Disease (causative agent)	Primary vector(s)	Approximate distribution	Incubation period (days)	Common initial signs and symptoms	Common laboratory abnormalities	Rash	Fatality rate (%)
Rocky Mountain Spotted fever (Rickettsia rickettsii)	American dog tick (Dermacentor variabilis), Rocky Mountain wood tick (Dermacentor andersoni), brown dog tick (Rhipicephalus sanguineus) in Arizona	Widespread in the United States, especially in south Atlantic and south central states	Two to 14	Fever, nausea, vomiting, myalgia, anorexia, headache	Thrombocytopenia, mild hyponatremia, mildly elevated hepatic transaminase levels	Maculopapular rash appears approximately two to four days after fever onset in 50 to 80 percent of adults and in more than 90 percent of children; may involve the palms and soles	5 to 10
Human monocytic ehrlichiosis (Ehrlichia chaffeensis)	Lone star tick (Amblyomma americanum)	Southern, south central, mid-Atlantic, and northern states; isolated areas of New England	Five to 14	Fever, headache, malaise, myalgia	Leukopenia, thrombocytopenia, elevated serum transaminase levels	Rash appears in less than 30 percent of adults and in about 60 percent of children	2 to 3
Human granulocytic anaplasmosis (Anaplasma phagocytophilum)	Black-legged tick (Ixodes scapularis and Ixodes pacificus) in the United States	North central and Pacific states; New England	Five to 21	Fever, headache, malaise, nausea, vomiting	Leukopenia, thrombocytopenia, elevated serum transaminase levels	Rare	Less than 1
Ehrlichia ewingii Infection	Lone star tick	South Atlantic and south central states; isolated areas of New England	Five to 14	Fever, headache, myalgia, nausea, vomiting	Leukopenia, thrombocytopenia, elevated serum transaminase levels	Rare	None documented