Monitoring the course of infection.

<p>(<b>A</b>) Bioluminescence (total flux) recorded from two BALB/c mice inoculated i.p. with 3×10⁴<i>T.b. brucei</i> GVR 35 (clone VSL2) vs peripheral blood parasitemia recorded over the course of 36 days. Following infection, the bioluminescence signal fluctuated, peaking at 2×10¹¹ photons/sec/cm² on day 18, and remaining above 5×10¹⁰ photons/sec/cm² until drug intervention. After treatment with berenil on day 32 (<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002571#s2" target="_blank">Materials and Methods</a>), total flux and peripheral parasitemia fell rapidly. (<b>B</b>) Ventral and dorsal <i>in vivo</i> imaging of both mice (<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002571#s2" target="_blank">Materials and Methods</a>) revealed the rapid growth and dissemination of parasites during the course of infection. Dorsal imaging suggests that as early as day 7, parasites can be detected in the head of both mice. After berenil treatment, the bioluminescent signal was rapidly cleared from the periphery and by day 36 was only weakly detectable. However, there was a strong focal signal localised to the head, particularly apparent when viewed from the dorsal perspective. These mice were sacrificed in accordance with animal welfare regulations. (<b>C</b>) Brains were removed from other mice 33 days post-infection and imaged after perfusion (<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002571#s2" target="_blank">Materials and Methods</a>). All brains from infected animals showed a clear bioluminescent signal.