Arthropods, like mosquitoes and ticks, are responsible for transmitting the vast majority of infectious diseases that affect humans in the United States. These arthropods often contain within them numerous bacteria that are also called microbes. We know very little about the role of these microbes in disease transmitting arthropods or if and how they interact with one another. Using the western black-legged tick, this study examines how the internal collection of microbes develops within the tick and whether the types or numbers of these microbes negatively or positively influence the ability of these arthropods to transmit disease causing bacteria to new hosts. To understand how a collection of microbes develops, ticks will be allowed to feed on different hosts, such as lizards or mice. Then researchers will examine how the different microbe collections within these ticks influence their ability to transmit the bacteria that causes Lyme disease from one host to another. An improved understanding of the role microbes play in the transmission of diseases will allow for the development of new perspectives and strategies for managing disease risk and conserving wildlife. This project also will train undergraduate and graduate students and will develop citizen science opportunities. The citizen science opportunities will include development of a mobile phone app to allow the public to provide scientists with tick distribution and encounter data while increasing the public's awareness of tick transmitted illnesses. This study has clear public health implications as Lyme disease is the most reported vector-borne disease in the United States.
An emerging question in the field of disease ecology is whether the microbial community of potential vectors can facilitate or inhibit the transmission of pathogens. This study will focus on the tick, Ixodes pacificus, which is the main vector of Lyme disease in the western United States, and will use a combination of lab and field experiments to examine how feeding on different host species affects the development of the tick microbiome and influences gut development and microbe transmission efficiency. To determine the role of host blood meal on the tick's microbiome and midgut structure, next generation 16S rRNA sequencing of the bacterial microbiome and fluorescent in situ hybridization (FISH) techniques will be used. To determine the effect of host blood meal history on the acquisition and transmission of Borrelia burgdorferi, quantitative PCR, microbiome analyses, and visualization techniques will be used. By experimentally manipulating and evaluating the factors that structure tick microbiomes and by understanding the mechanistic role that microbes play in pathogen transmission, this study will advance our understanding of how microbe-vector-associated communities are shaped and how these relationships influence disease ecology more broadly.
