Feline Immunodeficiency Virus (FIV): Frequently Asked Questions

Blanco, a 15 year old FIV-positive cat

Is this the same virus that causes AIDS in people?

No. The Feline Immunodeficiency Virus (FIV) is also sometimes called the Feline AIDS Virus.  It is likened to the Human Immunodeficiency Virus (HIV) that affects people because of the similarities in the two diseases which result.  Fortunately, most viruses are species specific.  This is the case with HIV and FIV.  The Human Immunodeficiency Virus only affects humans, and the Feline Immunodeficiency Virus only affects cats.

FIV is a type of retrovirus called a "lentivirus" (slow virus) that attacks many of the cells of the
immune system, leaving the cat at risk for diseases that a healthy immune system can usually fight. Once infected, the virus takes up residence in a cat's lymph nodes and infects T-lymphocytes. Sometimes, the lymph nodes can become enlarged tempporarily as the virus spreads to other lymph nodes.

How do cats get FIV?

FIV is transmitted primarily by biting that usually accompanies cat fights.  Other interactions of cats,

such as sharing common food and water bowls or grooming each other, have not been shown to be significant in transmission. FIV affects up to 3% of the healthy cat population in any given area, and is much higher in populations of high-risk or ill cats. In some cases, isolated stray or feral colonies my have up to 100% of the population infected but apparently healthy. Male cats, especially intact males, are at highest risk for disease as they are more likely to fight and spread the virus.

How is it diagnosed?

Evidence of exposure to FIV can be detected by a simple blood test.  A positive test means the cat has been exposed to the virus and will likely be infected for the remainder of its life.  A negative may mean that the cat has not been exposed; however, false negatives occur in two situations:

1.         From the time of initial virus inoculation into the cat, it may take up to two years for the test to turn positive.  Therefore, for up to two years, the test may be negative even though the virus is present in the cat.

2.         When some cats become terminally ill with FIV, the test may again turn negative.  This occurs because antibodies (immune proteins) produced against the virus become attached and bound to the large amount of virus present.  Since the test detects antibodies which are free in circulation, the test may be falsely negative.   This is not the normal occurrence, but it does happen to some cats.

What does a positive test result mean in a kitten?

The vast majority of kittens under 4 months of age who test positive have not been exposed to the virus.  Instead, the test is detecting the immunity (antibodies) that were passed from the mother to the kitten.  These antibodies may persist until the kitten is about 6 months old.  Therefore, the kitten should be retested at about 6 months of age.  If it remains positive, the possibility of true infection is much greater.  If the kitten tests negative, there is nothing to worry about.

How can a kitten become infected?

If a kitten is bitten by an FIV infected cat, it can develop a true infection.  However, the test will usually not turn positive for many months.  If a mother cat is infected with the FIV at the time she is pregnant or nursing, she can pass large quantities of the virus to her kittens.  This means of transmission may result in a positive test result in just a few weeks. 

What type of disease does the FIV cause?

An FIV infected cat will generally go through a prolonged period of normal life with normal risk for health issues (viral dormancy) before it becomes ill.  This incubation period may last 6-8 years or more.  Thus, we generally do not diagnosis an FIV sick cat at an early age.

When illness occurs, we usually see a variety of severe chronic illnesses. This is because the cat's immune system becomes weakened and can no longer fight off the normal bacteria, viruses, fungi and protozoa that a healthy immune system would easily eliminate from the body. The most common illness is a severe infection affecting the gums.  Abscesses from fight wounds that should heal within a week or two may remain active for several months.  Respiratory infections may linger for weeks.  The cat may lose weight and go through periods of not eating well; the hair coat may become unkempt.  The cat may have episodes of treatment-resistant diarrhea.  Ultimately, widespread organ failure occurs, and the cat dies.

What are the signs of an active FIV infection?

IDEXX.com

• Poor coat
• Persistent fever
• Poor appetite
• Poor oral health - gingivitis, stomatitis, dental abscesses
• Chronic, persistent or recurrent infections of the skin, respiratory system or bladder
• Weight loss
• Cancer and blood diseases
• Reproductive failure
• Seizures, behavior changes, neurological disorders

Is there a treatment for it?

