Feline Immunodeficiency Virus or FIV


FIV cat in France

Question: Dear Dr. Richard,

I am living in France. One of my cat, Francky, is FIV infected. We found it in October 2001 as he had a diarehoa and a not ending coriza. The other cats are negative.

Francky has no symptoms and is in a good shape. He has his own space and is no more in contact with the others. In France, veterinarians are a bit lost with this disease and do not treat FIV aggressively.

I take a care of this cat: check eyes, skin, mouth. However, are there any existing treatments or information I should know.

Many thanks for you help.

Regards, Frederique

Answer: Frederique-

It is a good idea to confirm a positive feline immunodeficiency virus test if it was done using an ELISA test kit at the veterinarian's office. The Western blot test is a good second test to help confirm that FIV is actually present since it tests for several of the virus' antigens rather than just one. If this test is positive, as well, then it is reasonable to assume that infection is present.

Most cats with FIV seem to do well without therapy directed specifically against the FIV virus itself. This seems to be a different situation than exists in humans infected with the HIV virus, although I am not familiar enough with the specifics of care for humans to be sure of that. A rapid progression to acquired immunodeficiency syndrome doesn't occur in the majority of cats, so most cats with FIV have a long period in which they are not highly immune compromised. For this group of cats, aggressive treatment of any other diseases that occur is usually sufficient to provide them with a good quality of life for several years. I do not know a published "average" time before clinical signs appear but many cats seem well for 5 to 10 years following infection, although many cats probably also have problems more quickly than that. It is very helpful to keep cats with FIV in an environment that limits the potential for acquiring an infectious disease, though. House cats with this condition are less likely to have secondary problems than free-roaming cats.

Eventually, the FIV will weaken the immune system and allow normally mild diseases to be quite severe in affected cats. When treatment is used for secondary problems such as ringworm or upper respiratory infections it often must be continued much longer than for cats who do not have FIV. Some cats do develop serious problems directly associated with the feline immunodeficiency virus, especially gum disease and kidney failure. These conditions are more difficult to treat in FIV infected cats but aggressive care for them is usually helpful. If anemia occurs blood transfusions can be helpful, as well.

Two of the medications used in humans for HIV infections seem to be helpful in cats. AZT has been shown to be helpful but can only be given for short periods of time in most cats. For this reason it is primarily used as "rescue" drug to try to get through times when clinical signs are severe. The usual dosage is 15mg/kg every 12 hours. PMEA is also used in cats for treatment of FIV virus in a similar manner, although it appears to have an even higher risk of causing severe side effects, especially bone marrow suppression. Bone marrow transplantation has been studied in FIV positive cats and was helpful, although I suspect that arranging for this therapy would be difficult.

It is possible to monitor FIV progression using the ratio of CD4+ lymphocytes to CD8+ lymphocytes (CD4+:CD8+ ratio). Only a few laboratories in the U.S. do this testing but it is likely that there is at least one in France. A low ratio indicates that there is more significant immune suppression. Monitoring this ratio could help in deciding when therapy such as AZT is warranted. Using testing procedures for other common secondary problems, such as toxoplasmosis, anemia and kidney failure, can also be helpful when it is unclear why a new round of clinical signs has occurred. This can get expensive to do over and over again so you may have to rely on your vet's best judgment for when testing is really necessary and when it is possible to wait on testing to see if there is a response to therapy.

I hope that this helps some.

Mike Richards, DVM 9/5/2001

FIV infection and treatment

Question: Dear Dr. Richards, I am fostering a cat that is struck with the FIV disease. I am at my wits end trying to find the most current literature available so I can help my cat. Please be kind enough to direct me to web sites or send me literature on the most current things being done in research for our friends. (CATS) I am enclosing my address and fax numbers for your convenience.

Thanks so much for your valuable service.

I am quite happy with your work even when you get backed up.

We need more VETS like you!

