Date of Award


Document Type


Degree Name

Master of Science (M.S.)


Biological Sciences

First Advisor

Tara Thiemann

First Committee Member

Zachary Stahlschmidt

Second Committee Member

Craig A. Vierra


Culex quinquefasciatus has been identified as one of the most prominent vectors of West Nile virus (WNV) in Southern California. WNV is a zoonotic disease that is endemic in North America and is known to primarily cause flu-like symptoms in humans, and in rare cases, life-threatening conditions. The goal of this study was to identify which animal species are most frequently fed upon by these mosquitoes in this region. To examine the relationship between blood-feeding patterns and West Nile virus activity in San Bernardino County, the feeding patterns of Cx. quinquefasciatus are determined in a variety of habitat types, which was the primary focus of this study. Furthermore, potential shifts in seasonal blood-feeding patterns of this population of Cx. quinquefasciatus towards increased mammalian feeding was examined. The WNV activity in the county during 2011 was also analyzed. Over 740 Cx. quinquefasciatus samples were collected by West Valley Mosquito and Vector Control District in San Bernardino County during 2011 from 34 different sites. DNA from the bloodmeals was extracted and purified, and a 658-base pair region of DNA located in the mitochondrial gene cytochrome c-oxidase I (COI) was amplified. This was followed by DNA sequencing of the PCR product, and identification of the individual sequences using the Bar Code of Life Data Systems. A total of 683 bloodmeals were successfully identified. These bloodmeals belong to 29 vertebrate species across four different habitats. It was found that species richness was not significantly different between habitats, even though the sample sizes for each habitat varied. Across habitats, the highest percentage of avian bloodmeals were taken from House Sparrows and House Finches. Bloodmeals were identified from five mammalian species which included Humans. A seasonal shift towards increased mammalian bloodmeal prevalence was observed in urban habitats. It was found that WNV activity during 2011 in San Bernardino County was relatively low when compared to the following six years.



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