A virus in the same family as Dengue. (credit: Oak Ridge National Lab)

The Dengue virus comes in four distinct but related varieties called serotypes, and they’re all bad. Rather than inducing tolerance for each other, infection with one Dengue serotype actually makes people more sensitive to the other three. Victims infected by a second serotype can develop hemorrhagic fevers, which can be fatal. Somewhere around 400 million people are infected with Dengue annually—more than any other mosquito-borne ailment. There is no cure.

Dengue is also in the same family as Zika and is spread by the same mosquitos, so learning more about one could have broad applications for the other. This week, researchers published a paper in Nature describing how the Dengue virus avoids one arm of our immune system.

There are two arms to our immune system. Adaptive immunity generates antibodies and T cell receptors to combat unique aspects of a specific pathogen. After the fight is over, these antibodies and receptors stick around to remember and attack that pathogen should we encounter it again. Antibodies and T cell receptors form the molecular premise upon which vaccines are based.