A 29-year-old bird collector presents to the local clinic with what he describes as flu-like symptoms. He doesn't look ill, and has a slight fever, headache, and a dry hacking cough. He denies the production of sputum or hemoptysis. There are no crackles heard on auscultation, and a radiograph shows small streaks of infiltrate. It is determined that he has pneumonia. What is the most likely organism causing his disease