A new tick virus infected 10.4% of 3,163 patients tested, and 7 of the coinfected died

Seven of 38 patients infected with both a newly described tick virus and a known hemorrhagic one died in China, an 18.4 percent fatality rate that the researchers could not attribute to either virus alone. The new pathogen, named Asian longhorned tick nairovirus (ALTNV), turned up in 10.4 percent of 3,163 patients screened at sentinel hospitals, according to a report in the New England Journal of Medicine.

Investigators at the State Key Laboratory of Pathogen and Biosecurity in Beijing, including Xiao-Ai Zhang and Bo Liu, went looking for ALTNV because of a diagnostic puzzle. Patients with tick-bite histories and symptoms resembling severe fever with thrombocytopenia syndrome, caused by Dabie bandavirus (DBV), kept testing negative for DBV, and the team set out to find what else the ticks were passing on.

Counting ALTNV in 3,163 sentinel-hospital patients

As CIDRAP reported, roughly 30 percent of patients with DBV-like illness had been testing negative for it, and sequencing and viral isolation on samples from sentinel hospitals in tick-endemic regions revealed an orthonairovirus nobody had catalogued. A patient counted as positive if tests found viral RNA or immunoglobulin M antibodies to ALTNV, the standard markers of current or recent infection. That definition matters for the 10.4 percent figure: it captures patients whose bodies showed evidence of the virus, including some who had already mounted an antibody response, and it was applied to everyone screened, DBV-positive and DBV-negative alike, which is why the overall rate sits well below the rate among DBV-negative patients. The sentinel-hospital design also means the sample reflects people ill enough to seek care after tick exposure, not the general population of the region.

Across all 3,163 patients, 10.4 percent met that definition. Among those who were negative for DBV, the share rose to 15.1 percent. Symptoms in people infected with ALTNV alone were common but mild by comparison: fatigue in 84 percent, gastrointestinal problems in 80 percent and thrombocytopenia, a drop in platelets, in 38 percent. Stony Brook Medicine’s explainer notes that all the patients with ALTNV alone recovered completely.

Stony Brook’s account places ALTNV in the orthonairovirus group, a family of tick-transmitted viruses, which is the same broad lineage that includes pathogens behind other hemorrhagic fevers. Taxonomy alone predicts little about severity: the ALTNV-only patients recovered, while the family’s better-known members are the ones that earn the hemorrhagic label. Naming a new member after the tick that carries it follows virology convention and signals the vector, not the geography.

Seven deaths among 38 coinfected patients

The worse news sat in the overlap. Of 38 patients carrying both ALTNV and DBV, 7 died, or 18.4 percent of that group. Coinfected patients had more respiratory symptoms than those with DBV alone (61 percent versus 38 percent) and more kidney impairment (84 percent versus 66 percent), the comparison given in the ScienceDaily summary of the paper.

The deaths cannot be assigned to ALTNV. DBV on its own is dangerous, with a fatality rate that outside accounts put at up to 30 percent in severe fever with thrombocytopenia syndrome, so the data show that the two viruses circulate together and that outcomes in the coinfected were grim, not that the newcomer caused any particular death.

The Beijing team’s conclusion was diagnostic: clinicians in endemic regions need better ways to tell the two infections apart.

An established tick with a new passenger

The shared vector is Haemaphysalis longicornis, the Asian longhorned tick. It is not confined to Asia. The Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report recorded the first detection outside quarantine in August 2017 on a sheep in New Jersey, and by September 2018 the tick had been confirmed in nine states and 45 counties. A single female can found a population without mating, one reason the species spreads fast.

That history is why the Chinese finding drew attention abroad. Medical Daily, citing Department of Agriculture records, reports that the tick is now established in 21 states and the District of Columbia, and that no human or tick case of ALTNV has been reported in the United States, though no American surveillance program currently tests for it, so an absence of cases partly reflects an absence of looking.

Dr. Sharon Nachman, a pediatric infectious disease specialist at Stony Brook, put the practical stance mildly. “Ticks can carry many different viruses, bacteria and parasites, and scientists continue to improve their ability to identify them,” she said, urging repellent, tick checks and prompt removal.

One comparison remains open in the summaries available: how many of 38 patients matched for age and illness stage would have died with DBV alone. The coinfected group’s 7 deaths and its higher respiratory and kidney complication rates are on record, but a matched DBV-only mortality figure is not, and that gap decides whether ALTNV adds lethal risk or merely rides along with an already deadly infection.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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