First identification of a single amino acid change in the spike protein region of feline coronavirus detected from a coronavirus-associated cutaneous nodule in a cat

Osumi, Takafumi; Mitsui, Ikki; Leutenegger, Christian M; Okabe, Ryo; Ide, Kaori; Nishifuji, Koji

Feline infectious peritonitis (FIP) is a fatal systemic viral disease caused by infection with mutated feline coronavirus (FCoV). 1 There is a spectrum of biotypes in FCoVs of varying pathogenicity; for example, the highly virulent FIP virus (FIPV) replicates in macrophages. FIPVs can have nucleotide substitutions in multiple genomic regions of FCoV, including two common substitutions in the genes encoding the putative fusion peptide of the spike protein. 2 FIP, which is most prevalent among younger cats, 3 can be classified into three forms based on clinical findings: (1) the effusive form, characterised by First identification of a single amino acid change in the spike protein region of feline coronavirus detected from a coronavirus-associated cutaneous nodule in a cat an accumulation of protein-enriched ascites and/or pleural effusion; (2) the non-effusive form, characterised by granulomatous inflammatory lesions in several organs; and (3) a mixed form.