Unveiling Nature's Puzzle: How Borrelia burgdorferi Infection and Geography Shape the Questing Behavior of Ixodes pacificus Ticks
Author: Timara Vereen
Faculty Supervisor: Andrea Swei
Department: Biology
Zoonotic diseases are becoming more prominent due to increased human-animal interactions, specifically with pathogen carrying vectors. Pathogen vectors, such as ticks, play critical roles as ectoparasites, contributing to microhabitat conditions, facilitating disease transmission when they are infected with pathogens and feed upon a host. This has resulted in high reported cases of diseases such as Lyme disease (LD) (a disease most commonly caused by the bacteria, Borrelia burgdorferi). Pathogen transmission by the vector can lead to internal impacts on the hosts, but also behavioral alterations of the vector due to infection by the pathogen. Behavioral alterations can result in increased biting rates, longer biting times, more time spent host-seeking, and increased movement ability. These attributes assist vectors to successfully find hosts to prey upon and survive. With the continuation of the pathogen-vector-host cycle, the threat of disease to human, wildlife, and domestic populations continue to rise. However, little is known about how geographic and environmental factors influence host-seeking vector behavior. We examined the influence of B. burgdorferi infection on questing behavior of Ixodes pacificus nymphal ticks. Additionally, we investigated the effects of geographic origin and population genetics on I. pacificus nymphal ticks collected from 3 distinct geographical locations in California: Northern California, San Francisco/Bay area, and Southern California. Over 21 days, questing behavior (e.g. climbing, mobility, speed) and DNA sampling for B. burgdorferi infection was documented within nymphs. Based on previous studies, I expect that questing behavior exhibited by infected nymphs will differ compared to un-infected nymphs. Additionally, I hypothesize that nymphal questing behavior will differ relative to geographical origin due to factors such as temperature and host availability. These results will advance the understanding of I. pacificus nymphal questing behavior in concordance with LD incidence and potential impacts they have on the structure and health of ecosystems.