The main difference between FeLV and FIV is that FeLV is transmitted by the exchange of saliva, milk, nasal secretions, urine, and feces during mutual grooming, from the queen (mother) to kittens and sharing of food and water bowls, whereas FIV is transmitted by the exchange of blood and saliva through bite wounds.
Key Areas Covered
1. What is FeLV
– Definition, Structure, Function
2. What is FIV
– Definition, Structure, Function
3. Similarities Between FeLV and FIV
– Outline of Common Features
4. Difference Between FeLV and FIV
– Comparison of Key Differences
FeLV, FIV, Feline Leukemia Virus, Feline Immunodeficiency Virus
What is FeLV
FeLV or feline leukemia virus is a retrovirus that infects cats. The transmission of the virus occurs through body fluids such as saliva and nasal secretions. The main feature of FeLV is that it defeats the immune system of the animal. Therefore, this virus leads to diseases that are lethal. The virus is cat-to-cat contagious. The signs and symptoms of FeLV disease are loss of appetite, infections of the skin, bladder, and respiratory tract, poor coat conditions, uneven pupils, oral disease, skin lesions, fatigue, anemia, diarrhea, and jaundice.
Furthermore, the FeLV virus has four subgroups: A, B, C, and T. Generally, an infected cat can have one or more other groups of the virus. In addition, the primary mode of transmission of FeLV is through bite wounds. Generally, it can occur through bite wounds from an infected cat. The casual and nonaggressive contact of animals such as mutual grooming and sharing water bowls also help to spread the virus.
What is FIV
FIV or feline immunodeficiency virus is another lentivirus that infects cats. It is also the most common and consequential infectious disease of cats in the world. In general, the FIV virus attacks the immune system of the cat, making the cat vulnerable to many other infections. The infected cats appear normal for many years but they become vulnerable to infections. Therefore, harmless bacteria, protozoa, viruses, and fungi can cause severe illness in infected cats. However, there is no cure for FIV infection. But, infected cats can live their average lifespan.
Moreover, the primary transmission of FIV occurs through bite wounds. It infects many cell types including macrophages, B lymphocytes, and T lymphocytes. Furthermore, the infection of FIV is tolerable by cats but eventually, with the exhaustion of T-helper (CD4+) cells, the cat becomes vulnerable to infections. Apart from that, the other important feature of FIV infection is that the virus transmits through deep bite wounds.
Similarities Between FeLV and FIV
- FeLV and FIV are two types of retroviruses that infect cats.
- Both transmit through body fluids such as saliva.
Difference Between FeLV and FIV
FeLV or feline leukemia virus refers to the type of virus that transmits from mother to kitten while FIV or feline immunodeficiency virus is a type of virus that transmits through bite wounds.
FeLV is a lentivirus while FIV is a gamma retrovirus.
Mode of Transmission
Moreover, FeLV transmits through saliva, nasal secretions, urine, feces, and milk, while FIV transmits through saliva.
FeLV transmits through mutual grooming, from the queen (mother) to kitten, and sharing of food while FIV transmits through bite wounds.
FeLV infects both males and females while FIV mostly infects fighting cats.
Furthermore, FeLV infection produces mild symptoms for several weeks and returns to an asymptomatic situation, while FIV infection progress continuously.
FeLV causes anemia, intestinal disease, cancers such as lymphoma and leukemia, etc. while FIV causes inflammation of gums, diarrhea, skin infections, upper respiratory infections, etc.
In brief, FeLV and FIV are two viruses that infect cats. FeLV or feline leukemia virus is the virus that transmits through saliva, nasal secretions, feces, urine, and milk. Moreover, the mechanism of transmission of FeLV occurs through mutual grooming, from mother to kitten, and sharing of food. Generally, FeLV infects both males and females. FIV or feline immunodeficiency virus, on the other hand, is a virus that transmits through saliva. In addition, the transmission of the virus occurs through bite wounds and fighting cats has a high risk for this viral infection. Therefore, the main difference between FeLV and FIV is the mode of transmission.
- “Feline Leukemia Virus.” Cornell University College of Veterinary Medicine, 19 Aug. 2021,
- “Feline Immunodeficiency Virus (FIV).” Cornell University College of Veterinary Medicine, 17 June 2021,