New Tick-Borne Virus Identified in China Raises Concerns, Vector Found in U.S.

A novel tick-borne virus, named Asian longhorned tick nairovirus (ALTNV), has been identified in China, infecting hundreds of patients with severe flu-like symptoms. The virus was detected in 329 patients across four provinces, including Hubei, the region where the Covid-19 outbreak began.

Patients infected with ALTNV experienced gastrointestinal issues and a low platelet count, which can lead to potentially fatal internal bleeding. The primary carrier identified is the Asian longhorned tick, an invasive species that has also been reported in 21 U.S. states, particularly in the Northeast and South. It remains unclear if the virus itself has reached the United States.

Discovery and Symptoms

Researchers in Beijing discovered ALTNV while investigating cases of severe fever with thrombocytopenia syndrome (SFTS), a serious infection caused by the dabie bandavirus (DBV). DBV is already known to circulate in East Asia and can have a fatality rate of approximately 15 percent. The study, published in the New England Journal of Medicine, analyzed samples from 3,163 individuals who reported a fever after a tick bite.

Of the 329 individuals who tested positive for ALTNV, symptoms included fever, fatigue, and gastrointestinal problems. Thirty-eight percent of these patients also showed thrombocytopenia. In some cases, coinfection with DBV appeared to worsen disease severity, leading to more severe symptoms such as respiratory problems and kidney impairment. Seven patients infected with both ALTNV and DBV died, representing 18.4 percent of that subgroup.

Tick Vector in the U.S.

The Asian longhorned tick, also known as the bush, cattle, or scrub tick, was first detected in the U.S. in New Jersey in 2017. It has since been found in numerous states from New York to Georgia and as far west as Missouri. The tick is known to be an invasive species and can reproduce rapidly. In laboratory settings, Asian longhorned ticks have demonstrated the ability to transmit ALTNV to mice, suggesting a potential pathway for human infection.

Research and Public Health

Scientists analyzed samples from approximately 47,000 ticks collected across 15 Chinese provinces. ALTNV was detected in 1.3 percent of the ticks overall, with 1.75 percent of Asian longhorned ticks testing positive for the virus. While no patients infected solely with ALTNV died, the co-infection with DBV showed a higher mortality rate. There are no specific treatments for either ALTNV or DBV, with current management for SFTS involving supportive care like IV fluids and blood transfusions.

The first documented case of ALTNV dates back to 2009. Researchers have noted that approximately 30 percent of patients presenting with symptoms similar to DBV do not test positive for the virus, prompting the investigation that led to the identification of ALTNV. The current status of ALTNV cases in China and the specific tick species responsible for each human infection are not yet clear.