根据病毒的致病性，猫冠状病毒(feline coronavirus, FCoV)可分为猫肠道冠状病毒(feline enteric coronavirus, FECV)和猫传染性腹膜炎病毒(feline infectious peritonitis virus, FIPV)两种生物型。为分析上海地区FIPV部分基因的序列特征，本研究对3株FIPV的非结构蛋白基因ORF3(3a、3b和3c)、ORF7(7a和7b)、S2基因序列进行测序及进化分析。收集上海某宠物医院于2018年7月～2018年9月接诊的3例经临床初步诊断患猫传染性腹膜炎(feline infectious peritonitis，FIP)的猫腹水样品，参照试剂盒说明书提取猫腹水中病毒RNA，采用反转录-聚合酶链反应(reverse transcription-polymerase chain reaction，RT-PCR)对3株FIPV的非结构蛋白基因ORF3、ORF7和S2基因序列进行扩增并测序，构建进化树进行分析。结果显示：3株FIPV的非结构蛋白基因ORF 3a、ORF 3b和ORF 3c的变异主要表现为点突变，ORF 7a基因在第47位发生氨基酸替换，2个具有完整的ORF 7b基因，而1个存在3个核苷酸(nucleotide, nt)的缺失；S基因的S1/S2裂解位点处有连续的R-R-S/A-R-R-S序列模体，符合FIPV裂解位点的氨基酸序列特征，且第 1 045 位甲硫氨酸被亮氨酸替换。遗传进化树显示，3株FIPV的非结构蛋白基因ORF 3c、ORF 7b及S2基因序列与血清型Ⅰ型毒株的亲缘关系最近，表明这3株病毒属于血清型Ⅰ型毒株。推测S基因的突变可能参与了FCoV组织嗜性的改变，这为FIPV的分子流行病学调查提供了资料。

In order to understand the molecular characteristics of a feline infectious peritonitis virus (FIPV) isolated in Shanghai, genes encoding three non-structural proteins ORF3 (3a, 3b and 3c), ORF7 (7a and 7b) and S2 of three FIPV strains were amplified by RT-PCR, sequenced and analyzed. On ORF3a, ORF3b and ORF3c substitutional mutations leading to amino acid changes were identified. On ORF7a gene, mutations were found at the 47th amino acid. A 3 nt deletion in ORF7b gene was identified in one strain. At the S1/S2 cleavage site of the S gene, there were continuous R-R-S/A-R-R-S sequence modules, which were consistent with the protein sequence characteristics of the FIPV cleavage site. The methionine was replaced by leucine at 1 045th amino acid in all samples. The phylogenetic tree showed that the sequences of FIPV ORF3c, ORF7b and S2 genes were closely related to serotype Ⅰ strains, indicating that the three strains belonged to serotype Ⅰ. The mutations in S genes may be involved in the change of tissue tropism in FCoV.