Analysing existing data sets on the Aedes aegypti mosquito helped Rhys Parry to characterize a new virus. James Gathany / CDC I didn’t set out to build a career on other people’s data. But five years after my first secondary-data analysis, I’m still doing it. In 2018, halfway through my PhD programme at the University of Queensland in Brisbane, Australia, I discovered a previously unknown virus in the laboratory’s Aedes aegypti mosquito cell lines. Insect cells often harbour persistent, unnoticed viral infections, so the finding wasn’t entirely surprising. But this new virus was uncharacterized. We found that it couldn’t infect mammalian cells and, unexpectedly, that it modestly reduced replication of the dengue virus. That drew our attention — insect-specific viruses that interfere with human pathogens could have implications for understanding, and potentially disrupting, how mosquitoes transmit disease.…