Sincerely, Buddy

Answer: Buddy-

In a cat with a positive test for feline immunodeficiency virus (FIV) but no clinical signs, it is also a good idea to confirm the infection if an ELISA antibody test was done in the vet's office as a screening procedure. The best way to do this is to send a sample for a Western blot test, which tests for more types of antibody than the ELISA test does. If your cat was obviously ill at the time of the test it may be less important to confirm the diagnosis but it still isn't a bad idea.

Treatment for feline immunodeficiency virus infection is something that seems best to individualize from patient to patient. It really seems like cats vary widely in how they respond to treatment, making it necessary to figure out from cat to cat how much direct anti-viral therapy they can tolerate and how aggressively secondary problems must be treated. For cats without symptoms despite infection with the virus it may be best to wait until clinical signs appear before considering treatment, since studies suggest that none of the currently available medications prolong the time period between inapparent infection and clinical disease. If clinical signs attributable to other infections occur, it may also be best to treat the other causes first and then treat for FIV if that isn't effective. Some cats never develop clinical disease from FIV infection but it probably eventually affects the majority of cats. When that happens, there are some options for treating the virus.

There is research going on with several medications for FIV in cats, partly due to the fact that the disease in cats is similar enough to HIV that it stimulates research efforts. At the present time, the best combination of effectiveness and safety for the cat appears to be zidovudine (AZT and Retrovir, Rx). It is given at dosages of 5 to 20mg/kg once daily. Zidovudine can cause bone marrow suppression in cats and sometimes causes vomiting, as well. The bone marrow suppression is a serious side effect in an immune compromised cat so it is important to monitor for this effect. Zidovudine was studied for use for 42 days for feline leukemia post-exposure prevention and cats in that study did not have serious side effects but longer term use apparently frequently results in bone marrow suppression. This can allow treatment of cats who seem to be having effects from the FIV long enough to help them get through a crisis, though. It is possible to use it long term by monitoring the hematocrit (HCT, percentage of red blood cells) and stopping when the HCT drops below 20% and then starting again after the HCT gets back into normal ranges. A second medication, phosphonomethoxyethyl adenine, usually referred to as PMEA, is also reported to be a reasonable "rescue" drug but has toxicity problems after periods of use as short as two or three weeks so is probably best used only when absolutely necessary. It is an injectable medication and is given subcutaneously twice daily at dosages of 2.5mg/kg. (Egberink, 1992)

There is better work in feline leukemia infected cats to support the use of interferon than in FIV infected cats, but this is also an option. The usual dosage is 30U daily used in intervals, such as 7 days on and 7 days off. This medication seems very safe at these dosages so at least if it doesn't work it might not cause any problems, either.

Aggressively treating any secondary infections, losses of appetite, increases or decreases in drinking or urinating or other clinical signs of disease that occur in a FIV positive cat is also beneficial. These cats should be examined by your vet at the first sign of illness to try to prevent serious secondary disease from occurring. Often, doing this is enough to keep cats comfortable and relatively healthy.

If there is a big breakthrough in FIV therapy I am sure it will make it into the VetInfo Digest immediately, but if you want to ask for updates on FIV treatment at any time please feel free to do so. I will try hard not to lose future questions.

Mike Richards, DVM 7/20/2001

Transmission of FIV - mother to kittens

Question: I am a subscriber who took in a stray cat in Dec. In Feb. she gave birth to 4 beautiful kittens. I have other cats in the house and I wanted to know if FIV or leukima can be transmitted from a mother or father cat to the kittens. If I have the mother tested and she tests negative do I still need to have the kittens tested? I want to keep all the cats in the house safe. Any infor would be greatly appreciated.

Answer: Karen-

Feline leukemia virus is transmitted in the uterus to some kittens but is more commonly transmitted to kittens from their mother when they are nursing. If the mother is negative on a feline leukemia test it is very unlikely that the kittens would be infected as long as they are not exposed to any cats other than their mother who might be positive.

