Comparative Sequence Analysis of Historic and Current Porcine Rotavirus C Strains and Their Pathogenesis in 3-Day-Old and 3-Week-Old Piglets
Comparative Sequence Analysis of Historic and Current Porcine Rotavirus C Strains and Their Pathogenesis in 3-Day-Old and 3-Week-Old Piglets
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DOI：
10.3389/fmicb.2020.00780
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发表时间：
2020-04-24
影响因子：
5.2
通讯作者：
Vlasova, Anastasia N.
中科院分区：
文献类型：
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作者：
Chepngeno, Juliet;Takanashi, Sayaka;Vlasova, Anastasia N.
猪C组轮状病毒（PRVC）在哺乳仔猪中的流行增加和新的遗传上不同的PRVC毒株的出现是令人关注的，因为它们给养猪业造成了相关的重大经济损失。我们对两个新的PRVC菌株RV 0104（G3）和RV 0143（G6）进行了测序和分析，并将它们的致病性与历史菌株Cowden（G1）在无菌（Gn）猪中的致病性进行了比较。近全基因组序列分析证实，这两个菌株是不同的彼此和考登菌株。Cowden和RV 0143之间的VP 1、VP 2、VP 6、NSP 1-NSP 3和NSP 5基因更相似，而Cowden和RV 0104之间的VP 3、VP 7和NSP 4具有更高的核苷酸同一性。用10（5）FFU/头Cowden、RV 0104或RV 0143或模拟物接种3日龄和3周龄Gn仔猪。所有3日龄仔猪均发生重度腹泻、厌食和嗜睡，在感染后第2天（PID），RV 0104和RV 0143仔猪的平均PRVC粪便散毒滴度达到峰值，且数值较高。小肠组织学检查显示，3日龄Cowden和RV 0104接种仔猪受到轻度影响，而RV 0143接种仔猪中观察到小肠绒毛显著破坏。与小肠中最高程度的病理变化一致，RV 0143接种的仔猪具有数值较高的血清IL-17和IFN-α细胞因子水平和数值较低的PRVC伊加几何平均抗体滴度。在3周龄与3日龄仔猪中观察到较轻的病理变化和总体较高的PRVC伊加抗体滴度。此外，仅在RV 0104和RV 0143（但不是Cowden）接种的3周龄仔猪中观察到腹泻，而血清IL-10和PRVC伊加抗体的水平在Cowden接种的猪中更高，与没有腹泻一致。因此，我们证实，这些目前的遗传异质性PRVC菌株具有不同的病理生物学特征，可能有助于增加新生仔猪PRVC腹泻的患病率。
The increased prevalence of porcine group C rotavirus (PRVC) in suckling piglets and the emergence of new genetically distinct PRVC strains are concerning due to the associated significant economic losses they cause to the swine industry. We sequenced and analyzed two new PRVC strains, RV0104 (G3), and RV0143 (G6) and compared their pathogenesis with that of the historic strain Cowden (G1) in gnotobiotic (Gn) pigs. Near complete genome sequence analysis confirmed that these two strains were distinct from one another and the Cowden strain. VP1, VP2, VP6, NSP1-NSP3, and NSP5 genes were more similar between Cowden and RV0143, whereas VP3, VP7, and NSP4 shared higher nucleotide identity between Cowden and RV0104. Three-day-old and 3-week-old Gn piglets were inoculated with 10(5) FFU/piglet of Cowden, RV0104 or RV0143, or mock. All 3-day-old piglets developed severe diarrhea, anorexia, and lethargy, with mean PRVC fecal shedding titers peaking and numerically higher in RV0104 and RV0143 piglets on post infection day (PID) 2. Histopathological examination of the small intestine revealed that the 3-day-old Cowden and RV0104 inoculated piglets were mildly affected, while significant destruction of small intestinal villi was observed in the RV0143 inoculated piglets. Consistent with the highest degree of pathological changes in the small intestines, the RV0143 inoculated piglets had numerically higher levels of serum IL-17 and IFN-alpha cytokines and numerically lower PRVC IgA geometric mean antibody titers. Milder pathological changes and overall higher titers of PRVC IgA antibodies were observed in 3-week-old vs. 3-day-old piglets. Additionally, diarrhea was only observed in RV0104 and RV0143 (but not Cowden) inoculated 3-week-old piglets, while levels of serum IL-10 and PRVC IgA antibodies were higher in Cowden inoculated pigs, consistent with the lack of diarrhea. Thus, we confirmed that these current, genetically heterogeneous PRVC strains possess distinct pathobiological characteristics that may contribute to the increased prevalence of PRVC diarrhea in neonatal suckling piglets.