Clinical Presentation
- Many of the diseases should be suspected in patients with:
- Flu-like illness that occurs not in flu season
- ± cytopenias, ± liver enzyme abnormalities
- Exposure history (outdoors activities, rats)
By Disease
| Lyme disease | Babesiosis | Anaplasmosis | Ehrlichiosis | RMSF | |
|---|---|---|---|---|---|
| Pathogen | B. burgdorferi | B. microti | A. phagocytophilum | E. chaffeensis | R. rickettsii |
| Incubation | 2-3 wk | 1-4 wk | 5-14 d | 5-14 d | 3-12 d |
| Tick | Black-legged tick | Black-legged tick | Black-legged tick | Black-legged tick, Lonestar tick | American dog tick |
| Symptoms | Fever | Fever, HA, n/v/d | Fever, HA | Fever, HA, myalgias, n/v | Fever, HA |
| Cells | Disseminates | Erythrocytes | Granulocytes | Monocytes | Vascular endothelial |
| Rash | Erythema migrans | Rare | Rare | Maculopapular (30%) | Maculopapular; Eschar with R. parkeri |
| Labs | Uncommon | Hemolytic anemia, thrombocytopenia, liver enzymes | Leukopenia, liver enzymes, thrombocytopenia | Leukopenia ± lymphocytosis, liver enzymes, thrombocytopenia | Thrombocytopenia, liver enzymes, hyponatremia |
| Complications | Carditis, neuro sx, arthritis | DIC, ARDS, CHF, AKI | Opportunistic infections, shock | Seizure, coma, CHF, pericardial effusion, shock | Coma/seizure (30%) |
| Diagnosis | EM, serology | Microscopy | Serology, ±microscopy | Serology, ±microscopy | Serology, biopsy |
| Mortality | Rare | 3-20% | 7-10% | 2-5% | 8% |
| Treatment | Doxycycline | Azithromycin, Atovaquone | Doxycycline | Doxycycline | Doxycycline |
By Tick
| Tick | Distribution | Transmits | Comments |
|---|---|---|---|
| American dog tick (Dermacentor variabilis) | East of the Rockies, and in limited areas in the Pacific coast | Tularemia and RMSF | Highest risk of bites in spring and summer. Sometimes called wood ticks. |
| Blacklegged tick (Ixodes scapularis) | Across the eastern US and in Ontario | Lyme disease, Anaplasma, B. miyamotoi, ehrlichiosis, babesiosis, and Powassan virus | Highest risk in spring through fall, but can be found any time it's above freezing. |
| Brown dog tick (Rhipicephalus sanguineus) | Worldwide | RMSF | Dogs are the primary host but it can also bite humans. |
| Gulf Coast tick (Amblyomma maculatum) | Coastal areas along the Guld of Mexico and southern Atlantic | Rickettsia parkeri | |
| Lone Star tick (Amblyomma americanum) | Southeastern and eastern United States | Ehrlichiosis, Heartland virus, tularemia, STARI | Very aggressive tick. Irritation at site does not indicate infection. |
| Rocky Mountain wood tick (Dermacentor andersoni) | Rocky Mountains and southwestern Canada from elevations of 4,000 to 10,500 feet | RMSF, Colorado tick fever, and tularemia | |
| Western blacklegged tick (Ixodes pacificus) | Pacific coast of the U.S., particularly northern California | Anaplasmosis and Lyme disease |
