Scientists in China have identified a previously unknown tick-borne virus, the Asian longhorned tick nairovirus (ALTNV), which can cause flu-like illness, fatigue, and gastrointestinal symptoms. The virus, part of the orthonairovirus group, has also been linked to thrombocytopenia, a condition characterized by reduced blood platelet counts, and laboratory evidence of liver-cell injury.
Researchers began tracking patients with unusual illnesses, including severe fever with thrombocytopenia syndrome (SFTS), in China in 2009. While many cases were associated with Dabie bandavirus (DBV), which can cause hemorrhagic fever, it was not the most common cause. After extensive testing of blood samples and viral fragments, scientists identified ALTNV, a virus genetically distinct from DBV.
The new virus was identified in 10.4% of 3,163 patients who had been bitten by ticks, according to a study published in the New England Journal of Medicine. The study also found that patients infected with both ALTNV and DBV were more likely to experience respiratory issues and kidney complications, with seven of these patients dying during the study period.
Symptoms of ALTNV infection can initially resemble the flu, including fever, muscle aches, fatigue, and sometimes respiratory issues. However, the study did not directly link ALTNV infection alone to severe bleeding or death; the fatal outcomes involved patients co-infected with DBV. The co-circulation of these viruses, transmitted by the same tick vector, highlights the need for improved differential diagnosis in regions where SFTS is endemic.
Experts emphasize that while effective antivirals exist for influenza, many tick-borne viruses, including ALTNV, currently lack specific treatments. For most patients, care focuses on managing symptoms through supportive measures. It is crucial to correctly identify the specific virus, as symptoms can overlap with numerous other infections, and antibiotics are ineffective against viral illnesses.
To prevent tick bites, public health recommendations include wearing appropriate clothing, such as long pants tucked into socks, and using tick repellents. Regularly checking for ticks on the skin after outdoor activities like hiking is also important, as the longer a tick remains attached, the higher the risk of disease transmission. While the Asian longhorned tick is not currently found in the U.S., various other tick species carrying different diseases are present, and the severity of a tick-borne illness can depend on individual health factors, age, and underlying medical conditions.