Helminths have developed complex mechanisms to suppress the host immune response. These mechanisms may impair the host vaccine response. This study aimed to evaluate the effect of Toxocara spp. infection on the vaccine immune response to bovine herpesvirus type 5 (BoHV–5). First, 30 heifers received two doses of an experimental BoHV–5 vaccine. At 42nd days after the primo vaccination the vaccine efficacy was evaluated, and the presence of anti-Toxocara antibodies. Second, 20 Balb/c mice were divided into two groups, one infected with T. canis and the other without infection. After infection, both groups received two doses of vaccine. The vaccine immune response was assessed by BoHV-5 serum neutralization and splenic cytokines transcription by qPCR. All heifers positive for Toxocara spp. (40%) showed BoHV-5 SN titer ≤1:32, whereas heifers negative for Toxocara spp. (60%) had BoHV-5 SN titer ≥1: 128. Infected T. canis mice showed BoHV-5 SN titer ≤1:2, whereas mice not infected with T. canis BoHV-5 SN titer ≥1:8. Splenocytes from control mice stimulated with BoHV-5 had a significant (p < .05) mRNA transcription for the cytokines IL-12, IL-17, and IL-23, whereas the same cytokines were down-regulated in T. canis infected mice. These results suggest that Toxocara spp. infection may impair BoHV-5 immunization and should be considered for efficient herd immunization.

蠕虫已经开发出复杂的机制来抑制宿主的免疫反应。这些机制可能会削弱宿主疫苗的反应。这项研究旨在评估Toxocara spp的影响。感染对疫苗对5型牛疱疹病毒（BoHV-5）的免疫反应。首先，30头小母牛接受了两剂BoHV-5实验疫苗。初次接种疫苗后第42天，评估疫苗效力以及抗弓形虫抗体的存在。其次，将20只Balb / c小鼠分为两组，一组感染了犬圆弧菌另一个没有感染。感染后，两组均接受两剂疫苗。通过BoHV-5血清中和和qPCR评估脾细胞因子转录水平，评估疫苗的免疫反应。所有小母牛对Toxocara spp都是阳性的。（40％）的BoHV-5 SN滴度≤1：32，而小母牛的Toxocara spp阴性。（60％）的BoHV-5 SN滴度≥1：128。被感染的犬T. canis小鼠的BoHV-5 SN滴度≤1：2，而未感染T. canis的BoHV-5 SN滴度≥1：8。BoHV-5刺激的对照小鼠的脾细胞有明显的（p <.05）细胞因子IL-12，IL-17和IL-23的mRNA转录，而相同的细胞因子在犬被T. canis感染的小鼠中被下调。这些结果表明Toxocara spp。感染可能会破坏BoHV-5免疫，应考虑进行有效的牛群免疫。