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Disease Agent Target Tissues Vector (Ixodes species) Prevalence of Infection Timing of Infection Early Clinical Features Diagnostic Tests Treatment (in Nonpregnant Adults) Lyme disease B. burdorferi Systemic bacterial infection North America (high prevalence in Northeast, Wisconsin, Minnesota, West Coast), Russia, Europe Ticks: 20% to 40% in New England; 0% to 14% in California; 0 to 4.6% in Southern United States Spring and summer 7–14 day incubation after tick detaches Stage I: erythema migrans lesion in 70% of cases (malaise, headache, and fatigue may accompany EM) Stage II: generalized annular rash, severe malaise and fatigue, migratory joint pains, neurologic symptoms (meningitis, facial palsies, radiculoneuritis) in 15% of untreated patients, and cardiac conduction abnormalities Antibodies to B. burdorferi IgM: positive as early as 2 weeks after infection IgG: postitive 6 weeks after infection; Western blotting Stage I:Doxycycline 100 mg; Cefuroxime 500 bid; or Amoxicillin 500 mg tid for 14 days Stage II:Ceftriaxone 2 g IV bid for 14 days Babesiosis B. microti Red blood cells North America (high prevalence in Northeastern and Pacific Northwestern United States) Ticks: 20% to 40% in New England Humans: 1% to 5% Peaks in June Incubation, 1 to 3 weeks Gradual onset of flu-like syndrome: malaise, anorexia, chills, myalgias, arthralgias, nausea, vomiting, cough, abdominal pain, sore throat Fever up to 40° C, hepatosplenomegaly Lymphadenopathy, rashes Anemia, thrombocytopenia, mild leukopenia, atypical lymphocytosis, elevated sedimentation rate, elevated liver injury markers Dark urine in severe cases. Intravascular hemolysis, hemoglobinuria, and proteinuria Increasing severity in patients older than 50, medical comorbidities Asplenia: ARDS, CHF, ARF, DIC Fatality rate of 20% to 40% Peripheral blood smear: intraerythrocytic parasites, thin smears required to distinguish trophozoites of babesia vs. Malaria. Maltese cross arrangement of trophozoites uncommon but pathognomonic Indirect immunofluorescent antibodies become positive at least a week after onset of illness IgM: sensitivity, 91% specificity, 99% IgG: Sensitivity, 88% to 96% Specificity, 90 −100% PCR amplification can detect parasitemia at levels as low as 3 parasites per 50 μL of blood Atovaquone 750 mg bid and azithromycin 250 mg qd for 10 days or clindamycin 600 mg po tid or 300 to 600 mg IV q6 hours and quinine 650 mg poq 6 to 8 hours Exchange transfusion for parasitemia >10% or significant hemolysis, renal, pulmonary, or hepatic compromise Human granu-locytic anap-lasmosis A. phagocyto-philium Neutrophils Ixodes species Fever, chills, headache Thrombocytopenia, leukopenia, elevated liver injury tests Increasing severity in immunosupression, chronic inflammatory illnesses and underlying malignancy Peripheral blood smear: intragranulo-cytic inclusions Acute and convalescent phase antibodies Doxycycline 100 mg bid for 10 days rifampin 300 mg bid for 10 days
