Disease Risk & Landscape Attributes of Tick-Borne Borrelia Pathogens in the San Francisco Bay Area, California

Daniel J Salkeld; Nathan C Nieto; Patricia Carbajales-Dale; Michael Carbajales-Dale; Stephanie S Cinkovich; Eric F Lambin

doi:10.1371/journal.pone.0134812

Disease Risk & Landscape Attributes of Tick-Borne Borrelia Pathogens in the San Francisco Bay Area, California

PLoS One. 2015 Aug 19;10(8):e0134812. doi: 10.1371/journal.pone.0134812. eCollection 2015.

Authors

Daniel J Salkeld¹, Nathan C Nieto², Patricia Carbajales-Dale³, Michael Carbajales-Dale⁴, Stephanie S Cinkovich⁵, Eric F Lambin⁶

Affiliations

¹ Department of Biology, Colorado State University, Fort Collins, Colorado, United States of America; Woods Institute for the Environment, Stanford University, Stanford, California, United States of America.
² Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America.
³ Center of Excellence for Next Generation Computing, Clemson University, Clemson, South Carolina, United States of America.
⁴ College of Engineering & Science, Clemson University, Clemson, South Carolina, United States of America.
⁵ Woods Institute for the Environment, Stanford University, Stanford, California, United States of America.
⁶ Woods Institute for the Environment, Stanford University, Stanford, California, United States of America; School of Earth, Energy and the Environment, Stanford University, Stanford, California, United States of America.

Abstract

Habitat heterogeneity influences pathogen ecology by affecting vector abundance and the reservoir host communities. We investigated spatial patterns of disease risk for two human pathogens in the Borrelia genus-B. burgdorferi and B. miyamotoi-that are transmitted by the western black-legged tick, Ixodes pacificus. We collected ticks (349 nymphs, 273 adults) at 20 sites in the San Francisco Bay Area, California, USA. Tick abundance, pathogen prevalence and density of infected nymphs varied widely across sites and habitat type, though nymphal western black-legged ticks were more frequently found, and were more abundant in coast live oak forest and desert/semi-desert scrub (dominated by California sagebrush) habitats. We observed Borrelia infections in ticks at all sites where we able to collect >10 ticks. The recently recognized human pathogen, B. miyamotoi, was observed at a higher prevalence (13/349 nymphs = 3.7%, 95% CI = 2.0-6.3; 5/273 adults = 1.8%, 95% CI = 0.6-4.2) than recent studies from nearby locations (Alameda County, east of the San Francisco Bay), demonstrating that tick-borne disease risk and ecology can vary substantially at small geographic scales, with consequences for public health and disease diagnosis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Arachnid Vectors / microbiology
Bays / microbiology
Bays / parasitology
Borrelia burgdorferi / pathogenicity
Ecosystem
Humans
Lyme Disease / epidemiology*
Lyme Disease / microbiology*
Lyme Disease / transmission
Molecular Sequence Data
Nymph / microbiology
Risk
San Francisco / epidemiology
Tick-Borne Diseases / epidemiology*
Tick-Borne Diseases / microbiology*
Tick-Borne Diseases / transmission
Ticks / microbiology*

Associated data

GENBANK/KT343318
GENBANK/KT343319
GENBANK/KT343320
GENBANK/KT343321
GENBANK/KT343322
GENBANK/KT343323
GENBANK/KT343324
GENBANK/KT343325
GENBANK/KT343326
GENBANK/KT343327
GENBANK/KT343328
GENBANK/KT343329
GENBANK/KT343330
GENBANK/KT343331
GENBANK/KT343332
GENBANK/KT343333
GENBANK/KT343334
GENBANK/KT343335
GENBANK/KT343336
GENBANK/KT343337
GENBANK/KT343338
GENBANK/KT343339
GENBANK/KT343340
GENBANK/KT343341
GENBANK/KT343342
GENBANK/KT343343
GENBANK/KT343344
GENBANK/KT343345
GENBANK/KT343346
GENBANK/KT343347
GENBANK/KT343348
GENBANK/KT343349
GENBANK/KT343350
GENBANK/KT343351

Grants and funding

This study was supported by a grant from the Bay Area Lyme Foundation, http://www.bayarealyme.org/, to DJS, NCN and EL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.