Feline immunodeficiency virus can be transmitted from the mother to kittens in the uterus and it is also transmitted from mothers to kittens when they are nursing. However, this is not thought to be a huge risk to kittens. Unlike feline leukemia, the test for feline immunodeficiency virus is an antibody test. This is a really important difference when trying to interpret the test. If a mother cat has FIV she will pass antibodies against the virus to her kittens in the colostrum (first milk). This antibody will cause FIV tests done on the kittens to be positive. It can take several months (at least four) in some cases for the antibody from the mother to get to low enough levels that it won't cause a positive test. For this reason, testing a young kitten for FIV is difficult. If the test is positive, you can't tell if the kitten is really positive or just carrying antibodies from its mother. If the test is negative, the kitten may have been exposed but may not have started to produce antibodies since there is a lag period between infection and antibody production that can be as short as two weeks or as long as two months. With these two problems interfering with testing, it is probably best not to try to test kittens until they are at least five months of age or to at least plan on retesting kittens around that time to clarify the results of any earlier tests.

I hope that this information is still useful.

Mike Richards, DVM


FIV and central nervous system problems

Question: Dear Dr. Richards,

I have an 8 year old male cat that was recently diagnosed with FIV. YD was a feral cat that we took in when he was less than one year old. We had him neutered, and he also got, and has been getting all of standard vaccinations.

We took him to our vet because he started having problems walking. He looses balance and stumbles. He often shakes his head just before he looses balance. This has been going on for about 3 weeks, and two weeks ago we took him in and learned of the FIV.

I know that the FIV has made him succeptible to secondary infections which may be causing him neurological problems.

How should we proceed from here? I want to find out what is causing the imbalance problems, and find out if there is any treatment. I also want to find out if there is any effective way of slowing or mitigating the effect of the FIV.

Of course, all of this is intended to keeping YD with us for as long as we can.

If you can direct me to specific topics in your library, or if you can give me some recommendations on how to proceed, I would be very grateful.


Answer: John-

Feline immunodeficiency virus (FIV) can have direct effects on the nervous system and it can also suppress the immune system enough to allow secondary problems of the immune system to develop. It can be difficult, or even impossible in some cases, to differentiate between primary and secondary neurologic disease. The most common treatable neurologic problem associated with FIV is probably toxoplasmosis. It is reasonable to try treating with clindamycin (Antirobe Rx) if your vet feels that this is a possible problem. There is no specific treatment that I am aware of for the neurologic signs caused by FIV directly. These do tend to wax and wane, making a spontaneous remission a possible outcome.

The treatment that has produced the most consistent results in FIV infection is AZT. There may be some benefit in using interferon. There isn't a lot of evidence to support its efficacy but it seems safe and it isn't too expensive and that combination makes it worth trying it even if the chance of improvement is low. There is starting to be research into using combinations of therapy, similar to the mixes used in human therapy but I can't find information on the success of these therapies at this time.

If your vet is not comfortable aggressively treating FIV it may be worthwhile to ask about referral to an internal medicine specialist, especially if you can find someone in your area with an interest in this disease or infectious diseases in general.

Many cats can live long life spans after diagnosis of FIV and I think that it is worthwhile to try to treat the secondary problems that arise as a result of FIV infection.

Mike Richards, DVM


FIV treatments

Question: Dear Dr. Richards,

I am the Cats Guide at About and I've had many occasions to link to your fine articles on various feline diseases and conditions. You perform a wonderful service to cat lovers.

My question is about my own 18 year old cat, Shannon, a neutered male. He has had the usual assortment of conditions common in older cats: arthritis, CRF (although currently stable), and increasing deafness, but for the most part has seemed to be in good health, considering his advancing years.

However, a couple of months ago, during a heat wave with temperatures of 110 and more, he became very ill one day. We rushed him to our local veterinarian, where subsequent tests disclosed a bladder infection, which turned out to be e coli. This was treated successfully, with 3 full courses of Clavamox, and his urine tests are clear.

