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Feline Leukemia Virus

Feline Leukemia Virus (FeLV) is a retrovirus that causes the immune system of a cat to break down. FeLV is not a form of cancer, but is the leading cause of illness and death of cats today. Most commonly transmitted by mutual grooming, biting, fighting or sharing food and water bowls, the organism can also be spread through urine, feces, sharing litter boxes, milk of nursing queen or intrauterine transmission to unborn kittens. FeLV particles will not survive long in the environment. Detergents, bleach, heat and drying will inactivate or kill

FeLV. Infection may be detected within two weeks to five weeks after exposure. FeLV may stay latent in bone marrow for several years or confined in the body for variable periods of time, during which the cat appears healthy. Disease can erupt when the animal is stressed or medicated with a drug that suppresses the immune system. Symptoms include gingivitis, oral ulcers, non-healing abscesses, persistent infections, chronic illness, anemia, jaundice, weight loss, decreased appetite, depression, diarrhea/constipation, blood in stool, enlarged lymph nodes, difficulty breathing, progressive weakness, abortion, infertility and birth of "fading kittens." Infected cats have an increased risk of developing certain types of cancer. No cure exists for the disease. The illness can be treated, but the treatment will no eliminate the virus. Several vaccines are available for FeLV, but USDA does not have standard requirements for them. Vaccine effectiveness is estimated between 75 percent and 85 percent.

Examples: Prolonged cat-to-cat exposure.

Exposure: Urine, feces, sharing litter boxes, milk of nursing queen, intrauterine transmission to unborn kittens, mutual grooming, biting, fighting, sharing of food and water bowls.

Biosecurity Control Points:

  • Avoid unnecessary exposure

  • Vaccinate

  • Clean and disinfect water and food bowls, litter boxes and housing areas regularly

Feline Immunodeficiency Virus

Feline Immunodeficiency Virus (FIV) is a retrovirus that belongs to the same virus family as HIV (human immunodeficiency virus) and immunodeficiency viruses in other species. FIV is a species-specific, life-long, slowly progressive disease. FIV is non-transmissible from cats to people. The disease is present in blood, saliva and cerebrospinal fluid of infected cats. Transmission primarily occurs through a bite wound during a fight. Male cats (especially those not neutered) are two times more likely than female cats to become infected. Outdoor cats that roam are more likely to contract the disease than indoor cats. Average age of infected cats is between three years and five years of age. Causal, non-aggressive contact between cats in not an efficient route to spreading FIV.

FIV has three stages; infected cats may have no clinical signs for several years. Acute-stage symptoms usually occur four weeks to six weeks after exposure to the virus. Clinical signs include fever, swollen lymph nodes, diarrhea, anemia and susceptible to skin infections. During the latent or subclinical stage the immune system is slowly destroyed. When immunodeficiency becomes severe, the third stage of infection occurs. This stage may last several years and the infected cat may show no clinical symptoms. The final or AIDS-like stage is most commonly seen in cats between 5 years and 12 years of age. The cat is very prone to infections. The infections, which usually become chronic, can be bacterial, fungal or parasitic. Because of the destruction of the immune system, the organisms rapidly multiply and cause disease-called opportunistic infections. Infected individuals will exhibit loss of appetite, weight loss, fever, lethargy and swollen lymph nodes.

Treatment includes keeping the cat indoors to protect it from disease exposure and also to prevent it from spreading the virus to other cats. Cats should be treated according to signs of the disease. Supportive care such as good nutrition, antibiotics for secondary infections, and fluids are very important.

Examples: Exposure to other cats.

Exposure: Bite wounds received from infected cat during a fight.

Biosecurity Control Points:

  • Testing and identifying positive cats

  • Separate positive cats from non-infected cats

  • Thoroughly clean and disinfect or replace food and water bowls, bedding, litter pans, toys, etc.

Feline Panleukopenia

Feline panleukopenia, also called feline distemper, cat fever or feline infectious enteritis is highly contagious and a severe parvovirus of kittens, cats, raccoons and mink. The fatality rate in susceptible kittens younger than six months old is up to 75 percent. Older cats are more resistant, but the fatality rate in the susceptible cats can be about 25 percent to 50 percent. Feline panleukopenia can survive up to one year in a suitable environment. This disease is resistant to most disinfectants except bleach. Transmission occurs by direct contact with infected cats or their urine, feces, blood, nasal secretions or vomit. It can also be transmitted by indirect contact, such as food and water bowls, clothing, shoes, hands, bedding, litter boxes, cages and by fleas from an infected cat.

