Tick-borne infections remain an important cause of undifferentiated febrile illness, particularly in regions where several pathogens with overlapping clinical presentations co-circulate. In 2017, surveillance in northeastern China identified a patient with fever, headache and a history of tick bites whose illness resembled tick-borne encephalitis, but testing for tick-borne encephalitis virus and other established tick-borne pathogens was negative.
Using virus isolation, electron microscopy and genome sequencing, the investigators identified a previously unknown segmented RNA virus, named Alongshan virus (ALSV). ALSV belongs to the jingmenvirus group within the family Flaviviridae and is genetically related to Jingmen tick virus, while remaining clearly distinct from other known members of the group.
Enhanced surveillance subsequently identified ALSV infection in 86 patients from Inner Mongolia and Heilongjiang. Most were farmers or forestry workers with a recent tick bite, and the predominant symptoms were headache, fever and fatigue; rash, myalgia or arthralgia, nausea and lymphadenopathy were also reported. All 19 patients with paired acute- and convalescent-phase serum samples showed seroconversion, supporting a causal association between ALSV infection and the febrile illness.
ALSV RNA was also detected in Ixodes persulcatus ticks collected in areas where patients had been bitten, and viral sequences from ticks were closely related to those identified in patients. No evidence of person-to-person transmission was observed. Although all patients in this cohort recovered, the findings illustrate how genomic approaches can reveal previously unrecognised causes of acute febrile disease and strengthen surveillance for emerging tick-borne viruses.
Original article:
Wang Z-D, Wang B, Wei F, et al. A New Segmented Virus Associated with Human Febrile Illness in China. New England Journal of Medicine. 2019;380:2116–2125. doi:10.1056/NEJMoa1805068.