However, during the testing procedure, it was discovered that his white cell count was very low. (2.8 in the first test and 1.4 two weeks later.) Further blood tests disclosed he is positive for FIV. (Both the Elisa and the Western Blot). Since our other cat, Bubba, 13, tested negative, we are assuming that Shannon picked up the virus years ago when he was active outdoors, as he has had no biting contact with any other cat for at least 8 years.

We asked our veterinarian about Interferon, and he prescribed 1 ml daily, and gave us a 100 day supply, to be refilled when gone. I've asked other "experts," including another veterinarian and a Net friend who rescues and raises FIV and FeLV cats. The Net friend tells me the dosage should be 10 days on/10 off so resistance is not built up. The veterinarian says that the standard dosage for *FeLV* cats is 7 days on/off, but that perhaps because of the severity of the condition, a daily dose is indicated.

My veterinarian is of the school that thinks aggressive treatment can be stressful in older cats, and can exacerbate, rather than relieve the symptoms. I am concerned about Shannon's weight loss, and am feeding him whatever he will eat at any given time, which currently is Sheba Crab and/ or Duck, as I'm more concerned with hepatic lipidosis at the present time than any residual bladder crystals. (He had several teeth extracted about six years ago, and has difficulty with dry food.) I've heard that echinacea, antioxidants and Omega 3/ Omega 6 fatty acids can also help boost his immune system, but I don't know the proper dosage for cats.

I realize at his age, his prognisis is "one day at a time," but for selfish reasons I would like to extend his time as long as possible, as long as he seems comfortable and happy. He's been a valuable and loved family member since a kitten, and I'm just not ready to give him up yet.

What is your opinion on an aggressive, yet *kind* program of treatment that will not stress him unduly? I don't want to "second-guess" my own veterinarian, but he has been amenable to my questions and suggestions, so far.

Thanks in advance, Franny

Answer: Franny-

There are a number of published protocols for the use of alpha-interferon (Roferon-A Rx) in cats with FIV. The most common recommendation is to use interferon for 7 days, stop for a week and then repeat the cycle. Alternatives are to use it 5 days on and 5 days off and the one you found, 10 days on and 10 days off. In the most recent volume of Kirk's Current Therapy (XIII), the recommendation is to use it 5 days on and 5 days off. I have not heard of many adverse effects from interferon, which is probably why it is used frequently, since in clinical trials it has not shown a great deal of benefit in FIV positive cats. Interferon seems a little more promising for feline leukemia infections (FeLV), although the best effects seem to occur with high dose therapy used for 3 to 7 weeks at 1,000 to 10,000 U/kg per day (Kirk's XIII).

I have not seen much information on dosing for echinacea but I know that people have used anywhere from 1/10 to 1/4th of the human dosage safely.

The omega fatty acids are increasingly recommended in inflammatory conditions but I haven't seen much written about benefits in immune system deficiencies. These are pretty safe to use and are sold in preparations made for pets. Just follow the directions on the label for the product that you choose.

I don't see any reason not to try these things. If you wish to be more aggressive, AZT has shown good effects in the treatment of FIV and the dosing information is also in Kirk's XIII.

I think it is very important to aggressively treat any secondary infections, including bladder infections, gastrointestinal disorders and upper respiratory infections. Don't hesitate to take Shannon to the vet's when it seems as if it might be necessary.

Good luck with this.

Mike Richards, DVM


Feline immunodeficiency virus (FIV) test

Question: I have a 7 year old neutered male cat who for the last 1 1/2 years has had episodes of anorexia lasting 2-3 weeks with weight loss down to 7 lbs., alternating with periods of ravenous appetite when he slowly regains his weight. Blood tests 1 year ago done in office showed negative for feline leukemia but positive for FIV. He has had several episodes of bacterial sinusitis responsive to antibiotics, also `ringworm'. I.E., infections consistent with FIV. Are there any labs doing more accurate FIV blood tests than in-office? Does his clinical course suggest any other possibilities? Any suggestions for other tests?