Clinical signs include loss of appetite, depression, listlessness, fever, vomiting and dehydration. The disease course may be short and sudden with great increase in the intensity and can cause death within hours. Temperature may fluctuate during the illness and then quickly drop to below normal levels just before death. Other signs in the later stages are diarrhea, anemia and continual vomiting. The signs are varied, depending of the age and immune status of the cat. Any sick cat should be taken to the veterinarian for a definite diagnosis.

Examples: Direct or indirect contact with infected cats or areas.

Exposure: Contaminated urine, feces, blood, nasal secretions, vomitus, food and water bowls, clothing, shoes, hands, bedding, litter boxes, cages and fleas.

Biosecurity Control Points:

  • Vaccinate kittens and cats; follow vaccination protocols and booster annually

  • Clean and disinfect with bleach solution indoors

  • Separate sick cats from healthy

  • Create an area that can be bleached


Toxoplasmosis is a zoonotic disease caused by a protozoan parasite. Domestic cats are important in the transmission of toxoplasma to other animals and humans. Another means of transmission is consumption of infected raw meat or prey, such as mice. Infection is uncommon in pet cats that do not hunt and are fed commercial cat foods. Usually three days to four days after the ingestion of infected food, cats will shed oocysts in their feces for about 10 days to 14 days, during the acute infection. Cats will develop an immune response to the parasite during the shedding period. Rarely some cats will repeat shedding after initial infection or after re-infection when the animal's immunity is failing.

Oocysts take one day to five days to mature in soil or litter, depending on the environmental conditions. Oocysts then become infective to animals and humans. Cysts remain viable indefinitely in living animals and for several days after the animal dies. Infected individuals may show no clinical signs.

Periodically, the clinical disease does occur, but is usually associated with an immunosuppressed disease, such as FeLV infection. Kittens and young adult cats are more affected than older cats. Early signs of the disease include fever, loss of appetite, depression and lethargy. Chronic toxoplasmosis in cats can be a relapsing disease with varying signs. Signs include anemia, loss of appetite, sterility, abortion, nervous symptoms and sometimes liver and heart disease. The fetus of a pregnant woman is susceptible only at the infective stage. A woman who has previously been exposed to the organism carries no risk in transmitting to the fetus if she later becomes pregnant. Most humans infections stem from eating undercooked meat (usually goat, mutton, and pork), or form the environment (soil and litter), not contact with cat feces.

Examples: Eating raw meat, contacting the disease from soil or litter.

Exposure: Hunting food, eating raw infected meat.

Biosecurity Control Points:

  • Restrict access to rodents and birds

  • Only feed commercial cat foods, fully cooked meat and pasteurized dairy products

  • Secure lids on garbage cans to discourage scavenging

  • Clean litter pans daily to remove the feces before the infective stage of the oocysts have developed

Feline Upper Respiratory Viruses

Feline upper respiratory virus is one of the most common feline diseases. Upper respiratory refers to nose, throat and sinus areas. Up to 80 percent of the feline upper respiratory infections are caused by two viruses: feline viral rhinotracheitis (FVR) and feline calicivirus (FCV). This infection is highly contagious to cats in close proximity. Calicivirus can survive eight days to 10 days in the environment, while the rhinotracheitis can only survive about 18 hours at room temperature. FVR usually causes fever, sneezing, excessive salivation, lethargy and loss of appetite. As the infection progresses, cats may develop conjunctivitis. Infected individuals may develop oral ulcers and FVR occasionally causes abortion in pregnant cats. FCV infection signs are usually milder than for feline viral rhinotracheitis. Symptoms include muscle and joint pain, swelling, and ulcers on the tongue, lip and roof of mouth.

Examples: Aerosol by contaminated environment, people, clothing or vaccine

Exposure: Aerosol, by person via hands, clothing, infection from mother, infection by live-virus vaccine and stress (overcrowding, transporting, surgery, etc.)

Biosecurity Control Points:

  • Vaccinate. Intranasal vaccines help to prevent spread

  • Isolate infected cats

  • Disinfect feed and water bowls