Kirisawa Rikio, Toishi Yuko, Akamatsu Ai, Soejima Kosuke, Miyashita Taisuke, Tsunoda Nobuo
Laboratory of Veterinary Virology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyoudai-Midorimachi, Ebetsu, Hokkaido 069-8501, Japan.
J Vet Med Sci. 2017 Mar 23;79(3):636-643. doi: 10.1292/jvms.16-0518. Epub 2017 Jan 27.
In the spring of 2015, two stallions reared in Farms A and B in Hokkaido in Japan showed symptoms of equine coital exanthema. Equine herpesvirus 3 (EHV-3) was isolated from penis swab samples of both stallions, and the isolates from each stallion in Farms A and B were designated as SS-1 and YS-1 strains, respectively. BamHI restriction profiles of SS-1 and Japanese reference strain Iwate-1 were indistinguishable, but the BamHI-A fragment of YS-1 was larger than those of SS-1 and Iwate-1 by 1.9 kbp because of the lack of two BamHI sites. Nucleotide sequence analyses of glycoprotein G (gG), gB, gC and VP13/14 coding regions revealed that SS-1 and YS-1 had 99.77% to 100% identities to each other. These results suggested that the origins of SS-1 and YS-1 were different. For a sero-epidemiological survey, serum neutralizing tests using SS-1 against 319 sera of horses from eight farms in Hokkaido were conducted. Six of the eight farms were EHV-3 antibody-positive, and positive rates ranged from 2.6% to 17.6%. To determine the infection time of four EHV-3 antibody-positive horses, a retrospective study was conducted. Infection time of the four horses was in the breeding season, and re-infection or reactivation of latently infected EHV-3 might have occurred in one horse. However, these four horses had never shown any clinical symptoms. The results suggested that several EHV-3 strains are distributed in Japan and that infection is maintained widely in horses without clinical symptoms.
2015年春季，日本北海道A农场和B农场饲养的两匹种马出现马交媾疹症状。从两匹种马的阴茎拭子样本中分离出了马疱疹病毒3型（EHV-3），A农场和B农场每匹种马的分离株分别被命名为SS-1和YS-1株。SS-1株和日本参考株岩手-1株的BamHI限制性酶切图谱无法区分，但由于缺少两个BamHI位点，YS-1株的BamHI-A片段比SS-1株和岩手-1株的大1.9 kbp。糖蛋白G（gG）、gB、gC和VP13/14编码区的核苷酸序列分析表明，SS-1和YS-1彼此间的同源性为99.77%至100%。这些结果表明SS-1和YS-1的来源不同。为进行血清流行病学调查，使用SS-1对北海道八个农场的319份马血清进行了血清中和试验。八个农场中有六个农场的EHV-3抗体呈阳性，阳性率在2.6%至17.6%之间。为确定四匹EHV-3抗体阳性马的感染时间，进行了一项回顾性研究。这四匹马的感染时间处于繁殖季节，其中一匹马可能发生了潜伏感染的EHV-3的再次感染或再激活。然而，这四匹马从未表现出任何临床症状。结果表明，日本分布有几种EHV-3毒株，且感染在马匹中广泛存在但无临床症状。
