Rickettsia parkeri rickettsiosis, transmitted by the Gulf Coast tick, causes fever, headache, and a near-pathognomonic black eschar at the bite site. The eschar is a useful contrast: classical Rocky Mountain spotted fever almost never produces one. R. parkeri is also milder, with no documented deaths, though doxycycline is still indicated.
Dermacentor occidentalis transmits Rickettsia 364D (now classified as Rickettsia rickettsii subsp. californica), the cause of Pacific…
Rhipicephalus sanguineus is a competent vector of Rickettsia rickettsii in the southwestern United States and northern Mexico, where…
The hallmark spotted rash of Rocky Mountain spotted fever does not appear until day 2 to 5 of illness, and roughly 10 percent of cases…
Amblyomma cajennense (sensu lato) - now recognized as a complex of six closely related species - is the principal Latin American vector of…
Amblyomma maculatum was once confined to a coastal band along the Gulf of Mexico. Established populations now reach Connecticut and the…
A single tick species, Amblyomma americanum, transmits ehrlichiosis from Ehrlichia chaffeensis and E. ewingii, tularemia, Heartland virus,…