The top six of 32 multinomial log-linear models analyzed.

<p>Models were ranked via a corrected Akaike’s Information Criterion (AICc) value. The K* column indicates the number of parameters for each model.</p

Forest unit categories and descriptions used to describe individual forest units.

<p>Forest unit categories and descriptions used to describe individual forest units.</p

The predicted probabilities of no infection (1None), infection with <i>B</i>. <i>burgdorferi</i> s. s. (2Bbss), or <i>B</i>. <i>bissettiae</i> (3Bbis) by month at the HVTR.

<p>Blue bars represent probabilities associated with Allen’s chipmunks (Ns, <i>Neotamias senex</i>) and gray bars represent probabilities associated with dusky-footed woodrats (Nf, <i>Neotoma fuscipes</i>).</p

Locations of California ground squirrels (<i>O</i>. <i>beecheyi</i>), northern flying squirrels (<i>G</i>. <i>sabrinus</i>), dusky-footed woodrats (<i>N</i>. <i>fuscipes</i>), and Allen’s chipmunks (<i>N</i>. <i>senex</i>) captured and tested for the presence of <i>B</i>. <i>burgdorferi</i> s. l. within the HVTR from June 2004 to May 2005.

<p>Each location represents one to many individuals because of overlapping capture locations.</p

Locations of Allen’s chipmunks (<i>N</i>. <i>senex</i>) and dusky-footed woodrats (<i>N</i>. <i>fuscipes</i>) infected with <i>B</i>. <i>burgdorferi</i> s. s. (Bbss) or <i>B</i>. <i>bissettiae</i> (Bbis) and associated significant clusters within the HVTR.

<p>Locations of Allen’s chipmunks (<i>N</i>. <i>senex</i>) and dusky-footed woodrats (<i>N</i>. <i>fuscipes</i>) infected with <i>B</i>. <i>burgdorferi</i> s. s. (Bbss) or <i>B</i>. <i>bissettiae</i> (Bbis) and associated significant clusters within the HVTR.</p

Numbers of Allen’s chipmunks (<i>N</i>. <i>senex</i>), dusky-footed woodrats (<i>N</i>. <i>fuscipes</i>), California ground squirrels (<i>O</i>. <i>beecheyi</i>), and northern flying squirrels (<i>G</i>. <i>sabrinus</i>) trapped at the HVTR from June 2004 through May 2005 and infection prevalence with Bbss (<i>B</i>. <i>burgdorferi</i> s. s.), Bbis (<i>B</i>. <i>bissettiae</i>), or unclassified Bbsl (<i>B</i>. <i>burgdorferi</i> s. l.).

<p>Numbers of Allen’s chipmunks (<i>N</i>. <i>senex</i>), dusky-footed woodrats (<i>N</i>. <i>fuscipes</i>), California ground squirrels (<i>O</i>. <i>beecheyi</i>), and northern flying squirrels (<i>G</i>. <i>sabrinus</i>) trapped at the HVTR from June 2004 through May 2005 and infection prevalence with Bbss (<i>B</i>. <i>burgdorferi</i> s. s.), Bbis (<i>B</i>. <i>bissettiae</i>), or unclassified Bbsl (<i>B</i>. <i>burgdorferi</i> s. l.).</p

Spatial clustering of <i>Borrelia burgdorferi</i> sensu lato within populations of Allen's chipmunks and dusky-footed woodrats in northwestern California

<div><p>The ecology of Lyme borreliosis is complex in northwestern California, with several potential reservoir hosts, tick vectors, and genospecies of <i>Borrelia burgdorferi</i> sensu lato. The primary objective of this study was to determine the fine-scale spatial distribution of different genospecies in four rodent species, the California ground squirrel (<i>Otospermophilus beecheyi</i>), northern flying squirrel (<i>Glaucomys sabrinus</i>), dusky-footed woodrat (<i>Neotoma fuscipes</i>), and Allen’s chipmunk (<i>Neotamias senex</i>). Rodents were live-trapped between June 2004 and May 2005 at the Hoopa Valley Tribal Reservation (HVTR) in Humboldt County, California. Ear-punch biopsies obtained from each rodent were tested by polymerase chain reaction (PCR) and sequencing analysis. The programs ArcGIS and SaTScan were used to examine the spatial distribution of genospecies. Multinomial log-linear models were used to model habitat and host-specific characteristics and their effect on the presence of each borrelial genospecies. The Akaike information criterion (AICc) was used to compare models and determine model fit. <i>Borrelia burgdorferi</i> sensu stricto was primarily associated with chipmunks and <i>B</i>. <i>bissettiae</i> largely with woodrats. The top model included the variables “host species”, “month”, and “elevation” (weight = 0.84). Spatial clustering of <i>B</i>. <i>bissettiae</i> was detected in the northwestern section of the HVTR, whereas <i>B</i>. <i>burgdorferi</i> sensu stricto was clustered in the southeastern section. We conclude that the spatial distribution of these borreliae are driven at least in part by host species, time-of-year, and elevation.</p></div

Coefficients, associated standard errors, and relative risk ratios from the top multinomial log-linear model as ranked by AICc.

<p>The abbreviations Bbss and Bbis stand for <i>Borrelia burgdorferi</i> sensu stricto and <i>Borrelia bissettiae</i>, respectively. The term “Chipmunk” refers to the Allen’s Chipmunk (<i>N</i>. <i>senex</i>).</p