Signs and Symptoms

Feline Immunodeficiency Virus (FIV) typically suppresses the immune system of a cat, leading to an increased susceptibility to other infections and illnesses.  There are no specific signs that are unique to FIV, but rather you may notice symptoms of illness caused by secondary infections.  Generally, infected cats will have periods of no symptoms and then intermittent spurts of infections that gradually get worse over time.  Even though there is not a set of symptoms specific to FIV, there are common indicators of illness to look for, as detailed below.

What It Looks Like

Cats that become infected with FIV may not display symptoms until years after the initial infection.  Even though the virus takes time to cause serious illness, a cat’s immune system becomes severely suppressed right away.  During the first few weeks after infection, the virus may weaken the immune system and present as a fever and swollen lymph nodes.  There may be a period of time where a cat shows no symptoms, and then another spurt of illness.

If your cat is experiencing frequent urination or diarrhea, we suggest using one of these highly rated hidden litter boxes:


Good Pet Stuff Company Hidden Cat Litter Box

Customer Rating

  • Looks like a planter
  • Durable
  • Filtered vent system
  • Leaves look fake
Our Review:
This large-capacity cat litter box is a great option if you want something to hide the box and still look tasteful in your home.

Internet's Best Decorative Cat Litter Box & Side Table

Customer Rating

  • Multi-functional
  • Hinged door
  • Wide top
  • Best for small cats
Our Review:
This hidden litter box table adds a warm and nice design to any room in your house.

Pidan Studio Snow House Igloo Litter Box

Customer Rating

  • Dog-proof
  • Grated doorway
  • Hidden litter box
  • Best for small cats
Our Review:
This product keeps litter inside the box rather than on your floor.


To diagnose FIV, blood samples are examined for the presence of antibodies to the virus.  If a cat has not had sufficient time after the initial infection to have an immune response or if the cat cannot have an immune response due to immunosuppression, antibodies may not be detected even though the cat is ill.  A diagnosis for FIV should only be confirmed by a veterinarian.  No test is 100% accurate, however your vet can interpret test results and make an educated decision as to whether or not more testing needs to be done, or if a positive or negative test result can be confirmed.  Antibodies can be detected using a number of techniques, such as those listed below.

Immunofluorescence (IFA) Assays

An Immunofluorescence Assay (IFA) is a test that is used to detect the Feline Immunodeficiency Virus antibody.  It is a test with high sensitivity and specificity, which is considered a useful diagnostic tool.  This test can also be used for a range of infectious diseases, such as Human Immunodeficiency Virus (HIV), and the test has been recognized to be just as effective as a Western Blot Analysis.  In order to perform the test, a blood sample is required from a cat.  The sample is then placed onto a substrate, such as a tissue that contains the antigen.  The sample is mixed with a serum, and if present, the antibody in the serum will bind to the antigen (Vetstream).

Enzyme-Linked Immunosorbent Assay (ELISA) Test

ELISA stands for enzyme-linked immunosorbent assay, and this test can be used to detect FIV in cats.  The ELISA can be used to identify specific antiviral antibodies that are circulating in the blood.  This test can often produce false positives, so it is typically followed up with a Western Blot Test.

Western Blot

A Western Blot Test is considered the “gold standard” for FIV testing.  A Western Blot separates protein in the blood and can detect specific proteins and the presence of FIV-antibodies.  This test is typically performed after an ELISA test, as an ELISA can produce a false positive.  If the result of the Western Blot comes out positive, you can consider the cat being tested to be infected with FIV.


How is FIV similar to HIV?

FIV contains a specific protein that is also found in HIV.  The viruses both attack the immune system of their hosts, however each virus is species-specific.

How long will an FIV infected cat live?

An FIV-positive cat can live a long and normal life, however, infected cats are highly susceptible to secondary illnesses due to a weakened immune system.  A secondary disease could be severe and life-threatening.

Can FIV be transmitted throuh saliva?

Yes!  FIV is primarily transmitted to other cats through a deep wound, as the virus is always present in an infected cat’s saliva.

Can FIV cause seizures?

Some infected cats can experience seizures and other neurological disorders.

Can FIV be passed to dogs?

No.  Even through a bite wound, FIV can only impact cats.


Can FIV be passed to other cats?

Yes.  An infected cat can spread the feline immunodeficiency virus (FIV) to another cat through a deep bite wound.

Where did FIV come from?

The virus was first discovered during a disease outbreak in the US, where cats had been showing similar signs to humans with AIDS.