Developing a tick-borne Rickettsia isolate library.

Project Summary Tick-borne diseases are an endemic and emergent public health threat in the US. The historic geographic range of established tick vectors have expanded and new invasive tick species have been introduced over the last decade. Additionally, novel tick-borne pathogens of human importance have been discovered at a rate unparallel by other vector-pathogen complexes over the last 50 years. Unfortunately, our understanding about the pathogenicity and ability to detect human tick-borne disease has been outpaced by the identification of new species of tick-borne pathogens. This is especially true for spotted fever group Rickettsia (SFGR), which has expreicenced a significant rise in disease and the identification of multiple novel pathogenic members of the family since its initial discovery in 1920. We critically need new tools and resources to tackle this growing public health problem. The overarching goal of this proposal is to develop a bank of Rickettsia spp. isolates from ticks collected in the southern US and Central America to be used as a resource for further research into host- pathogen interaction, pathogenicity, diagnostic, and vaccine development for SFGR. Our specific aims are as follows: (1) Develop a Rickettsia isolate library using a cohort of previously collected and processed ticks from the southern US and Central America, and (2) Conduct molecular characterization of Rickettsia spp. isolates obtained from ticks collected in the southern US and Central America. We will utilize a cohort of >3,500 ticks previously collected from Texas and Belize to conduct this research. We will select a stratified sample for culture of 350 ticks from the 1,878 (53%) ticks that screened positive for Rickettsia that are representative of all Rickettsia spp. and locations. We will conduct molecular characterization of the isolated species uing PCR and sequencing of gltA, ompA, ompB, and htrA genes. Ultimately, we will make the isolate libarary available to the broader scientific community for future research to advance the field. This study brings together a well-suited team to tackle a growing public health problem. Our findings will serve as the foundation for many important future studies to determine pathogenicity and develop effective diagnostic tests. Additionally, it will serve as an important resource for the larger scientific community.