Back in December 2020, my kitty cat Bandit tested positive for FeLV with the commonly administered “SNAP” Test at our local vet. As a first time cat parent hearing this result, the first things that came to my mind was, “What does FeLV? How reliable is this “Snap” test, and what should I do to help my boy?”
This information wasn't easily found and while under stress difficult o get my head around. To help with anyone else who is dealing with this situation, I wanted to provide a list of the main three types of tests that are used when reviewing and understanding the intensity of the infection concerning FeLV. It's also just good to know even if you are not dealing with FeLV itself! I found knowledge helped me the most during this challenging time!
First and foremost, please know that I am not a professional veterinarian and encourage you to bring any data you have to an established veterinarian to get their professional opinion about your unique situation on whether any additional testing is necessary.
I’m just an overprotective cat guardian on the internet who wants to defeat FeLV, and share what I have learned!
I attended a webinar that was led by the established Dr. Richard B. Ford, DVM, MS, Diplomate ACVIM & ACVPM (Hon). I will be breaking down the data I have gathered into a few Blog posts over time!
If you want to see the webinar for yourself, EveryCat Health Foundation has graciously posted it on their Youtube page here: Feline Leukemia Virus (FeLV): How Real is the Threat?
These details below are a summary in how I understood the breakdown on these tests.
These three tests below all look for different data regarding FeLV.
- If the Virus is actively transmitting between cells
- If the Virus is being passive or active
- The amount of the Virus that exists within the cat
TEST 1
Common name: The “SNAP Test“
Professional name: ELISA (Enzyme-Linked Immunosorbent Assay) Test
Purpose: To check for three key diseases that could be detected outside the cells in your cat.
Virus data reviewed: Is the Virus actively transmitting between cells
Accuracy: Extremely Accurate.
False results are usually the result of human error, not because of the test.
This test is the most common test, and can be done at most vet clinics quickly which gives it the nick name “Snap” test. (Can be done in a snap!)
The three diseases that are checked for in this test are:
- feline immunodeficiency virus (FIV) antibody
- feline leukemia virus (FeLV) antigen
- feline heartworm (FHW) antigen
If a cat tests positive for FeLV with the SNAP test, then the other tests below can be considered. Please talk to a veterinarian to confirm the next best course of action for the cat’s care.
Note A, it is not possible for vaccines being administered to affect the SNAP Test results. If a cat tests positive after having their vaccine dose, it is because the cat received the infection through another source.
Note B: If FeLV is testing positive, then the virus in your cat is active and can be spread to other cats through body fluids like saliva and blood. It is ideal to keep this kitty away from other kittens when possible to avoid exposure. As cats get older, they become more resistant to FeLV, but not immune. Please check with a veterinarian for their recommendations in a multiple cat household.
TEST 2
Common name: IFA Test
Professional name: Indirect Fluorescent Antibody (IFA) Assay
Purpose: Uses fluorescent microscopy to detect antibodies to specific antigenic material, or simply put, it allows us to identify the activity of the FeLV Virus in a cell and tell if the virus is being successfully restricted by the cat’s immune system currently.
Virus data reviewed: If the Virus is being passive or active.
Accuracy: Highly Accurate.
There are two results that we can receive with this test.
- Negative (AKA “Regressive” status): The virus is currently dormant due to the immune system of the cat. The virus is not actively replicating and just resting within the cat’s bone marrow. This is the more ideal result. However unfortunately this does not mean that your kitty will always remain in this state.
- It is not clear what triggers or possibly tips this disease to become active, but it can change to become “Progressive”. It doesn’t mean it will.
- Positive (AKA “Progressive” Status): The virus is currently actively replicating and infecting the other cells of the cat. Unfortunately this is not the ideal state to be in and causes your cat to be highly susceptible to multiple issues, one of the most common ones being the development of tumors.
- This is not necessarily a death sentence. The cat can still live a long time with medical care, love, and a bit of luck.
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During my time caring for Bandit and Ghost, I was given many success stories of cats living long lives with this disease. These examples exist for a reason, and hope is good to have.
However every story is unique, so hang in there.💗 - It is extremely rare for a cat’s state to change from Progressive to Regressive.
Note: When in a regressive state, a cat should test negative on both the SNAP and IFA test. That is why the test above has been mostly retired from a lot of practices, as it doesn’t confirm the existence of the virus in a cat and could cause issues with activities like blood donations or breeding. IFA tests are now more commonly replaced with the more informative test below:
TEST 3:
Common name: PCR Test
Professional name: Polymerase chain reaction (PCR) test
Purpose: Detects the presence of infectious agents by identifying the genomic material of the agent being investigated, or simply put, it identifies how much of the virus exists per milliliter (mL) of blood.
Virus data reviewed: The amount of the Virus that exists within the cat.
Accuracy: Highly Accurate.
This test is the more recommended test for reviewing the amount of FeLV (sometimes referred to as the “load” of the virus) within a cat. Since this identifies the amount within a cat, this test is considered a better way to understand how far along a cat may be infected.
- The ideal amount to be qualified as a regressive state is to have less than 1x10^6 copies of the virus per mL.
- If the cat has a higher amount than 1x10^6 copies of the virus per mL, it might indicate that the FeLV virus has changed from a Regressive to Progressive status, however please make sure that listen to your veterinarian as they will have a more accurate interpretation of an individual cat’s health.
Note: If a cat has any amount of the virus inside them, they can still pass it to their litters. It is best to consider this test if you know someone who is considering breeding options with their kitty.
Overall the details above are to help inform you on what options a person may have in these situations and help give yourself an understanding on what you can ask about to find the best treatment and care for any cat dealing with this illness.
Sending good health vibes to you and any cat parents!
Best wishes, and signing Me-owt!
