ALTNV: Novel Tick-Borne Orthonairovirus Identified in China

ALTNV infected 10.4% of 3,163 febrile patients tested in tick-endemic regions of China, according to a New England Journal of Medicine report published September 28, 2026, that formally names the previously unknown pathogen Asian longhorned tick nairovirus.

The discovery grew out of an effort to explain why roughly 30% of patients with suspected severe fever with thrombocytopenia syndrome (SFTS) test negative for Dabie bandavirus (DBV), the tick-borne hemorrhagic fever virus endemic in Asia with a 10% to 30% case-fatality rate. The World Health Organization lists DBV as a priority pathogen.

How did researchers identify ALTNV?

A team led by the State Key Laboratory of Pathogen and Biosecurity in Beijing collected samples from tick-bitten patients treated at sentinel hospitals in regions where tick-borne viruses circulate. RNA sequencing and viral isolation recovered a virus the investigators placed in the orthonairovirus genus, family Nairoviridae. Its proteins shared less than 80% amino-acid identity with other species in the genus, meeting the threshold for a new species.

The team propagated the virus in cultured human cells, confirmed identity with immunofluorescence, and visualized typical orthonairovirus morphology by electron microscopy. The full citation appears as Zhang et al., NEJM 2026; 395(9): 929, DOI 10.1056/NEJMc2602496.

What did patient testing show?

Among 3,163 patients enrolled:

• 10.4% tested positive for ALTNV by viral RNA or IgM antibodies
• 15.1% of patients who tested negative for DBV were ALTNV-positive
• Monoinfected patients presented with fatigue (84%), GI signs (80%), thrombocytopenia (38%), and elevated aminotransferases (36%); all recovered

Why does coinfection matter?

Thirty-eight patients carried both ALTNV and DBV. Compared with DBV-monoinfected controls, they more often developed:

• Respiratory signs: 61% vs 38%
• Kidney impairment: 84% vs 66%
• Death: 7 of 38 (18.4%)

The authors concluded: "The cocirculation of ALTNV and DBV in the same areas, coupled with their shared tick vector, underscores the need for improved differential diagnosis between infections with these viruses in regions where SFTS is endemic."

Where did ticks carry the virus?

The team screened 47,428 ticks from 15 provinces. ALTNV RNA appeared in 1.3%, with the highest prevalence in Haemaphysalis longicornis — the Asian longhorned tick — at 1.8%. Laboratory transmission experiments confirmed H. longicornis could pass ALTNV to mice.

What changes at the exam table and in the barn?

For companion-animal and equine practitioners, and for clinicians working with livestock that move through tick-endemic regions, the takeaway is concrete: ALTNV broadens the differential for tick-bitten patients with otherwise-unexplained fever, fatigue, GI signs, thrombocytopenia, or transaminase elevation. Because H. longicornis feeds on cattle, sheep, goats, dogs, and cats, surveillance in food and companion animals may help flag geographic spread beyond the 15 provinces sampled.

The public-health implication is direct. Roughly 10% of febrile tick-bitten patients in endemic Chinese regions now have a second, distinct viral explanation for their illness, layered on top of a pathogen that already kills 10% to 30% of those it infects. As more laboratories add ALTNV RNA testing to their SFTS workups, the authors' call for improved differential diagnostics will move from a regional research priority to a routine clinical question for any practice serving animals and people exposed to H. longicornis habitat.