New Virus Infecting People in China, and Ticks May Be the Culprit

A newly discovered virus has been found infecting people in China, and it may be transmitted by ticks, according to a new report.



Researchers have dubbed the virus "Alongshan virus" after the town in northeastern China where it was first discovered, according to the report, published yesterday (May 29) in the New England Journal of Medicine. In humans, the virus is linked to a number of symptoms, including fever, headache and fatigue, and in some cases, nausea, rash and even coma.

So far, the virus has been found only in northeastern China, but it could potentially have a much wider range, experts say.

The 'first' patient

The virus was first identified in a 42-year-old farmer from Alongshan who became mysteriously ill with a fever, headache and nausea; he visited a hospital in the region of Inner Mongolia in April 2017. The farmer also reported a history of tick bites. At first, doctors thought the patient was infected with tickborne encephalitis virus (TBEV), another virus that's spread by ticks and is endemic to the region.

But the patient tested negative for TBEV, leading the researchers to look for other causes. Further research revealed that the patient was infected with a virus that is genetically distinct from other known viruses, the report said.




Image showing the Alongshan virus particles (arrows).
Credit: The New England Journal of Medicine ©2019
After identifying the virus, the researchers began examining blood samples from other patients who visited their hospital with similar symptoms, and reported a history of tick bites. They found that, of the 374 patients who visited the hospital over the following five months and met this criteria, 86 patients were infected with the Alongshan virus. Nearly all of these patients were farmers or forestry workers, the report said.

When the researchers tested ticks and mosquitoes in the region, they found the virus was present in both insects.

Where is the virus found?
The researchers suspect the virus is transmitted by the taiga tick (Ixodes persulcatus), which is found in parts of eastern Europe and Asia, including China, Korea, Japan, Mongolia and Russia. Still, the study can't prove this tick does indeed transmit the disease, and can't rule out the possibility that mosquitoes are transmitting the disease, the authors said.

Laura Goodman, an assistant research professor at Cornell University's College of Veterinary Medicine in Ithaca, New York, called the new work an "excellent study," but said it leaves some unanswered questions. Critically, researchers will need to confirm which disease "vectors" are able to transmit the disease to people. "Until we can really know the answer to that question,we can't fully confirm the potential geographic range" of the virus, Goodman told Live Science.

Still, the researchers of the new study were able to characterize the entire genome of the Alongshan virus, and this information will help in broader surveillance for the virus, said Goodman, who wasn't involved with the study.

The Alongshan virus belongs to a family of viruses called Flaviviridae, the same family that includes TBEV as well as mosquito-borne viruses, such as dengue fever, West Nile virus, and Zika virus, according to the Centers for Disease Control and Prevention (CDC). The Alongshan virus is most closely related to another tickborne virus, called the Jingmen tick virus, which was first discovered in 2014.

If the taiga tick does turn out to transmit the Alongshan virus, then the range of the virus could potentially include the entire range of that tick, Goodman said. In addition, the virus might be found in other parts of the world — including other continents — if it can be transmitted by other types of ticks. Goodman noted that the closely related Jingmen tick virus has been found in both China and parts of Central and South America.

Goodman also noted that the Asian longhorned tick (Haemaphysalis longicornis), which is native to Asia and has recently shown up in the United States, can also carry the Jingmen tick virus. However, there's no evidence that the Asian longhorned tick can carry the Alongshan virus. And in the U.S., the Asian longhorned tick has not been found to transmit any diseases.

In the new study, all 86 patients were treated based on their symptoms with a combination of an antiviral and antibiotic drug; their symptoms went away in about 6 to 8 days of treatment. Patients spent an average of 10 to 14 days in the hospital; and all of the patients eventually recovered without any long-term complications, the report said.

"Our findings suggest that [the Alongshan virus] may be the cause of a previously unknown febrile disease, and more studies should be conducted to determine the geographic distribution of this disease outside its current areas of identification," the authors concluded.

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