Department of Veterinary Pathology, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
Department of Animal Health, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
J Comp Pathol. 2021 Oct;188:13-20. doi: 10.1016/j.jcpa.2021.08.001. Epub 2021 Sep 10.
Mycoplasma bovis (M. bovis) is a common inhabitant of the upper and lower respiratory tracts of cattle and is considered to be the main aetiological agent of otitis media in calves. The eustachian tube appears to be the most common portal for pathogens to enter the middle ear. We investigated the transmission route of M. bovis causing otitis media that progressed to meningitis or meningoencephalitis in Japanese Black cattle. M. bovis was detected in 10 cases by a loop-mediated isothermal amplification method or by immunohistochemistry. One case of caseonecrotic granulomatous meningoencephalitis, one case of caseonecrotic granulomatous meningitis, one case of suppurative meningoencephalitis, eight cases of eustachitis, nine cases of tonsillitis and six cases of suppurative bronchopneumonia were identified by histopathological examination. M. bovis antigen was detected in the eustachian tubes of eight cases. In nine cases, M. bovis was also detected in tonsillar epithelial crypts and lumina, in intraluminal inflammatory cells and in the epithelial cells of minor salivary glands located around the eustachian tubes and tonsils. The results suggest that M. bovis can infect and colonize the tonsils and enter the eustachian tubes, causing otitis media, which, in cases of chronic infection, can progress to meningitis.
牛支原体（M. bovis）是牛的上呼吸道和下呼吸道的常见居民，被认为是犊牛中耳炎的主要病因。咽鼓管似乎是病原体进入中耳最常见的门户。我们研究了导致日本黑牛中耳炎发展为脑膜炎或脑膜脑炎的牛支原体的传播途径。通过环介导等温扩增法或免疫组织化学法检测到 10 例 M. bovis。通过组织病理学检查鉴定出 1 例坏死性肉芽肿性脑膜脑炎、1 例坏死性肉芽肿性脑膜炎、1 例化脓性脑膜脑炎、8 例咽鼓管炎、9 例扁桃体炎和 6 例化脓性支气管肺炎。在 8 例咽鼓管中检测到牛支原体抗原。在 9 例中，还在扁桃体上皮隐窝和管腔、管腔内炎症细胞和位于咽鼓管和扁桃体周围的小唾液腺的上皮细胞中检测到 M. bovis。结果表明，M. bovis 可以感染和定植扁桃体，并进入咽鼓管，导致中耳炎，在慢性感染的情况下，可能发展为脑膜炎。
