What Can I Do if My Cat Has a Serious Viral Infection?

Feline leukemia virus (FeLV) is one of the most common and destructive of all cat viruses, but there are other serious cat viral diseases.

Feline Leukemia Virus: What Is It?

It is highly contagious and is spread primarily by saliva during cat fights, grooming or mating. The virus is also spread by blood, urine and feces. Kittens may become infected while still in the womb, during birth or during nursing.

Not all cats exposed to FeLV become infected. About 40 percent of exposed cats have immune systems that destroy the invading virus. The remainder of exposed cats become persistently infected (30 percent) or develop a latent infection (30 percent).

The latter group has inactive virus in the bone marrow, and these virus particles may later become active when the cat becomes ill from another disease, stress or certain drugs.

Of the cats persistently infected, about 25 percent will die within one year and 75 percent will die within three years. Some may live a normal life but tend to have various chronic illnesses.

There are no signs specific for FeLV infection. The main effect of the virus is to disrupt the cat’s immune system. While anemia is the most common disorder caused by the virus, cancer and various other diseases are common.

Disorders commonly associated with FeLV infection include chronic respiratory disease; chronic infection of the mouth, gums and tongue; chronic eye disease; frequent or chronic skin disease; disease (abortion, stillbirths and kitten deaths); frequent or chronic urinary tract infections; chronic digestive tract disease; and other systemic diseases (infectious peritonitis, hemobartonellosis, toxoplasmosis, polyarthritis).

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How Can I Protect My Cat From FeLV?

Vaccination before exposure to the virus imay be one means of preventing FeLV infection. Optimizing the strength of the immune system is the best means of prevention. Preventing direct contact with infected cats is critical.

Outdoor cats have a high risk for developing FeLV infection (if they encounter other leukemia-infected cats). Indoor cats are at low risk for developing FeLV infection. Keep indoor unvaccinated cats away from outdoor cats, or have them vaccinated. Because infected cats are at high risk for developing cancer or other life-threatening diseases they should be maintained as indoor cats.

Currently, there is no uniformly effective treatment for cats infected with FeLV. Immune optimization with homeopathy, natural diet, etc., can improve quality of life and the disease-free interval.

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Feline Immunodeficiency Virus (FIV): Is It the Same Virus That Causes AIDS in People?

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

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How Do Cats Get FIV?

The FIV is transmitted primarily by the biting that occurs in 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.

Evidence of exposure to the 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:

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.
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.

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What Does a Positive FIV Test Result Mean in a Kitten?

The vast majority of kittens under four 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 six months old, when the kitten should be retested. If the result remains positive, the possibility of true infection is much greater. If the kitten tests negative, there is nothing to worry about.

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.

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What Type of Disease Does FIV Cause?

An FIV infected cat will generally go through a prolonged period of viral dormancy before it becomes ill. This incubation period may last as long as six years. 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. 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.

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Is There a Treatment or a Vaccine for FIV?

There is no treatment that will rid the cat of the FIV. Sometimes, the disease state can be treated and the cat experiences a period of recovery and relatively good health. This can be promoted by use of proper nutrition and supplementation with immune system enhancers. 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.

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 restrict a FIV-positive cat to your house. Owners of infected cats must be responsible so that the likelihood of transmission to someone else’s cat is minimized.

Unfortunately, there is no effective vaccine available against FIV.

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Feline Infectious Peritonitis (FIP): What Causes It?

Feline Infectious Peritonitis (FIP) is a severe disease of domestic cats and some exotic cats. It does not affect non-feline species, such as dogs. It is caused by a coronavirus.

The incubation period is controversial. In experiments with the virus, cats will develop the disease within two weeks of infection. However, in household situations, it appears that the virus may be dormant in some cats for several months, or even years, before the disease occurs.

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What Are the Clinical Signs of FIP?

FIP is a chronic, wasting disease that results in poor appetite, fever, and weight loss over several weeks; it is ultimately fatal. Because various organs may be affected (i.e., liver, kidneys, brain, eyes, etc.), a variety of clinical signs may be associated with this disease. For example, blindness or seizures may occur in one cat, while another will have signs of liver disease (jaundice).

There are two forms, the wet (effusive) form and the dry form. The wet form results in accumulation of large quantities of fluid in the chest or abdomen. If it occurs in the chest, the cat will experience difficulty breathing. When it occurs in the abdomen, a large, bloated appearance will result. The dry form affects the target organs in a similar fashion, but no fluid is produced. If enough time passes without the cat dying, the dry form may progress into the wet form. Diagnosis of FIP is much easier if fluid is present.

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How is FIP Diagnosed?

Diagnosis of FIP may be difficult and frustrating. There are no specific tests which are reliable in all cases. Although organ biopsy is the most reliable, this requires surgery. For obvious reasons, surgery may not be advisable in a sick cat. The following tests are usually used on cats with suspicious clinical signs.

