Mannheimia haemolytica pleuropneumonia in goats associated with shipping stress

ABSTRACT: This study described the epidemiological, clinical, pathological and bacteriological aspects of Mannheimia haemolytica pleuropneumonia in goats associated with shipping stress. Forty goats transported from the Northeast to the Southern region of Brazil died during shipment, or 2-3 days after unloading. Clinical signs included dyspnea, mucopurulent nasal discharge, and coughing. All goats were necropsied, and multiple tissues were collected for histopathological analysis and involved agent identifications. All lungs showed pulmonary consolidation, predominantly affecting the cranioventral lobes, in addition to the marked fibrinous pleuritis, pleural thickening, and pleural adhesions, that affected 90% of the goats. Histologically, there was fibrino-suppurative pleuropneumonia characterized by a diffuse neutrophilic infiltrate admixed with fibrin. Non-hemolytic [85% (34/40)] and hemolytic [15% (6/40)] species were obtained in bacteriological culture. Fir Mannheimia spp. was reported in 26 isolates and subsequently confirmed as M. haemolytica (99% identity), after amplification and partial sequencing of the 16S rDNA gene. Stress may trigger the development of bacterial pleuropneumonia in goats, and non-hemolytic strains of M. haemolytica may cause this condition in goats with severe immunosuppression.

摘要：本研究针对与运输应激相关的山羊溶血曼海姆菌（Mannheimia haemolytica）胸膜肺炎，阐述了其流行病学、临床学、病理学及细菌学特征。40只从巴西东北部运往南部地区的山羊在运输途中或卸车后2~3天内死亡。临床症状表现为呼吸困难、黏液脓性鼻漏以及咳嗽。对所有山羊进行了剖检，并采集多份组织样本用于组织病理学分析及病原体鉴定。所有受试山羊的肺部均出现肺实变，主要累及前腹侧肺叶；同时90%的山羊可见明显的纤维素性胸膜炎、胸膜增厚及胸膜粘连。组织病理学检查显示为纤维素性化脓性胸膜肺炎，特征为弥漫性中性粒细胞浸润并伴有纤维素渗出。细菌培养分离得到非溶血性菌株[85%（34/40）]与溶血性菌株[15%（6/40）]。对26株曼海姆菌属（Mannheimia spp.）分离株进行16S rDNA基因扩增及部分测序后，确认其为溶血曼海姆菌（同源性达99%）。应激可能诱发山羊细菌性胸膜肺炎，而溶血曼海姆菌的非溶血性菌株可在重度免疫抑制的山羊中引发该病症。