My name is Helen Wagner, I was an undergrad in the QBIC and Honors programs at FIU. I am currently seeking a Ph.D. degree in the DeGennaro Lab.
Aedes aegypti has been classified as the most effective and therefore main vector for dengue virus transmission. Ae. aegypti are susceptible as well to ZIKV, and global health concern is increasing on other infectious diseases spread including Chikungunya and yellow fever. In order to reduce mosquito development, different traps have been utilized to remove and therefore decrease subsequent mosquito generations, however, insecticide use is typically used and required as the first line of defense in mosquito control programs. The use of insecticide-treated preventative measures have increased throughout the years, reducing mosquito density and survival, and therefore reducing this synanthropic mosquito’s contact with humans. The effectiveness of this form of control is now being compromised by mosquito resistance to the four insecticide classes including carbamates, organochlorines, organophosphates and pyrethroids. In most instances of insecticide-resistance, it is due to mutations that allow for detoxification of the insecticide prior to target-site acquisition or reducing the insecticide affinity for its target. In terms of molecular diversity, there are new-curated genes that have not been fully explored that code for esteraseand Glutathione-S-transferases (GSTs) that may be involved in Ae. aegypti resistance to insecticides and therefore their survival as disease vectors.
Populations of Ae. aegypti are expanding through Florida due to the state’s tropical and subtropical climate which cater to the life cycle of Ae. aegypti, suitable for the mosquito’s survival. Pyrethroids, organophosphates and other biological toxins have been used against mosquitos in Florida for this reason, although the exposure of insecticides is not evenly distributed through every county. Every county has their own regulation and until now, interest in regulating pesticide use in Florida is impeded by the desire for local jurisdiction. Ae. aegypti populations may be influenced by the exposure to different volumes and types of insecticide use, and so genetic diversity may exist in target populations. With the availability of the new AaegL5 genome and the high-resolution genetic variance it comprises not seen in previous genomes released, next generation sequencing (NGS) can be used to determine the structure of the different populations in Florida. Currently only low levels of genetic variability have been observed throughout South Florida when studied with microsatellite loci and mitochondrial genes, however, the availability of genome-wide analysis as a potent tool may reveal different levels of gene flow and variability .
The aims of this project include the sequencing of Ae. aegypti populations throughout Florida using genome-wide sequencing in order to determine the level of genetic variance in Florida in relevance to insecticide-resistance. The sequencing of insecticide-susceptible and specific insecticide-resistant strains will be conducted for comparison to Florida population results. Using F2 hybrid screening with susceptible laboratory strains and the resistant wild strains will allow us to screen for insecticide resistant individuals. The F2 hybrid screen will be employed to improve resistance allele frequency estimates, as well as permit the identification and rescue of resistance alleles in varying mosquito strain populations. Finally, mapping Ae. aegypti genetic diversity in relation to insecticide-resistance by using a geographic information system (GIS) will be used to correlate local Florida conditions to the resulting genetic variation.