ConditionPathogenVectorClinical presentationDiagnosisTreatment optionsPrevention

  • Ehrlichiosis

  • Ehrlichia, Neorickettsia

  • Amblyomma americanum (Lone star) tick

  • Fever, headache, malaise, myalgia

  • Clinical: nonspecific flulike illness, meningoencephalitis

  • Elevated transaminases, leukopenia, thrombocytopenia

  • Characteristic inclusions (morulae) may be demonstrated on blood smears

  • Serologic confirmatory tests are available

  • Doxycycline: 100 mg every 12 hours (adults), 2.2 mg per kg every 12 hours (children < 45 kg [100 lb])

  • Tick avoidance*

  • Nationally notifiable disease†

  • Tick-borne spotted fever rickettsial infections (including Rocky Mountain spotted fever)

  • Rickettsia

  • Dermacentor, Rhipicephalus and Amblyomma maculatum (Gulf Coast) ticks

  • Abdominal pain, fever, myalgias, rash on the extremities, eschar

  • Clinical: nonspecific flulike illness

  • Rash is initially macular and later petechial, and can involve the hands and soles (Rocky Mountain spotted fever)

  • Culture, microscopic, molecular, and serologic methods are available; only polymerase chain reaction and culture are specific for Rocky Mountain spotted fever ( http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5504a1.htm)

  • Doxycycline: 100 mg every 12 hours (adults), 2.2 mg per kg every 12 hours (children < 45 kg)

  • Treatment should be initiated promptly on clinical suspicion, without waiting for laboratory confirmation

  • Tick avoidance*

  • Nationally notifiable disease†

  • Tularemia

  • Francisella tularensis

  • Dermacentor and Amblyomma ticks, Chrysops discalis (deer fly)

  • Fever, skin ulcer at site of inoculation, regional lymphadenopathy

  • Primarily a clinical diagnosis, with appropriate exposure history

  • Serologic confirmatory tests are available

  • Streptomycin: 15 mg per kg IM twice per day for 10 days

  • Alternatives

  • Doxycycline: 100 mg orally or IV twice per day for 14 to 21 days

  • Ciprofloxacin: 400 mg IV or 750 mg orally twice per day for 10 days

  • Tick avoidance*

  • Glove use when skinning or handling rabbits or rodents

  • Cook meat well

  • Nationally notifiable disease†

  • Typhus (e.g., flea-borne [murine typhus], louse-borne [epidemic typhus], mite-borne [scrub typhus])

  • Rickettsia, Orientia

  • Rat flea (Xenopsylla), human body louse (Pediculus), squirrel flea (Orchospea), larval mite chigger (Leptotrombidium)

  • Murine: fever, headache, myalgias, rash

  • Epidemic: intractable headache, unproductive cough, rash (late)

  • Scrub: eschar, deafness, fever, headache, malaise, myalgias, regional lymphadenopathy, tinnitus

  • Primarily a clinical diagnosis, with appropriate exposure history

  • Biopsy, molecular, and serologic confirmatory tests are available

  • Doxycycline: 100 mg every 12 hours (adults), 2.2 mg per kg every 12 hours (children < 45 kg)

  • Tick avoidance*

  • Avoidance of crowded conditions, good personal hygiene to decrease exposure to body lice