Holyoak G R, Little T V, McCollam W H, Timoney P J
Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington 40546-0099.
J Comp Pathol. 1993 Jul;109(1):29-46. doi: 10.1016/s0021-9975(08)80238-1.
The relationship between stage of reproductive tract maturity and susceptibility to the experimental establishment of persistent infection with equine arteritis virus (EAV) was investigated in 21 prepubertal and 15 peripubertal colts. Five of six prepubertal colts inoculated intranasally remained infected in the reproductive tract from post-challenge day 28 to 93 and two of six from post-challenge day 120 to 180. No virus was detected in five of these animals killed on post-challenge day 210. Each of two peripubertal colts remained infected in the reproductive tract at post-challenge day 60 and one of nine was found to be persistently infected with EAV 15 months after challenge. These findings confirm that the virus can replicate in the reproductive tract of a significant proportion of colts for a variable period of time after clinical recovery in the absence of circulating concentrations of testosterone equivalent to those found in sexually mature stallions. Long-term persistent infection with EAV does not appear to occur in colts exposed to the virus before the onset of peripubertal development. We suggest that colts should be vaccinated at approximately 6 months of age, before peripubertal development but after the disappearance of maternally acquired antibodies.
在21匹青春期前和15匹青春期前后的雄驹中，研究了生殖道成熟阶段与马动脉炎病毒（EAV）持续性感染实验建立易感性之间的关系。6匹经鼻接种的青春期前雄驹中有5匹在攻毒后第28天至93天生殖道仍有感染，6匹中有2匹在攻毒后第120天至180天仍有感染。在攻毒后第210天处死的这些动物中有5匹未检测到病毒。2匹青春期前后的雄驹在攻毒后第60天生殖道仍有感染，9匹中有1匹在攻毒15个月后被发现持续感染EAV。这些发现证实，在没有与性成熟种马相当的循环睾酮浓度的情况下，在临床恢复后的一段可变时间内，该病毒可在相当比例的雄驹生殖道中复制。在青春期前发育开始之前接触该病毒的雄驹似乎不会发生EAV的长期持续性感染。我们建议，雄驹应在大约6月龄时接种疫苗，即在青春期前发育之前但在母源抗体消失之后。
