Scientists in China have identified a previously unknown virus carried by ticks after testing thousands of patients with unusual illnesses. The Asian longhorned tick nairovirus, known as ALTNV, can cause flu like illness, fatigue and gastrointestinal symptoms, according to a new study.

ALTNV is part of the orthonairovirus group. Researchers have also found that it can cause thrombocytopenia, which is a reduced blood platelet count, along with laboratory evidence of liver cell injury or inflammation.

Chinese researchers have tracked patients with unusual illnesses since 2009, according to Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Children’s Hospital in New York. Those illnesses included severe fever with thrombocytopenia syndrome, also known as SFTS.

"Thrombocytopenia is low platelet count, so those patients bled, and it had about a 30% mortality, which is quite high," Nachman told Fox News Digital. "So, they kept following those patients."

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Many cases were connected to Dabie bandavirus, known as DBV, a virus carried by ticks that causes hemorrhagic fever. However, DBV was not the most common virus detected as researchers continued examining patients and their blood samples.

After conducting extensive testing of blood samples and viral fragments, researchers identified ALTNV as a new virus that is genetically distinct from DBV. Researchers from the State Key Laboratory of Pathogen and Biosecurity in Beijing detected ALTNV in 10.4% of 3,163 patients who had been bitten by ticks.

Some patients were infected with both ALTNV and DBV. These patients were more likely to experience respiratory issues and kidney complications, and seven of them, or 18.4%, died during the study.

"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 study authors concluded.

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The findings were published this week in the New England Journal of Medicine. Nachman said the discovery reflects the number of viruses ticks can carry and the increasing ability of researchers to identify them.

"The big picture is that ticks carry lots of viruses ," Nachman said. "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.'"

An ALTNV infection can initially resemble the flu. Reported symptoms include fever, muscle aches, fatigue and, in some cases, respiratory symptoms, making identification of the specific virus important when symptoms overlap with those of other infections.

Although ALTNV can cause low platelet counts, the study did not connect infection with ALTNV alone to severe bleeding or death. The fatal cases involved patients who were also infected with DBV, which causes severe fever with thrombocytopenia syndrome.

Nachman said supportive care is provided to most patients to help manage their symptoms. At the same time, she cautioned against using antibiotics for viral infections because antibiotics work against bacteria rather than viruses.

Avoiding tick bites remains a key precaution for families. Nachman recommended wearing long pants, tucking them into socks and applying tick repellents to an adult’s skin or to a young child’s clothing.

She also stressed the importance of checking the skin for ticks and removing them promptly. "The longer the tick is on your skin, the more it's engorged, the more it’s likely to pass an infection to you," Nachman said.

The Asian longhorn tick is not yet seen in the U.S., but Nachman noted that many other ticks are present and can carry other diseases. She said the potential effects depend not simply on the tick, but also on the disease it carries and the health of the person who is infected.

"I don't want to say one tick is worse than another tick. It's rather all about the diseases they carry and who you are," Nachman said.

Underlying illness, age and overall health can influence how sick a person becomes, according to Nachman. The newly identified virus adds another target for researchers examining unexplained illnesses among patients who have been bitten by ticks.