact with FIV-negative cats in the household.
Disinfect all bedding, food and water dishes, litter pans, and toys. Bedding, food and food dishes, water bowls, litter pans, and toys used by FIV-positive cats never should be used by FIV-negative cats.
Test all remaining untested cats in the household for FIV.
Quarantine all FIV-negative cats to one area. Retest these cats in three months. If they are negative at that time, they are considered free of FIV.
Quarantine and test all new cats that enter the household and isolate them from other cats in the household for three months. Re-test these cats after three months. If negative on re-testing, these cats are considered free of FIV.
Cats are considered free of infection when two negative test results separated by three months have been obtained.
Retest all FIV-positive cats. Cats that test negative for FIV after having testing positive on the first test should remain isolated. Re-testing should be carried out after 3 additional months.
Actual follow-up depends on the severity of your cat’s disease, response to therapy, your veterinarian’s recommendations and your own views.
There is now a vaccine available to help reduce the risk of acquiring FIV. Discuss the use of this vaccine in at-risk cats with your veterinarian.
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