Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) cause acute diarrhea/vomiting in neonatal pigs and share similar tissue or cellular tropisms in the gastrointestinal tract. We investigated if or how these two swine enteric coronaviruses interact with each other in gnotobiotic (Gn) piglets. Seventeen 9−10-day-old Gn piglets were randomly assigned to 5 groups and inoculated with PEDV strain PC21A [9.3 log₁₀ genomic equivalents (GE)/pig] and/or PDCoV strain OH-FD22 (8.6 log₁₀ GE/pig) as follows: dually with PEDV and PDCoV [16 h later (n = 4) or simultaneously (n = 3)] or singly with PEDV (n = 4), PDCoV (n = 4), or mock (n = 3). No enhanced clinical disease or fecal PEDV shedding were observed in dually inoculated pigs compared with PEDV or PDCoV singly inoculated pigs, coinciding with no significant differences in jejunal VH:CD ratios and PEDV antigen-positive scores at post-inoculation days (PIDs) 3–4 among the groups. These observations indicate no increased severity of PEDV infectivity by PDCoV co-infection. Notably, compared with PDCoV singly inoculated pigs, low to moderate fecal PDCoV RNA titers were detected only at PID 1 in both dually inoculated pig groups. At PIDs 2–4, however, there was no detectable PDCoV RNA in the feces, coinciding with no or few PDCoV antigen-positive cells in the small and large intestine of the dually inoculated pigs at PIDs 3–4. These observations indicate a possible interference or inhibition of PDCoV replication in the gastrointestinal tract of pigs co-infected with PEDV and may influence PDCoV infection in PEDV co-infected pigs.

猪流行性腹泻病毒 (PEDV) 和猪 deltacoronavirus (PDCoV) 会引起新生猪的急性腹泻/呕吐，并且在胃肠道中具有相似的组织或细胞趋向性。我们研究了这两种猪肠道冠状病毒是否或如何在无菌 (Gn) 仔猪中相互作用。17 头 9-10 日龄 Gn 仔猪被随机分配到 5 组并接种 PEDV 菌株 PC21A [9.3 log ₁₀基因组当量 (GE)/猪] 和/或 PDCoV 菌株 OH-FD22（8.6 log ₁₀GE/pig) 如下：与 PEDV 和 PDCoV [16 小时后 (n = 4) 或同时 (n = 3)] 或单独与 PEDV (n = 4)、PDCoV (n = 4) 或模拟 (n = 3)。与单独接种 PEDV 或 PDCoV 的猪相比，在双重接种的猪中未观察到增强的临床疾病或粪便 PEDV 脱落，同时空肠 VH:CD 比率和接种后天数 (PID) 3– 的 PEDV 抗原阳性评分没有显着差异组中 4 人。这些观察结果表明 PDCoV 合并感染不会增加 PEDV 感染的严重程度。值得注意的是，与单独接种 PDCoV 的猪相比，在两个双重接种的猪组中，仅在 PID 1 时检测到低至中等的粪便 PDCoV RNA 滴度。然而，在 PID 2-4，粪便中没有可检测到的 PDCoV RNA，与在 PID 3-4 时双重接种的猪的小肠和大肠中没有或几乎没有 PDCoV 抗原阳性细胞一致。这些观察结果表明，可能干扰或抑制了 PEDV 共感染猪胃肠道中 PDCoV 的复制，并可能影响 PEDV 共感染猪的 PDCoV 感染。