FIG. 2.

T. cruzi infects primarily in the nasolacrimal duct after conjunctival infection. The lines drawn through the mouse heads in the first panel of each row (a, e, i, and m) indicate macroscopically the area being studied. Included are H&E-stained sections (b, f, j, and n) and T. cruzi-specific immunostaining (c, d, g, h, k, l, o, and p) of four different sections through the nasolacrimal duct of mice challenged conjunctivally 12 days earlier with T. cruzi IMT. Parasites were deposited atraumatically on the corneal surface of anesthetized mice. The H&E-stained sections show a low-power (×9 magnification) view of the section to orient the reader (b, f, j, and n). The boxed areas in the H&E views identify the regions studied in adjacent sections by immunohistochemistry and shown at higher power to the right. Panels c, f, k, and o show parasite-specific immunohistochemical staining (×40 magnification). Panels d, h, l, and p show the same sections at ×100 magnification. Intracellular amastigotes stain brightly red-orange by immunohistochemistry. These results indicate infection and parasite replication along the length of the nasolacrimal duct.