Of 38 patients in China who were infected with both a newly identified tick virus and a known one, seven died, a fatality rate of 18.4% in that group. The new pathogen is called Asian longhorned tick nairovirus, or ALTNV, and it surfaced because roughly 30% of patients with suspected tick-borne illness kept testing negative for the virus clinicians expected to find.
The finding comes from a team at the State Key Laboratory of Pathogen and Biosecurity in Beijing, with Xiao-Ai Zhang as first author and Li-Qun Fang and Wei Liu among the final authors. It was published as a letter in the New England Journal of Medicine headed “A Zoonotic Orthonairovirus from Febrile Patients in China,” and it reports a virus that sits in the same family as Crimean-Congo hemorrhagic fever virus.
A negative test that pointed to a new virus
The known culprit was Dabie bandavirus, the cause of severe fever with thrombocytopenia syndrome, or SFTS, a tick-borne disease first reported in Shandong Province in 2012. According to CIDRAP’s report, the Beijing group investigated why so many patients bitten by ticks tested negative for that virus, applying RNA sequencing and viral isolation to their samples. The result was a previously undescribed orthonairovirus, which the authors named for the tick species that carries it.
ALTNV is not the first such discovery in the region. An earlier NEJM letter described a different novel tickborne orthonairovirus infecting people in China, so ALTNV joins a short list of orthonairoviruses recognised in Chinese ticks and patients in recent publications.
Seven deaths among 38 coinfected patients
The NEJM letter screened 3,163 patients from sentinel hospitals in tick-endemic regions across 15 provinces. Of those, 10.4% tested positive for ALTNV by viral RNA or immunoglobulin M antibodies, and the share rose to 15.1% among patients negative for Dabie bandavirus. Considered by itself, ALTNV looked like a flu-like illness, with fever alongside fatigue and gut symptoms, and the authors tabulated its laboratory signature: fatigue in 84% of patients, gastrointestinal symptoms in 80%, low platelet counts in 38% and elevated liver enzymes in 36%, and most patients recovered completely.
Detection used two routes, which is why the 10.4% figure is not a simple count of infections caught in the act. A positive result could rest on viral RNA, a sign of current infection, or on immunoglobulin M antibodies, which can persist after the virus has cleared. A coinfected group of 38 can therefore contain people identified by different markers at different points in their illness, one more reason the fatality figure is better read as a description of that group than as a rate that can be applied to everyone bitten by an infected tick.
Patients carrying both viruses fared worse, and the difference is visible in the organ systems affected as well as in the deaths. In the ScienceDaily summary of the letter, 38 patients were coinfected with ALTNV and Dabie bandavirus. Respiratory symptoms occurred in 61% of them, against 38% in patients with Dabie bandavirus alone, and kidney impairment in 84%, against 66%. Seven of the 38 died, which is the 18.4% in question.
The wording matters. The sources describe those deaths as occurring in coinfected patients; none assigns them to ALTNV alone, and none of the available reports gives the fatality rate for Dabie bandavirus infection alone in the same cohort. SFTS is itself lethal, so the extra deaths, if any, that coinfection adds cannot be separated out from the figures published so far. Describing the new virus as having “killed” seven people compresses a finding that is really about a dangerous overlap of two infections.
Ticks, provinces and what diagnosis has to do next
The team also tested 47,428 ticks from 15 provinces and found ALTNV RNA in 1.3% of them. Prevalence was highest, at 1.8%, in Haemaphysalis longicornis, the Asian longhorned tick, which also carries Dabie bandavirus. New Atlas notes that this species is widespread in China, though its range may limit exposure for many people elsewhere.
The shared vector is the practical problem. As CIDRAP relays it, the authors conclude that ALTNV and Dabie bandavirus circulate in the same areas and share a tick vector, so clinicians in regions where SFTS is endemic need better differential diagnosis between infections with the two viruses. Their wording is a call for testing that tells the two apart, since an assay built to detect Dabie bandavirus will return a negative result for a patient who carries ALTNV, which is how the new virus was found in the first place.
As a correspondence-length report, the letter leaves questions open that a full paper would be expected to address, among them how many of the 38 coinfected patients had underlying conditions, how soon after a tick bite they were treated, and what the death rate among Dabie bandavirus patients without ALTNV was in the same hospitals. Until those numbers are published, 7 of 38 stands as a signal and not a measured effect of the new virus.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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