Tofla virus: A newly identified Nairovirus of the Crimean-Congo hemorrhagic fever group isolated from ticks in Japan.
ABSTRACT
Ixodid ticks transmit several important viral pathogens. We isolated a
new virus (Tofla virus: TFLV) from Heamaphysalis flava and Heamaphysalis
formsensis in Japan. The full-genome sequences revealed that TFLV belonged
to the genus Nairovirus, family Bunyaviridae. Phylogenetic analyses and
neutralization tests suggested that TFLV is closely related to the Hazara
virus and that it is classified into the Crimean-Congo hemorrhagic fever
group. TFLV caused lethal infection in IFNAR KO mice. The TFLV-infected
mice exhibited a gastrointestinal disorder, and positron emission tomography-computed
tomography images showed a significant uptake of (18)F-fluorodeoxyglucose
in the intestinal tract. TFLV was able to infect and propagate in cultured
cells of African green monkey-derived Vero E6 cells and human-derived SK-N-SH,
T98-G and HEK-293 cells. Although TFLV infections in humans and animals
are currently unknown, our findings may provide clues to understand the
potential infectivity and to develop of pre-emptive countermeasures against
this new tick-borne Nairovirus.