Browsing by Author "Bova, Jacob Edward"

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    Morphological differentiation of eggs and comparative efficacy of oviposition and gravid traps for Aedes vectors at different habitats
    Bova, Jacob Edward (Virginia Tech, 2014-07-03)
    Mosquito surveillance is an integral part of understanding mosquito-borne disease, including and not limited to the La Crosse virus. The primary container-inhabiting Aedeni vectors include Aedes triseritatus, Aedes albopictus, and Aedes japonicus. To better understand the efficacy of gravid traps and oviposition traps as surveillance methods for these mosquitoes, field studies were conducted in three different habitat types. Ae. triseriatus, Ae. albopictus, Ae. japonicus, and Aedes aegypti eggs were described with the aid of color images and SEM. All eggs were broadly cigar shaped with Ae. triseriatus and Ae. japonicus eggs being dull or matte black while Ae. albopictus and Ae. aegypti eggs were shiny jet black. Ae. triseriatus eggs were larger, lighter in color, and have a rougher appearance when compared to Ae. japonicus. Ae. albopictus and Ae. aegypti can be differentiated by the distinct presence of a micropylar collars in Ae. aegypti. Ovitrap and gravid trap efficacy for the surveillance of Ae. triseriatus, Ae. albopictus, and Ae. japonicus were measured in three different habitats on two different sites. Both sites contained the same 2ha habitats with varying degrees of forest canopy disturbance. Ae. triseriatus was the most abundant mosquito on all sites. Ovitraps and gravid traps were efficient in collecting Ae. triseriatus, while ovitraps were not efficient in collecting Ae. japonicus and Ae. albopictus.
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    Overwintering Mechanisms of La Crosse Virus Vectors
    Bova, Jacob Edward (Virginia Tech, 2018-12-05)
    The La Crosse virus (LACV) is an emerging pathogen in the Appalachian region of the United States. The virus maintains a complex natural cycle through horizontal transmission with sciurid rodents and Aedes mosquitoes in Virginia. Transovarial transmission also occurs in this host-parasite system and has evolved for the virus to persist through winter. The virus perpetuates in diapause induced embryos and infects naive rodents the following spring. As global temperatures rise, it is imperative we evaluate how the virus and its vectors overwinter. We conducted experiments to evaluate and determine the diapause induction, or prediapause stage, in Aedes japonicus japonicus, and the ecophysiology and low temperature biology of how LACV affects Aedes triseriatus and Aedes albopictus embryos at low temperatures. We found that the prediapause stage of Ae. j. japonicus is the maternal stage, the developing adult female that lays diapause eggs. This more closely resembles Ae. albopictus and not Ae. triseriatus. As measured in the field and laboratory, LACV has a clear negative effect on the ability of Ae. triseriatus and Ae. albopictus to survive the winter. There was no major effect of LACV infection on the ability of these two species to enter diapause or their critical photoperiods, but there was a significant negative effect of LACV infection on survivorship of embryos that were placed in their natural habitat and in their susceptibility to low temperatures. LACV infection had a more significant negative effect on Ae. albopictus than on Ae. triseriatus and suggests that Ae. albopictus is a subordinate vector relative to Ae. triseriatus in the maintenance of the virus over the winter season. Our findings highlight the need for the increased surveillance of LACV as temperatures continue to rise due to climate change.