Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
Department of Clinical Sciences and Public Health, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Sci Rep. 2021 Feb 4;11(1):3040. doi: 10.1038/s41598-021-82738-8.
Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) cause an enteric disease characterized by diarrhea clinically indistinguishable. Both viruses are simultaneously detected in clinical cases, but a study involving the co-infection has not been reported. The study was therefore conducted to investigate the disease severity following a co-infection with PEDV and PDCoV. In the study, 4-day-old pigs were orally inoculated with PEDV and PDCoV, either alone or in combination. Following challenge, fecal score was monitored on a daily basis. Fecal swabs were collected and assayed for the presence of viruses. Three pigs per group were necropsied at 3 and 5 days post inoculation (dpi). Microscopic lesions and villous height to crypt depth (VH:CD) ratio, together with the presence of PEDV and PDCoV antigens, were evaluated in small intestinal tissues. Expressions of interferon alpha (IFN-α) and interleukin 12 (IL12) were investigated in small intestinal mucosa. The findings indicated that coinoculation increased the disease severity, demonstrated by significantly prolonged fecal score and virus shedding and decreasing VH:CD ratio in the jejunum compared with pigs inoculated with either PEDV or PDCoV alone. Notably, in single-inoculated groups, PEDV and PDCoV antigens were detected only in villous enterocytes wile in the coinoculated group, PDCoV antigen was detected in both villous enterocytes and crypts. IFN-α and IL12 were significantly up-regulated in coinoculated groups in comparison with single-inoculated groups. In conclusion, co-infection with PEDV and PDCoV exacerbate clinical signs and have a synergetic on the regulatory effect inflammatory cytokines compared to a single infection with either virus.
猪流行性腹泻病毒（PEDV）和猪德尔塔冠状病毒（PDCoV）引起以临床症状无法区分的腹泻为特征的肠道疾病。这两种病毒在临床病例中同时被检测到，但尚未有涉及合并感染的研究报道。因此，本研究旨在调查 PEDV 和 PDCoV 合并感染后的疾病严重程度。在该研究中，4 日龄仔猪经口接种 PEDV 和 PDCoV，单独或联合接种。攻毒后，每天监测粪便评分。采集粪便拭子并检测病毒的存在。每组 3 头猪，分别于攻毒后 3 和 5 天剖检。评估小肠组织的微观病变和绒毛高度与隐窝深度（VH:CD）比值，以及 PEDV 和 PDCoV 抗原的存在。检测小肠黏膜中干扰素α（IFN-α）和白细胞介素 12（IL12）的表达。结果表明，与单独接种 PEDV 或 PDCoV 的仔猪相比，混合接种增加了疾病的严重程度，表现为粪便评分和病毒脱落显著延长，空肠 VH:CD 比值降低。值得注意的是，在单独接种组中，PEDV 和 PDCoV 抗原仅在绒毛状肠细胞中检测到，而在混合接种组中，PDCoV 抗原在绒毛状肠细胞和隐窝中均被检测到。与单独接种组相比，混合接种组的 IFN-α和 IL12 显著上调。总之，与单独感染一种病毒相比，PEDV 和 PDCoV 的合并感染会加重临床症状，并对调节炎症细胞因子产生协同作用。
