File(s) under embargo
Tracking Tick Feeding: Attempting to develop a protocol for the determination of blood-meal host species of nymphal I. scapularis
Lyme disease poses a major public health threat throughout many parts of North America, and is expected to become worse as climate change progresses. As a result, understanding what drives the spread of the pathogen that causes this disease is of utmost importance. Changes in the prevalence of Lyme disease are driven at various spatial scales, and by both biotic and abiotic factors. Vertebrates that serve as blood-meal hosts for ticks are an important factor in the spread of the bacteria that causes Lyme disease, but their impacts are not fully understood due to the difficulties of sampling vertebrates directly in the field. Throughout the past year, I've attempted to develop a protocol to determine the larval blood-meal host species of questing nymphal Ixodes scapularis. In order to identify the blood-meal hosts of nymphal ticks, extracted DNA was amplified using PCR with universal mammal primers targeting the 12s rRNA gene for DNA barcoding. These samples were subsequently sent for Sanger sequencing, and the resulting amplicons were checked against the NCBI's BLAST database to determine the identity of the amplified DNA for each sample. Due to high rates of human contamination, the likely blood-meal host was only identified for 13 of the 112 field-collected nymphal ticks for this project, giving a success rate of 11.6%. However, I was able to identify a diverse selection of local vertebrates as blood-meal hosts for nymphal I. scapularis, and found Sciurus carolinensis to be the most common larval blood-meal host. Additionally, I determined many subsequent steps that can be taken to refine this procedure in the future, such as further primer design and the exploration of additional detection methods.
History
Institution
- Middlebury College
Department or Program
- Biology
Degree
- Bachelor of Arts, Honors
Academic Advisor
David Allen, Ph.DConditions
- Restricted to Campus