Mosquitoes 2 (IMAGE) Penn State Caption Researchers have found that Wolbachia bacteria's ability to block transmission of dengue virus may be maintained by natural selection, alleviating concern that this benefit could diminish over time. Credit Dan Lesher, Penn State Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.