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Care Guide

About Care Guides[x] These care guides are written to help your clients understand common conditions, tests, and procedures, as well as to provide basic information about pet care. They are based on the most up-to-date, documented information, recommendations, and guidelines available in the United States at the time of writing. Pharmaceutical product licensing, availability, and usage recommendations are based on US product information. Use the Download Handout button to generate a PDF for printing or e-mailing to your clients.

Feline Leukemia and Rabies

    • Feline leukemia and rabies are contagious and commonly fatal.
    • Cats that go outside are at increased risk for exposure to feline leukemia and rabies.
    • Vaccination can protect cats from disease associated with the feline leukemia and rabies viruses.

    What Are Feline Leukemia and Rabies?

    Feline leukemia virus (FeLV) is contagious among cats.  Unlike many other viruses that enter specific cells in the body and destroy them, FeLV enters certain cells in a cat’s body and changes the cells’ genetic characteristics. This permits FeLV to continue reproducing within the cat each time infected cells divide. This allows FeLV to become dormant (inactive) in some cats, making disease transmission and prognosis (outlook) difficult to predict.

    Rabies virus is dangerous and infects animals and humans worldwide. Rabies is generally fatal in all species, and any warm-blooded animal can become infected. Foxes, skunks, coyotes, and certain rodents spread the disease in many cases. Surprisingly, cats are more commonly involved in spreading rabies than dogs are. In fact, cats are the number-one domestic animal carrier of rabies in the United States. 

    How Do Cats Become Infected With Feline Leukemia and Rabies?

    Feline leukemia is generally transmitted through contact with saliva from an infected cat. Other body fluids, like nasal secretions, urine, feces, and milk can also contain virus. Certain “social” behaviors such as mutual grooming and sharing food or water bowls can spread the disease; some cats become infected through bite wounds. Kittens can become infected during fetal development or during the first days of life as their mothers nurse and care for them.

    FeLV is killed by many disinfectants and does not live for very long in the environment, so contact with an infected cat (or food/water bowls) is the most common way for the disease to spread. However, predicting which cats can transmit the disease is complicated because some cats that are potentially contagious may not show signs of illness. 

    Like FeLV, rabies is also transmitted through contact with saliva from an infected animal. With rabies, the most common means of saliva contact is through bite wounds. Cats that go outside, fight with other cats, or encounter wild animals are at increased risk for exposure to rabies.  

    Signs of Feline Leukemia and Rabies

    Not every cat that becomes infected with FeLV develops clinical signs or long-term complications associated with the virus. However, some cats may experience various illnesses and immune suppression before eventually dying of FeLV-associated complications.

    Because FeLV can affect almost any organ system in the body, clinical signs and associated illnesses can vary significantly and include the following:

    • Anemia (inadequate numbers of red blood cells)
    • Leukemia
    • Immune suppression
    • Fever
    • Lethargy (tiredness)
    • Chronic respiratory infections
    • Chronic oral and gum infections
    • Cancer of the lymphatic system (and other cancers)

    The clinical signs of rabies can be vague and difficult to identify. The virus is usually introduced into the body through a bite wound from an infected animal. After entering the body, the rabies virus makes its way into the nervous system and then into the salivary glands (glands in the neck that produce saliva). Once the virus enters the salivary glands, the animal can pass the infection to other animals and humans through saliva. The incubation period associated with rabies can be as brief as a few days or as long as several months. Death can occur from respiratory failure, seizures, or other complications. Unfortunately, early clinical signs may not be apparent before the animal becomes infective, which means that an infected cat can spread the disease before it shows signs of being sick.

    Clinical signs of rabies progress through several stages, and not all infected cats show evidence of all stages:

    • Early signs: Fever, acting nervous or agitated, hiding
    • Later signs: Aggression, increased agitation, erratic behavior
    • End stage: Muscle weakness and paralysis, coma, death

    Diagnosis and Treatment

    Because there are several stages of FeLV and not every cat handles the infection the same way, diagnosis is not always straightforward. Some infected cats test positive on routine FeLV screening tests, whereas specific tests on blood or bone marrow are required to confirm infection in other cats. Some cats may test positive on blood tests when they are young kittens but test negative later. Similarly, some cats may test negative at one point and test positive later, as the virus progresses through various stages in the body. Because FeLV infection can have many clinical presentations, your veterinarian may want to test your cat if he or she seems to be ill—especially if a fever is present. Some cats need to have multiple tests done to confirm infection.      

    Treatment options for FeLV are limited, and no treatment can eliminate the virus.  Some antiviral or immunomodulating drugs have been investigated, but most treatments are aimed at managing the clinical signs and complications. Cats that are anemic may receive blood transfusions; cats that are dehydrated or not eating may receive intravenous fluids and feedings; chemotherapy is sometimes helpful in managing cancers; and antibiotics may be used to treat associated infections.

    The tests used to confirm a diagnosis of rabies are performed by examining and testing the brain after the animal has died or been euthanized. Unfortunately, there are no diagnostic tests considered accurate enough to confirm rabies in a living animal, and there are no effective treatments for rabies in animals. Because of the high fatality rate associated with rabies, the best way to protect your cat is to minimize exposure to animals that may transmit the infection and keep your cat’s rabies vaccination up to date.

    Vaccination and Prevention

    Several vaccines are available for preventing disease associated with FeLV infection and rabies. Some of the available FeLV vaccines are combination vaccines that also protect against feline herpesvirus, panleukopenia (feline distemper), and calicivirus. Available rabies vaccines may be single-organism vaccines or combination formulations that protect against other feline viruses. All of the available FeLV and rabies vaccines have been tested and found to be safe and effective when administered as directed.

    Kittens can generally be vaccinated against FeLV around 8 to 9 weeks of age. A booster vaccination is given 3 to 4 weeks later, followed by boosters each year as long as the risk for exposure remains. If risk for exposure is low, your veterinarian may not recommend the FeLV vaccine for your cat.

    Initial rabies vaccinations are generally given to kittens between 12 and 16 weeks of age. A booster vaccination is given a year later. Depending on which rabies vaccine is used, subsequent boosters may be given every 1 to 3 years.

    Some municipalities have regulations mandating that cats receive vaccinations against rabies. Vaccination against FeLV is not required by law but is highly recommended for cats at risk for exposure to the virus. Cats that go outside or live with other cats are at greater risk for exposure to FeLV compared with cats that stay indoors and have limited contact with other cats. Similarly, cats that go outside where they can encounter stray or wild animals are at greater risk for exposure to rabies. Ask your veterinarian about how to protect your cat from these infectious diseases.

    Because FeLV is transmitted through contact, keeping sick cats separated from healthy cats can reduce the likelihood of transmission. Any new kitten or cat being introduced into the home should be examined by a veterinarian as soon as possible and separated from all other household pets for a quarantine period of several weeks. During that time, the new cat should be tested for FeLV and monitored closely for any signs of illness. Any problems should be reported to your veterinarian before introducing the new cat to your other pets. 

    Feline leukemia is not considered contagious to humans. In contrast, rabies is contagious (and fatal) to any warm-blooded animal, including humans. If your cat is known or suspected to have either of these diseases, contact your veterinarian promptly to discuss how you can protect your other pets and family members.