TRANSMISSION OF FOOT-AND-MOUTH-DISEASE BY VACCINATED CATTLE FOLLOWING NATURAL CHALLENGE
TRANSMISSION OF FOOT-AND-MOUTH-DISEASE BY VACCINATED CATTLE FOLLOWING NATURAL CHALLENGE
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DOI：
10.1016/s0034-5288(18)31109-3
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发表时间：
1989-01-01
影响因子：
2.4
通讯作者：
KITCHING, RP
中科院分区：
文献类型：
--
作者：
DONALDSON, AI;KITCHING, RP
接种常规单价O1型口蹄疫疫苗的牛在接种后4至21天内短期暴露于猪产生的空气传播同源病毒。然后通过将易感牛与接种疫苗的动物关在一起并检测和观察所有动物的感染迹象和临床疾病来评估传播。在攻毒前三周接种疫苗的所有18头牛都抵抗了临床疾病，尽管有4头感染了亚临床感染，但没有传播给接触的易感牛。在两周前接种疫苗的两组牛中，有一组从感染后第0天起将亚临床感染（但不是疾病）传播给与它们一起饲养的易感动物。亚临床感染表现为短暂的病毒血症，随后没有可检测到的循环抗体反应。在两个实验中的一个中，从接种疫苗到攻击的较短时间（7或4天）导致疾病从临床正常接种疫苗的动物传播到接触动物。患病的接触动物所带来的严重挑战随后压倒了接种疫苗动物的免疫力。结果表明，在紧急疫苗接种规划期间，建议对疫苗接种区内所有口蹄疫易感动物进行疫苗接种，并在疫苗接种区外边界将接种疫苗的动物与未接种疫苗的动物隔离至少3周。
Cattle vaccinated with a conventional monovalent type O1 foot-and-mouth disease (FMD) vaccine were challenged between four and 21 days after vaccination by short-term exposure to homologous airborne virus produced by pigs. Transmission was then assessed by housing susceptible cattle with the vaccinated animals and testing and observing all the animals for signs of infection and clinical disease. All 18 cattle vaccinated three weeks before challenge resisted clinical disease and although four contracted subclinical infection, there was no transmission to susceptible cattle in contact. One of the two groups of cattle vaccinated two weeks previously transmitted subclinical infection, but not disease, to susceptible animals housed with them from day 0 after challenge. Subclinical infection was manifested by a transient viraemia which was not followed by a detectable circulating antibody response. Shorter periods (seven or four days) from vaccination to challenge resulted in transmission of disease from clinically normal vaccinated to in-contact animals in one of two experiments. The severe challenge presented by the diseased in-contact animals then overwhelmed the immunity of the vaccinated animals. The results indicate that during emergency vaccination programmes it is advisable to vaccinate all FMD-susceptible animals within the vaccination zone and that at the outer boundary of the zone vaccinated animals should be kept separated from unvaccinated animals for at least three weeks.