Horizontal Transmission of Leukemia Virus and Leukemia in the Cat

Abstract

Neonatal and adult cats were exposed to cats that had been inoculated with feline leukemia virus (FeLV). A range of techniques was used on both sets of animals to monitor the presence or absence of virus, group-specific antigen, and antibodies to the virus and feline oncornavirus-associated cell membrane antigen (FOCMA). Horizontal transmission, occurring in most cases, took place between littermates when only a proportion was inoculated at birth and also when litters inoculated neonatally were housed, from birth, with unrelated litters. Adults became infected when exposed to cats that had been inoculated with FeLV as adults. Transfer of infection was demonstrable within a month of mixing; transmission of virus in this way could lead to the development of tumors in cats exposed as kittens or as adults. A wide variety of tissues was examined electron microscopically to determine possible routes of excretion of FeLV. Virus was most common in the trachea and oral mucosa, but it was also recovered from the urine and urinary bladder. Four adult cats became infected after being housed for 1 week with a cat with a naturally occurring alimentary lymphosarcoma.