Pathogenicity of tick-derived lymphocytic choriomeningitis virus in BALB/c mice.

Background: Lymphocytic choriomeningitis virus (LCMV) is a zoonotic pathogen primarily transmitted by rodents. Recently, LCMV has been detected in ticks from northeastern China; however, the pathogenicity of this virus in murine models remains to be elucidated.

Results: Here, we examined the tick-derived LCMV strain JX14 by inoculating BALB/c mice with 3.5 × 10⁵ pfu of virus. The mice infected with LCMV displayed clinical manifestations including unkempt fur, anorexia, depression, and oliguria, which subsequently resolved by 10 days post infection (dpi) leading to survival of the infection. During the early phase of infection, low viral titers were detected in throat and anal swabs. The excreted virions demonstrated proliferation in Vero cells and were capable of inducing infection in mock-infected mice. Viral RNA was detected in the blood and organs, with detectable levels persisting for up to six months specifically in the heart. A total of 16 amino acid substitutions were identified in the L, Z, and GPC proteins between the original JX14 strain and the strain obtained after six months of infection in BALB/c mice. Pathological lesions were identified in most organs within 5 dpi except for the kidneys and testicles. Interferon gamma (IFN-γ) level was significantly elevated during the early stage of infection and returned to baseline levels within 10 days.

Conclusions: This study furnishes significant insights into the pathogenic traits of the tick-derived LCMV strain JX14, thereby potentially providing a valuable in vivo research model for examining the immunological responses elicited by chronic viral infections.