Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia.
Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia.
Vet Microbiol. 2017 Oct;210:167-173. doi: 10.1016/j.vetmic.2017.09.013. Epub 2017 Sep 22.
Mycoplasma bovis is an important pathogen of cattle, causing pneumonia, arthritis and otitis media in young calves, and mastitis in lactating cows, resulting in increased morbidity and, in some instances, mortality. The objective of this study was to evaluate the survival of a M. bovis isolate following nebulisation and to establish whether respiratory disease similar to that seen in the field could be induced in calves by exposing them to an aerosolised culture of M. bovis. A group of eight M. bovis-free calves 14-28days old were exposed to an aerosolised culture of a field isolate of M. bovis that had originally been recovered from a joint lesion in a calf. Three weeks after aerosol exposure necropsies were conducted on all calves. Lung lesions were seen in 7 of 8 calves exposed to the aerosol of M. bovis, whilst calves exposed to the culture medium alone did not develop lesions. Two calves in the infected group had detectable concentrations of serum antibody against M. bovis on day 7 post infection and 4 calves had detectable concentrations of serum antibody against M. bovis on day 21 post infection when tested by MilA IgG ELISA. M. bovis was reisolated from the upper trachea of 6 of the 8 infected calves. The infection method described here appeared to induce lung lesions typical of naturally occurring disease associated with infection with M. bovis and should be applicable to testing the safety and efficacy of attenuated vaccine candidates to control disease caused by this pathogen.
牛支原体是牛的重要病原体,可引起犊牛肺炎、关节炎和中耳炎,以及哺乳期奶牛乳腺炎,导致发病率增加,在某些情况下导致死亡。本研究的目的是评估牛支原体分离株经雾化后的存活情况,并确定通过向牛暴露于雾化培养的牛支原体来诱导类似于田间所见的呼吸道疾病是否可行。一组 8 头无支原体的犊牛 14-28 日龄,暴露于从犊牛关节病变中最初分离的牛支原体田间分离株的雾化培养物中。雾化暴露 3 周后对所有犊牛进行尸检。7/8 头暴露于牛支原体气溶胶的犊牛肺部出现病变,而单独暴露于培养基的犊牛未出现病变。感染组的 2 头犊牛在感染后第 7 天血清中可检测到针对牛支原体的抗体,而在感染后第 21 天 4 头犊牛通过 MilA IgG ELISA 检测到针对牛支原体的血清抗体可检测到。6/8 头感染的犊牛上气管中重新分离出牛支原体。此处描述的感染方法似乎可诱导与牛支原体感染相关的自然发生疾病的典型肺部病变,并且应该适用于测试减毒疫苗候选物的安全性和有效性,以控制该病原体引起的疾病。