Inefficient transmission of BbITS by a single infected tick relative to injection of tick homogenate.

<p>Individual infected nymphs (from the same cohort of BbITS-infected ticks analyzed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101009#pone-0101009-g004" target="_blank">Figures 4</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101009#pone-0101009-g005" target="_blank">5</a>) were fed on naïve mice. Fed ticks were immediately crushed and a portion of each fed tick homogenate injected into another naïve mouse. Spirochetes were isolated from the remainder of the fed tick homogenate and from mouse tissues approximately 4 weeks later, from the same set of tissues as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101009#pone-0101009-g005" target="_blank">Figure 5</a>. Genomic DNA of <i>B. burgdorferi</i> isolates was used in PCR screens to identify the BbITS population in both mice and ticks. An example of the data from a single tick/mouse infection is shown in (<b>A</b>). Each tagged clone, identified at the head of each column, is represented by a different color, and the presence of a color block denotes isolation of this clone from the fed tick or from the mice infected by either tick bite or injection of crushed tick material. The data for 9 individual tick/mouse sets are summarized in (<b>B</b>). Bars, identified in the key at the upper right of the graph, indicate total number of BbITS present in isolates from individual ticks or collectively present in tissues of the corresponding mice infected by either tick bite or by injection of fed tick homogenate. A Mann-Whitney non-parametric test was used to compare the collective data for the number of BbITS present in individual fed nymphal ticks with the number of BbITS present in the infected mice on which they had fed (P<0.001), or in the mice infected by injection of the same fed tick material (P = 0.834).