Masters Theses

Date of Award

8-2016

Degree Type

Thesis

Degree Name

Master of Science

Major

Entomology and Plant Pathology

Major Professor

Rebecca Trout Fryxell

Committee Members

Doris D'Souza, Margaret Staton, Lisa Muller

Abstract

La Crosse virus (LACV), transmitted by infected Aedes triseriatus, Ae. albopictus, and Ae. japonicus mosquitoes is the leading cause of pediatric arboviral encephalitis. Severe cases of LAC encephalitis occur in individuals 16-years-old or younger and may cause permanent neurological damage or fatality. No vaccines exist making mosquito control and disease prevention crucial to public health. Effective screening and surveillance practices are key components to these goals. While a number of standard mosquito surveillance methods exist, continuous testing and improved understanding of vector biology to determine the best ways to implement these methods is important. Additionally, the current standard for screening LACV, RT-PCR, is time consuming, expensive, and inaccessible by many laboratories. I hypothesized that different LACV vectors would be active at different times (objective 1) and that a more efficient molecular method for virus detection can be developed (objective 2). For objective 1, I collected mosquitoes from 19 sites around Knox County from June-September in 2015 using traps previously found to be effective for monitoring LACV vectors. Nets were changed twice a day during “work” or “off-work” hours (9:00-17:00 or 17:00-9:00). Mosquitoes were identified and trap and time of day recorded. A total of 1,223 Aedes albopictus, 49 Ae. japonicus, and 90 Ae. triseriatus were collected. Significantly more LACV vectors were collected from 17:00-9:00. For objective 2, using a positive control, a reverse transcriptase loop mediated isothermal amplification (RT-LAMP) method of virus detection was developed and a dilution series was conducted to compare the developed assay to the standard. Both assays were found equally effective at detecting LACV, but the RT-LAMP is preferable for cost effectiveness and reduced detection time. This thesis provides research laboratories, health departments, and citizens with important vector surveillance information and an accurate and inexpensive method of screening for the virus. Surveillance information will make it easier for mosquito control districts to effectively monitor vectors. The diagnostic assay can be used in field-lab settings and will provide accurate results in a shorter time than with traditional methods. Together, the increased efficiency in vector surveillance and virus detection provide rapid and accurate results for low cost.

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