Zhangjiakou Hepatitis C Virus

What happens if you investigate 986 ticks, representing six species, collected from the diverse ecological landscapes of Hebei Province in northern China? Well, you find a host of known and unknown viruses[1].

A novel viral agent, provisionally named Zhangjiakou Hepacivirus, was discovered in a Haemaphysalis japonica. This virus shared less than 80% nucleotide identity with the rodent-associated Hepacivirus P, consistent with a rodent origin and possible cross-species transmission[2].

Hepacivirus P, in turn, indicated that it shares common ancestry with other rodent hepaciviruses (species Hepacivirus E, and species Hepacivirus F), Norway rat hepacivirus 1 (species Hepacivirus G), and Norway rat hepacivirus 2 (species Hepacivirus H).

But the problem is that, Zhangjiakou Hepacivirus constitutes the first report of a hepacivirus sequence within a tick specimens, raising intriguing questions about transmission ecology. Historically, hepaciviruses are presumed to be vertebrate-specific, with no known arthropod vectors.

The association of Zhangjiakou Hepacivirus with Haemaphysalis japonica suggests that ticks could theoretically serve as mechanical vectors or paratenic hosts, passively transferring the virus between rodent reservoirs and other susceptible hosts.

However, biological plausibility necessitates caution. Hepaciviruses, including Hepatitis C Virus, are strictly hepatotropic ('liver-loving') and typically rely on the liver-specific microRNA-122 (miR-122) for viral RNA stability and replication.

Since ticks lack a liver, and presumably the specific miR-122 machinery, active replication within the vector seems unlikely unless this novel lineage has evolved alternative replication mechanisms[3].

Given that the ticks were collected directly from rodents, the most plausible explanation is 'passive acquisition' via a viremic blood meal.

[1] Geng et al: Metatranscriptomic Analysis of Tick Virome Diversity in Hebei Province, China in Virusses - 2026
[2] Li et al: Detection and characterization of a novel hepacivirus in long-tailed ground squirrels (Spermophilus undulatus) in China in Archives of Virolology – 2019
[3] Bandiera et al: miR-122--a key factor and therapeutic target in liver disease in Journal of Hepatology - 2015