A research team has identified a new species of virus specific to insects that can be engineered to house genes from related viruses that cause diseases such as Zika and yellow fever. By serving as a platform for recombinant approaches, the new virus represents a flexible and non-infectious research tool for testing diagnostics and vaccines for various infectious diseases. Flaviviruses are a family of insect-transmitted viruses that can cause dangerous infections such as yellow fever, dengue and West Nile encephalitis. Although these viruses represent a major health burden worldwide, the development of new diagnostics and vaccines has been hampered because they require using infectious strains that pose a danger to people. In this study, Jody Hobson-Peters and colleagues detail a new species of flavivirus named Binjari virus that only infects insects, which they discovered after sequencing extracts from mosquitoes in Australia. After evaluating its genetic structure, the researchers found they could swap some of the virus's genes with genes from disease-causing flaviviruses. They engineered chimera Binjari virus particles that contained genes from Zika or West Nile virus, and observed the particles rapidly reproduced in mosquito cells but could not infect vertebrate cells. The Binjari chimeras could be used for various applications: a vaccine based on Binjari-Zika particles protected mice from Zika virus infection, and other chimeras could replace infectious flaviviruses in several assays that test for dengue or West Nile virus. The high replication rate and non-infectious nature of Binjari virus indicates it could be easily manufactured and modified for various medical applications without posing a risk to human health.