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How do feline leukemia virus and feline immunodeficiency virus spread between cats?

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Young boy in a red shirt smiles while hugging a fluffy tabby cat, their faces close together. — cats as pets A boy hugging a pet cat.

In the context of cats as pets, the feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) spread through different primary mechanisms:

Feline Leukemia Virus (FeLV): This virus is transmitted through cat-to-cat contact. Common modes of transmission include bite wounds and mutual grooming between infected and healthy cats.1
Feline Immunodeficiency Virus (FIV): The primary mode of transmission for FIV is through bite wounds. Consequently, unneutered, free-roaming male cats are at the highest risk of contracting the virus.1

Both viruses are species-specific and cannot be transmitted to humans. While there is a vaccine available to help prevent FeLV, there is currently no vaccine for FIV. Managing these conditions often involves supportive care to help maintain the cat's immune system and overall health.12