Cano Guillermo, Cavalcanti Marcia Oliveira, Orveillon Francois-Xavier, Kroll Jeremy, Gomez-Duran Oliver, Morillo Alberto, Kraft Christian
Tests and Trials S.L., Monzon, Spain.
Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG, Hannover, Germany.
Porcine Health Manag. 2016 Oct 1;2:22. doi: 10.1186/s40813-016-0038-x. eCollection 2016.
PRRS is a viral disease of pigs and sows that is one of the most costly to the pig industry worldwide. The disease can be controlled by focusing on different aspects. One of them is the vaccination of piglets, which is more controversial and difficult to manage than the vaccination of sows. However, pig producers could consider a piglet vaccination strategy if it reduces the negative clinical disease and improves zootechnical performance, decreases the probability to be infected and/or reduces the spread of the virus once the vaccinated piglet is infected. The efficacy of a novel PRRS modified live vaccine (Ingelvac PRRSFLEX® EU) was studied in a blinded, side-by-side placebo controlled field study of piglet vaccination including piglets weaned for three consecutive weeks (week groups 1, 2 and 3).
This study established that PRRS piglet vaccination resulted in significantly better weight gain, seen as early as 4 weeks after vaccination, in naturally challenged pigs. Vaccine efficacy was supported by statistically significant increases in Average Daily Weight Gain (ADWG) among week group 3 vaccinated pigs from vaccination to the end of the study and statistically significant increases in bodyweight and ADWG from inclusion to 10 weeks of age in week group 2 vaccinated piglets. However, no differences were noted in week group 1 presumably because more than 30 % of the vaccinated pigs were viremic at the time of vaccination. Furthermore, the proportion of pigs showing any abnormal clinical sign at least once at any of the examination time points was lower in vaccinated pigs than in control pigs. Based on the viremia results (qPCR), early onset of PRRS was detected in this herd. Viremia occurred at the time of vaccination in week group 1 and shortly after vaccination in week groups 2 and 3. Peak wild type PRRSV infection was assumed at 4 weeks post vaccination in all groups based on the number of PRRS positive pigs in the control groups.
This study establishes that vaccination of piglets with Ingelvac PRRSFLEX® EU at 4 weeks of age improves weight gain and reduces the appearance of clinical sings during the growing period, even when the piglets are infected shortly after vaccination.
猪繁殖与呼吸综合征（PRRS）是一种猪和母猪的病毒性疾病，是全球养猪业成本最高的疾病之一。该疾病可通过关注不同方面来控制。其中之一是仔猪疫苗接种，这比母猪疫苗接种更具争议性且更难管理。然而，如果仔猪疫苗接种策略能减少负面临床疾病、改善畜牧技术性能、降低感染概率和/或在接种疫苗的仔猪感染后减少病毒传播，养猪生产者可考虑采用该策略。在一项对仔猪接种疫苗的双盲、平行安慰剂对照田间研究中，研究了一种新型PRRS弱毒活疫苗（英特威PRRSFLEX® EU）的效力，该研究包括连续三周断奶的仔猪（第1、2和3周组）。
本研究证实，在自然感染的猪中，PRRS仔猪疫苗接种早在接种后4周就使体重增加显著更好。从接种到研究结束，第3周组接种疫苗的猪的平均日增重（ADWG）有统计学显著增加，以及从入组到第2周组接种疫苗的仔猪10周龄时体重和ADWG有统计学显著增加，均支持了疫苗效力。然而，第1周组未观察到差异，可能是因为超过30%的接种疫苗的猪在接种时处于病毒血症状态。此外，在任何检查时间点至少出现一次任何异常临床症状的猪的比例，接种疫苗的猪低于对照猪。基于病毒血症结果（qPCR），在该猪群中检测到PRRS的早期发作。第1周组在接种时出现病毒血症，第2和3周组在接种后不久出现病毒血症。根据对照组中PRRS阳性猪的数量，假设所有组在接种后4周出现野生型PRRSV感染高峰。
本研究证实，4周龄仔猪接种英特威PRRSFLEX® EU疫苗可改善体重增加，并减少生长期间临床症状的出现，即使仔猪在接种后不久被感染。
