Serhii Filatov1, Aparna Krishnavajhala2, Brittany A Armstrong2,3, Alexander R Kneubehl2,3, Nathan C Nieto4, Adalberto A Pérez De León5, Job E Lopez2,3. 1. National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, Ukraine. 2. Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, USA. 3. Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA. 4. Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA. 5. United States Department of Agriculture-Agricultural Research Service, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Kerrville, Texas, USA.
Abstract
BACKGROUND: Tick-borne relapsing fever (TBRF) is a neglected zoonotic bacterial disease known to occur on 5 continents. We report a laboratory-acquired case of TBRF caused by Borrelia caucasica, which is endemic in Ukraine and transmitted by Ornithodoros verrucosus ticks. METHODS: We isolated spirochetes and characterized them by partially sequencing the 16s ribosomal ribonucleic acid (rrs), flagellin (flaB), and deoxyribonucleic acid gyrase (gyrB) genes and conducting a phylogenetic analysis. RESULTS: These analyses revealed a close relationship of Ukrainian spirochetes with the Asian TBRF species, Borrelia persica. The taxonomic and nomenclature problems related to insufficient knowledge on the spirochetes and their vectors in the region are discussed. CONCLUSIONS: Although these findings enhance our understanding of species identities for TBRF Borrelia in Eurasia, further work is required to address the neglected status of TBRF in this part of the world. Public health practitioners should consider TBRF and include the disease into differential diagnosis of febrile illnesses with unknown etiology.
BACKGROUND: Tick-borne relapsingfever (TBRF) is a neglected zoonotic bacterial disease known to occur on 5 continents. We report a laboratory-acquired case of TBRF caused by Borrelia caucasica, which is endemic in Ukraine and transmitted by Ornithodoros verrucosus ticks. METHODS: We isolated spirochetes and characterized them by partially sequencing the 16s ribosomal ribonucleic acid (rrs), flagellin (flaB), and deoxyribonucleic acid gyrase (gyrB) genes and conducting a phylogenetic analysis. RESULTS: These analyses revealed a close relationship of Ukrainian spirochetes with the Asian TBRF species, Borrelia persica. The taxonomic and nomenclature problems related to insufficient knowledge on the spirochetes and their vectors in the region are discussed. CONCLUSIONS: Although these findings enhance our understanding of species identities for TBRF Borrelia in Eurasia, further work is required to address the neglected status of TBRF in this part of the world. Public health practitioners should consider TBRF and include the disease into differential diagnosis of febrile illnesses with unknown etiology.