A new kind of virus is making scientists rethink how infection works. This virus, found in mosquitoes, is broken up into several pieces. If the mosquito doesn’t come into contact with at least a few pieces, it won’t get infected.

This shakes up our existing knowledge, which is that once you come in contact with any part of a virus you get the full infection. In a study published Thursday in the journal Cell Host and Microbe, scientists describe how this new virus — named Guaico Culex after the Culex mosquito found in Guaico, Trinidad — works.

Other viruses have all their genes packaged together. Guiaco Culex has five genes packaged separately, and a mosquito needs to come in contact with at least four different pieces for anything to happen. The fifth one seems to be optional, or could control how deadly the virus is, study author Jason Ladner told NPR.

Guaico Culex can’t seem to infect humans, though Ladner’s team did find a similar virus in a monkey in Uganda, suggesting that it’s not out of the question that these types of viruses can affect us.

The study is part of a larger project looking at how viruses in mosquitoes work, and how that could affect humans. Mosquitoes — which are bloodsucking machines — are considered one of the most deadly animals because of their ability to transmit disease, including West Nile virus, yellow fever, and Zika. Earlier this summer, the US Food and Drug Administration even approved a plan to genetically modify them to fight Zika. The more we know about them, the more we can stop the transmission of disease before things like Zika become public health emergencies.