Posts Tagged: FIV by Differences and Similarities between Feline FIV and FeLV Feline Leukemia (FeLV) and Feline Immunodeficiency Virus (FIV) are both caused by retroviruses that can be transmitted it to other cats. Both viruses depress the immune system opening the door to secondary infections and diseases. The most common contagious infection is upper-respiratory. The most common non-contagious disease is cancer. An individual cat can contract both […] Read More