Ehrlichia chaffeensis

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Ehrlichia chaffeensis


Higher order taxa

Domain: Bacteria; Phylum: Proteobacteria; Class: Alphaproteobacteria; Order: Rickettsiales; family: Anaplasmataceae [Others may be used. Use NCBI link to find]


NCBI: [}

Ehrlichia chaffeensis

Description and significance

Ehrlichia chaffeensis causes a tick-borne disease affecting both animals and humans. The first incident of human ehrlichiosis (the infection caused by the Ehrlichia bacterium) was reported in Japan in 1954. An event of human ehrlichiosis was not reported in the United States until 1986. In 1991, E. chaffeensis was isolated from a military recruit stationed at Fort Chaffee, Arkansas, this was the first isolation from a human in the US. (3 Dawson) Public attention peaked after this bacterium was found to be the causative agent of human monocytotropic ehrlichiosis (HME). According to the Center for Disease Control and Prevention (CDC), HME is one of the most frequent life-threatening tick-borne zoonoses (a disease that can be transmitted from an animal to a human) but frequently goes unreported in the United States since symptoms are similar to many other diseases or infections a person may get from insect bites, like Lyme disease from a tick. E. chaffeensis has been isolated in white-tailed deer and even dogs, with the latter being a possible carrier of the tick which can infect humans with HME. E. chaffeensis is also easily contracted in nature where bare skin is exposed and a tick carrying the bacteria can attach and infect. HME is mostly found in the southern states of the US but there are cases reported all over the country as well as in other parts of the world. (2 McQuiston)

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.


Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.


How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required


[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by Armen Sarkisian, student of Rachel Larsen and Kit Pogliano