Babesiosis | 1–4 wk | Fever, chills, myalgias, nausea, headache, nonproductive cough; may also have jaundice Illness much more severe in asplenic patients, other immunocompromised hosts, or chronic heart, hepatic, or lung disease | Thick and thin smears with Giemsa/Wright staining (can see trophozoites looking like a Maltese Cross) Anemia, low haptoglobin, elevated lactate dehydrogenase and reticulocyte count; thrombocytopenia is common |
Colorado tick fever | 3–7 d | Biphasic fever (for 3–4 d, then afebrile 1–3 d, then febrile again × 2–3 d), retro-orbital headache, photophobia, myalgia, nausea, vomiting Complications: meningoencephalitis, hemorrhagic fever | Serologies Ancillary: leukopenia, thrombocytopenia, elevated hepatic transaminases and creatine kinase |
Human granulocytic anaplasmosis | 5–10 d | Fever, chills, headache, malaise, myalgia; rash after 1 wk of illness. Complications: ARDS, meningoencephalitis (lymphocytic CSF pleocytosis), DIC, renal failure | Serology (4-fold change in acute and convalescent titers) or PCR Cross-reactivity exists with ehrlichiosis Ancillary: leucopenia, thrombocytopenia, elevated hepatic transaminases |
Human monocytic ehrlichiosis | 5–10 d | Fever, chills, headache, malaise, myalgia; rash after 1 wk of illness. Complications: ARDS, meningoencephalitis (lymphocytic CSF pleocytosis), DIC, renal failure Ehrlichiosis often causes more severe disease manifestations than anaplasmosis | Serology (4-fold change in acute and convalescent titers) or PCR Cross-reactivity exists with anaplasmosis Ancillary: leukopenia, thrombocytopenia, elevated hepatic transaminases |
Lyme disease | 3–30 d | Stage 1: erythema migrans (EM) at site of bite, fever, malaise, myalgias, arthralgias, regional adenopathy Stage 2: multiple EM, cranial nerve palsies, meningitis, headache, AV block, myocarditis, oligoarticular arthritis Stage 3: more chronic neurological (encephalopathy) and arthritic (refractory joint pain) symptoms | For stage 1 Lyme, diagnosis is clinical and better than serologic diagnosis (treatment in stage 1 can blunt antibody response) For latter stages, serology, PCR diagnosis for arthritis and meningitis or encephalitis |
Q fever | 2–3 wk | Fever, headache, malaise, myalgias, cough, chest pain, gastroenteritis Complications: pneumonia, hepatitis, myocarditis, meningoencephalitis Chronic Q fever occurs in 1% of acutely ill patients (higher risk in pregnant or immunocompromised patients), and manifestations may include endocarditis, hepatitis, and aneurysms. | Serology (4-fold change in acute and convalescent titers) or PCR Culture usually is not attempted given risk to laboratory workers |
Rocky Mountain spotted fever | 2–14 d | “Classic” triad of fever, rash, and headache seen in a minority of children; also may see myalgia, vomiting, abdominal pain, photophobia Rash after 2–5 d of fever: initially blanching erythematous macules on wrists/ankles, then spreads centrally and becomes petechial | Serology takes up to 7–10 d to become positive Do not wait for confirmation to initiate therapy! Ancillary: anemia, thrombocytopenia, hyponatremia, elevated hepatic transaminases, increased bilirubin and creatine kinase |
Tularemia | 3–5 d | Abrupt onset of fever, chills, myalgia, headache. Several syndromes exist: ulceroglandular, glandular, oculoglandular, oropharyngeal, and vesicular skin lesions Complications: pneumonic tularemia | Serology (can cross-react with Brucella, Legionella) Alert laboratory if suspect tularemia, as it can pose a hazard to workers |