There is no treatment that will rid the cat of FIV.  Sometimes, the disease state can be treated and the cat experiences a period of recovery and relatively good health.  However, the virus will still be in the cat and may become active at a later date.  Therefore, the long term prognosis is not good.

What should I do with a cat that is FIV positive but is not ill?

If you have a cat that tests FIV positive but is not ill, it is not necessary to euthanize it immediately.  As long as it does not fight with your other cats or those of your neighbors, transmission is not likely to occur.  However, if it is prone to fight or if another cat often instigates fights with it, transmission is likely.  In fairness to your neighbors, it is generally recommended to prevent an FIV positive cat from roaming the neighborhood. Owners of infected cats must be responsible so that the likelihood of transmission to someone else's cat is minimized. Additionally, living an indoor life will reduce the positive cat's exposure to communicable diseases, parasites and other infectious agents that are common in the outdoor environment.

Wellness visits should be scheduled every 6 months, and you should keep a close eye on your FIV positive cat's weight, since weight loss is often the first sign that a cat is feeling ill.

FIV is not a contraindication for spay and neuter surgeries. 

Cats that are FIV positive should not eat a raw diet or unpasteurized dairy.  Food borne illnesses or parasites that a healthy cat is likely able to fight off are a higher risk for immunosuppressed cats.

There is a growing body of research into anti-viral therapies, but so far, no therapy stands out as a conclusive benefit to the health and longevity of FIV positive cats.

If an FIV positive cat has spent a period of time in your house, you will want to use normal cleaning and disinfecting methods to sanitize the area where the cat lived. FIV does not last long outside the body of a cat, however any secondary infections - bacterial, viral, fungal or protozoal, may linger on food dishes, bedding, litter pans and toys. A dilute bleach solution should be sufficient to clean these items.

For a little more information about one of our patient who is currently a 15 year old FIV survivor, you can read about Blanco on our blog!

Is there a vaccine for FIV?

Unfortunately, there is not a recommended vaccine available for FIV. Vaccination with the currently available FIV vaccine will cause your cat to test positive on an FIV test.

When should FIV testing be performed?

As a general rule, it takes 8-12 weeks for antibodies to appear after infection, so a post-exposure test should be performed a minimum of 60 days after a known exposure, such as a bite wound from an unknown animal. The antibody test is the standard initial screening test, and can be performed in the veterinary office within a few minutes. However, if the test is positive, it is generally recommended to confirm the test using an alternate method. In the past, the Western Blot test has always been the gold standard of confirmation testing, however, PCR tests are extremely sensitive (possibly too sensitive at this time?) and are showing promise as a superior testing method. 

• Sick cats
• Untested cats, or cats with an uncertain history of testing
• Newly adopted cats
• After a possible exposure (escaping out of the house with or without an obvious bite wound, living in a house with cats with unknown FIV status or uncertain testing history)
• After definite exposure (spending time in the vicinity of a positive cat with or without a bite wound) 

Additional Resources:

PetMD
Wikipedia
Oral Health-Retrovirus Connection

Ringworm infection in cats - it's not really a worm!

Ringworm

WHAT KIND OF INFECTION IS IT?

Ringworm lesion

Generalized ringworm lesions

"Ringworm" is the common name for the skin infection caused by certain types of fungi. Despite the name, ringworm is not caused by a worm at all. The fungi feed upon the dead cells of skin, nail beds and hair. In people, this causes a classic round, red lesion with a ring of scale around the edges and normal recovering skin in the center. Because the ring of irritated, itchy skin looked like a worm, the infection was erroneously named. The fungi responsible are called "dermatophytes," meaning "plants that live on the skin" thus the more correct term for ringworm is "dermatophytosis." The characteristic "ring" appearance is primarily a human phenomenon. In animals, ringworm frequently looks like a dry, gray, scaly patch but can also mimic any other skin lesion and have any appearance. The fungi live in the hair follicles and cause the hairs to break off at the surface of the skin. As the fungus multiplies, small round lesions can become large, irregularly shaped patches of hair loss and spread across the whole body. Most commonly, ringworm is seen in kittens, likely due to their weaker immune system. Ringworm most commonly affects the face, head and ears. Less commonly, the feet, tail and nails are affected, and even less commonly do we see generalized infections covering the entire body. High humidity and large populations of cats tend to increase the risk of ringworm infection, and certain breeds like Himalayans and Persians are at higher risk, as well. You can read about Samson and his battle with ringworm on one of our other blog posts. This may be due to increased difficulty in grooming all the way down to the skin due to large amounts of long thick fur. FIV positive or otherwise immunocompromised cats are also at higher risk. Regular or frequent bathing of cats may remove protective skin secretions that help protect the skin from fungal infection.

