FeLV and FIV
Feline Viral Diseases
The three major feline viral diseases are feline infectious peritonitis (FIP), feline leukemia virus (FeLV), and feline immunodeficiency virus (FIV). These viruses are specific to cats and cannot be transmitted to humans or other animals. The occurrence of FeLV and FIV and the rate of transmission of these diseases in house cats and feral cat groups is very low. Large epidemiologic studies “indicate FeLV and FIV are present in approximately 4% of feral cats, which is not substantially different from the infection rate reported for pet cats” (Levy and Crawford, 2004).
Feline Leukemia Virus (FeLV)
What is Feline Leukemia?
The feline leukemia virus (FeLV) is a retrovirus belonging to the subfamily Oncovirinae, which means it is a cancer-causing virus. In addition to causing feline leukemia, FeLV suppresses the cat’s immune system, leaving them vulnerable to a variety of other diseases. The signs and symptoms of infection with FeLV are varied and include loss of appetite, poor coat condition, infections of the skin, bladder and respiratory tract, oral disease, seizures, swollen lymph nodes, fatigue, fever, weight loss, recurring bacterial and viral illnesses, anemia, diarrhea, and jaundice (Cornell, “Feline Leukemia Virus,” 2014). Some cats can be carriers of the disease and show no signs of illness for many years.
Transmission
Feline leukemia only affects cats; it cannot be transmitted to people or other animals. Infected cats shed FeLV primarily in their saliva, although the virus may also be present in the blood, tears, feces, or urine. Grooming and fighting appear to be the most common ways for the infection to spread. Other modes of FeLV transmission include sharing food dishes and litter boxes, and in utero transfer from a mother cat to her kittens. A mother cat can also transmit FeLV to her kittens through infected milk.
The disease is often spread by seemingly healthy cats, so cats that appear healthy may still be infected and able to transmit the virus.
Diagnosis
A simple blood test can be performed in a veterinary office to determine if a cat has contracted FeLV; however, most TNR programs choose not to test feral cats for the disease. Whether a feral cat tests negative for the disease or she is not tested, we strongly recommend all feral cats receive an FeLV vaccine to reduce the risk of transmission.
Risk
Resistance seems to increase with age, so older cats are less likely to contract the infection. Indoor-only cats are also at low risk of contracting FeLV. Cats in multi-cat households are at a higher risk, especially if they share water and food dishes and litter boxes.
Symptoms
Cats infected with the virus may exhibit one or more of the following symptoms: pale gums, yellow color in the mouth and whites of eyes, enlarged lymph nodes, bladder, skin, or upper respiratory infections, weight loss and/or loss of appetite, poor coat condition, weakness and lethargy, fever, diarrhea, difficulty breathing, and stomatitis.
Treatment
There is no cure for FeLV, although veterinarians can treat or alleviate the opportunistic infections associated with the virus. Regular vet check-ups and good preventive health care can help keep infected cats feeling well for some time and help prevent secondary infection. Bi-annual physical exams, lab testing, and parasite control can prevent complications and promptly identify any problems. FeLV infected cats should be kept indoors as well as be fixed. Their environments should be as stress-free as possible. Additionally, nutritional support (herbs, vitamins) and other alternative treatments can help strengthen a cat’s impaired immune system.
Prognosis
Although the majority of cats with aggressive FeLV will die within three years of diagnosis, exposure to the feline leukemia virus doesn’t mean an automatic death sentence. About 70% of cats who encounter the virus are able to resist infection or eliminate the virus on their own.
Prevention
Keeping your cat indoors and away from infected cats will prevent him from contracting FeLV. The virus cannot survive long outside the body of a cat and is easily killed outside with hand soap or dish detergent, so if you hand an FeLV+ cat, or have one in your home with FeLV- cats, take care to wash your hands between interacting with the positive cat and do not let the cats be in the same rooms at the same time.
Vaccines are an option for cats at high risk, such as those who go outside. In order to receive the vaccine, cats must first test negative for FeLV, and even after receiving the vaccine, cats should be tested to determine if there has been a possible exposure to the virus. According to the American Association of Feline Practitioners, any cat who is sick should be tested for FeLV, because there are a number of health issues that can be associated with the virus.
New cats or kittens over eight weeks of age should be tested for the virus before being introduced to a multi-cat household. Most veterinarians discourage introducing new cats into a household with an FeLV-positive cat, as they may be at risk for contracting the infection, even with the vaccine. However, as mentioned above, certain precautions can make it very unlikely that the FeLV- cat will contract the virus from the FeLV+ cat.
Feline Immunodeficiency Virus (FIV)
What is FIV?
