Successful introgression of wMel Wolbachia into Aedes aegypti populations in Fiji, Vanuatu and Kiribati
Cameron P. Simmons, Wesley Donald, Lekon Tagavi, Len Tarivonda, Timothy Quai, Raynelyn Tavoa, Tebikau Noran, Erirau Manikaoti, Lavinia Kareaua, Tabomoa Tinte Abwai, Dip Chand, Vineshwaran Rama, Vimal Deo, Kharishma Karti Deo, Aminiasi Tavuii, Wame Valentine, Raviikash Prasad, Eremasi Seru, Leikitah Naituku, Anaseini Ratu, Mark Hesketh, Nichola Kenny, Sarah C. Beebe, Anjali A. Goundar, Andrew McCaw, Molly K. Buntine, B.R. Green, Tibor Frossard, Jérémie Gilles, D. Albert Joubert, Geoff Wilson, Le Quyen Duong, Jean B Bouvier, Darren Stanford, Carolyn Forder, Johanna M. Duyvestyn, Etiene Casagrande Pacidônio, Heather A. Flores, Natalie Wittmeier, Kate Retzki, Peter A. Ryan, Jai A. Denton, Ruth Smithyman, Stephanie K. Tanamas, Peter Kyrylos, Yi Dong, Abdul Nasir Khalid, Lauren Hodgson, Katherine L. Anders, Scott L. O’Neill
Abstract
Pacific Island countries have experienced periodic dengue, chikungunya and Zika outbreaks for decades. The prevention and control of these mosquito-borne diseases rely heavily on control of Aedes aegypti mosquitoes, which in most settings are the primary vector. Introgression of the intracellular bacterium Wolbachia pipientis (wMel strain) into Ae. aegypti populations reduces their vector competence and consequently lowers dengue incidence in the human population. Here we describe successful area-wide deployments of wMel-infected Ae. aegypti in Suva, Lautoka, Nadi (Fiji), Port Vila (Vanuatu) and South Tarawa (Kiribati). With community support, weekly releases of wMel-infected Ae. aegypti mosquitoes for between 2 to 5 months resulted in wMel introgression in nearly all locations. Long term monitoring confirmed a high, self-sustaining prevalence of wMel infecting mosquitoes in almost all deployment areas. Measurement of public health outcomes were disrupted by the Covid19 pandemic but are expected to emerge in the coming years.