Untreated Rocky Mountain spotted fever kills roughly 20 to 25 percent of patients, with most deaths in the second week of illness. Doxycycline started within five days of symptom onset cuts mortality to around 5 percent. Children are five times more likely than adults to die: under-10s account for under 6 percent of cases but 22 percent of deaths.
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…
A 2001 NEJM trial by Robert Nadelman and colleagues showed that a single 200 mg oral dose of doxycycline within 72 hours of removing an…
Rhipicephalus sanguineus is a competent vector of Rickettsia rickettsii in the southwestern United States and northern Mexico, where…
Rickettsia parkeri rickettsiosis, transmitted by the Gulf Coast tick, causes fever, headache, and a near-pathognomonic black eschar at the…
Dermacentor occidentalis transmits Rickettsia 364D (now classified as Rickettsia rickettsii subsp. californica), the cause of Pacific…
Roughly 10 to 15 percent of patients hospitalized with Powassan virus encephalitis die, and around half of survivors have lasting…