Feline immunodeficiency virus (FIV) is a retrovirus that virologists classify as a lentivirus, or “slow-acting virus.” Cats diagnosed with FIV may live long, healthy lives, never showing symptoms of the virus, though some cats may experience “recurrent illness interspersed with periods of relative health” (Cornell, “Feline Immunodeficiency Virus,” 2014). FIV suppresses the cat’s immune system, compromising her ability to fight off infections.
Symptoms
Common signs and symptoms of the disease include poor coat condition, persistent fever, loss of appetite, weight loss, inflammation of the gums and mouth, chronic or recurrent skin, urinary tract, bladder, and upper respiratory infections, and a variety of eye conditions may occur. FIV positive cats are also much more susceptible to various kinds of cancer and blood diseases, and some experience seizures, or behavioral and neurological disorders (Cornell, “Feline Immunodeficiency Virus,” 2014).
Transmission
Fortunately, FIV is not transmitted as easily as FeLV. The most common mode of transmission is through bite wounds. This explains why the cats most likely to become infected are free-roaming, unneutered males who are prone to territorial fighting. FIV does not appear to spread through casual contact among cats, so it is possible to keep an FIV-positive cat in the same household as a healthy cat with little risk of transmission, provided the cats tolerate one another and do not fight. There is no danger of FIV spreading through sexual contact, and only rarely does a mother pass it on to her kittens, either through birth or infected milk (Cornell, “Feline Immunodeficiency Virus,” 2014).
Diagnosis
A simple blood test can be performed in a veterinary office to determine if a cat has contracted FIV. However, most TNR programs choose not to test feral cats for the disease. Kittens testing positive for FIV are not necessarily infected. If a kitten tests positive, the test is probably detecting antibodies passed from the mother to the kitten through colostrum, the first milk that the mother cat produces. Positive kittens should be retested between four and six months of age, when any antibodies obtained from the mother cat will have disappeared.
Vaccine
There is a vaccine to protect against FIV, though it is rarely administered. Any cat who receives the vaccine will then test positive for the disease, because she will be carrying antibodies.
Treatment
There is no cure for FIV; however, like FeLV, veterinarians can treat or at least alleviate the infections associated with the virus. Proper nutrition and good supportive care can help strengthen a cat’s impaired immune system and improve her quality of life.
Prognosis
Providing medical supportive care and keeping FIV-positive cats in a stress-free, indoor environment can allow them to live comfortable lives for months to years.
FIV/FeLV and Euthanasia of Feral Cats
While FIV and FeLV affect only cats, not all cats that are infected will develop the diseases. FIV and FeLV are not a death sentence. Cats that test positive for FIV regularly live long, healthy lives. In fact, most veterinarians don’t test feral cats for FeLV or FIV, as most feral cats have good health and have no higher rates of infection than owned cats. In fact, both owned and feral cats have an incidence rate of FIV and FeLV at an equally low rate, approximately 4%. Furthermore, several large spay/neuter clinics report only 1-2% of FeLV infections when cats are tested.
There are numerous reasons as to why feral cats who test positive for FIV or FeLV should not be euthanized. Aside from the fact that cats who test positive go on to live happy, healthy lives, test results can be unreliable, and can result in false positives. Sterilizing cats helps prohibit the spread of the viruses, as it prevents fighting and breeding.
Cats who test positive are also often asymptomatic. They can remain healthy and exhibit no signs of illness for multiple years, or their entire life. As a result, more cats die just from testing positive and being euthanized than die from FIV-related complications. Furthermore, FIV tests do not differentiate between the FIV infection and the FIV vaccination. Therefore, a positive test can often mean that vaccinated cats who are not infected are euthanized.
Ultimately, there are numerous reasons why it isn’t recommended to test feral cats for FIV/FeLV, as it is cost prohibitive as well as the numbers of positives are similar to those of owned cats. When the feral cats are sterilized, the risk of transmission is incredibly low. Feral cats live happy, healthy lives even when testing positive for FIV/FeLV, and there is no reason to deprive them of that.
Resources
Cornell Feline Health Center. “Feline Infectious Peritonitis.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Cornell Feline Health Center. “Feline Leukemia Virus.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Cornell Feline Health Center. “Feline Immunodeficiency Virus.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Flowers, Amy. “Feline Leukemia Virus (FeLV) Symptoms, Vaccine, Treatment.” WebMD, WebMD, 10 Sept. 2018, https://pets.webmd.com/cats/facts-about-feline-leukemia-virus#1. 5 Dec. 2019
Jones, Sarah. “Unlicensed GS-441524-Like Antiviral Therapy Can Be Effective for at-Home Treatment of Feline Infectious Peritonitis.” MDPI, www.mdpi.com/2076-2615/11/8/2257.
Levy, Julie K., and P. Cynda Crawford. “Humane Strategies for Controlling Feral Cat Populations.” Journal of the American Veterinary Medical Association 225.9 (2004): 1354–60. Avmajournals.avma.org (Atypon). Web. 18 Aug. 2014.
