Sherman J, Mitchell W R, Martin S W, Thorsen J, Ingram D G
Can J Comp Med. 1979 Jan;43(1):1-9.
The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly susceptible to upper respiratory disease and showed the greatest rate of seroconversion to influenza viruses. Major outbreaks of respiratory disease occurred when the proportion of young horses which had not previously been exposed to epidemics of respiratory disease reached 30 to 40% of the population at the track. Most horses over four years of age appeared to develop resistance to the infections.
在三年时间里，对标准赛马场马匹上呼吸道感染的爆发情况进行了调查。呼吸道疾病最严重的流行发生在冬春季节。研究表明，马群中同时存在流感病毒和马疱疹病毒1型。疱疹病毒与呼吸道疾病有关，尤其是在冬季，但马流感病毒显然是这些赛马场呼吸道疾病主要流行的原因。两三岁的幼马对上呼吸道疾病特别易感，并且对流感病毒的血清转化率最高。当此前未接触过呼吸道疾病流行的幼马比例达到赛马场马匹总数的30%至40%时，就会发生呼吸道疾病的主要爆发。大多数四岁以上的马似乎对感染产生了抵抗力。
