Chinese Researchers Identify New Tickborne Virus in Febrile Patients

Researchers investigating why many patients with suspected severe fever with thrombocytopenia syndrome (SFTS) test negative for Dabie bandavirus (DBV) have identified a new tickborne orthonairovirus, Asian longhorned tick nairovirus (ALTNV). The research team reported its findings Sept. 2 in the New England Journal of Medicine. The study findings are specific to China, where ALTNV and DBV cocirculate. ALTNV has not been reported in the United States.

The authors noted that more than 30% of patients with clinically diagnosed SFTS test negative for DBV, the virus that causes the disease, which suggests that other pathogens may be involved. Researchers screened 3,163 febrile patients with a history of tick exposure and detected ALTNV RNA or IgM in 10.4%. Among DBV-negative patients, 15.1% tested positive.

Among 56 patients with ALTNV monoinfection, symptoms were primarily influenza-like, with fatigue (84%), gastrointestinal symptoms (80%), thrombocytopenia (38%) and elevated aminotransferase levels (36%) among the most common findings. All recovered without sequelae. Coinfection with ALTNV and DBV was associated with more frequent respiratory symptoms (61% versus 38%) and renal impairment (84% versus 66%) than DBV infection alone; 7 of 38 coinfected patients (18.4%) died.

Researchers detected ALTNV RNA in 1.29% of 47,428 ticks across 15 provinces, with the highest prevalence among the Asian longhorned tick, Haemaphysalis longicornis (1.75%).

The authors concluded that cocirculation of the two viruses and their shared tick vector underscore the need for improved differential diagnosis between ALTNV and DBV infections in regions where SFTS is endemic.