In 1964, a group of cats were found to all have lymphosarcoma* in one community, and because there were so many who carried this diagnosis it suggested that there was an infectious agent among cats. This is how Feline Leukemia Virus (FeLV) was first discovered.
*Lymphosarcoma (lymphoma) is one of the most common cancers diagnosed in cats. It is a cancer of the lymphocytes (a type of white blood cell) and lymphoid tissues.
During my time I was caring for Bandit and Ghost, I never really understood what this disease was, how it affected a cat’s body, and why it was sometimes terrible or completely benign. To not understand this disease was very frustrating as I didn’t know how to best help my boys, and many vets I spoke to were unfortunately not aware of ways on how to help either.
Because of this, I wanted to write up what I have learned here to hey give some direction::
- How easily does it get transferred?
- How does this disease infect the body?
- What are some common side effects that could be caused by this disease to look out for?
First and foremost, please know that I am not a professional veterinarian, and encourage you to ask an established veterinarian to get their professional opinion before any actions are taken. I’m just an overprotective guardian of cats 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?
1) How easily does it get transferred?
In short, cats can pass the virus between themselves through saliva and close contact/sharing living quarters.
Examples of exposure can be having an FeLV cat biting another cat, and (rarely) through a litter box or food dish used by an infected cat.
Even if you adopt a kitten while they’re very young, it is also possible that a kitten can contract this disease while they are in the womb if their parent is FeLV positive.
To help ease any concerns, there is a strong amount of evidence that indicates FeLV is not infectious to dogs or humans, so sharing your home with an FeLV cat along with other dogs is no problem! Companionship is important and despite what common media portrays cats are social and often live in packs so having other furry pals around will definitely go a long way in quality of life! One rescue I spoke with said that they have a resident FeLV cat that lives with their bunnies, and has been living a happy 7 year long life so far!
Side Notes: It is also proven that cats living in higher populated areas like in the cities are more likely to have exposure to FeLV than cats living in rural areas due to population alone. Also it has been reported that intact male cats are more likely have exposure or infection with FeLV than neutered male cats.
2) How does FeLV infect the body?
When it enters the body, the virus seeks out the white blood cells in Bone Marrow, also known as a Bone Marrow Lymphocyte.
Once it finds the lymphocyte, the virus will share RNA data that enters into the nucleus of the white blood cell and fuse with the DNA of the cell itself. Then it creates a provirus, which is a duplicate of the virus used to infect other cells and transfers onto the next cell to infect.
Because this disease basically transforms the DNA of the white blood cell, it makes this virus hard to cure or stop.
Now if a cat is exposed, it doesn’t mean that your cat will 100% be infected with the most aggressive form of FeLV. It’s been reported that roughly 20-30% of cats that are exposed will “Abort” or overcome the infection and their immune system will destroy and stop FeLV. (Best case scenario!)
To learn more about tricks on how approach diagnosing this disease in a cat, please see my Blog post: “SNAP, IFA, PCR Tests? Where do I even start?”
3) What are some common effects that could be caused by this disease to look out for?
Because FeLV targets white blood cells it is known to be the cause of lymphoma, Leukemia, tumors.
- Lymphoma is a cancer of the lymphatic system, which is part of the body's germ-fighting network.
- Common signs are: weight loss, vomiting, and diarrhea
- Leukemia is cancer of the body's blood-forming tissues
- Common signs are: Pale gums, weight loss, yellow color in the mouth and whites of eyes
- Tumors is a mass of tissue that forms when cells grow and divide more than they should or not die when they should.
- It is apparently more common for tumors to possibly develop in the breathing passage or intestine of a host. If your cat starts to have any breathing issues like heavy breathing or snorting, please have them checked by a vet right away.
It is also good to pay attention to the body language of your cat. It has been discovered that cats have an easier time breathing when laying fully on their right side. If your cat does this suddenly often and it’s out of character, please seek a professional opinion.
I hope that these details above help in understanding what this disease really is and how difficult it is to cure. However the disease known as FIV which was believed to be incurable had a treatment discovered and so science will push on! I have faith we will find a cure, and when that day comes, you know I’ll be dancing.
Let me know if you see anything incorrect and I will be happy to update it! Thanks!
