Table 1.

Biological characteristics of representative Ehrlichia species

Species1 (Type strain)	Diseases	Mammalian Host	Tick Vector/Host	Geographic Distribution	References
Ehrlichia. sp. HF (HF565)	Acute fatal infection of mice (experimental)	Unknown	Ixodes ovatus , I. ricinus, and I. apronophorus ticks	Japan, France, Serbia, Romania	[5–10]
E. chaffeensis (Arkansas)2	Human monocytic ehrlichiosis (HME)	Deer, Human, Dog, Coyote, Fox3	Amblyomma americanum (Lone star tick)	USA, Africa, South America, Europe, Japan	[11–16]
E. muris subsp. muris (AS145)	Murine monocytic ehrlichiosis (chronic systemic infection of mice)	Mouse, Vole	Ticks (Haemaphysalis flava or Ixodes persulcatus)	Japan, Russia4	[17, 18]
E. muris subsp. eauclairensis (Wisconsin)	Human or murine monocytic ehrlichiosis (fatal infection of mice)	Human, Mouse	Ixodes scapularis (black-legged tick)	Wisconsin and Minnesota, USA	[19, 20]
E. canis (Oklahoma)	Canine tropical pancytopenia, Venezuelan Human Ehrlichiosis 5	Dog, Human	Rhipicephalus sanguineus (brown dog tick)	Global	[21–25]
E. ruminantium (Welgevonden)	Heartwater	Ruminants (Cattle, Sheep, Goats, Antelope)	Various Amblyomma species of ticks	Africa, Caribbean6	[26–33]
E. ewingii (Stillwater)	Canine granulocytic ehrlichiosis, Human ewingii ehrlichiosis	Deer, Dog, Human	Amblyomma americanum	USA, Japan	[34–36]
E. minasensis (UFMG-EV)	Ehrlichiosis	Cattle, Deer, Dog 7	Rhipicephalus microplus tick	Brazil, Global	[37–45]

¹Based on International Code of Nomenclature of Prokaryotes, and published in International Journal of Systematic and Evolutionary Microbiology, which lists officially approved list of bacterial classification and nomenclature, the genus Ehrlichia currently consists of six validly published species with correct names (https://lpsn.dsmz.de/genus/ehrlichia)

²Ehrlichia sp. HF, or Ixodes ovatus Ehrlichia (IOE) agent, is a field tick isolate of Ehrlichia species in Fukushima Prefecture, Japan from 1993 to 1994. Ehrlichia sp. HF DNA was also detected in I. ricinus tick from Brittany, France and Serbia, and I. apronophorus tick in Romania

³E. chaffeensis DNA was detected in 71% of free-ranging coyotes in Oklahoma and experimentally infected red foxes

⁴E muris DNA was found in I. persulcatus ticks and small mammals in Russia

⁵Human Infection with E. canis with clinical signs was reported in Venezuela, and E. canis was culture isolated from a VHE patient. In addition, E. canis DNA was detected in human blood bank donors in Costa Rica

⁶Heartwater in Caribbean islands of Guadeloupe was caused E. ruminantium Gardel, which is transmitted by Amblyomma variegatum (Tropical bont tick) and exceptionally virulent in Dutch goats. More heartwater cases in wild and domestic ruminants have been reported in five Caribbean islands, posing an increasing threat to domestic and wild ruminants in the continental US

⁷E. minasensis strain UFMG-EVT was isolated from the haemolymph of engorged Rhipicephalus microplus female ticks in Brazil, whereas strain Cuiaba was isolated from the whole blood of a naturally infected cattle. E. minasensis DNAs have also been reported in ticks, cervids, and dogs from France, Pakistan, Ethiopia, and Israel