Full Viral Genome Sequencing and Phylogenomic Analysis of Feline Herpesvirus Type 1 (FHV-1) in Cheetahs (Acinonyx jubatus)

Abstract

Feline herpesvirus type 1 (FHV-1) is endemic in captive cheetahs and sporadically causes devastating disease. Modified live vaccines (MLV), intended for use in domestic cats, are used in some captive cheetah populations and have been anecdotally linked to disease in certain subpopulations. Ten FHV-1 isolates from ten captive cheetahs and one isolate from an MLV used to inoculate four of the host animals were analyzed. Viral DNA was extracted for full-genome sequencing by Illumina MiSeq with viral genomes then used for phylogenomic and recombinational analyses. The FHV-1 shed by vaccinated cheetahs were almost identical to the MLV, with few variants among viral genomes. Eight cheetah FHV-1 isolates and the MLV were grouped in a clade along with FHV-1 isolates from domestic cats in the USA. The remaining two cheetah FHV-1 isolates (unknown host vaccine status) were not associated with a clade. The likely ancestral origin of these two isolates involves recombination events between Australian domestic cat and cheetah FHV-1 isolates. Collectively, these data suggest that the MLV is capable of causing clinical disease and viral shedding in some cheetahs and represents evidence of interspecies transmission of virus between domestic and wild cats.

Surveillance for feline herpesvirus type 1 mutation and development of resistance in cats treated with antiviral medications

“…On the same day as sample collection, viral isolation was performed using Crandell Rees feline kidney cells (CRFK) (ATCC), as previously described ( 1 , 3 ). Cells were cultured in Dulbecco’s modified Eagle medium (DMEM; Life Technologies) with 10% fetal bovine serum (VWR) and 1% penicillin and streptomycin sulfate (Life Technologies) at 37°C/5% CO2.…”

“…Viral DNA extracted from the frozen supernatant was prepared using a commercial kit according to the manufacturer’s instructions (PureLink Viral RNA/DNA Mini Kit), as previously described ( 3 ). DNA purity and concentration were assessed using a Qubit dsDNA HS Assay Kit (Life Technologies).…”

“…Viral genome sequencing was performed as previously described ( 3 , 23 ). DNA samples were diluted to 1 ng DNA in 5 mL solution and libraries were constructed according to the Nextera XT DNA Library Preparation Kit protocol (FC-131-1096; Illumina Inc.).…”

“…Feline herpesvirus type 1 (FHV-1) is a double stranded DNA virus with a narrow host range, including domestic cats ( 1 , 2 ) and wild felids ( 3 ). Previous assessments of the FHV-1 genome have confirmed that FHV-1 demonstrates relatively low viral genomic diversity ( 1 , 3–5 ) and that host disease severity is unlikely to be related to viral genome variants ( 6 ). FHV-1 in domestic cats is frequently treated with antiviral medications targeting viral genes responsible for viral replication (UL23, UL30, and UL42).…”

“…The objective of the present study was to detail a practical method to screen FHV-1 genomes for mutation development and to assess the functional impact of these mutations, if present. We hypothesized that we would not detect clinically significant FHV-1 genome mutations and development of functional antiviral resistance in this small sample of FHV-1 isolates, based on sample size and previous assessments demonstrating that the FHV-1 genome is highly conserved ( 1 , 3 , 5 , 6 ).…”