New tick-borne virus identified in China can cause flu-like symptoms

Scientists in China have identified a previously unknown tick-borne virus that can cause flu-like illness, fatigue, and gastrointestinal symptoms, according to a new study. The virus, named the Asian longhorned tick nairovirus (ALTNV), is part of the orthonairovirus group and has also been found to cause thrombocytopenia (reduced blood platelet counts) and laboratory evidence of liver-cell injury or inflammation. Since 2009, Chinese researchers have been tracking patients with unusual illnesses, including severe fever with thrombocytopenia syndrome (SFTS), according to Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Children’s Hospital in New York. Dr. Nachman stated, "Thrombocytopenia is low platelet count, so those patients bled, and it had about a 30% mortality, which is quite high." Many of the cases were linked to Dabie bandavirus (DBV), a tick-borne hemorrhagic fever, but it was not the most common virus. After extensive testing of blood samples and viral fragments, researchers identified the new virus, ALTNV, which is genetically distinct from DBV. Researchers from the State Key Laboratory of Pathogen and Biosecurity in Beijing identified the virus in 10.4% of 3,163 patients who had been bitten by ticks. Patients who had both ALTNV and DBV were more likely to have respiratory issues and kidney complications. Seven (18.4%) of these patients died during the course of the study. 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." The findings were published in the New England Journal of Medicine. Dr. Nachman noted, "The big picture is that ticks carry lots of viruses. We’re getting smarter at identifying those viruses. And when one blood sample is negative, it’s important to say, ‘Maybe there was a new virus there, and let’s look for it.'" Illness from ALTNV can initially resemble the flu, causing fever, muscle aches, fatigue, and sometimes respiratory symptoms. Although an ALTNV infection can cause low platelet counts, the study did not link the virus alone to severe bleeding or deaths. The fatal cases involved patients who were also infected with DBV, which causes severe fever with thrombocytopenia syndrome. Dr. Nachman emphasized the importance of identifying the specific virus due to overlapping symptoms with many infections. "Effective antivirals exist for flu, but not for many tick-borne viruses, including the newly identified one," she said. For most patients, supportive care is given to help manage symptoms, and Dr. Nachman advised against using antibiotics, as they are ineffective against viruses. She also shared best practices for avoiding tick bites, such as wearing long pants and using tick repellents. Dr. Nachman stated, "The longer the tick is on your skin, the more it’s engorged, the more it’s likely to pass an infection to you." While the Asian longhorn tick is not yet seen in the U.S., she noted that there are many other ticks that carry diseases. Dr. Nachman concluded, "It’s not really about the ticks. It’s about the patient. Who are you? What’s your underlying illness if you have any? How old are you, and how healthy are you?"