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Updated: Nov 21, 2025
Author Spotlight: Controlled Human Exposure Model for Tick Research and Lyme Disease Studies
Published on: December 1, 2023
Spatial and temporal patterns of the emerging tick-borne pathogen Borrelia miyamotoi in blacklegged ticks (Ixodes
F Keesing1, D J McHenry2, M H Hersh3
1Program in Biology, Bard College, Annandale-on-Hudson, NY, 12504, USA. keesing@bard.edu.
Abstract:
Borrelia miyamotoi, a bacterium that causes relapsing fever, is found in ixodid ticks throughout the northern hemisphere. The first cases of human infection with B. miyamotoi were identified in 2011. In the eastern USA, blacklegged ticks (Ixodes scapularis) become infected by feeding on an infected vertebrate host, or through transovarial transmission. We surveyed B. miyamotoi prevalence in ticks within forested habitats in Dutchess County, New York, and identified possible reservoir hosts. To assess spatial variation in infection, we collected questing nymphal ticks at > 150 sites. To assess temporal variation in infection, we collected questing nymphs for 8 years at a single study site. We collected questing larval ticks from nine plots to estimate the amount of transovarial transmission. To evaluate potential reservoir hosts, we captured 14 species of mammal and bird hosts naturally infested with larval blacklegged ticks and held these hosts in the laboratory until ticks fed to repletion and molted to nymphs. We determined infection for all ticks using quantitative polymerase chain reaction. The overall infection prevalence of questing nymphal ticks across all sites was ~ 1%, but prevalence at individual sites was as high as 9.1%. We detected no significant increase in infection through time. Only 0.4% of questing larval ticks were infected. Ticks having fed as larvae from short-tailed shrews, red squirrels, and opossums tended to have higher infection prevalence than did ticks having fed on other hosts. Further studies of the role of hosts in transmission are warranted. The locally high prevalence of B. miyamotoi in the New York/New England landscape suggests the importance of vigilance by health practitioners and the public.
Insights
Borrelia miyamotoi bacteria, a cause of relapsing fever, show high prevalence in ticks in New York. Short-tailed shrews, red squirrels, and opossums may be key hosts for this tick-borne illness.
Area of Science:
- Veterinary Entomology
- Infectious Diseases
- Medical Entomology
Background:
- Borrelia miyamotoi is a relapsing fever-causing bacterium found in ticks across the Northern Hemisphere.
- Human infections with B. miyamotoi were first identified in 2011.
- In the eastern USA, blacklegged ticks (Ixodes scapularis) transmit B. miyamotoi through host feeding or transovarial transmission.
Purpose of the Study:
- To survey B. miyamotoi prevalence in questing nymphal and larval ticks in Dutchess County, New York.
- To assess spatial and temporal variations in tick infection rates.
- To identify potential reservoir hosts for B. miyamotoi.
Main Methods:
- Questing nymphal ticks were collected from over 150 sites for spatial analysis.
- Questing nymphal ticks were collected for 8 years at one site for temporal analysis.
- Larval ticks were collected to estimate transovarial transmission, and potential hosts were evaluated by allowing ticks to feed and molt.
Main Results:
- Overall prevalence of B. miyamotoi in questing nymphal ticks was approximately 1%, with some sites reaching 9.1%.
- No significant temporal increase in infection prevalence was detected.
- Infected larval ticks constituted only 0.4% of the total.
- Ticks that fed on short-tailed shrews, red squirrels, and opossums showed higher infection prevalence.
Conclusions:
- Locally high B. miyamotoi prevalence in ticks necessitates vigilance from healthcare providers and the public.
- Further research is needed to fully understand the role of various hosts in B. miyamotoi transmission.
- The findings highlight the ecological dynamics of B. miyamotoi in the New York/New England region.
