Brittany Armstrong

PATHOGEN-VECTOR TRANSCRIPTIONAL RESPONSES DURING THE INFECTIOUS CYCLE OF RELAPSING FEVER SPIROCHETES

Brittany A. Armstrong, Aparna Krishnavajhala1, Vinayak Kapatral2,

Daniel Schmitt2, Benjamin Vaisvil2, Luiz Oliviera3, Jesus Valenzuela3, and Job E. Lopez

1Department of Pediatrics-Tropical Medicine, Baylor College of Medicine, Houston, TX, 2Igenbio, Chicago, IL, 3Vector Molecular Biology, NIAID, Bethesda, MD

Tick-borne relapsing fever (TBRF) is a neglected disease caused by Borrelia species and maintained primarily in the Ornithodoros tick vector. When the tick imbibes an infectious blood meal, the spirochetes colonize the midgut and over the next 10-14 days a population migrates to colonize the salivary glands. Since transmission can occur within 15 seconds of the tick biting, colonization of the salivary glands is crucial for transmission, as there is not enough time for the Borrelia to migrate from the midgut to the salivary glands. Additionally once infected, the tick remains colonized throughout its life span and consistently transmits the pathogen during subsequent blood meals. While there is a broad understanding of vector colonization by TBRF Borrelia, the underlying molecular mechanisms still remain elusive. To address these gaps in knowledge we used our Borrelia turicatae-Ornithodoros turicata system and a dual RNA-seq approach to assess both bacterial and tick transcriptional responses to Borrelia colonization of the midgut and salivary glands of the tick. Our overall objective is to identify gene candidates, in both the pathogen and vector that are crucial for persistent vector colonization that could be targeted for novel control measures.