Ehrlichia chaffeensis is an obligatory intracellular bacterium that infects monocytes and macrophages and is the etiologic agent of human ehrlichiosis in the United States .
ehrlichia chaffeensis is an obligatory intracellular bacterium that infects monocytes and macrophages and is the etiologic agent of human ehrlichiosis in the united states .
B-mono_cell I-mono_cell O O B-mono_cell I-mono_cell I-mono_cell O O B-cell_type O B-cell_type O O O O O O B-mono_cell I-mono_cell O O B-other_name I-other_name O