“PetMD, LLC.” PetMD, https://www.petmd.com/cat/conditions/infectious-parasitic/c_ct_feline_infectious_peritonitis. 4 Dec. 2019
What is Feline Leukemia?
The feline leukemia virus (FeLV) is a retrovirus belonging to the subfamily Oncovirinae, which means it is a cancer-causing virus. In addition to causing feline leukemia, FeLV suppresses the cat’s immune system, leaving them vulnerable to a variety of other diseases. The signs and symptoms of infection with FeLV are varied and include loss of appetite, poor coat condition, infections of the skin, bladder and respiratory tract, oral disease, seizures, swollen lymph nodes, fatigue, fever, weight loss, recurring bacterial and viral illnesses, anemia, diarrhea, and jaundice (Cornell, “Feline Leukemia Virus,” 2014). Some cats can be carriers of the disease and show no signs of illness for many years.
Transmission
Feline leukemia only affects cats; it cannot be transmitted to people or other animals. Infected cats shed FeLV primarily in their saliva, although the virus may also be present in the blood, tears, feces, or urine. Grooming and fighting appear to be the most common ways for the infection to spread. Other modes of FeLV transmission include sharing food dishes and litter boxes, and in utero transfer from a mother cat to her kittens. A mother cat can also transmit FeLV to her kittens through infected milk.
The disease is often spread by seemingly healthy cats, so cats that appear healthy may still be infected and able to transmit the virus.
Diagnosis
A simple blood test can be performed in a veterinary office to determine if a cat has contracted FeLV; however, most TNR programs choose not to test feral cats for the disease. Whether a feral cat tests negative for the disease or she is not tested, we strongly recommend all feral cats receive an FeLV vaccine to reduce the risk of transmission.
Risk
Resistance seems to increase with age, so older cats are less likely to contract the infection. Indoor-only cats are also at low risk of contracting FeLV. Cats in multi-cat households are at a higher risk, especially if they share water and food dishes and litter boxes.
Symptoms
Cats infected with the virus may exhibit one or more of the following symptoms: pale gums, yellow color in the mouth and whites of eyes, enlarged lymph nodes, bladder, skin, or upper respiratory infections, weight loss and/or loss of appetite, poor coat condition, weakness and lethargy, fever, diarrhea, difficulty breathing, and stomatitis.
Treatment
There is no cure for FeLV, although veterinarians can treat or alleviate the opportunistic infections associated with the virus. Regular vet check-ups and good preventive health care can help keep infected cats feeling well for some time and help prevent secondary infection. Bi-annual physical exams, lab testing, and parasite control can prevent complications and promptly identify any problems. FeLV infected cats should be kept indoors as well as be fixed. Their environments should be as stress-free as possible. Additionally, nutritional support (herbs, vitamins) and other alternative treatments can help strengthen a cat’s impaired immune system.
Prognosis
Although the majority of cats with aggressive FeLV will die within three years of diagnosis, exposure to the feline leukemia virus doesn’t mean an automatic death sentence. About 70% of cats who encounter the virus are able to resist infection or eliminate the virus on their own.
Prevention
Keeping your cat indoors and away from infected cats will prevent him from contracting FeLV. The virus cannot survive long outside the body of a cat and is easily killed outside with hand soap or dish detergent, so if you hand an FeLV+ cat, or have one in your home with FeLV- cats, take care to wash your hands between interacting with the positive cat and do not let the cats be in the same rooms at the same time.
Vaccines are an option for cats at high risk, such as those who go outside. In order to receive the vaccine, cats must first test negative for FeLV, and even after receiving the vaccine, cats should be tested to determine if there has been a possible exposure to the virus. According to the American Association of Feline Practitioners, any cat who is sick should be tested for FeLV, because there are a number of health issues that can be associated with the virus.
New cats or kittens over eight weeks of age should be tested for the virus before being introduced to a multi-cat household. Most veterinarians discourage introducing new cats into a household with an FeLV-positive cat, as they may be at risk for contracting the infection, even with the vaccine. However, as mentioned above, certain precautions can make it very unlikely that the FeLV- cat will contract the virus from the FeLV+ cat.
Feline Immunodeficiency Virus (FIV)
What is FIV?
Feline immunodeficiency virus (FIV) is a retrovirus that virologists classify as a lentivirus, or “slow-acting virus.” Cats diagnosed with FIV may live long, healthy lives, never showing symptoms of the virus, though some cats may experience “recurrent illness interspersed with periods of relative health” (Cornell, “Feline Immunodeficiency Virus,” 2014). FIV suppresses the cat’s immune system, compromising her ability to fight off infections.
