Natural Rickettsia infection rate in Amblyomma americanum and Dermacentor variabilis in Georgia, United States. Restricted; Files Only
Long, Audrey (Spring 2023)
Abstract
Purpose: Rickettsia prevalence in Georgia, United States is poorly understood. Amblyomma americanum ticks have the potential to be a vector for human illness due to Rickettsia spp. pathogens, and understanding the infection rate compared to Dermacentor variabilis, the vector associated with Rocky Mountain Spotted Fever transmission, is important in determining the risk of pathogen transmission to humans in Georgia.
Methods: Host-seeking ticks were collected using flagging methods, then pooled and DNA was extracted. Two molecular methods of detection were used, a real-time PCR and a conventional PCR both designed to test for the Rickettsia genus. 64 pools of ticks were tested using both methods, and sanger sequenced to determine the Rickettsia species found in positive ticks.
Results: One hundred percent of the 32 pools of A. americanum ticks tested positive for Rickettsia genus bacteria. Sequencing results from these ticks were one hundred percent Rickettsia amblyommatis. 9.38 % (three pools) of D. variabilis ticks were positive for rickettsia. Two pools was sequenced as R. amblyommatis and the other as R. montanensis. No samples were positive for R. rickettsii. The sensitivity of both tests (100%) were the same, however the specificity of the real-time PCR was 72.4% compared to the 100% of the conventional PCR.
Conclusions: A. americanum may be an important vector of Spotted Fever Group Rickettsiae infection in humans. The conventional PCR was a better method for detecting Rickettsia spp. in ticks, due to the occasional false positives in the real-time PCR test.
Table of Contents
Introduction 1
Introduction and Rationale 1
Hypothesis 3
Significance 4
Literature Review 6
Background 6
Previous Findings 8
Tick Surveillance 11
Methods 13
Introduction 13
Procedures 14
Plans for Data Analysis 19
Ethical Considerations 20
Limitations 20
Results 21
Overview of Results 21
Findings 21
Discussion 26
Discussion 26
Limitations and Suggestions 28
Conclusion 29
References 30
Appendix 38
About this Master's Thesis
School | |
---|---|
Department | |
Degree | |
Submission | |
Language |
|
Research Field | |
Keyword | |
Committee Chair / Thesis Advisor |
Primary PDF
Thumbnail | Title | Date Uploaded | Actions |
---|---|---|---|
File download under embargo until 18 May 2025 | 2023-04-21 09:51:12 -0400 | File download under embargo until 18 May 2025 |
Supplemental Files
Thumbnail | Title | Date Uploaded | Actions |
---|