Van Alstine W G, Stevenson G W, Kanitz C L
Animal Disease Diagnostic Laboratory, Purdue University, W. Lafayette, IN 47907-1175, USA.
Vet Microbiol. 1996 Apr;49(3-4):297-303. doi: 10.1016/0378-1135(95)00191-3.
The purpose of this study was to determine if Porcine Reproductive and Respiratory Syndrome (PRRS) virus infection altered the severity of acute Mycoplasma hyopneumoniae (MH) infection in young pigs. Twenty five, 3-week-old male pigs were randomly assigned by litter and weight to one of 3 groups. Groups 1 (PRRS only, n = 5) and 2 (PRRS + MH, n = 10) were inoculated intranasally with PRRS virus (IN-5 isolate, 10(5) TCID50) and viremia in all pigs was confirmed by virus isolation from serum 3 days later. Group 3 (MH only, n = 10) was inoculated at the same time with virus free culture media. Seven days after virus inoculation, Groups 2 and 3 were inoculated intratracheally with MH (strain P-5722-3, 10(7) CCU). All pigs were euthanized and necropsied 28 days later, when maximum lesions of mycoplasmosis occurs. Pigs in group 1 did not cough and had no gross lung lesions, but were still viremic at necropsy. MH was isolated from all pigs in groups 2 (avg. log 5.2 +/- 1.3) and 3 (avg. log 5.1 +/- 1.5), but differences were not significant (P = 0.87). Similarly, there were no differences in average days coughing (8.9 +/- 2.8 v 11.2 +/- 4.5, P = 0.17), grossly pneumonic lung (16.5% v 17%, P = 0.91), or microscopic lung lesion scores (10.1 +/- 2.6 v 11.1 +/- 1.9, P = 0.35) between pigs in groups 2 and 3. Under these experimental conditions, PRRS virus infection did not increase the severity of experimental Mycoplasma hyopneumoniae infection in young pigs.
本研究的目的是确定猪繁殖与呼吸综合征（PRRS）病毒感染是否会改变幼猪急性猪肺炎支原体（MH）感染的严重程度。25头3周龄雄性仔猪按窝别和体重随机分为3组。第1组（仅感染PRRS，n = 5）和第2组（感染PRRS + MH，n = 10）经鼻接种PRRS病毒（IN - 5分离株，10⁵TCID₅₀），3天后通过血清病毒分离确认所有猪出现病毒血症。第3组（仅感染MH，n = 10）同时接种无病毒的培养基。病毒接种7天后，第2组和第3组经气管内接种MH（P - 5722 - 3株，10⁷CCU）。28天后，当支原体病出现最大病变时，所有猪均被安乐死并进行剖检。第1组的猪不咳嗽，肺部无肉眼可见病变，但在剖检时仍有病毒血症。第2组（平均对数5.2 +/- 1.3）和第3组（平均对数5.1 +/- 1.5）的所有猪均分离到MH，但差异不显著（P = 0.87）。同样，第2组和第3组猪在平均咳嗽天数（8.9 +/- 2.8对11.2 +/- 4.5，P = 0.17）、肉眼可见的肺炎肺脏（16.5%对17%，P = 0.91）或微观肺病变评分（10.1 +/- 2.6对11.1 +/- 1.9，P = 0.35）方面均无差异。在这些实验条件下，PRRS病毒感染并未增加幼猪实验性猪肺炎支原体感染的严重程度。
