Feline Leukemia and Feline Immunodeficiency can worry a lot of cat owners. These diseases are difficult to detect and are especially common in cat populations within North America. Before you start worrying unnecessarily, however, read through this simple article and you should be sufficiently prepared to deal with these diseases.

How is it caused? Feline Leukemia and Feline Immunodeficiency are caused by the Feline Leukemia Virus (FeLV) and the Feline Immunodeficiency Virus (FIV), respectively. These diseases cannot be transmitted to humans and other species. In many cases, however, it has proven to be fatal to cats. An infection with the virus can cause a condition called persistent viremia, which can be very difficult to treat.

Symptoms of FeLV and FIV- The actual symptoms of these diseases can vary from cat to cat, but below is a list of some common ones. If you see any of the following symptoms in your cat, get in touch with a veterinarian immediately:
• Recurring fever
• Loss of appetite
• Pale gums
• Weight loss
• Enlarged lymph nodes/Swelling behind the jaw
• Immune system suppression
• Debilitation and general weakness
• Diarrhea
• Discolored stools
• Difficulty in breathing
• Recurring upper respiratory tract infections

What is the prognosis of the disease? Once a cat picks up the infection from another infected cat, the virus spreads rapidly all over the body. It usually targets lymphatic tissue and because most lymphatic tissue organs are supplied with a rich supply of blood, the infection can spread rapidly from there to all over the body. Once the infection has established itself, there are three possible scenarios:

1. The cat resists the infection. Some healthy cats may have an immune system strong enough to fight off and resist the infection. Still, the virus does remain in the body for a period of about 12 weeks. This stage of temporary infection is called “transient viremia”. As a result, the initial infection can be present in some cats without being contagious to other cats.

2. The cat cannot completely fight off the infection. Sometimes cats cannot resist the infection and it persists in the blood stream for more than 12 weeks. This is called “persistent viremia.” The virus continues to incapacitate the immune system and in the worst-case scenario, the infection can eventually kill the cat. The virus also makes the cat susceptible to other kinds of infections, thus putting them at a greater risk. Almost 80% of the infected cats die within three years of getting infected. A few of the infected cats also get a variant of cancer called Lymphosarcoma. In this type of cancer, lymphatic tissue found in the lymph nodes and bone marrow undergoes rapid cancerous transformations under the influence of the virus. The cancer spreads fast and involves a large number of organs before symptoms become evident. It is important to realize, however, that not every cat with feline leukemia will develop cancer.

3. The cat becomes a carrier. The cat might not be able to destroy the virus completely and the virus persists in the cat’s body but does not kill it. These cats now become carriers of the infection. The disease is suppressed but the virus remains infectious to other cats. Live forms of the virus persist in the blood, saliva and feces of the infected cat.

Researchers are not really sure how long carrier cats can survive, but most infected cats die within a span of three to four years. It’s extremely necessary that you pay close attention to the cat and that any worsening of symptoms be immediately brought to the vet’s attention.

Testing for FeLV: At present, there are only two tests available to detect the viral protein floating in the blood. The ELISA (or “kit” test) and the IFA (immunofluorescence assay) are commonly recommended. The ELISA test is a screening test, but if it comes out positive then it is necessary to do an IFA test to confirm the diagnosis.

Are there vaccinations for the disease? There are vaccinations for both FIV and FeLV. Speak with your veterinarian about whether your cat needs one or both of these vaccines. As they say, an ounce of prevention is better than a pound of cure.