Our Understanding of a Disease Changes over Time

Thanks to medical research we always learn more


January 11, 2016 (published)

Once upon a time, a positive test result for feline immunodeficiency virus, FIV, was a nearly immediate death sentence. Veterinarians would look at a positive result from testing, feel helpless with nothing to offer, nothing to do, and would recommend euthanasia.

The diagnosis was like slamming into a brick wall from a fast speed.

Today, any veterinarian who recommends immediate euthanasia without offering any options needs to get some continuing education. And they need to do it quickly! We're way past that instant recommendation because, as with people and human immunodeficiency virus, the disease can be managed in felines.

Why do we no longer go into utter panic at diagnosis? Because our understanding of this disease, and many others, keeps expanding thanks to medical research. Consider our understanding of HIV. When HIV was first discovered in the 1980s, people were terrified of it because there was so little that could be done to manage it. Today HIV is so manageable that it is hardly mentioned in the news, even though it should be in the hopes of slowing it down more.

Cats are not likely to show any signs of FIV for the long period before the immune system starts to have problems due to a reduced white blood cell count. Our job, yours and mine, is to prolong this asymptomatic period, and decrease the inadvertent spread of the disease. The average life expectancy from onset is 5 years; that means if a senior cat is diagnosed, the likelihood is that the cat will die of old age, not FIV. Diagnosis requires blood tests; it can be found on a regular blood panel and these days is often found that way.

FIV transmission can happen through transfer of blood, saliva, and cerebrospinal fluid from infected felines, so a cat biting another one is a common means of transmission. Mating can also transmit the virus.

We used to say that FIV-positive cats should be only cats, or live with only other FIV-positive cats. Unless cats tend to fight with other household cats, isolating them from their non FIV-positive feline housemates is unnecessary. The best way to prevent spreading this disease to other neighborhood cats is to keep your FIV cat indoors. Outdoor cats are more likely to engage in fisticuffs, since they must protect their cat kingdom from marauding invaders! After all, they just can’t trust that green-eyed tabby next door!

Clinical signs of FIV are usually from an infection or from a chronic degenerative condition, such as pneumonia or other viral infections, not from the FIV virus itself. Signs vary widely, but keep an eye out for weight loss, fever that keeps returning, poor coat condition, lethargy, inflamed gums and mouth, lack of appetite, chronic skin disease, subcutaneous abscesses, and neurologic disease. Cats with FIV are prone to having more than one infection at a time.

If your cat is diagnosed with FIV, clinical trials are an option. Ask your veterinarian about it, or check Veterinary Partner to see if there are any current trials for FIV (or any disease). Usually you do not need to live near the research site, as the researchers will work with your veterinarian.

An FIV vaccine can be given, but whether or not that's a good idea for your cat is still a bit up in the air; not everyone agrees the pros outweigh the cons. There are five strains, or clades, of FIV; the vaccine was made using strain A and D and tested with strain A. The response has been variable between the different strains, and one might not be effective against the strain most common in a given region. The vaccine is supposed to protect 82% of cats using it, meaning that the rest aren't protected anyway. Thus, a pet owner could believe the cat is fully vaccinated when the vaccine won't work with whatever strains are in their area. Additionally, the FIV vaccine is adjuvanted, meaning is contains an additive used with killed vaccines; adjuvanted vaccines have been implicated in the growth of some tumors in cats.

Lastly, because cats given this vaccine test positive on all current methods of testing for FIV, we can't tell the difference between a cat that's been vaccinated and a cat that has the disease.

Cat docs at the American Association of Feline Practitioners say that vaccination isn't recommended for every cat and the decision to vaccinate, or not, should be made on an individual basis between a cat owner and the cat's veterinarian. It just depends! They also recommend that vaccinated cats should be identified such means as a microchip, tattoo, or on the collar.

Thanks to medical research, our understanding of any disease - not just FIV - and ways to decrease its spread, continues to improve. Keeping up with the times and understanding these changes is your veterinarian’s job.

1 Comment

Dale Kressin, DVM
February 27, 2016

Our thinking, our views and our understanding about the importance of dental care and oral health has dramatically changed over time and this trend will continue!  Thoughts?

VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email

Information and opinions expressed in letters to the editor are those of the author and are independent of the VIN News Service. Letters may be edited for style. We do not verify their content for accuracy.