CSIRO-Australian Animal Health Laboratory, 5 Portarlington Rd, Geelong, Australia.
Canadian Food Inspection Agency, National Centre for Foreign Animal Diseases, 1015 Arlington St, Winnipeg, Canada.
Vaccine. 2018 Oct 1;36(41):6095-6102. doi: 10.1016/j.vaccine.2018.08.073. Epub 2018 Sep 6.
Foot-and-mouth disease virus (FMDV) serotype Asia-1 is prevalent in countries considered high risk for incursion into Australia, and has recently been responsible for a number of outbreaks in India, Bangladesh, Pakistan and Turkey. In vitro vaccine matching has shown a number of contemporary FMDV Asia-1 strains vary antigenically to the Asia-1 Shamir vaccine strain, which could result in poor protection with use of this vaccine. Therefore it was important to test the ability of the Asia-1 Shamir vaccine to protect sheep from challenge with a recent, heterologous strain at different days post-vaccination (dpv), including in an emergency vaccination scenario (challenge 4 or 7 dpv). Sheep (5 per group) were challenged with the Asia-1/PAK/19/2014 isolate by intra-nasopharyngeal instillation 21 (V21), 7 (V7) or 4 (V4) dpv with high-potency (>6 PD) Asia-1 Shamir vaccine. An additional five sheep were mock-vaccinated with adjuvant only (antigen-free preparation) 4 days prior to challenge (A4), and five unvaccinated (UV) control sheep were also challenged. All V21, V7 and V4 sheep were protected from clinical FMD. Eighty percent of V21 sheep and 40% of V7 sheep had sterile immunity, however all V4 sheep became systemically infected. Vaccination reduced excretion of virus in nasal and oral secretions but had no effect on the development of persistent infection. All A4 sheep and UV control sheep developed clinical FMD. The high-potency Asia-1 Shamir vaccine will protect against disease should an outbreak of contemporary Asia-1 viruses occur. Intranasopharyngeal instillation is an effective challenge method for use in vaccine efficacy studies in sheep.
口蹄疫病毒（FMDV）血清型亚洲-1 在被认为有高入侵风险的国家流行，最近在印度、孟加拉国、巴基斯坦和土耳其发生了多起疫情。体外疫苗匹配表明，一些当代 FMDV 亚洲-1 株与亚洲-1 沙米尔疫苗株在抗原性上存在差异，这可能导致使用该疫苗的保护效果不佳。因此，重要的是要测试亚洲-1 沙米尔疫苗在不同的接种后天数（dpv），包括在紧急接种情况下（接种后 4 或 7 dpv 时），保护绵羊免受最近的、异源毒株挑战的能力。用高滴度（>6 PD）亚洲-1 沙米尔疫苗通过鼻腔内滴注，于接种后 21 天（V21）、7 天（V7）或 4 天（V4）时对绵羊（每组 5 只）进行亚洲-1/PAK/19/2014 分离株的攻毒。在攻毒前 4 天（A4），另外 5 只绵羊用仅佐剂（无抗原制剂）进行模拟接种，5 只未接种（UV）对照绵羊也进行攻毒。所有 V21、V7 和 V4 绵羊均免受临床 FMD 感染。80%的 V21 绵羊和 40%的 V7 绵羊产生了无菌免疫，但所有 V4 绵羊都发生了全身性感染。接种可减少鼻腔和口腔分泌物中病毒的排出，但对持续性感染的发展没有影响。所有 A4 绵羊和 UV 对照绵羊均出现了临床 FMD。如果当代亚洲-1 病毒爆发，高滴度亚洲-1 沙米尔疫苗将能预防疾病。鼻腔内滴注是在绵羊中进行疫苗效力研究的有效攻毒方法。
