A 55-year-old man presents to an urgent care center with a 10-day history of escalating fever, profound fatigue, and a throbbing headache that has become increasingly debilitating. He reports experiencing diffuse body aches and a poor appetite. Five days prior, he noticed a reddish, blanching rash that started on his forearms and shins, which has since spread to his palms and soles and now includes scattered small purpuric lesions. He recently returned from a week-long fishing trip in a heavily wooded area of the Appalachian Mountains. His medical history includes well-controlled hypertension and type 2 diabetes. He denies any recent sick contacts or exposure to sick animals. His temperature is 38.8 °C, blood pressure 110/70 mmHg, pulse 98/min, and respirations 20/min. Physical examination reveals an ill-appearing man with noticeable conjunctival injection. Cardiac and pulmonary exams are unremarkable. Neurological examination shows no focal deficits, and Kernig and Brudzinski signs are absent. The skin examination confirms a generalized maculopapular rash, predominantly on the extremities, including palms and soles, with some areas exhibiting petechial transformation. Which of the following represents the most likely diagnosis and the most appropriate initial management strategy for this patient?