Risk factors and feline coronavirus gene mutations associated with clinical characteristics of feline coronavirus infection

Abstract

In domestic cats, feline coronavirus (FCoV) infection is widespread, and its outcomes range from no signs to severe or potentially fatal disease. This study investigated the prevalence of infection and associated factors in a population of 277 owned cats in Thailand. The overall proportion of FCoV infections was 45.8%, with positive detections observed for all sample types. The positivity rates were 60.6% for rectal swabs, 51.3% for body fluids, and 11.1% for EDTA blood samples. Although the positive rate was slightly higher in males and more common in younger cats, neither difference was statistically significant. Mathematical modeling revealed a significant association between FCoV infection and the sampling period, with the highest positivity observed in April and June. Through S gene sequencing, positive samples from rectal swabs and body fluids [feline infectious peritonitis (FIP)-cats] were identified as FCoV genotype I. All rectal swab samples had a methionine codon at position 1058 of the S gene, and 62.5% of body fluid samples exhibited a notable substitution (M1058L). Additionally, analysis of the S1/S2 cleavage motif revealed that most FCoV-positive samples contained a polybasic R-R-S/A-R-R-S recognition motif. Notably, 37.5% of rectal swabs exhibited a mutation at the P1 residue (arginine to serine) and 14.3% of FIP-suspected cats exhibited a mutation at the P4 residue (arginine to glycine). These findings contribute to our understanding of the epidemiology of FCoV and its behavior in infected cats. Such insights are crucial for developing effective diagnostics, understanding the FCoV transmission dynamics, and informing potential control strategies.