Spatial clustering of Borrelia burgdorferi sensu lato within chipmunk and woodrat populations in northwestern California

Graduation Date

2014

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Wildlife, 2014

Committee Chair Name

Richard Brown

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Borrelia burgdorferi, Chipmunks, Woodrats, Clustering, Disease, Lyme disease, Spatial, Rodents, Humboldt State University -- Theses -- Wildlife, Habitat, Northern California

Abstract

Lyme borreliosis is recognized as the most common emerging tick-borne disease affecting humans in the United States. In northwestern California, the ecology of Lyme borreliosis is complex, with several potential reservoirs, multiple tick vectors, and multiple genospecies of Borrelia burgdorferi sensu lato. The primary objective of this study was to identify spatial aggregation in rodents positive for various genospecies of Borrelia burgdorferi sensu lato. I looked at spatial clustering of different genospecies within dusky-footed woodrats (Neotoma fuscipes) and Allen's chipmunks (Neotamias senex). Rodents were live-trapped between March of 2004 and August of 2005. Ear punch biopsies were collected to determine presence of borreliae and positive products of polymerase chain reactions (PCR) were sequenced to determine genospecies associations. ArcGIS and Satscan were used to examine spatial clustering of genospecies from rodent samples. Fisher's exact tests and a multinomial log linear model were used to model habitat and species specific characteristics and their effect on genospecies prevalence. Akaike's information criterion (AICc) was used to compare models and determine which model best fit the data. Borrelia burgdorferi sensu stricto was more often associated with chipmunks and B. bissettii was more often associated with woodrats (P = 0.002 and P=0.043, respectively). The top model included "host species", "month", and "location" variables (weight = 0.87). Spatial clustering was found in the northwest and southeast corners of the study area (P ≤ 0.001). My results indicate that location within the study area strongly correlates with genospecies variation among hosts. This suggests a relationship between host species, time of year, borrelial genospecies, and location. These variables seem to be important in the ecology of transmission of borrelial genospecies and may help in determining areas of increased risk of human exposure to these pathogens.

https://scholarworks.calstate.edu/concern/theses/t722hb97j

Share

 
COinS