New research is shedding light on how an emerging class of tick-borne viruses manages to evade the human immune system, in discoveries that researchers hope will lead to preventive methods and treatments.
Several so-called nairoviruses are carried by ticks that bite humans and can cause high fevers and impair organ function, researchers reported in ACS Infectious Diseases.
The Crimean-Congo hemorrhagic fever virus, for example, is often fatal and is a threat to people in Africa, the Middle East and Asia.
Scientists already know that some nairoviruses evade the immune system by producing enzymes that make them undetectable. The enzymes remove small proteins attached to human proteins that would have alerted the immune system to an infection.
For the current study, researchers wanted to see whether this was true of some newly identified nairoviruses, including one called PCTNV that’s so far been found in ticks on the U.S. Pacific Coast but not in humans.
Their experiments suggested that PCTNV might be well equipped to evade the human immune system using these enzymes – and because PCTNV is carried by a human-biting tick already known to transmit Rocky Mountain spotted fever, people along the U.S. West Coast could be at risk for exposure.
“This study reinforces the need to be vigilant about not just tick bites but the type of ticks that an individual has been bitten by as they may carry diseases beyond what we have been used to looking for,” study leader Scott Pegan of the University of California, Riverside said in a statement.
Learning how these viruses skirt host immunity will aid development of countermeasures and biosurveillance tools, he added, noting that his team has been able to train computers to identify disease-causing nairoviruses using models that could ultimately contribute to a biosurveillance system.