Experimental infection of a US spike-insertion deletion porcine epidemic diarrhea virus in conventional nursing piglets and cross-protection to the original US PEDV infection.
Experimental infection of a US spike-insertion deletion porcine epidemic diarrhea virus in conventional nursing piglets and cross-protection to the original US PEDV infection.
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DOI：
10.1186/s13567-015-0278-9
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发表时间：
2015-11-20
影响因子：
4.4
通讯作者：
Wang Q
中科院分区：
文献类型：
--
作者：
Lin CM;Annamalai T;Liu X;Gao X;Lu Z;El-Tholoth M;Hu H;Saif LJ;Wang Q
虽然最初的美国猪流行性腹泻病毒（PEDV）被多项研究证实为高毒力，但是刺突插入缺失（S-INDEL）PEDV毒株的毒力是不确定的。在本研究中，用S-INDEL PEDV Iowa 106（4个猪窝）接种3-4日龄常规哺乳仔猪以研究其毒力。用原始US PEDV PC 21 A或模拟物分别作为阳性和阴性对照接种两窝年龄匹配的仔猪。随后，在接种后21-29天（dpi）用原始US PEDV PC 21 A攻击所有猪以评估交叉保护。所有S-INDEL Iowa 106和原始US PC 21 A接种仔猪均发生腹泻。然而，临床体征的严重程度、死亡率（0-75%）和粪便PEDV RNA脱落滴度在四只S-INDEL Iowa 106接种的窝仔中不同。与原始PC 21 A相比，因S-INDEL Iowa 106感染而急性安乐死/死亡的仔猪具有相对较轻的绒毛萎缩、较低的抗原评分和更有限的肠道感染。4头S-INDEL Iowa 106感染母猪中的2头和最初的PC 21 A感染母猪表现出1-4天的厌食和水样腹泻。在初始PC 21 A攻毒后，S-INDEL Iowa 106接种仔猪的一个亚组（13/16）发生腹泻，而模拟和初始PC 21 A接种仔猪中的所有（5/5）和无（0/4）仔猪分别发生腹泻。我们的结果表明，S-INDEL PEDV Iowa 106在哺乳猪中的毒力低于原始US PEDV PC 21 A，在哺乳猪中具有100%的发病率和18%（6/33）的总体（0-75%）死亡率，这取决于诸如母猪的健康和哺乳以及仔猪的出生体重等因素。S-INDEL Iowa 106的既往感染为仔猪在21-29 dpi时提供了针对原始PC 21 A攻毒的部分交叉保护。
Although the original US porcine epidemic diarrhea virus (PEDV) was confirmed as highly virulent by multiple studies, the virulence of spike-insertion deletion (S-INDEL) PEDV strains is undefined. In this study, 3–4 day-old conventional suckling piglets were inoculated with S-INDEL PEDV Iowa106 (4 pig litters) to study its virulence. Two litters of age-matched piglets were inoculated with either the original US PEDV PC21A or mock as positive and negative controls, respectively. Subsequently, all pigs were challenged with the original US PEDV PC21A on 21–29 days post-inoculation (dpi) to assess cross-protection. All S-INDEL Iowa106- and the original US PC21A-inoculated piglets developed diarrhea. However, the severity of clinical signs, mortality (0–75%) and fecal PEDV RNA shedding titers varied among the four S-INDEL Iowa106-inoculated litters. Compared with the original PC21A, piglets euthanized/died acutely from S-INDEL Iowa106 infection had relatively milder villous atrophy, lower antigen scores and more limited intestinal infection. Two of four S-INDEL Iowa106-infected sows and the original PC21A-infected sow showed anorexia and watery diarrhea for 1–4 days. After the original PC21A challenge, a subset (13/16) of S-INDEL Iowa106-inoculated piglets developed diarrhea, whereas all (5/5) and no (0/4) pigs in the mock and original PC21A-inoculated pigs had diarrhea, respectively. Our results suggest that the virulence of S-INDEL PEDV Iowa106 was less than the original US PEDV PC21A in suckling pigs, with 100% morbidity and 18% (6/33) overall (0–75%) mortality in suckling pigs depending on factors such as the sow’s health and lactation and the piglets’ birth weight. Prior infection by S-INDEL Iowa106 provided partial cross-protection to piglets against the original PC21A challenge at 21–29 dpi.