Uveitis is common in cats, and is often a feature of feline infectious peritonitis (FIP). We evaluated 3 tools for detection of feline coronavirus (FCoV) in aqueous humor: 1) a 7b gene reverse-transcription real-time PCR (7b-RT-rtPCR) assay to detect FCoV RNA, 2) a spike gene mutation RT-rtPCR (S-RT-rtPCR) assay to detect 2 point mutations in the spike gene of FCoV in cats positive by 7b-RT-rtPCR, and 3) immunocytochemistry (ICC) for detection of FCoV antigen in aqueous humor macrophages. We studied 58 cats, including 31 cats with FIP and 27 control cats. FIP was excluded by postmortem examination and negative immunohistochemistry (IHC). Aqueous humor samples obtained postmortem were assessed using 7b-RT-rtPCR in all cats, and positive samples were evaluated with S-RT-rtPCR. ICC evaluation of aqueous humor samples from 36 of the 58 cats was done using an avidin–biotin complex method and monoclonal anti-FCoV IgG 2A. Sensitivity, specificity, and negative and positive predictive values were calculated including 95% CIs. 7b-RT-rtPCR had a specificity of 100.0% (95% CI: 87.2–100.0) and sensitivity of 35.5% (95% CI: 19.2–54.6). Specificity of S-RT-rtPCR could not be determined because there were no FCoV 7b-RT-rtPCR–positive samples in the control group. Sensitivity of S-RT-rtPCR was 12.9% (95% CI 3.6–29.8). Sensitivity and specificity of ICC were 62.5% (95% CI: 40.6–81.2) and 80.0% (95% CI: 44.4–97.5), respectively. The combination of 7b-RT-rtPCR and IHC could be useful in diagnosing FIP; S-RT-rtPCR did not add value; and ICC of aqueous humor samples cannot be recommended for the diagnosis of FIP.

葡萄膜炎在猫中很常见，并且通常是猫传染性腹膜炎（FIP）的一个特征。我们评估了 3 种检测眼房水中猫冠状病毒 (FCoV) 的工具：1) 7b基因逆转录实时 PCR ( 7b -RT-rtPCR) 检测法，用于检测 FCoV RNA；2) 刺突基因突变 RT-rtPCR ( S -RT-rtPCR) 法检测7b -RT-rtPCR 阳性猫中 FCoV 刺突基因的 2 个点突变，3) 免疫细胞化学 (ICC) 检测房水巨噬细胞中的 FCoV 抗原。我们研究了 58 只猫，其中 31 只患有 FIP 的猫和 27 只对照猫。通过尸检和免疫组织化学 (IHC) 阴性结果排除 FIP。使用7b -RT-rtPCR 对所有猫进行死后获得的房水样本进行评估，并使用S -RT-rtPCR 评估阳性样本。使用抗生物素蛋白-生物素复合物方法和单克隆抗 FCoV IgG 2A 对 58 只猫中 36 只的房水样本进行 ICC 评估。计算了敏感性、特异性以及阴性和阳性预测值，包括 95% CI。 7b -RT-rtPCR 的特异性为 100.0% (95% CI: 87.2–100.0)，敏感性为 35.5% (95% CI: 19.2–54.6)。无法确定S -RT-rtPCR 的特异性，因为对照组中没有 FCoV 7b -RT-rtPCR 阳性样本。 S -RT-rtPCR 的灵敏度为 12.9% (95% CI 3.6–29.8)。 ICC 的敏感性和特异性分别为 62.5% (95% CI: 40.6–81.2) 和 80.0% (95% CI: 44.4–97.5)。 7b -RT-rtPCR 和 IHC 的组合可用于诊断 FIP； S -RT-rtPCR没有增加价值；房水样本的 ICC 和 ICC 不推荐用于 FIP 的诊断。