The Feline Leukemia virus (FeLV) is a highly contagious, easily spread disease among cats that weakens their immune system. It was initially discovered in the 1960s, and the cause is an easily transmissible RNA retrovirus. Though easily vaccinated against, it is one of the leading diagnoses of sick cats in the United States, and is responsible for a large number of feline deaths each year.
There is a simple blood test available for this disease, and as infected cats may not always show symptoms, it is important for all new cats entering the household to be tested. It is also a wise idea to test all sick cats to rule out the possibility.
Transmission occurs through direct contact with an infected cat. In these cats, the virus is shed in their body fluids. This includes their saliva, blood, nasal secretions, urine, and fecal matter. While it is well-known that FeLV is spread through bite wounds, fewer people are aware that it can occur through grooming, sharing food, or sharing a litter box as well. Infected mothers can pass the virus to their offspring during the pregnancy, or the kittens may become infected by nursing from the infected mother.
The symptoms of this disease are numerous. Upper respiratory infections frequently accompany FeLV, and this results in sneezing, coughing, and a high fever. Respiratory distress may also be present. There may be diarrhea and vomiting, and many infected cats display a decrease in their appetite and obvious weight loss. Skin issues may develop, and one of the first signs is a poor coat condition. Many cats with FeLV do not groom themselves as thoroughly as they did before their infections.
Some cats will become jaundiced; their gums and ears will turn yellow. Others will develop very pale, anemic gums. Most infected cats become lethargic, and many will display changes in behavior. Seizures or vision problems may develop, and in female cats, reproductive problems are a common result of infection.
It is not impossible for a cat with FeLV to live a long and happy life. They should be kept indoors for their own safety, as they are immune-compromised and can be badly affected by even small illnesses, as well as to prevent the infection of other cats. Unfortunately, other cats in the household are at risk for catching this virus. These cats should also visit their vet every 6 months for regular exams, as this ensures that any developing problems are caught early.