Distribution of Ticks of Medical and Veterinary Importance along the Chisholm Trail and Development of a Molecular Assay to Detect Rickettsia Spp. In Field-collected Ticks in Oklahoma

Abstract

Cases of tick-borne rickettsial diseases are increasing in the Central United States, augmenting the need for updated distribution maps for primary tick vectors and the development of new surveillance tools to detect changing disease patterns. Throughout the summer of 2014, ticks were collected at state parks and other public use lands in counties surrounding the Chisholm Trail in central Oklahoma. Results demonstrated that established populations of A. americanum currently exist in 20 out of 21 sampled counties in eastern and central Oklahoma. Ticks were more prevalent in the eastern part of the state compared to the western side. These results augment previously published studies and demonstrate the importance of updating distribution maps. Loop-mediated isothermal amplification (LAMP) is a novel molecular tool which can be developed to detect arthropod-borne pathogens in field-collected arthropods. The aim of this part of the project was to design and validate a novel LAMP assay to detect Rickettsia spp. in field-collected ticks. All results were compared with a pan-specific PCR assay which targeted the 17 kDa gene of Rickettsia spp. The 802 field-collected ticks from various Oklahoma state parks during the summer of 2014 were tested using the two assays. Preliminary results indicated that the two tests correlated, signifying that LAMP assay is a promising molecular surveillance tool which can be used to effectively detect pathogens in field-collected ticks. This assay can then be further developed for use in resource-limited countries to assist with surveillance of tick-borne pathogens.