WHERE WOULD MY PET PICK UP THIS INFECTION?

There are about 40 different species of dermatophyte fungi. The most common species to infect humans is the Tinea family of fungi. Cats tend to become infected by Microsporum canis, Microsporum gypseum, and Trichophyton spp. Microsporum canis is responsible for up to 98% of dermatophyte infections and is considered "true" ringworm.

Different types of dermatophytes look different on culture medium

The spores of dermatophyte fungi are extremely hardy in the environment; they can live for years. All it takes is skin contact with a spore to cause infection. Infected animals are continuously dropping hairs covered with thousands to millions of spores, because infected hairs become fragile and easily break off and shed into the environment. Some animals (about 20%) are carriers and never show signs of skin irritation themselves, but can infect others readily. Ringworm can be transmitted between people, dogs and cats by direct contact, as well as being picked up from the environment. Environmental “hot spots” for contracting ringworm are schools or daycares, gyms, and the out-of-doors in general. Spores may live in bedding or carpet for 18 months or more. Different species of fungi come from different kinds of animals or even from soil, so determining the dermatophyte species can help determine the source of the fungal infection.

CAN I GET THIS INFECTION?

Ringworm lesion in a human

Yes, ringworm is contagious to people; however, some people are at greater risk than others. The fungus takes advantage of skin belonging to those with reduced immune capacity. This puts young animals and children, elderly people and pets, those who are HIV+, people receiving chemotherapy or taking medication after blood transfusion or organ transplant and highly stressed people and animals at high risk. If you have cuts or abrasions to the skin, that allows the fungal spores a better foothold, as normal, unbroken and healthy skin is resistant to fungal infection. In general, if you do not already have ringworm at the time your pet is diagnosed, you probably will not get it, since lesions appear about 10-12 days after infection. If you find suspicious lesions on your body, check with your family physician.

HOW DOES THE DOCTOR KNOW THIS IS REALLY RINGWORM?

In some cases, we know for sure that dermatophyte fungi are present while in other cases we are only highly suspicious. Lesions on animal skin are rarely the classic ring-shaped as in people (in fact, in animals, lesions are often not even itchy) thus some testing is usually necessary. On many animals, ringworm presents as roughly circular areas of broken hairs or bare skin, often with scaly, inflamed skin. Sometimes, ringworm infections can look almost identical to flea allergy dermatitis or other skin diseases. Hair loss is usually involved, but the degree of itchiness and inflammation is highly variable.

Hair shaft fluorescence under Wood's Lamp

WOOD'S LIGHT
Microsporum canis, the most common ringworm fungus, will fluoresce apple green in approximately 50% of cases. Fluorescence is an easy test to perform and may provide a strong clue that dermatophytes are present. Further testing is usually needed, however, to absolutely confirm diagnosis. It is important not to mistake scabrous material, dust particles and free-floating skin flakes as fluorescence. If the fluorescence is present, it will light up along the hair shafts at the edge of the lesion.

MICROSCOPIC EXAMINATION
Your veterinarian may wish to examine some hairs for microscopic spores. If spores can be seen on damaged hairs then the diagnosis of ringworm is confirmed; however, as spores are very difficult to see, many veterinarians skip this step.

FUNGAL CULTURE
For a fungal culture, some hairs and skin scales are placed on a special culture medium in an attempt to grow the ringworm fungi. The advantage of this test is that it not only can confirm ringworm but also can tell exactly which species of fungus is present. Knowing the identity of the fungus may help determine the source of infection. The disadvantage, however, is that fungi require about 10 days to mature to the phase where they can be identified by their special "fruiting bodies" and spores.
 

Also, this is the only test that is helpful in determining if animal is an asymptomatic carrier. The other tests require an apparent skin lesion to test. A pet with no apparent lesions can be combed over its whole body and the fur and skin that are removed can be cultured. Carrier animals are usually cats living with several other cats.

