Histopathology of the lung following 1.25×104Orientia challenge.

H & E stained uninfected lung tissue (A-20×) and IHC of uninfected lung (B-40×) compared with lung from i.p. inoculated mice 12 dpi (H&E C-20×, IHC D-40×), and lung from i.v. inoculated 15 dpi (H&E E-20×, IHC F-40×). All i.p. infections were lethal with less severe pulmonary cellular infiltrate when compared to that of i.v. infected mice with capillary endothelial cell infection of the aveolar septa.