FIGURE 9.

Borrelia burgdorferi N40 strain infection with or without B. microti co-infection resulted in colonization of the forebrain at day 21 p.i., as shown in multiple sections by immunostaining. (A) Deeply anesthetized mice were perfused with PBS and fixative before euthanasia. Brain sections were labeled with anti-B. burgdorferi antibodies conjugated to FITC (white arrows) and endothelial cells using anti-CD31 antibodies tagged with PE (red), marked by arrowheads. The nuclei of the host cells are stained blue by DAPI. Aggregates of green spirochetes (arrows) were detected in brain sections from N40 infected and co-infected mice when examined by Nikon Eclipse Ti A1 scanning confocal microscope. Control B. microti infected mice brain did not show any spirochetes. (B) Additional sections of brains of mice infection with N40 alone or co-infected with B. microti also showed presence of the spirochetes when the sections were examined using Nikon Ti2 microscope illuminated using a Lumencor Spectra X light engine and images captured with a Hamamatsu ORCA Flash4.0 V3 sCMOS camera and Nikon NIS Elements software. Arrows mark green spirochetes in the image while arrowheads depict red endothelial cells. Bar represents 100 μm.