A 38-year-old woman presented to the emergency department with aggravated dyspnea at rest and productive cough for one week from late July. She was born and married in Brazil. Then she immigrated to Japan, and she had lived in an old wooden house with her husband, one son and a dog for six years. She had no smoking history and no history of significant respiratory disease. Fine crackles were detected on auscultation of her lungs. Room air arterial oxygen saturation by pulse oximetry was 98%. Laboratory tests showed an increased white blood cell count of 13,600/μL, an elevated C-reactive protein level of 5.1 mg/dL (reference value,
