BACKGROUND: Rocky Mountain spotted fever (RMSF) has emerged as a significant cause of morbidity and mortality since 2002 on tribal lands in Arizona. The explosive nature of this outbreak and the recognition of an unexpected tick vector, Rhipicephalus sanguineus, prompted an investigation to characterize RMSF in this unique setting, and compare RMSF cases to similar illnesses. METHODS: We compared medical records of 205 RMSF cases and 175 non-RMSF illnesses that prompted RMSF testing during 2002-2011 from two Indian reservations in Arizona. RESULTS: RMSF cases occurred year-round and peaked later (July-September) than RMSF cases reported from other U.S regions. Cases were younger (median age 11 years) and reported fever and rash less frequently as well as less tick exposure compared to other U.S. cases. Fever was present in 81% of cases but not significantly different from that in non-RMSF illnesses. Classic laboratory abnormalities such as low sodium and platelet counts had small and subtle differences between cases and non-RMSF illnesses. Imaging studies reflected the variability and complexity of the illness, but proved unhelpful in clarifying the early diagnosis. CONCLUSIONS: RMSF epidemiology in this region appears different than RMSF elsewhere in the U.S. No specific pattern of signs, symptoms or laboratory findings occurred with enough frequency to consistently differentiate RMSF from other illnesses. Due to the non-specific and variable nature of RMSF presentations, clinicians in this region should aggressively treat febrile illnesses and sepsis with doxycycline for suspected RMSF.

On September 30, 2014, the Texas Department of State Health Services reported a case of Ebola virus disease (Ebola) diagnosed in Dallas, Texas, and confirmed by CDC, the first case of Ebola diagnosed in the United States. The patient (patient 1) had traveled from Liberia, a country which, along with Sierra Leone and Guinea, is currently experiencing the largest recorded Ebola outbreak. A nurse (patient 2) who provided hospital bedside care to patient 1 in Texas visited an emergency department (ED) with fever and was diagnosed with laboratory-confirmed Ebola on October 11, and a second nurse (patient 3) who also provided hospital bedside care visited an ED with fever and rash on October 14 and was diagnosed with laboratory-confirmed Ebola on October 15. Patient 3 visited Ohio during October 10-13, traveling by commercial airline between Dallas, Texas, and Cleveland, Ohio. Based on the medical history and clinical and laboratory findings on October 14, the date of illness onset was uncertain; therefore, CDC, in collaboration with state and local partners, included the period October 10-13 as being part of the potentially infectious period, out of an abundance of caution to ensure all potential contacts were monitored. On October 15, the Ohio Department of Health requested CDC assistance to identify and monitor contacts of patient 3, assess the risk for disease transmission, provide infection control recommendations, and assess and guide regional health care system preparedness. The description of this contact investigation and hospital assessment is provided to help other states in planning for similar events.