Under-the-radar dengue virus infections in natural populations of Aedes aegypti mosquitoes

Sean M. Boyles; Carla N. Mavian; Esteban Finol; Maria Ukhanova; Caroline J. Stephenson; Gabriela Hamerlinck; Seokyoung Kang; Caleb Baumgartner; Mary Geesey; Israel Stinton; Kate Williams; Derrick K. Mathias; Mattia Prosperi; Volker Mai; Marco Salemi; Eva A. Buckner; John A. Lednicky; Adam R. Rivers; Rhoel R. Dinglasan

Approximately 40% of the globe is at risk of infection by flaviviruses, such as dengue virus 2 (DENV): an enveloped, single-stranded RNA virus transmitted primarily by Aedes aegypti 3 mosquitoes [1, 2] . Since severe disease from DENV infections can manifest as dengue 4 hemorrhagic fever/dengue shock syndrome [1] , DENV establishment in the continental United 5 States is a major concern for public health agencies. In the USA, Florida has experienced 6 increases in local DENV transmission since 2009 [3] , driven in part by human and pathogen 7 movement. Ae. aegypti is endemic throughout subtropical Florida and the vector population 8 has resurged recently, following its near displacement by Ae. albopictus [4] . Autochthonous 9 DENV infection occurs sporadically, primarily in Southern Florida with limited local cases 10 elsewhere in the state [3] . In 2019, 16 cases of locally acquired DENV were reported for the 11 state, including an area along the West-Central Florida Gulf Coast. 12 13 Recently, reports have indicated that certain insect-specific viruses (ISVs) can negatively 14 impact or enhance arbovirus (including DENV) infections in insect cells [5, 6] and mosquitoes 15 [7] , respectively. Although the impacts of many ISVs on arboviral competence have yet to be 16 determined, the evidence to date clearly indicates that the mosquito virome cannot be safely 17 ignored and likely influences the risk of autochthonous DENV transmission once the virus is 18 introduced into an area. Therefore, we conducted a metaviromic study of F1 (first-generation, 19 lab-raised mosquitoes from wild parents) Ae. aegypti adult females collected as eggs from 20 ovitraps in 2016-2017 from Manatee County to assess the potential risk of flavivirus 21 transmission outside of Southern Florida. Although no indexed human case of DENV4 was 22 reported during 2016-2017 in the county, we detected and sequenced DENV4, which may 23 author/funder. All rights reserved. No reuse allowed without permission.