title: Evaluation of the natural perinatal transmission of bovine leukaemia virus.
abstract: The perinatal transmission of bovine leukaemia virus (BLV) plays a critical role in the spread and persistence of BLV infection in cattle herds. The purpose of this study was to examine the frequency of perinatal infections in an area in Japan and investigate some risk factors associated with infection. Altogether, 129 calves born to BLV-infected cows in a herd in Japan were tested for infection immediately after birth and again at one month of age using nested PCR. Twenty-four calves (18.6 per cent) were infected with BLV, of which 14 (10.8 per cent) and 10 (7.7 per cent) calves were infected via the transplacental and the birth canal routes, respectively. Maternal viral loads, breed, the presence or absence of assistance during parturition and the number of births per dam were evaluated to investigate risk factors associated with infection. Maternal viral load was significantly correlated with the frequency of perinatal infection, and more than 40 per cent of newborn calves born to dams with high viral loads were infected with BLV. The results of this study could contribute towards developing effective eradication programmes by providing necessary data for replacement of breeding cow in the field.
authors.affiliation: Project for Zoonoses Education and Research, Department of Veterinary Medicine, 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.affiliation: Laboratory of Animal Infectious Disease and Prevention, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sekiguchi
authors.affiliation: Laboratory of Infectious Diseases, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Sapporo 060-0818, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Konnai
authors.affiliation: Project for Zoonoses Education and Research, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kirino
authors.affiliation: Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Honkawa
authors.affiliation: Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Nariaki
authors.initials: N
authors.lastname: Nonaka
authors.affiliation: Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Horii
authors.affiliation: Laboratory of Animal Infectious Disease and Prevention, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.
authors.forename: Junzo
authors.initials: J
authors.lastname: Norimine
mesh_terms: D000818:Animals; D002417:Cattle; D004279:DNA, Viral / Q000302:isolation & purification; D016583:Enzootic Bovine Leukosis / Q000453:epidemiology / Q000635:transmission*; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D007564:Japan / Q000453:epidemiology; D001909:Leukemia Virus, Bovine / Q000235:genetics / Q000302:isolation & purification*; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012307:Risk Factors; D019562:Viral Load / Q000662:veterinary
chemical_list: D004279:DNA, Viral
keywords: Calves; Cattle; PCR; Retroviruses