Enzootic bovine leukosis: Experimental induction with two sources of virus Leucosis enzoótica bovina. Inducción experimental de la infección con dos fuentes del virus

Abstract

A group of nine Holstein Friesian calves, 9 months of age, belonging to the same herd, and not showing antibody gp 51 in two serologic control tests were used. Three of them were inoculated with 100 μl of heparinized blood obtained from the one dairy cow positive to antibody gp 51. These animals produced antibody gp 51, detected by ELISA, 30 days post inoculation and by IDAG 60 days after. Besides, the lymphocytes obtained from calves induced syncytia in cocultures with foetal lamb kidney cells (RFD) from day 120 of inoculation. Three calves inoculated with 100 μl of supernatant of RFD cultures infected with the BLV did not generate antibody anti gp 51 during the 365 days of the experience. Of the three animals in the control group, one of them produced the natural infection and developed antibody anti gp 51 120 days after the start of the assay. The control group grazed together with the inoculated animals in the same pasture, isolated from other animals, and had a similar management. The possibility of natural infection in the experimental model used is discussed