Molecular characteristics of feline coronavirus in South Korea, 2016-2023

Feline coronavirus is highly contagious and ubiquitous in cat populations. FCoV is classified into two serotypes, types I and II, each including two biotypes, feline enteric coronavirus (FECV) and feline infectious peritonitis virus (FIPV)In this study, FCoV detected in samples collected by the Animal and Plant Quarantine Agency from 2016 to 2023, and analyzed genetic diversity of FCoV for currently circulation in Korea. In a total of 925 cats, FCoV was detected in 294 cats (31.8 %). Among the 73 cases with a final diagnosis, 47.9 % (35/73) were finally found to be FIPV, and 52.1 % (38/73) were confirmed to be FECV. Of the 294 FCoV-positive cases, 24 partial S genes were successfully sequenced. Partial S2 subunit sequencing indicated that types I and II accounted for 91.7 % (22/24) and 8.3 % (2/24) of the cases, respectively. One case, 23D103, contained a different six-nucleotide deletion in the S gene. Phylogenetic analysis of types I and II showed clear discrimination based on the S gene. Types I and II also exhibited 63.2-99.8 % nucleotide acid homology with the S gene of the reference strains. This study provides updated information regarding the current infection status and molecular characteristics of FCoV in Korea.