Coronavirus Test This test detects antibodies to any coronavirus. Antibodies are the circulating defense agents of the immune system. There are two coronaviruses that affect the cat: the FIP virus and the enteric coronavirus. If positive, this test indicates that one or both of those viruses WAS or IS present in the cat. However, we do not know which virus is reacting to the test. Since antibodies may persist even if the virus is no longer present, a positive test can be misleading in some cases. Also, terminally ill cats may have their antibodies “tied up” when large amounts of the FIP virus are present. This can result in a false negative test result. Therefore, this test must be interpreted in conjunction with results of other tests. These tests are listed below.
Polymerase Chain Reaction (PC) This new test is more specific for the FIP virus than the coronavirus antibody test; however, it is still just a test for the presence of the FIP virus. A positive test means the virus is present, but does not necessarily mean the disease is present. This test is also subject to some false negative results.
Serum Protetin Levels If the total serum protein is elevated AND the A:G ratio (ratio of two different blood proteins ) is less than normal, FIP becomes a more likely diagnosis. A few other diseases may also cause this, but these are also very severe and usually fatal. These findings occur in 50 percent of the cases of FIP.
White Blood Cell Count If the white blood cell count is greater than 25,000 cells/ul, FIP becomes a stronger possibility. However, several other diseases may cause this and some of these are not fatal. Also, many cases of FIP have a normal white blood cell count (less than 18,000 cells/ul).
Abdominal Chest Fluid Presence If fluid is present, this is a very meaningful test. If the characteristics of the fluid are appropriate and the cat has the correct clinical signs, a diagnosis can be made with greater assurance. Unfortunately, this fluid is not present in the dry form of FIP.
Fine Needle Aspiration of the Liver or Kidneys A few cells may be aspirated from the liver or kidney without stressing the cat (i.e., with a local anesthetic in the skin). FIP produces a particular inflammatory pattern in these organs which, although not diagnostic, is strongly suggestive for the disease. This helps to rule out other diseases.
Radiographs (X-Rays) of the Chest or Abdomen Radiographs serve to identify enlargements in organs and the presence of fluid in the chest or abdomen. They are helpful but not diagnostic and are used to decide which other tests are appropriate.
A Combination of Three Blood Tests Cats with the combination of a low lymphocyte (a white blood cell) count, a high blood globulin (protein) level, and a positive coronavirus antibody test have been shown to have a 94 percent chance of having FIP.
Organ Biopsy Organ biopsy is the only test which is diagnostic of FIP. However, it is not always possible since the organ involved may be the eye or the brain.

A case workup in the absence of organ biopsy often includes several or all of the above tests. Strongly suggestive findings with several tests often provides the basis for a presumptive diagnosis of FIP.

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Is FIP Contagious?

As with other viruses, spread of infection to other cats is a concern. However, there are three stages of FIP infection, and significant risk to other cats occurs in only the first two stages.

The first stage is initial infection. During the two- to four-week period following viral infection of the cat, a large amount of virus is shed; other cats in direct contact with virus will be exposed.
The second stage is one of dormancy. The virus is inactive within the cat, so it causes no disease. If the cat is stressed during this stage, some virus shedding may occur. Otherwise, the cat is not contagious. This stage may last a few weeks to several years.
The third stage is clinical illness. It usually lasts a few weeks and terminates in death of the cat. As a rule, the cat is not contagious during this stage.

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What Is the Treatment and Prognosis for a Cat With FIP?

Many treatments have been tried for cats with FIP, but none have been consistently successful. Apparently, an occasional cat will recover, but this is the exception rather than the rule. Removing fluid from the chest or abdomen in cats with the wet form will make them comfortable for a short while, and a few drugs will make some of them feel better. However, there is no known curative treatment.

The prognosis for a cat with FIP is very poor. Once a reasonably reliable presumptive diagnosis has been made, euthanasia is often the most appropriate course of action. [If you jump to “euthanasia,” use your browser’s BACK BUTTON to return to this page].

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Is There a Way to Disinfect the Premises or Otherwise Protect Against FIP?

The coronavirus may live for up to three weeks in the environment. If viral shedding into the environment seems likely, a l:30 mixture of household bleach and water (i.e., 1 cup of bleach in a gallon of water) should be used to disinfect food and water bowls, litter pans, cages, bedding material, and items that will not be adversely affected by household bleach.

A preventive vaccine against FIP is available, but neither veterinarians nor the manufacturer recommend that the vaccine be given routinely to all cats. The vaccine is generally recommended for cats living in households that have had a cat with FIP. Initially, two doses are given at a 2-4 week interval. An annual booster is needed to maintain immunity. I do not advise this vaccination.

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Please note: The information provided here is meant to supplement that provided by your veterinarian. Nothing can replace a complete history and physical examination performed by your veterinarian. – Dr. Jeff

I greatly value your feedback. Please let me know what you think of this site and whatyou would like to see on it. drjeff@homevet.com

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