Feline Immunodeficiency Virus

Feline Immunodeficiency virus (FIV) is classified as a lentivirus (“slow virus”) and is in the retrovirus family. The feline immunodeficiency virus was isolated in 1986 from a cat with clinical symptoms that were strikingly similar to those seen in humans with acquired immunodeficiency syndrome (AIDS), the disease associated with human immunodeficiency virus (HIV) infection.

Transmission FIV is primarily transmitted from cat to cat through deep bite wounds. FIV can also be transmitted from a queen to her kittens via intrauterine, during the queening process, or through infected milk.

FIV Signalment FIV can infect all cats, but intact male cats, because of their propensity for fighting, are more likely to be infected. While signs of the disease are most likely to be seen in adult cats, FIV infection often occurs in cats under 1 year of age Up to 4 percent of free- roaming or stray cats may be infected with the virus.

The Cause of FIV The genetic material of FIV, like that of other retroviruses, consists of single-stranded RNA. The production of a double-stranded DNA copy of this RNA is an essential step in the replication (reproduction) of FIV within the host. This step requires a special viral enzyme, reverse transcriptase, which the virus carries with it when it infects a cell. The double-stranded copy of the viral genetic material then is inserted into the DNA of the host cell, where it may remain in an inactive state for some time before production of new virus particles is initiated. The replication of the infected cell is what causes a mass viral infection throughout the body of the host.

The FIV Cause/Replication Process

Clinical Signs The clinical signs of FIV are divided into three stages: Acute infection Stage (The first 4-6 weeks of being infected) Asymptomatic or Latent Stage (This stage can last for months to years) Persistent generalized lymphadenopathy (Because this stage is usually short-term it can be difficult to observe) AIDS-related complex or ARC (Usually begin to show signs of respiratory and GI disease) Immunodeficiency syndrome

Clinical Signs Continued Acute Infection Stage: – The establishment of a persistent infection occurs in this stage. – Cats in this stage will have a major decrease in CD4+ T cells due to the replication and destruction of the virus.

Clinical Signs Continued Asymptomatic Stage: – In this stage the infected cat appears normal and shows no signs of having Feline Immunodeficiency Virus.

Clinical Signs Continued Lymphadenopathy Stage: – Following initial infection, FIV is carried to regional lymph nodes, where it replicates in a subpopulation of white blood cells known as T lymphocytes or T cells. These cells are primary target cells of FIV. The virus then spreads to lymph nodes throughout the body, resulting in a generalized lymphadenopathy (enlargement of the lymph nodes). – This stage of the disease usually passes unnoticed by an owner unless the nodes are greatly enlarged.

Clinical Signs Continued AIDS-Related Complex (ARC) Stage – a complex of signs and symptoms representing a less severe stage of feline immunodeficiency virus (FIV) infection characterized by chronic generalized lymphadenopathy, fever, weight loss, prolonged diarrhea, minor opportunistic infections, cytopenia, and T-cell abnormalities of the kind associated with AIDS. – Fever of 103'F or greater is often present in this stage.

Clinical Signs Continued Immunodeficiency Syndrome: – The clinical signs of the immunodeficiency syndrome are diverse in nature because they involve an array of secondary infections. Lethargy may be the first outward sign that a problem exists. – Loss of appetite or evidence of pain while eating, caused by infection of the gums and mouth may be seen in this stage

Organs effected by FIV The respiratory system, the GI system, the ears & skin are generally effected by the Feline Immunodeficiency Virus. Neurological effects may occur in some cats

Diagnosing FIV Diagnosis of FIV requires an FIV antibody test. ELISA (enzyme-linked immunosorbent assay) is a simple test that can be done in most veterinary laboratories and clinics. A simple FeLV/FIV combination Snap test can be used for this as well. BEWARE: False positives occur in kittens that retain their mother’s antibodies and cats that have been vaccinated against FIV due to the antibodies present in the vaccination itself.

FIV Prognosis The lifespan of FIV-infected cats is highly variable. More than 50% of FIV-infected cats remain asymptomatic for years. About 20% of FIV-infected cats die within 2 years of diagnosis (i.e., 4 to 6 years after infection). Cats in stage 5 of the disease usually die within a year. If the cat is in an early stage, the client may elect treatment.

Treating FIV Unfortunately, there is no specific antiviral treatment for FIV. Cats can carry the virus for a long period of time before becoming symptomatic. Therefore, treatment focuses mainly on extending the asymptomatic period or, if symptoms have set in, on easing the secondary effects of the virus. Your veterinarian may prescribe some of the following treatments: – Medication for secondary infections – Healthy, palatable diet to encourage good nutrition – Fluid and electrolyte replacement therapy – Anti-inflammatory drugs – Immune-enhancing drugs – Parasite control

Prevention of FIV The best way to prevent FIV is to separate the negative from the positive. Keep your cat indoors to lessen the chance of an encounter with an FIV positive cat. Supervise your cat while outdoors. A vaccine against FIV, produced by Fort Dodge, was approved for use in Spring It does not provide 100% protection, and vaccinated cats will test positive on the antibody test

Client Education While FIV is similar to Human Immunodeficiency Virus (HIV) and results in a feline disease similar to AIDS in humans, FIV infections are restricted solely to cats. Further educate clients about FIV by discussing the importance of prevention. Hand out pamphlets with each client visit.

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