[Researchers] showed that Aedes aegypti mosquitoes, the chief carriers of the dengue virus, resist spreading that virus if they are infected with a particular kind of bacteria. Then they tested whether these resistant mosquitoes could displace their ordinary cousins in the wild, thus reducing the number of dengue-spreading mosquitoes. [...] For the experiment, scientists released more than 140,000 resistant mosquitoes over 10 weeks in each of two isolated communities near Cairns in northeastern Australia, starting last January. By mid-April, monitoring found that resistant mosquitoes made up 90 percent to 100 percent of the wild population.