title: Natural mode of transmission of the bovine leukemia virus: role of bloodsucking insects.
abstract: The development of bovine leukemia virus (BLV) infection was studied in 14 noninfected young adult cattle exposed to 25 to 30 BLV-infected cows in an area of approximately 0.5 ha. Of 7 cattle (group 1) exposed beginning in July and August (midsummer) of 1976, 4 were infected by October, and all 7 by November (4 months' exposure). Of 7 cattle (group 2) exposed from February 1977 (midwinter), all remained negative for 3 months, and only 1 was positive after 6 months. By October 1977, however, 4 cattle in this group were infected, indicating that contact transmission of BLV is prevalent during the summer months. This, and the fact that BLV-infected lymphocytes were recovered from tabanids allowed to feed on a BLV-positive cow, supports the idea that bloodsucking insects play a major role in the spread of BLV.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000635:transmission*; D004175:Diptera; D005260:Female; D007303:Insect Vectors; D007938:Leukemia / Q000276:immunology / Q000635:transmission / Q000662:veterinary*; D001909:Leukemia Virus, Bovine / Q000276:immunology / Q000302:isolation & purification; D008214:Lymphocytes / Q000382:microbiology; D008297:Male; D009500:Neutralization Tests
chemical_list: D000914:Antibodies, Viral