La Sota vaccination may not protect against virus shedding and the lesions of velogenic Newcastle disease in commercial turkeys
La Sota vaccination may not protect against virus shedding and the lesions of velogenic Newcastle disease in commercial turkeys
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拉索塔疫苗接种可能无法防止商业火鸡的病毒脱落和烈性新城疫病变
DOI：
10.1007/s11250-017-1439-9
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发表时间：
2018
影响因子：
1.7
通讯作者：
J. Okoye
中科院分区：
文献类型：
--
作者：
O. Okoroafor;P. Eze;W. Ezema;C. Nwosu;Christian O. Okorie;P. C. Animoke;B. Anene;J. Okoye
该项目的目的是研究商业火鸡中烈性新城疫 (vND) 的临床症状和病变，并查明 La Sota 疫苗接种是否可以针对这些症状和病变提供保护。公鸡被纳入作为阳性对照。将 120 只火鸡幼禽和公鸡分为如下 8 组：未接种疫苗的未攻击火鸡 (UUT)、未接种疫苗的攻击火鸡 (UCT)、接种疫苗的未攻击火鸡 (VUT)、接种疫苗的攻击火鸡 (VCT)，同样，公鸡组为 UUC、UCC、VUC 和接种疫苗的攻击公鸡（VCC）。疫苗接种是在 3 周龄时进行，攻击是在 6 周龄时进行。未接种疫苗的火鸡和公鸡（UCT 和 UCC）在攻击时表现出不同程度的抑郁、腹泻和随后的瘫痪。 6 天内，公鸡的总死亡率为 100%，而火鸡的总死亡率为 60%。 VCC 中也发现了类似但较温和的临床症状，总死亡率为 13.3%。 VCT 显示饲料和水消耗量略有下降，并且没有死亡。与对照组相比，所有接受挑战的组的体重均显着减轻（p < 0.05）。尸检显示，虽然UCC有严重的前脑室出血、肠和盲肠扁桃体溃疡，但UCT没有消化道病变。所有攻击组的淋巴器官均出现严重萎缩。所有受攻击组的法氏囊、脾脏和胸腺的组织病理学切片，尤其是死亡率分别为0%和60%的接种疫苗和未接种疫苗的火鸡，均具有非常严重的淋巴组织坏死和耗竭。从泄殖腔拭子中分离出病毒。攻击组中的血凝抑制抗体显着高于未攻击组 (p<0.05)。上述 UCT 肠道观察结果具有诊断意义，而 UCT 和 VCT 中的肉眼和微观病变表明，La Sota 疫苗接种可能无法保护火鸡免受 vND 对淋巴器官的破坏，正如之前在鸡中报道的那样。这可能会导致 vND 流行地区出现免疫抑制和生产问题。
The aim of this project is to study the clinical signs and lesion of velogenic Newcastle disease (vND) in commercial turkeys, and also to find out if La Sota vaccination offered protection against these signs and lesions. The cockerels were included as positive controls. One hundred and twenty turkey poults and cockerels were divided into eight groups as follows: unvaccinated unchallenged turkeys (UUT), unvaccinated challenged turkeys (UCT), vaccinated unchallenged turkeys (VUT), vaccinated challenged turkeys (VCT), and along the same lines, the cockerel groups were UUC, UCC, VUC and vaccinated challenged cockerels (VCC). Vaccination was at 3 weeks of age while challenge was at 6 weeks of age. The unvaccinated turkeys and cockerels (UCT and UCC) showed different degrees of depression, diarrhoea and later paralysis at challenge. Total mortality was 100% in cockerels within 6 days, but 60% in turkeys. Similar but milder clinical signs were found in the VCC with a total mortality of 13.3%. The VCT showed mild drop in feed and water consumption, and no mortality. All the challenged groups had significant (p< 0.05) loss of weight when compared with their controls. Necropsy showed that while the UCC had severe proventricular haemorrhages, intestinal and caecal tonsil ulcers, the UCT had no digestive tract lesion. There was severe atrophy of the lymphoid organs in all the challenged groups. Histopathological sections of the bursa, spleen and thymus in all the challenged groups with special emphasis on the vaccinated and unvaccinated turkeys with mortalities of 0 and 60%, respectively, had very severe necrosis and depletion of the lymphoid tissue. Virus was isolated from the cloacal swabs. The haemagglutination inhibition antibodies were significantly higher (p< 0.05) in the challenged groups than the unchallenged. The above observations in the intestinal tracts of UCT are of diagnostic significance while the gross and microscopic lesions in the UCT and VCT show that La Sota vaccination may not protect turkeys against the destruction of the lymphoid organs by vND as earlier reported in chickens. This may lead to immunosuppression and production problems in areas where vND is enzootic.