Isolation and Molecular Characterization of Feline Herpesvirus 1 from Naturally Infected Korean Cats

Abstract

Feline herpesvirus type 1 (FHV-1) causes respiratory and ocular disease in cats. Although isolates of FHV-1 circulating in cats have been reported worldwide, Korean FHV-1 isolates and their features have not been reported thus far. We aimed to investigate the biological and molecular characterization of two FHV-1 isolates based on the nucleotide sequence of thymidine kinase (TK) and glycoprotein B (gB) gene. In total, 48 samples from 12 cats were prepared for virus isolation. For the diagnosis, virus isolation, indirect fluorescence assay (IFA), electron microscopy (EM), and polymerase chain reaction (PCR) and for the molecular characterization, cloning and sequencing were used. Based on many methods such as virus isolation with specific cytopathic effects, IFA, EM, and PCR, two isolates were confirmed as FHV-1 and they showed the highest viral titer (10 8.3 to 10 8.5 TCID 50 /mL) in the Crandell-Rees Feline Kidney cells at 48 h after inoculation, but did not grow in MDCK and Vero cells. The nucleotide and amino acid sequences of the full TK and gB gene of FHV191071 and FHV191072 isolates were determined and compared with those of other herpesvirus strains. Two isolates possessed the same nucleotide sequences belonging to FHV-1 group and had the highest similarity (99.9%) with the KANS-02 strain, which was isolated from shelter in USA in 2016. Two isolates were confirmed as FHV-1 and they will be a useful basic resource for evaluating current FHV-1 vaccine and developing diagnostic tools.

Immunogenicity of a new inactivated vaccine against feline panleukopenia virus, calicivirus, and herpesvirus-1 for cats

“…CRFK (CCL-94; ATCC, USA) cells were routinely maintained in Dulbecco's modified Eagle's medium (DMEM) with 10% (v/v) heat-inactivated fetal bovine serum and antibiotic-antimycotic solution (Gibco, USA). The FPV19D01, FC-V17D03, FCV17D283, and FHV191071 strains isolated from naturally infected Korean cats in 2017 and 2019 [15][16][17] were passaged in CRFK cells and used to assess immune responses. FP-V19D01-70P (FP70, KTCT number: 18984P), FCV17D03-50P (FC50, 18985P), FCV17D283-80P (FC80, 18986P), and FHV191071-100P (FH100, 18987P) served as seed viruses for developing a new inactivated feline vaccine.…”

“…FPV19D01-1P(FP1), FP70, FCV17D03-1P (FC1), FC50, FCV17D283-1P (FC2), FC80, FHV191071-1P (FH1), and FH100 titers were evaluated. Briefly, CRFK cells grown in 25 cm 2 flasks were inoculated with virus at 1,000 50% tissue culture infectious dose (TCID 50 /mL) and harvested as described previously [15][16][17]. After three continuous freeze-thaw cycles, viral titers were determined based on fluorescence and typical cytopathic effects (CPEs).…”

Incidence and sero-surveillance of feline viruses in Korean cats residing in Gyeonggi-do

“…The cells were used to propagate FPV, the 2 FCVs, FHV-1, and FIPV, and for the virus neutralization assay (VNA). The FPV1901, FCV17D03, FCV17D283, and FHV191071 strains were isolated from naturally infected Korean cats in 2017 and 2019, respectively [17][18][19]. The FIPV strain was obtained from a commercial live FIPV vaccine.…”

“…Among these serological methods, the HI test to detect FPV antibodies has been used as a standard method, and the VN test has been used to measure antibodies against FCV, FHV-1, and FIPV. Although FPV, FCV, FHV-1, and FIPV infections have been reported in South Korean cats [17][18][19][20], a recent incidence and serologic investigations of major feline pathogens are lacking. In this study, we analyzed the incidence of feline viral diseases since 2015.…”

First Report of Isolation and Molecular Characterization of Felid Herpesvirus-1 from Symptomatic Domestic Cats in Egypt

“…FHV-1 has been shown to contain 23 virion associated proteins [18]. Four viral proteins have been considered as virulence factors: thymidine kinase (TK), serine/threonine protein kinase (US3), gE, and gC [19].…”