How would you manage an otherwise healthy woman in her early 70s with 5 days of severe watery diarrhea beginning on the last day of a 2 week trip to Spain and Portugal without fever, hematochezia, or significant hypotension, found to have mild electrolyte abnormalities with sodium 133, potassium 3.3, and CBC with differential with normal platelets and hemoglobin but WBC of 3.4k and 26% bands?