Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA.
Zoetis, Kalamazoo, MI 49007, USA.
Viruses. 2022 Aug 17;14(8):1801. doi: 10.3390/v14081801.
A safe and efficacious live-attenuated vaccine for porcine epidemic diarrhea virus (PEDV) is not commercially available in the United States yet. Two major PEDV strains are currently circulating in US swine: highly virulent non-S-INDEL strain and milder virulent S-INDEL strain. In this study, the safety and protective efficacy of a plaque-purified S-INDEL PEDV isolate formulated as a vaccine candidate was evaluated. Ten pregnant gilts were divided into three groups and orally inoculated at 79 days of gestation and then boosted at 100 days gestation (T01: n = 4, vaccination/challenge; T02: n = 4, non-vaccination/challenge; T03: n = 2, non-vaccination/non-challenge). None of the gilts had adverse clinical signs after vaccination. Only one T01 gilt (#5026) had viral replication and detectible viral RNA in feces. The same gilt had consistent levels of PEDV-specific IgG and IgA antibodies in serum and colostrum/milk. Farrowed piglets at 3 to 5 days of age from T01 and T02 gilts were orally challenged with 10 TCID50/pig of the virulent non-S-INDEL PEDV while T03 piglets were orally inoculated with virus-negative medium. T01 litters had overall lower mortality than T02 (T01 36.4% vs. T02 74.4%). Specifically, there was 0% litter mortality from T01 gilt 5026. Overall, it appears that vaccination of pregnant gilts with S-INDEL PEDV can passively protect piglets if there is virus replication and immune response induction in the pregnant gilts.
在美国，还没有可商售的安全有效的猪流行性腹泻病毒（PEDV）活疫苗。目前，美国猪群中存在两种主要的 PEDV 毒株：高致病性非 S-INDEL 株和低致病性 S-INDEL 株。本研究评估了一种纯化的 S-INDEL PEDV 分离株作为候选疫苗的安全性和保护效力。10 头妊娠母猪分为三组，于 79 日龄妊娠时口服接种，然后于 100 日龄妊娠时加强免疫（T01：n = 4，接种/攻毒；T02：n = 4，未接种/攻毒；T03：n = 2，未接种/未攻毒）。接种后，所有母猪均无临床不良反应。仅有一头 T01 母猪（#5026）粪便中出现病毒复制和可检测到的病毒 RNA。同一头母猪血清和初乳/奶中均具有持续水平的 PEDV 特异性 IgG 和 IgA 抗体。T01 和 T02 母猪所产的仔猪于 3-5 日龄时口服接种 10 TCID50/头的强毒非 S-INDEL PEDV，T03 仔猪口服接种病毒阴性培养基。T01 窝仔猪的死亡率总体低于 T02（T01 36.4%比 T02 74.4%）。具体而言，来自 T01 母猪 5026 的仔猪窝死亡率为 0%。总体而言，如果妊娠母猪发生病毒复制和免疫应答，用 S-INDEL PEDV 对妊娠母猪进行免疫接种似乎可以被动保护仔猪。
