|Description:||This 1978 transmission electron microscopic (TEM) image depicted a brain capillary of a mouse that had been experimentally infected intravenously with Orientia tsutsugamushi rickettsial micro-organisms. Revealed by this TEM, was the presence of pericapillary hemorrhage and edema. Several of the O. tsutsugamushi organisms were visible within the cytoplasm of a degenerating capillary endothelial cell.|
Scrub typhus is an acute febrile disease caused by Orientia tsutsugamushi. The disease occurs mainly in the large triangular region extending from Japan in the north, to Australia in the southwest, and the South Pacific Islands in the southeast. Humans are infected by the bite of the larva of the trombiculid mite harboring O. tsutsugamushi. This pathogen attacks endothelial cells resulting in vasculitis. The clinical manifestations are characterized by a papular rash, headache, fever, chills, and an eschar at the site of the chigger bite.