Disease	Signs and symptoms	Diagnosis	Treatment
Rocky Mountain spotted fever	Malaise, myalgias, fever, frontal headache, nausea, vomiting, nonproductive cough, sore throat, pleuritic chest pain, abdominal petechial rash affecting pads and soles of feet	Clinical signs and symptoms; skin biopsy of rash with immunofluorescent staining (60 percent sensitive); laboratory testing is of limited usefulness; routine findings include thrombocytopenia and hyponatremia	Doxycycline (Vibramycin); tetracycline; chloramphenicol (Chloromycetin)
Lyme disease	Stage 1 (early localized): erythema migrans rash at bite of bite, influenza-like symptoms, fever, fatigue, arthralgias, headache, cough, lymphadenopathy	Laboratory testing usually not necessary; enzyme-linked immunosorbent assay, confirmed by Western blotting; polymerase chain reaction of joint fluid may be helpful if available, but culture is difficult and lengthy	Children: amoxicillin; doxycycline (if older than 12 years) Adults: doxycycline; amoxicillin; cefuroxime (Ceftin) or erythromycin (if allergic to penicillin)
	Stage 2 (early disseminated): secondary cutaneous annular lesions, fever, adenopathy, central nervous system symptoms; cough and pharyngitis may occur
	Stage 3 (late chronic): arthritis, central nervous system impairment, dermatitis, keratitis, neurologic and myocardial abnormalities
Ehrlichiosis	Influenza-like syndrome, fever, chills, cough, malaise, headache, and myalgia; macular, maculopapular, or petechial rash (rare with human granulocytic ehrlichiosis)	Laboratory findings include leukopenia, thrombocytopenia, and elevated serum transaminase levels; diagnosis made with seroconversion during convalescence	Doxycycline; tetracycline
Tularemia	Fever, chills, headache, malaise, fatigue, myalgia; may include: cough, sore throat, skin ulcers, pleural effusions, pneumonia, acute respiratory distress syndrome, pericarditis, nausea, or vomiting	Clinical signs and symptoms; exposure to rabbits, wild rodents, or ticks; acute and convalescenttiters; presence of leukocytosis (however, white blood cell count may be normal); chest radiograph showing triad of oval opacities, hilar adenopathy, and pleural effusions	Streptomycin; gentamicin
Babesiosis	Influenza-like symptoms, fever, sweating, myalgia, headache, hemolytic anemia, hemoglobinuria, jaundice, renal failure	Fever, hemolytic anemia, and exposure history; peripheral smear shows protozoa in “Maltese cross” pattern; serologic testing and polymerase chain reaction tests also are used	Quinine (Quinamm) plus clindamycin (Cleocin); mild disease requires only symptomatic treatment; exchange transfusion can be used in severely ill patients
Colorado tick fever	Influenza-like symptoms, sore throat, “saddleback” fever	Diagnosis usually made with blood smears stained with immunofluorescence; laboratory findings may include leukopenia or thrombocytopenia	Supportive only
Relapsing fever	Influenza-like symptoms, arthralgias, dizziness, nausea, vomiting, high fever with irregular pattern, delirium, splenomegaly, meningeal signs; may include: epistaxis, hemoptysis, iridocyclitis, coma, cranial nerve palsy, pneumonitis, myocarditis, and rupture of the spleen	Detection of spirochetes in blood, bone marrow, cerebrospinal fluid during febrile episode; laboratory findings may include normal or elevated leukocyte count thrombocytopenia	Doxycycline; erythromycin treatment may lead to Jarisch-Herxheimer reaction