Characteristic growth and media color change on fungal culture

 

BIOPSY
Sometimes the lesions on the skin are so uncharacteristic that a skin biopsy is necessary to obtain a diagnosis. Fungal spores are quite clear in these samples and the diagnosis may be ruled in or out. Depending on the outcome of preliminary tests, your veterinarian may begin ringworm treatment right away or postpone it until after more definitive results are available.

TREATMENT

Commitment is the key to success especially if you have more than one pet. Infected animals are constantly shedding spores into the environment (your house) thus disinfection is just as important as treatment of the affected pet. Areas of hair loss will likely get bigger before they get smaller. Within 1-2 weeks, hair loss should stop, there should be no new areas of hair loss, and the crusting on the skin should subside. If any of these do not occur within 2 weeks, we should see your pet again. Infected pets generally remain contagious for about 3 weeks after treatment begins.

ORAL MEDICATION FOR INFECTED PETS

There are two primary medications being used to treat ringworm: Griseofulvin and Itraconazole (brand name "Sporonox"). Veterinary dermatologists disagree as to which is better. Both medications are relatively expensive, must be given with food, and have significant potential to cause birth defects in pregnant pets.

Treatment with either medication typically is continued for 1-2 months and should not be discontinued until the pet cultures negative. Stopping when the pet simply looks well visually frequently leads to recurrence of the disease.

Characteristic Microsporum fungal macroconidia and spores

GRISEOFULVIN (brand name Fulvicin)
This medication must be given with a fatty meal in order for an effective dose to be absorbed by the pet. Persian cats and young kittens are felt to be sensitive to its side effects which usually are limited to nausea but can include liver disease and serious white blood cell changes. Cats infected with the Feline Immunodeficiency Virus commonly develop life-threatening blood cell changes and should never be exposed to this medication. Despite the side effects, which can be severe for some individuals, Griseofulvin is still the traditional medication for the treatment of ringworm and is usually somewhat less expensive than Itraconazole.

ITRACONAZOLE
This medication is highly effective in the treatment of ringworm but is available in capsules far too large to be useful to most small animals. This means that a special compounding pharmacy must reformulate the medication into a more useful size. Nausea is a potential side effect for this medication, but otherwise, side-effects are fewer than with Griseofulvin. The primary reason it is sometimes passed by in favor of griseofulvin is expense. Itraconazole is also effective in treating many life-threatening fungal infections whereas Griseofulvin only treats ringworm.

By increasing the amount of Itraconazole in the environment, we may be creating resistance in more dangerous fungi which could become a problem over the years. On the average, cats treated with Itraconazole and nothing else were able to achieve cure two weeks sooner than cats treated with Griseofulvin.

DOES PROGRAM CURE RINGWORM?
In the late fall of 2000, the Journal of the American Veterinary Medical Association published a study of over 200 cases indicating that Lufenuron (the active ingredient of Program) could be an effective treatment for Ringworm. This began as an observation that animals using Program or Sentinel for flea control did not get ringworm. Questions about this work have come up from the public since the release of this work. The fact is that the study is still under scrutiny by members of the American College of Veterinary Dermatology and “the jury is still out.” It is clear that the doses purported to be helpful with Ringworm should not be harmful. At this time the use of Lufenuron for Ringworm is reasonable if other more conventional treatments are used at the same time, but its efficacy is controversial and it should not be considered as the only method of treatment.

TOPICAL TREATMENT FOR INFECTED PETS

Both the above medications work by interfering with fungal reproduction rather than by directly killing the fungus. This is fine from the pet's perspective as either medication should be able to clear the fungus without further therapy; however, we also would like to reduce contamination of the environment. This means actually killing the fungus on the pet so that the hairs dropped will not be infectious but applying topical therapy. For many years cats with ringworm lesions were shaved to allow for easier topical treatment. We now know that shaving may be spreading the fungus by creating microabrasions on the skin and allowing the spores to take hold in new locations, or simply by spreading spores across the body as the clippers are moved from one area to another. Because of this, shaving is not always recommended (depending on the number of cats present in the home and the length and thickness of the hair).

Ringworm lesions on an ear

LIME SULFUR DIP
Dips are recommended twice a week and can be performed either by the hospital or at home. If you attempt this kind of dipping at home, you should expect:

• Lime Sulfur will stain clothing and jewelry
• Lime Sulfur will cause temporary yellowing of white fur
• Lime Sulfur smells strongly of rotten eggs.

