Taberner Ester, Gibert Marta, Montbrau Carlos, Muñoz Ruiz Irene, Mallorquí Joaquim, Santo Tomás Héctor, Prenafeta Antoni, March Ricard
Hipra Scientific S.L.U., R&D Department, Amer, Spain.
Hipra, Marketing Department, Amer, Spain.
Vet Med (Auckl). 2024 Dec 10;15:221-238. doi: 10.2147/VMRR.S474655. eCollection 2024.
To demonstrate the efficacy of DIVENCE, a vaccine against BVDV types 1 and 2 (BVDV-1 and BVDV-2) transplacental infection, following a booster regimen in heifers.
Calves of two-to-three months of age were given two intramuscular doses three weeks apart and a booster vaccine six months later. Efficacy was evaluated by means of a challenge with virulent BVDV-1 or BVDV-2 administered via the intranasal route at 85 days of gestation. Clinical signs, serology, viral shedding, WBC count and viremia were monitored after the challenge. Sixty-six days post-challenge, the fetuses were assessed for BVDV to detect transplacental infection.
Vaccinated animals showed a significant ( < 0.05) reduction in hyperthermia after both challenges. The WBC counts in vaccinated animals were significantly ( < 0.05) higher than in control animals on Days 5 and 6 after both challenges. Vaccinated animals exhibited no shedding after BVDV-1 challenge and the percentage of shedding animals was significantly ( < 0.05) higher among control animals compared to vaccinated animals after BVDV-2 challenge. Viremia were detected in pregnant heifers from all control animals, while only 3/14 and 3/17 pregnant vaccinated heifers showed viremia after BVDV-1 and BVDV-2 challenges, respectively. All the fetuses (n=8) from the control animals were positive for BVDV-1 via virus titration after BVDV-1 challenge. Only one out of fourteen fetuses from the vaccinated animals was positive for BVDV-1. After BVDV-2 challenge, all the control animals had BVDV-2 in all fetal tissues assessed and only one of the seventeen vaccinated animals had BVDV-2 in its fetal samples.
DIVENCE administered prior to breeding protected 94% of the fetuses against BVDV transplacental infection overall across both challenge trials (BVDV-1 and BVDV-2). A reduction in the hyperthermia, leukopenia, viral shedding, and viremia in vaccinated animals post-challenge with BVDV-1 and BVDV-2 was achieved. The efficacy of DIVENCE against BVDV-1 and BVDV-2 transplacental infection has been demonstrated in this study.
证明DIVENCE疫苗在后备小母牛加强免疫方案后，对牛病毒性腹泻病毒1型和2型（BVDV - 1和BVDV - 2）经胎盘感染的有效性。
给2至3月龄的犊牛间隔三周进行两次肌肉注射，并在6个月后进行一次加强免疫。在妊娠85天时，通过鼻内途径接种强毒BVDV - 1或BVDV - 2进行攻毒，以评估疫苗的有效性。攻毒后监测临床症状、血清学、病毒排出、白细胞计数和病毒血症。攻毒后66天，评估胎儿是否感染BVDV以检测经胎盘感染情况。
两次攻毒后，接种疫苗的动物体温过高情况显著（<0.05）减轻。两次攻毒后第5天和第6天，接种疫苗动物的白细胞计数显著（<0.05）高于对照动物。接种疫苗的动物在BVDV - 1攻毒后未出现病毒排出，而在BVDV - 2攻毒后，对照动物中出现病毒排出的动物百分比显著（<0.05）高于接种疫苗的动物。所有对照动物的怀孕小母牛均检测到病毒血症，而在BVDV - 1和BVDV - 2攻毒后，分别只有3/14和3/17接种疫苗的怀孕小母牛出现病毒血症。BVDV - 1攻毒后，通过病毒滴定，所有对照动物的8个胎儿均为BVDV - 1阳性。接种疫苗动物的14个胎儿中只有1个为BVDV - 1阳性。BVDV - 2攻毒后，所有对照动物评估的所有胎儿组织中均检测到BVDV - 2，而接种疫苗的17个动物中只有1个胎儿样本检测到BVDV - 2。
在配种前接种DIVENCE疫苗，在两项攻毒试验（BVDV - 1和BVDV - 2）中，总体上保护了94%的胎儿免受BVDV经胎盘感染。接种疫苗的动物在BVDV - 1和BVDV - 2攻毒后，体温过高、白细胞减少、病毒排出和病毒血症均有所减轻。本研究证明了DIVENCE疫苗对BVDV - 1和BVDV - 2经胎盘感染的有效性。
