National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
Vet Microbiol. 2011 Feb 24;148(1):84-8. doi: 10.1016/j.vetmic.2010.08.001. Epub 2010 Aug 18.
A seroepidemiological survey of bovine leukemia virus (BLV) infection was conducted in Japan in 2007 using an enzyme-linked immunosorbent assay (ELISA) and an agar gel immunodiffusion (AGID) test. A total of 5420 cattle (dairy, 3966; breeding beef, 797; fattening beef, 657) from 209 farms in seven prefectures in Japan were tested. The overall prevalence of BLV infection was 28.6%. The prevalence of BLV infection in dairy cattle (34.7%) was higher than for both fattening beef cattle (7.9%) and breeding beef cattle (16.3%). Age-specific prevalence showed that BLV prevalence increased with age in all types of cattle and was notably different between dairy and beef cattle under 1 year of age. Among 207 farms, 141 herds (68.1%) had one or more positive animals. The proportion of these positive farms was significantly higher among dairy farms (79.1%) than among beef breeding farms (39.5%) and beef fattening farms (51.9%) (P<0.001). Dairy farms (40.5%) also showed a significantly higher within-herd prevalence than beef breeding (27.4%) and fattening (14.9%) farms (P=0.001). This study indicated that BLV is more widely spread in dairy cattle than in beef breeding cattle in Japan. Given the prevalence of BLV infection in dairy and beef cattle was 8- and 1.7-fold higher, respectively, than rates previously found in 1980-1982, BLV appears to be spreading particularly among the dairy cattle population during the last two decades. Further investigation is required to determine the risk factors necessary to control BLV infection that take into account the different farming practices that exist between dairy and beef sectors.
2007 年，日本使用酶联免疫吸附试验（ELISA）和琼脂凝胶免疫扩散（AGID）试验对牛白血病病毒（BLV）感染进行了血清流行病学调查。共检测了来自日本 7 个县 209 个农场的 5420 头牛（奶牛 3966 头；繁殖肉牛 797 头；育肥牛 657 头）。BLV 感染的总流行率为 28.6%。奶牛（34.7%）的 BLV 感染流行率高于育肥牛（7.9%）和繁殖肉牛（16.3%）。按年龄划分的流行率显示，所有类型的牛的 BLV 流行率随年龄增长而增加，1 岁以下的奶牛和肉牛之间的差异尤为明显。在 207 个农场中，有 141 个牛群（68.1%）有一个或多个阳性动物。阳性农场的比例在奶牛场（79.1%）显著高于繁殖肉牛场（39.5%）和育肥牛场（51.9%）（P<0.001）。奶牛场（40.5%）的牛群内流行率也显著高于繁殖肉牛（27.4%）和育肥牛（14.9%）场（P=0.001）。本研究表明，BLV 在日本的奶牛中比在繁殖肉牛中更为广泛传播。鉴于奶牛和肉牛中 BLV 感染的流行率分别比 1980-1982 年的水平高 8 倍和 1.7 倍，BLV 似乎在过去 20 年中在奶牛种群中传播特别迅速。需要进一步调查以确定在考虑到奶牛和肉牛部门之间存在的不同养殖实践的情况下，控制 BLV 感染所需的危险因素。
