Murine Gammaherpesvirus 68 (MHV-68), a Newly Discovered Tick Borne Virus

MHV-68, closely related to human gammaherpesviruses (Epstein-Barr virus and Kaposi ’ s sarcoma herpesvirus), is a natural pathogen of murid rodents commonly infested with ticks. After the first finding of MHV-68 in immature Ixodes ricinus ticks removed from wild green lizards, its occurrence was proved in free-living Dermacentor reticulatus , I. ricinus , and Haemaphysalis concinna ticks. Next, finding of live MHV-68 in salivary glands, intestine, and ovaries of D. reticulatus ticks strongly supported the idea that MHV-68 could be transmitted from infected to uninfected host via blood-feeding ticks. Recently, experimental transmission of MHV-68 between I. ricinus ticks and mouse and vice versa proved that MHV-68 could be vertically and horizontally transmitted from F0 to F1 tick generation, and thus, MHV-68 is a tick-borne virus (arbovirus). Therefore, ticks commonly attack humans transmitting important pathogens (e.g., tick-borne encephalitis virus and the Lyme disease spirochete); there is the speculation that MHV-68 can also infect humans via ticks. Earlier studies documented antibodies to MHV-68 in the sera of laboratory workers, hunters, and general population as well. In future, we need to carefully test whether people bitten by ticks are at real risk of infection with MHV-68 that normally infects murid rodents, and what effect it may have.