New tick-borne virus behind unexplained fevers found in China

Overview

Updated Sep 30

Nearly one in ten patients with tick-bite fevers in a new Chinese study carried a virus that had never been seen before. Researchers named it Asian longhorned tick nairovirus (ALTNV), after the tick species that spreads it, and reported the finding in the New England Journal of Medicine.

Most ALTNV infections cleared on their own, leaving patients with fatigue, stomach problems, and low platelet counts. But patients who carried both ALTNV and the severe fever with thrombocytopenia syndrome (SFTS) virus died at a rate of 18.4%, which makes telling the two diseases apart a matter of life and death in the regions where both circulate.

Why it matters

The tick that carries ALTNV already infests the US and parts of Asia, so a virus found only in China could surface in new regions.

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Key Indicators

10.4%

Tick-bite patients with ALTNV

Share of 3,163 screened patients who tested positive for the new virus.

18.4%

Fatality rate in ALTNV + SFTS-virus coinfection

Seven of 38 patients carrying both viruses died; ALTNV-only patients recovered fully.

1.3%

Ticks carrying ALTNV RNA

Found in 1.3% of 47,428 ticks tested across 15 Chinese provinces.

Provinces with ALTNV in ticks

The Asian longhorned tick showed the highest prevalence at 1.8%.

Voices

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People Involved

State Key Laboratory of Pathogen and Biosecurity virology team

Lead researchers who identified ALTNV

Study published in the New England Journal of Medicine

Organizations Involved

State Key Laboratory of Pathogen and Biosecurity

Government research laboratory

Lead researchers on the ALTNV discovery

Beijing-based laboratory that led the study identifying ALTNV.

New England Journal of Medicine

Peer-reviewed medical journal

Published the ALTNV study

One of the world's most cited medical journals.

World Health Organization

International agency

Lists the SFTS virus as a priority pathogen

UN agency that identifies priority pathogens for research.

Timeline

3 events Latest: September 29th, 2026 · 1 week ago

September 2026
Virus reaches international attention
Latest Report

Newsweek and other outlets report ALTNV, noting the Asian longhorned tick already infests parts of the US.
September 29th, 2026
Coinfection risks detailed in health reports
Report

CIDRAP and ScienceDaily publish study details showing 7 of 38 patients with both ALTNV and the SFTS virus died.
September 28th, 2026
New virus identified in NEJM study
Discovery

Researchers report Asian longhorned tick nairovirus (ALTNV), found in 10.4% of 3,163 tick-bite patients screened.
September 2nd, 2026

Scenarios

ALTNV detected in ticks outside China

Uncertain Resolves by Q2 2028

Discussed by: Newsweek, which noted the Asian longhorned tick already infests parts of the US

The Asian longhorned tick reached the US in 2017 and has spread across the eastern states, and it also appears in parts of Asia. If ALTNV exists in those tick populations, a tick survey or a cluster of unexplained febrile illness could reveal it. That would move the virus from a China-specific finding to a global surveillance concern. Detection would most likely come from a tick-collection program or a reference lab.

WHO or China CDC adds ALTNV to tick-fever testing guidance

Likely Resolves by End of 2027

Discussed by: The study authors, who called for improved differential diagnosis

Because ALTNV and the SFTS virus circulate in the same areas and share a tick vector, clinical guidance may be updated to require ALTNV testing in suspected SFTS cases. The study found 15.1% of SFTS-virus-negative patients actually carried ALTNV. A formal recommendation would change diagnostic practice across endemic regions and pressure test makers to supply ALTNV assays.

Larger study revises coinfection fatality estimate

Possible Resolves by End of 2029

Discussed by: Infectious disease researchers, given the small 38-patient coinfection sample

The 18.4% fatality rate among coinfected patients comes from just 38 people, a small sample for a severity estimate. A prospective study across the 15 provinces where ALTNV circulates could confirm the risk or show it is lower. If the severity holds up, coinfection would rank among the more dangerous tick-borne presentations in Asia.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2011

Severe fever with thrombocytopenia syndrome virus (2011)

In 2011, Chinese researchers identified a new virus in rural patients with fever, fatigue, and bleeding who had been bitten by ticks. The virus, later named Dabie bandavirus, was isolated from Haemaphysalis longicornis ticks and became known as the cause of severe fever with thrombocytopenia syndrome (SFTS).

Then

SFTS is now recognized across Asia with a 10-30% case-fatality rate.

Now

The WHO lists Dabie bandavirus as a priority pathogen, and SFTS testing and treatment protocols are standard across the region.

Why this matters now

ALTNV was discovered because a third of patients with SFTS symptoms tested negative for the SFTS virus — the same approach of probing unexplained illness that found the original virus.

2009-2012

Heartland virus discovery (2009-2012)

Two Missouri farmers were hospitalized in 2009 with fever, fatigue, and low platelets, and no known cause. The CDC identified the cause as a new phlebovirus, named Heartland virus, and later confirmed the Lone Star tick as its vector.

Then

Heartland virus is now recognized across the eastern and central US, with dozens of cases reported.

Now

It expanded the known range of tick-borne disease and prompted wider tick surveillance.

Why this matters now

The same pattern — an unexplained tick-borne fever yielding a new virus — produced ALTNV, and Heartland's later spread shows how a newly identified virus can turn out to be far more widespread than first thought.

August 2017

Asian longhorned tick reaches the US (2017)

In 2017, the Asian longhorned tick was found on a sheep in Hunterdon County, New Jersey — the first confirmed US detection of a species native to East Asia. It has since been found in many eastern US states.

Then

US authorities added the tick to watch lists and began tracking its range.

Now

The tick is established across the eastern US, and it is the primary vector for ALTNV in China.

Why this matters now

Because this same tick carries ALTNV in China, the virus's natural vector already lives in the US — the key reason the discovery matters beyond Asia.