Symptoms
Common signs and symptoms of the disease include poor coat condition, persistent fever, loss of appetite, weight loss, inflammation of the gums and mouth, chronic or recurrent skin, urinary tract, bladder, and upper respiratory infections, and a variety of eye conditions may occur. FIV positive cats are also much more susceptible to various kinds of cancer and blood diseases, and some experience seizures, or behavioral and neurological disorders (Cornell, “Feline Immunodeficiency Virus,” 2014).
Transmission
Fortunately, FIV is not transmitted as easily as FeLV. The most common mode of transmission is through bite wounds. This explains why the cats most likely to become infected are free-roaming, unneutered males who are prone to territorial fighting. FIV does not appear to spread through casual contact among cats, so it is possible to keep an FIV-positive cat in the same household as a healthy cat with little risk of transmission, provided the cats tolerate one another and do not fight. There is no danger of FIV spreading through sexual contact, and only rarely does a mother pass it on to her kittens, either through birth or infected milk (Cornell, “Feline Immunodeficiency Virus,” 2014).
Diagnosis
A simple blood test can be performed in a veterinary office to determine if a cat has contracted FIV. However, most TNR programs choose not to test feral cats for the disease. Kittens testing positive for FIV are not necessarily infected. If a kitten tests positive, the test is probably detecting antibodies passed from the mother to the kitten through colostrum, the first milk that the mother cat produces. Positive kittens should be retested between four and six months of age, when any antibodies obtained from the mother cat will have disappeared.
Vaccine
There is a vaccine to protect against FIV, though it is rarely administered. Any cat who receives the vaccine will then test positive for the disease, because she will be carrying antibodies.
Treatment
There is no cure for FIV; however, like FeLV, veterinarians can treat or at least alleviate the infections associated with the virus. Proper nutrition and good supportive care can help strengthen a cat’s impaired immune system and improve her quality of life.
Prognosis
Providing medical supportive care and keeping FIV-positive cats in a stress-free, indoor environment can allow them to live comfortable lives for months to years.
FIV/FeLV and Euthanasia of Feral Cats
While FIV and FeLV affect only cats, not all cats that are infected will develop the diseases. FIV and FeLV are not a death sentence. Cats that test positive for FIV regularly live long, healthy lives. In fact, most veterinarians don’t test feral cats for FeLV or FIV, as most feral cats have good health and have no higher rates of infection than owned cats. In fact, both owned and feral cats have an incidence rate of FIV and FeLV at an equally low rate, approximately 4%. Furthermore, several large spay/neuter clinics report only 1-2% of FeLV infections when cats are tested.
There are numerous reasons as to why feral cats who test positive for FIV or FeLV should not be euthanized. Aside from the fact that cats who test positive go on to live happy, healthy lives, test results can be unreliable, and can result in false positives. Sterilizing cats helps prohibit the spread of the viruses, as it prevents fighting and breeding.
Cats who test positive are also often asymptomatic. They can remain healthy and exhibit no signs of illness for multiple years, or their entire life. As a result, more cats die just from testing positive and being euthanized than die from FIV-related complications. Furthermore, FIV tests do not differentiate between the FIV infection and the FIV vaccination. Therefore, a positive test can often mean that vaccinated cats who are not infected are euthanized.
Ultimately, there are numerous reasons why it isn’t recommended to test feral cats for FIV/FeLV, as it is cost prohibitive as well as the numbers of positives are similar to those of owned cats. When the feral cats are sterilized, the risk of transmission is incredibly low. Feral cats live happy, healthy lives even when testing positive for FIV/FeLV, and there is no reason to deprive them of that.
Resources
Cornell Feline Health Center. “Feline Infectious Peritonitis.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Cornell Feline Health Center. “Feline Leukemia Virus.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Cornell Feline Health Center. “Feline Immunodeficiency Virus.” Ithaca, New York: Cornell University College of Veterinary Medicine, 2014. Web. 29 Sept. 2014.
Flowers, Amy. “Feline Leukemia Virus (FeLV) Symptoms, Vaccine, Treatment.” WebMD, WebMD, 10 Sept. 2018, https://pets.webmd.com/cats/facts-about-feline-leukemia-virus#1. 5 Dec. 2019
Jones, Sarah. “Unlicensed GS-441524-Like Antiviral Therapy Can Be Effective for at-Home Treatment of Feline Infectious Peritonitis.” MDPI, www.mdpi.com/2076-2615/11/8/2257.
Levy, Julie K., and P. Cynda Crawford. “Humane Strategies for Controlling Feral Cat Populations.” Journal of the American Veterinary Medical Association 225.9 (2004): 1354–60. Avmajournals.avma.org (Atypon). Web. 18 Aug. 2014.
“PetMD, LLC.” PetMD, https://www.petmd.com/cat/conditions/infectious-parasitic/c_ct_feline_infectious_peritonitis. 4 Dec. 2019