Of 3,163 patients with acute fever tested in China, 10.4 percent carried a virus that had no name until this week. Researchers at the State Key Laboratory of Pathogen and Biosecurity in Beijing call it Asian longhorned tick nairovirus, or ALTNV, and reported it in a September 28 correspondence in the New England Journal of Medicine.
Roughly 330 people in the cohort were infected. Most who had ALTNV alone recovered fully. The trouble came from patients infected with ALTNV and a second tick-borne pathogen at once, and seven of those patients died.
A screening cohort that turned up a second virus
The team, led by Xiao-Ai Zhang, describes ALTNV as a new orthonairovirus, the genus that also contains Crimean-Congo hemorrhagic fever virus. According to the report from the University of Minnesota’s CIDRAP, 10.4 percent of the 3,163 patients tested were positive, and among the subset who had tested negative for Dabie bandavirus, the tick-borne pathogen behind severe fever with thrombocytopenia syndrome, the rate was 15.1 percent. The citation is Zhang and colleagues, volume 395, issue 9, page 929.
The makeup of the cohort matters for reading the 10.4 percent figure. New Atlas reports that these were patients with symptoms consistent with Dabie bandavirus infection, and Stony Brook Medicine’s explainer describes people with tick bites and unexplained fever. A tick-exposed, hospital-tested group is not a random slice of China’s fever patients, so 10.4 percent is a rate inside a screened population, not a national infection rate. The full paper sits behind the journal’s DOI page, which was not readable for this article, so study dates and hospital sites are not reported here.
What ALTNV alone does to patients
The clinical picture from CIDRAP’s summary is flu-like and unglamorous: fatigue in 84 percent of ALTNV-only patients, gastrointestinal problems in 80 percent, low platelet counts in 38 percent and elevated liver enzymes in 36 percent. New Atlas quotes the description as symptoms akin to influenza A, with fever, fatigue and stomach upset. Stony Brook Medicine’s summary of the paper adds that all 56 patients with ALTNV alone recovered.
Neither ALTNV nor Dabie bandavirus has a specific treatment, New Atlas notes, and antibiotics do nothing against viruses. Care is supportive, which makes the finding of a second circulating virus in the same ticks a diagnostic problem as much as a curiosity: a clinician facing a feverish patient after a tick bite in China now has at least two candidate viruses to consider, and a negative Dabie bandavirus result no longer rules out a tick-borne virus, as the 15.1 percent positivity among DBV-negative patients shows.
Seven deaths among 38 patients with both viruses
Thirty-eight patients were infected with ALTNV and Dabie bandavirus together, and CIDRAP quotes the paper directly: “Seven (18.4%) coinfected patients died.” Compared with patients who had Dabie bandavirus alone, the coinfected group had more respiratory symptoms, 61 percent against 38 percent, and more kidney impairment, 84 percent against 66 percent.
It is tempting to set 18.4 percent beside the roughly 5.1 percent average case fatality rate for severe fever with thrombocytopenia syndrome in mainland China from 2010 to 2021, a figure given in a 2025 case report and review in IDCases. The comparison is loose. One number comes from 38 hospital patients in one study and the other from a decade of national surveillance, and seven deaths is a small count to build a rate on. What the data can support is narrower: the sickest patients in the cohort were the ones carrying two viruses, and whether the second virus made the illness worse or simply travels with a heavy tick exposure is not something a correspondence can settle.
A tick that already lives in the eastern United States
The vector question has a partial answer. ALTNV RNA turned up in 1.3 percent of 47,428 ticks collected across 15 provinces, with the highest rate, 1.8 percent, in Haemaphysalis longicornis, the Asian longhorned tick. Experiments showed that this species can pass the virus to mice, which CIDRAP says establishes it as a likely vector.
That tick is not confined to Asia. The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service says it was first identified in November 2017 in Hunterdon County, New Jersey, and has since been collected from New York south to Georgia and west to Missouri. Populations in the United States reproduce without mating, so a single female can start an infestation.
Stony Brook Medicine is careful about what follows from that. No ALTNV cases have been confirmed in the United States, and in its words “the presence of the tick does not mean that ALTNV is circulating here.” Whether American longhorned ticks carry the virus has not been tested in any study cited so far, which leaves the study’s own 1.3 percent tick-positivity figure as the only field measurement of how common ALTNV is in its vector.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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