Insecticides Pyrethroids are commonly used. This widespread use of pyrethroids and DDT has caused Knockdown resistance (kdr) mutations. Almost no research has been done on the fitness implications. studies by Kumar et al., 2009 on deltamethrin in India, Plernsub et al., 2013 on permethrin in Thailand, by Jaramillo-O et al., 2014 on λ-cyhalothrin in Colombia, by Alvarez-Gonzalez et al., 2017 on deltamethrin in Venezuela, are all substantially confounded. As of 2019, understanding of selective pressure under withdrawal of insecticide is hence limited. Genetic modificationAe. aegypti has been genetically modified to suppress its own species in an approach similar to the sterile insect technique, thereby reducing the risk of disease. The mosquitoes, known as , were developed by Oxitec, a spinout of Oxford University. Field trials in the Cayman Islands, in Juazeiro Brazil by Carvalho et al., 2015, and in Panama by Neira et al., 2014 have shown that the OX513A mosquitoes reduced the target mosquito populations by more than 90%. This mosquito suppression effect is achieved by a self-limiting gene that prevents the offspring from surviving. Male modified mosquitoes, which do not bite or spread disease, are released to mate with the pest females. Their offspring inherit the self-limiting gene and die before reaching adulthood—before they can reproduce or spread disease. The OX513A mosquitoes and their offspring also carry a fluorescent marker for simple monitoring. To produce more OX513A mosquitoes for control projects, the self-limiting gene is switched off (using the Tet-Off system) in the mosquito production facility using an antidote (the antibiotic tetracycline), allowing the mosquitoes to reproduce naturally. In the environment, the antidote is unavailable to rescue mosquito reproduction, so the pest population is suppressed. The mosquito control effect is nontoxic and species-specific, as the OX513A mosquitoes are Ae. aegypti and only breed with Ae. aegypti. The result of the self-limiting approach is that the released insects and their offspring die and do not persist in the environment. In Brazil, the modified mosquitoes were approved by the National Biosecurity Technical Commission for releases throughout the country. Insects were released into the wild populations of Brazil, Malaysia, and the Cayman Islands in 2012. In July 2015, the city of Piracicaba, São Paulo, started releasing the OX513A mosquitoes. In 2015, the UK House of Lords called on the government to support more work on genetically modified insects in the interest of global health. In 2016, the United States Food and