Zimmerman Alicia D, Springer Eric W, Barling Kerry S, Buterbaugh Robin E, Pooley Ryan D, Scholz Douglas A, Rhoades James R, Chase Christopher C L
Rural Technologies Inc, 1008 32nd Ave, Brookings, SD 57006, USA.
J Am Vet Med Assoc. 2013 Jun 1;242(11):1573-7. doi: 10.2460/javma.242.11.1573.
To evaluate immunity induced by a multivalent vaccine containing a US Leptospira borgpetersenii serovar Hardjo type hardjo bovis (LHB) isolate in heifers challenged 12 months after vaccination.
Prospective vaccine challenge study.
36 one-month old Holstein heifers.
18 heifers were vaccinated at 4 and 8 weeks of age with an inactivated vaccine containing Leptospira fractions. Additionally, 18 heifers were vaccinated at the same age with the same vaccine without any Leptospira fractions. All heifers were challenged with a US-origin LHB 12 months following booster vaccination. Urine samples were collected weekly for 8 weeks after challenge, and serum was collected at -1, 28, and 56 days after challenge for serologic testing. At 8 weeks after challenge, all heifers were necropsied, and kidney and reproductive system samples were collected for bacteriologic culture.
4 of 18 vaccinates had positive results of bacteriologic culture of urine samples, but only at 1 time point. All control heifers had positive results of bacteriologic culture of urine samples for at least 5 time points. Vaccinates had negative results of bacteriologic culture of kidney and reproductive system samples following necropsy, whereas all control heifers had positive results of bacteriologic culture of kidney samples and 5 of 18 had positive results of bacteriologic culture of reproductive system samples.
The vaccine administered to calves at 1 month of age prevented leptospire colonization of kidney and reproductive system tissue and significantly reduced urine shedding following challenge 12 months after vaccination. This vaccine provides an opportunity to protect calves at an early age from becoming infected and ultimately from becoming an LHB reservoir.
评估在接种疫苗12个月后受到攻击的小母牛中，一种含有美国波摩那钩端螺旋体哈氏黄疸出血群牛型（LHB）分离株的多价疫苗所诱导的免疫力。
前瞻性疫苗攻击研究。
36头1月龄的荷斯坦小母牛。
18头小母牛在4周龄和8周龄时接种含有钩端螺旋体成分的灭活疫苗。另外，18头小母牛在相同年龄接种不含任何钩端螺旋体成分的相同疫苗。所有小母牛在加强免疫接种12个月后用源自美国的LHB进行攻击。攻击后每周收集8周的尿液样本，并在攻击后第-1、28和56天收集血清进行血清学检测。攻击后8周，对所有小母牛进行尸检，并收集肾脏和生殖系统样本进行细菌培养。
18头接种疫苗的小母牛中有4头尿液样本细菌培养呈阳性，但仅在1个时间点呈阳性。所有对照小母牛的尿液样本细菌培养至少在5个时间点呈阳性。接种疫苗的小母牛在尸检后肾脏和生殖系统样本细菌培养结果为阴性，而所有对照小母牛肾脏样本细菌培养结果为阳性，18头中有5头生殖系统样本细菌培养结果为阳性。
1月龄犊牛接种的疫苗可预防钩端螺旋体在肾脏和生殖系统组织中的定植，并在接种疫苗12个月后受到攻击后显著减少尿液排菌。这种疫苗为在幼年时保护犊牛免受感染并最终避免成为LHB宿主提供了机会。