Answer: T-

A positive antibody test for feline immunodeficiency virus (FIV) is usually sufficient proof of infection. If you wish to be cautious you could ask your vet to arrange for a test such as a Western blot test, just to confirm that antibodies to FIV are present.

It is possible to test directly for the virus itself in many viral illnesses. These tests are antigen tests. When it is possible to do this, an antigen test is considered to be better evidence for infection than an antibody test. FIV virus is quickly removed from the circulation by the white blood cells, making it very difficult to test for FIV antigen, though. The virus is not eliminated from the body as happens with many other viral illnesses, though. For this reason, a positive antibody test for FIV is almost certain proof that the virus is present in the body, making the need for an antigen test less important. There are some ways to do antigen testing for FIV but all are done in experimental labs and are not available as commercial tests, to the best of my knowledge.

Cats with FIV and signs of acquired immune deficiency tend to be middle aged or older male cats with a history of fighting. There are many cats who have this virus who do not fit this profile, though. Once the immune deficiency problems begin, the episodes of illness such as you have been seeing are pretty typical of this disease.

Until recently, aggressive treatment of secondary infections was the most successful way to keep cats with FIV in reasonably good health and to help them with this disease. Now there is evidence that administration of AZT has been shown to help some cats with FIV infection, just as it helps humans with HIV infection. This is an option that might be worth considering after discussing it with your vet. There is information on this in the new edition (XIII) of "Kirk's Current Veterinary Therapy", if your vet needs more information.

Cats with FIV infection are more prone to kidney failure than cats who do not have this virus, so you may want to monitor for this problem by checking blood values pertaining to kidney function on a regular basis (every 3 to 6 months). If you go ahead and do a regular serum chemistry panel at the same time it would eliminate some worries about other possible conditions, although I really think that the FIV positive status and clinical signs are typical enough that searching for other problems is probably not necessary. Keeping a vigilant eye out for secondary complications to FIV is a good idea, though.

It is possible to manage most patients with FIV for a very long time. I hope that this is the case with your cat, too.

Mike Richards, DVM



Q: I have just had three adult cats and one 3 month old kitten diagnosed with FIV and one of the adult cats tested positive for FELV. I need help, info and support. Help, please. I am heartbroken and really scared for my cats.

They are my only family. Thank you.

A: Carol-

Feline immunodeficiency virus infection does not lead to acquired immunodeficiency syndrome in cats as often as human immunodeficiency virus leads to AIDS in people. Feline leukemia virus infection in a cat that persistently tests positive is more of a problem. This cat should be kept separate from your kitten, in particular, and all the other cats, in general. If these cats are all the cats in the household you will just have to be aggressive about seeking treatment for illnesses that crop up and try to keep the stress levels as low as possible. If you have other cats the choices are much harder as these are contagious illnesses. Many people do manage multi-cat households in which they keep infected and uninfected cats separate. It is hard but it is possible.

Mike Richards, DVM

FIV and diet

Q:Dr. Richards,

I have a cat with FIV, and he's recently lost some weight. What foods and vitamins should I be giving him?

Thank you,


A: Beth-

I am sorry to take so long replying to your note. I know of no special foods that help with FIV. A good quality cat food should be sufficient. It should not be necessary to supplement vitamins if you are feeding a balanced cat food as the primary diet (greater than 90% of the total food your cat consumes daily).

It would be a good idea to have your veterinarian examine your cat if the weight loss continues. Cats with FIV also get diabetes, kidney failure, hyperthyroidism, liver disease and other cause of weight loss. Aggressive treatment of any problems that are present will help to prolong his life. Many cats with FIV live nearly normal lifespans and good health management can make those pretty happy lives, too.

Mike Richards, DVM

FIV Transmission

Q: Hello. I live in a multi-cat household. One of our cats has recently been diagnosed with FIV but not FELV. He is not showing any symptoms. How easily is it transmitted through the same drinking water? Thanks.


