Isolation and Genomic Characteristics of a Novel Pathogenicity Type I Feline Coronavirus in Mainland China

Abstract

Feline coronavirus (FCoV) is an enveloped, positive‐sense RNA virus, which is widespread among feline populations, and can cause a fatal serious disease called feline infectious peritonitis (FIP). According to the differences of antigen and genetic composition, FCoV consists of two genotypes, FCoV I and FCoV II. In this study, we have isolated and identified a FCoV I strain named HL2019. Based on the complete genome of HL2019, phylogenetic analysis showed that HL2019 strain formed in the cluster FCoV I which is more closed to human coronavirus 229E (HCoV 229E) and HCoV NL63, while the FCoV I stains is distantly related to FCoV II strains. Analyzing with RDP4 and Simplot software showed that the virus HL2019 is recombinant by the FCoV I China/ZJU1709 and FCoV I Netherlands/UU16 strains. Furthermore, the pathogenicity of HL2019 was evaluated in 9–12‐month‐old cats. Two of three challenged cats developed serious clinical signs and died at 28‐day postchallenge (dpc). Real‐time polymerase chain reaction (PCR) analysis showed that HL2019 has broad tissue tropism, especially in the duodenum with viral load up to 104 copies/mg. In summary, our data show that we have successfully isolated a strain of FCoV I named HL2019 that is highly pathogenic to cats.