Evaluation of protective immunity in pigs following oral administration of an avirulent live vaccine of Lawsonia intracellularis
Evaluation of protective immunity in pigs following oral administration of an avirulent live vaccine of Lawsonia intracellularis
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DOI：
10.2460/ajvr.2004.65.559
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发表时间：
2004-05-01
影响因子：
1
通讯作者：
McOrist, S
中科院分区：
文献类型：
--
作者：
Kroll, JJ;Roof, MB;McOrist, S
目的-评价口服无毒力活疫苗保护猪免受强毒胞内劳森氏菌攻击暴露的效力。动物-108只断奶的3周龄猪（实验1中35只，实验2中73只）。在第0天，接种组猪通过灌服或饮用水经口接种疫苗，而攻毒对照组猪接种培养基。在第21天，用细胞内乳杆菌的强毒异源分离株攻击暴露猪。测量临床观察结果、体重、血清转化和粪便排泄的胞内乳杆菌，直至第42天。在研究结束时，对猪实施安乐死，并检查回肠和结肠的细胞内乳酸杆菌特异性病变发展。结果-接受单剂量疫苗的猪在暴露于毒性细胞内乳酸杆菌（至少10（77）TCID 50/剂量）的攻击时受到保护。在实验1中，与攻毒对照组猪相比，免疫组猪的粪便排泄量显著减少（第35天和第42天分别为47%和40%）。在实验2中，与攻毒对照组猪相比，接种组猪的粪便排泄量显著减少（第35天和第42天分别为50%和58%）。在接种猪的回肠中，病变发展明显减少（实验1和2在第42天分别为70%和56%），结论和临床相关性-通过灌服或饮用水口服细胞内李斯特菌无毒力活疫苗，在接种者中产生了对增殖性肠病的实质性保护，并提供了更好的免疫保护。减少猪在接种疫苗期间的压力。
Objective - To evaluate the efficacy of an orally administered avirulent live vaccine to protect pigs against challenge exposure with virulent Lawsonia intracellularis.Animals -108 weaned 3-week-old pigs (35 in experiment 1 and 73 in experiment 2).Procedure - 2 experiments were conducted. On day 0, vaccinates were orally administered vaccine via drench or in drinking water, whereas challenge-control pigs were administered cultured medium. On day 21, pigs were challenge exposed with a virulent heterologous isolate of L intracellularis. Clinical observations, weights, seroconversion, and fecal excretion of L intracellularis were measured until day 42. At study termination, pigs were euthanatized and examined for L intracellularis-specific lesion development of the ileum and colon.Results - Pigs receiving a single dose of vaccine were protected when challenge exposed with virulent L intracellularis (at least 10(77) TCID50/dose). In experiment 1, vaccinates had significantly less fecal excretion (47% and 40% for days 35 and 42, respectively), compared with challenge-control pigs. In experiment 2, vaccinates had significantly less fecal excretion (50% and 58% for days 35 and 42, respectively), compared with challenge-control pigs. Significant reductions in lesion development were evident in the ileum of vaccinated pigs (70% and 56% at day 42 for experiments 1 and 2, respectively), compared with challenge-control pigs.Conclusions and Clinical Relevance - Oral administration by drench or via drinking water of an avirulent live vaccine against L intracellularis resulted in substantial protection against proliferative enteropathy among vaccinates and offers a better way to reduce stress of pigs during vaccine administration.