A: Michele-

Feline immunodeficiency virus (FIV) is not easily passed from cat to cat. Drinking the same water should not pose much threat to uninfected cats. Mutual grooming may be sufficient contact for the virus to be spread but bite wounds are still thought to be the primary method of transmission for this disease.

Mike Richards, DVM

FIV - Feline Immunodeficiency Virus

Q: Dear Dr. Mike, My 7 year old cat was just diagnosed with FIV. We're not sure how he got it, though he is an outdoor cat. The vet says his blood count is good. However, he has had an eye infection that has not cleared up with repeated antibiotic (oral and topical) doses. Soon after the eye problem came about (9 months ago), he had an abscess removed from his side. He also has a small cyst on the back of his neck. Additionally, he has had recurrent skin infection almost every Spring (allergies, we assumed) that quickly cleared up with cortizone shots. Which of these disorders may be related to the FIV? Please tell me what exactly FIV is and what I might expect to happen to my trusted friend Jokes. Thank you for your insight. Sincerely, Pam

A: Pam- FIV, or feline immunodeficiency virus, is a retrovirus in the same family of viruses as the human immunodeficiency virus (HIV). At present, with extensive research already finished, there does not appear to be any risk of cross-infection between humans and cats. The viruses are somewhat similar in their actions, although cats as a species seem to be well adapted to living with this virus. There are a multitude of possible symptoms associated with FIV virus due to its effects on the immune system. The T-cells of cats are infected first but the infection spreads to lymph nodes and suppression of all types of white blood cells can eventually occur. Due to this, secondary infections occur. Skin, urinary bladder and upper respiratory infections are common since these areas are constantly fending off bacterial invaders. Diarrhea, gum disease, weight loss, neurologic signs, heart problems and increased susceptibility to parasite infections are also pretty common.

There is no treatment that has proven to be effective against the FIV virus at this time. Currently treatment is aimed at preventing or controlling the secondary problems that occur. Ensuring good nutrition and quickly attending to any obvious health problems is essential for keeping FIV infected cats healthy. With aggressive care many of these cats live out nearly normal lifespans.

The eye problem may be a result of FIV and its effects on the immune system. Feline herpesvirus (rhinotracheitis) is capable of causing recurrent eye infections that stubbornly resist treatment, with or without the presence of FIV, though.

Keep working with your vet to keep Jokes as healthy as possible. We have used cortisones to control allergy symptoms in FIV positive cats when it was necessary to keep the skin from being constantly infected. This is always a little worrisome but so far we have not regretted the use of cortisone when it seemed to be appropriate. An alternative is use of antihistamines and essential fatty acids if this combination will work for Jokes.

Mike Richards, DVM

Help for FIV

Q: I know that there isn't a cure for FIV, but do you know of any homeopathic items that might help the symptoms subside?

A: I do not believe in the philosophy underlying homeopathy, so I have not attempted to learn the various homeopathic remedies.

In most cases we feel that we can manage cats with FIV by treating any secondary problems that arise fairly aggressively. Most commonly we see an increase in respiratory disease, skin problems and cystitis in these cats. If these problems are controlled with appropriate therapy most cats with FIV will live pretty normal, reasonably long lives.

Mike Richards, DVM

Upper respiratory problems and FIV

Q: Dear Dr. Mike, Our 4.5 yr old long-haired male tabby, "George" is FIV+. He started sneezing about two weeks ago and it has become more persistant in the last few days. The sneeze has turned into what appears to be continuous coughing that lasts for more than several seconds at times. He has brought up mucos a couple of times. Other than that he seems to be normal. Last week he vomited as a result of becoming car-sick (long story) and we wonder if he may have asperated. He was also exposed to air-conditioning (in the car). We're looking for causes and remedies before we rush him off to the vet. Any advice would be appreciated.

A: Tracy - It is my honest opinion that you should not wait before taking a cat who is FIV positive and showing any clinical signs of illness to your vet. The decrease in immune function associated with this condition makes waiting riskier than in an uninfected cat. It is best to be aggressive in the treatment of any secondary problems.

Mike Richards, DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...