HGE

[SOMERS at PICARD.EVMS.EDU]

Regarding the query about HGE.  Bruce, HGE is caused by a rickettsia and is
a Gram-negative bacillus.  The predominant form in this country is Ehrlichia
chaffeensis, an intracellular pathogen in monocytes.  The recently described
HGE (human granulocytic ehrlichiosis) infects granulocytes and the proposed
name is E. phagocytophila.  Human ehrlichiosis is transmitted by ticks.  I
believe E. chaffeensis is transmitted predominantly by Dermacentor (dog tick)
whereas E. phagocytophila and HGE is transmitted both by Dermacentor (dog)
and Ixodes (deer) ticks.  A neat photomicrograph of ehrlichiosis can be found
in the May 25, 1995 issue of the New England J. Med. 332:1417, 1995 "Images
in Clinical Medicine".

Ken Somers