Ehrlichia ewingii is a species of rickettsiales

Rickettsiales

The Rickettsiales, also called rickettsias, are an order of small proteobacteria. Most of those described survive only as endosymbionts of other cells. Some are notable pathogens, including Rickettsia, which causes a variety of diseases in humans...

 bacteria.

Previously known to infect dogs, it has recently been associated with human infection (see Human ewingii ehrlichiosis

Human ewingii ehrlichiosis

Ehrlichiosis ewingii infection is an infectious disease caused by an intracellular bacteria, Ehrlichia ewingii. The infection is transmitted to humans by Amblyomma americanum...

).

There is currently no serological test.
PCR can be used in diagnosis.

The name Ehrlichia ewingii was proposed in 1992.

It is classified as a member of genus Ehrlichia

Ehrlichia

Ehrlichia is a genus of rickettsiales bacteria. They are transmitted by ticks. Several species can cause infection in humans. The genus is named after German microbiologist Paul Ehrlich...

.

The bacteria use tick

Tick

Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...

s as a vector.