Order of authorship in the original paper: Dutra, Rocha, Moreira. The authors infected lab populations of mosquitos with Wolbachia pipientis, a common parasitic microbe that infects a high proportion of insects. They then released the infected mosquitos into native populations of wild mosquitos, infecting the Aedes aegypti mosquitos. It was found that the infected mosquitos did not transmit the Zika virus because the Wolbachia stops or blocks Zika virus transmission in the mosquitos. Digital facsimile from PubMedCentral at this link.

(Thanks to Juan Weiss for this reference and its interpretation.)