title: Horizontal transmission and phylogenetic analysis of bovine leukemia virus in two districts of Miyazaki, Japan.
abstract: Horizontal transmission is recognized as a major infection route for bovine leukemia virus (BLV), and cattle with high viral loads are considered to be a major infectious source in a herd. However, a correlation between viral loads and the risk of infection has been insufficient to use as a foundation for BLV control strategies. In this report, we examined the epidemiology of BLV infection and the infectious source in a local area. In 2013-2014, BLV infection was investigated in 1,823 cattle from 117 farms in two adjacent districts, Miyazaki, Japan. Seropositive samples for BLV were detected with 88 cattle and in 14 farms. Phylogenetic analysis revealed that 94% of the isolates clustered into genotype I and the remaining isolate into genotype III. Among genotype I, genetically distinct strains were spread at each farm, and cattle infected with less than 3 copies/100 cells did not transmit BLV to other cattle for more than thirty months. This is the first report of concrete data of viral load in relation to viral horizontal transmission under the field condition. The data facilitate farmers and veterinarians understanding the status of BLV infected cattle. This research contributes to BLV infection control and the development of effective BLV eradication programs.
authors.affiliation: Project for Zoonoses Education and Research, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Mekata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sekiguchi
authors.forename: Satoru
authors.initials: S
authors.lastname: Konnai
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kirino
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Horii
authors.forename: Junzo
authors.initials: J
authors.lastname: Norimine
mesh_terms: D000818:Animals; D002417:Cattle; D004279:DNA, Viral / Q000235:genetics; D018562:Disease Transmission, Infectious / Q000662:veterinary; D016583:Enzootic Bovine Leukosis / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005838:Genotype; D007564:Japan / Q000453:epidemiology; D001909:Leukemia Virus, Bovine / Q000235:genetics* / Q000502:physiology; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D016036:Seroepidemiologic Studies; D019562:Viral Load / Q000662:veterinary
chemical_list: D004279:DNA, Viral