A Novel Subtype of Bovine Hepacivirus Identified in Ticks Reveals the Genetic Diversity and Evolution of Bovine Hepacivirus

Abstract

Hepaciviruses represent a group of viruses that pose a significant threat to the health of humans and animals. New members of the genus Hepacivirus in the family Flaviviridae have recently been identified in a wide variety of host species worldwide. Similar to the Hepatitis C virus (HCV), bovine hepacivirus (BovHepV) is hepatotropic and causes acute or persistent infections in cattle. BovHepVs are distributed worldwide and classified into two genotypes with seven subtypes in genotype 1. In this study, three BovHepV strains were identified in the samples of ticks sucking blood on cattle in the Guangdong province of China, through unbiased high-throughput sequencing. Genetic analysis revealed the polyprotein-coding gene of these viral sequences herein shared 67.7–84.8% nt identity and 76.1–95.6% aa identity with other BovHepVs identified worldwide. As per the demarcation criteria adopted for the genotyping and subtyping of HCV, these three BovHepV strains belonged to a novel subtype within the genotype 1. Additionally, purifying selection was the dominant evolutionary pressure acting on the genomes of BovHepV, and genetic recombination was not common among BovHepVs. These results expand the knowledge about the genetic diversity and evolution of BovHepV distributed globally, and also indicate genetically divergent BovHepV strains were co-circulating in cattle populations in China.

First identification of bovine hepacivirus in wild boars

“…Hepatitis C virus has been long considered to be the unique species of Hepacivirus genus, restricted to the human host. However, since the early 2010s, new HCV-like have been described in several animal species and non-vertebrate hosts 5 , 15 , 16 , 19 , 23 – 25 . BovHepV was first described in 2015 by two independent research groups in Ghana and Germany 11 , 12 .…”

“…Thus, indirect contact with food, feces and wild animal carcasses, could easily lead intra / inter-species pathogen transmission 21 , 22 . In addition, the recently described possible involvement of blood-sucking ticks as mechanical carriers of BovHepV 19 , could also represent a further route of infection in both cattle and wild boars.…”

“…It has been detected in bovine serum samples in several countries with a prevalence of infection ranging from 0.15% to 14.8% and in commercial bovine sera used for cell cultures in Asia, America, Oceania and Europe, thus suggesting a worldwide circulation 14 , 17 . BovHepV is characterized by high genetic heterogeneity, resulting in several clusters/subtypes named from A to G 14 , 17 , moreover, other recent strains detected in blood-sucking ticks of cattle, have been identified as a novel subtype H 19 . Nevertheless, the knowledge about the host range, the zoonotic potential and host tropism of this virus are still unclear 20 .…”

A Highly Divergent Hepacivirus Identified in Domestic Ducks Further Reveals the Genetic Diversity of Hepaciviruses

“…Viruses 2022, 14, 371 2 of 12 described, including catshark [13], birds [14,15], fish, and other vertebrates [16][17][18]. Moreover, some highly divergent hepaciviruses were recently detected in mosquitoes and ticks, although their true host is uncertain [19][20][21]. Furthermore, a novel hepacivirus tentatively named RHV-GS2015 was recently identified in long-tailed ground squirrels in China [22].…”

Expanded Diversity and Host Range of Bovine Hepacivirus—Genomic and Serological Evidence in Domestic and Wild Ruminant Species

“…A novel genotype is defined if the viral sequence shows <77% identity on the amino acid (aa) level to all other known strains, and a novel subtype must exhibit <85% nucleotide (nt) identity to sequences of the same genotype. So far, two BovHepV genotypes have been described [ 34 , 35 ] and eight subtypes (A-H) have been assigned to the genotype 1 [ 35 , 36 ]. Accordingly, subtypes A and F include two clusters of BovHepV infecting cattle from Germany [ 37 ].…”