Ehrlichia chaffeensis is causative agent of
Ehrlichiae
These are gram negative, obligate intracellular bacteria which have affinity towards blood cells,
They grow within phagosomes of phagocytes as mulberry-like clusters called morula.
They are tick-borne.
Three human infections caused by this group of organisms have been identified :-
 
Human monocytic ehrlichiosis (HME)
It is caused by E. chaffeensis, and transmitted by Amblyomma ticks.
Deer and rodents are believed to be reservoir hosts.
There is leukopenia, thrombocytopenia and elevated liver enzymes.
 
2) Human granulocytic ehrlichiosis (HGE)
It is caused by E. equi (E. phagocytophila), and transmitted by ixodes ticks.
Deer, cattle and sheep are suspected reservoirs.
There is leucopenia and thrombocytopenia.
 
Glandular like fever
It is caused by Ehrlichia sennetsu
No arthopod vector has been identified and infection is caused by ingestion offish carrying infected flukes.
Theres is lymphoid hyperplasia with atypical lymphocytosis.
Doxycvcline is recommended for treatment of ehrlichiosis.
Human monocytic ehrlichiosis
Human granulocytic ehrlichiosis
Glandular fever
None