The dip is mixed according the the label and is not rinsed off at the end of the bath. The pet should be towel dried. Shampooing is not necessary.

ENVIRONMENTAL TREATMENT

The problem with decontaminating the environment is that very few products are effective. Bleach diluted 1:10 will kill 80% of fungal spores with one application and any surface that can be bleached, should be bleached. Vigorous vacuuming and steam cleaning of carpets will help remove spores and, of course, vacuum bags should be discarded. To reduce environmental contamination, infected cats should be confined to one room until they have cultured negative. The rest of the house can be disinfected during this confinement period.

THE RINGWORM VACCINE FOR CATS

In 1994, Fort Dodge released a vaccine which could be used either in the prevention of ringworm infection or in its treatment. Our hospital does not recommend the use of this product as, while it may prevent the development of obvious lesions in a cat, it probably will not prevent infection. This means that vaccinated cats could more easily become carriers of infection. The vaccine does not appear to be available any longer (since 2003), and was meant to be used in a treatment situation where many cats were infected. It was designed as a supplement to the treatments described above rather than as a preventive for cats in general.

WILL RINGWORM GO AWAY BY ITSELF?

There have been several studies which showed that this fungal infection should eventually resolve on its own. Typically, this takes four months, a long time in a home environment for contamination to be occurring continuously. We recommend treatment for this infection rather than waiting for it to go away.

Blanco: The Trials and Tribulations of a Battle-Scarred Tomcat

Blanco is a 15 year old neutered male cat. He appeared, one day, and won the hearts of a family with his rough and tumble scruffiness. He was several years old at the time, and you could read his past like a newspaper on his raggedy coat. He was probably about 5-6 years old when he was taken in, neutered and tested. He was also FIV positive - not surprising, since he was a battle-scarred un-neutered male wandering the streets. However, he was otherwise healthy, and his FIV positive status did not deter his family. They confirmed that he was positive with an IFA test, and then continued to treat his battle wounds.

Dermatitis of Blanco's ear

All four of his canine teeth were fractured from fighting, and one was infected. The other three had broken far enough down the tooth that the canal to the nerve and blood supply was open and at risk for infection. He was scheduled for dental care, and lost a total of 10 diseased teeth, and 4 more teeth were discovered to be missing. He also got a microchip.

After his dentistry, his owners noticed that he was no longer "teething" and chewing on things around the house.

Dermatitis of Blanco's nail beds

Starting in 2011, Blanco began to have issues with itchy skin. He ran through several different antibiotics and tapering doses of steroids, before his dermatitis responded well to a combination of Prednisolone and Atopica. Since that time, he has been comfortable in his skin.

Later in 2011, Blanco began losing weight, and his senior bloodwork showed that he had developed hyperthyroid disease. A month later, he came in to our hospital to stay with us for a week while he received Radioactive Iodine treatment for his hyperthyroidism. His thyroid has been normal ever since.

In 2013, his kidney values began to creep up. So far, they continue to be only mildly elevated, but we are continuing to monitor them regularly.

Blanco's right eye is becoming cloudy and discolored

In 2014, Blanco started to suffer discomfort from old injuries to his right eye. The lens had been displaced by the trauma from a fight long ago, and when he started to form a cataract due to old age, the problem became worse. The body started treating the lens as a foreign body and he developed a condition called "uveitis".  The pressure in the eye decreased, and the eye became sensitive and  painful. On October 14, he had an enucleation surgery to remove the eye, and on November 6th, he came in for suture removal. His mom and dad were very happy and reported that he was brighter, more active and must have been in a lot of pain before his eye was removed. Now he is doing great, and as long as he is doing well, we don't plan to see him again for 6 months. At that time, he is planning on participating in the high blood pressure screening study that is going on, right now at our hospital.

If anyone wonders whether FIV positive cats can live a long and fruitful life, Blanco is happy to say that he has been FIV positive for close to 10 years, and feels great due to the loving family he has, and due to the exceptional care they give him. We appreciate that they turn to us to help give him that care, and we hope that he has many more FIV positive years ahead of him!

Blanco's right side after suture removal

Blanco's proud, scarred face

We can't wait to see how handsome he is when all his fur has grown back!