Experimental horizontal transmission of feline leukemia viruses of subgroups A, B, and C.

Experiments were conducted with cats in metal cages inside plastic isolators to determine whether feline leukemia virus (FeLV) of the three known antigenic subgroups (A, B, and C) is transmitted horizontally from infected cats to normal "contact" cats. Blood smears collected at weekly intervals were examined by the fixed-cell, indirect immunofluorescence test for FeLV internal p30 to follow the spread of infection from inoculated cat to contact cats. These studies established that viruses of all three subgroups are transmitted horizontally among kittens and adults with slightly varying degrees of speed. Virus was reisolated from one horizontally infected contact cat of each group, and its envelope antigenic type was the same as that originally inoculated into one cat of the same group. After the cats acquired the infection, they became chronic carriers of virus (viremic) during the observation period of 9 or 11 weeks post inoculation.