Hedger R S
J Hyg (Lond). 1970 Mar;68(1):53-60. doi: 10.1017/s0022172400028497.
An outbreak of foot-and-mouth disease in a partially immune population of cattle in Botswana is described. The results show that when cattle immunized by vaccination were presented with natural field challenge of FMD, many animals with immunity sufficient to protect them against clinical disease were, however, susceptible to pharyngeal infection and subsequently became virus carriers. The proportion of animals becoming carriers appeared to vary with the degree of severity of the challenge.Vaccination before exposure to virus appeared to have little effect on the duration of the carrier state. No evidence was obtained of the spread of carrier virus to immune herds following the outbreak.Antibody titres during the outbreak were higher in the clinically infected animals than in the carrier animals and the uninfected animals. Evidence suggested that natural challenge boosted the titres of immune animals. After the outbreak, however, it was not possible to distinguish by their antibody titres between the carrier animal and the virus-negative animal.Antigenic studies on the strains of virus isolated are described.
描述了博茨瓦纳部分免疫牛群中口蹄疫的一次暴发。结果表明，当通过疫苗接种免疫的牛受到口蹄疫自然田间挑战时，许多具有足以保护它们免受临床疾病侵害的免疫力的动物，然而，易受咽部感染并随后成为病毒携带者。成为携带者的动物比例似乎随挑战的严重程度而变化。在接触病毒之前进行疫苗接种似乎对携带者状态的持续时间影响不大。未获得暴发后携带者病毒传播到免疫牛群的证据。暴发期间临床感染动物的抗体滴度高于携带者动物和未感染动物。有证据表明自然挑战提高了免疫动物的抗体滴度。然而，暴发后，无法通过抗体滴度区分携带者动物和病毒阴性动物。描述了对分离出的病毒株的抗原性研究。
