Bovine leukosis virus (BLV) was transmitted experimentally by sequenti
al rectal examination of BLV-seropositive and BLV-seronegative cattle
by a veterinarian who did not change gloves between examinations. Five
weeks after repeated rectal examination the first of the three cattle
became BLV seropositive. The other two cattle seroconverted after 8 a
nd 11 weeks.