| Pathogen* | Clinical features and epidemiologic associations |
| Influenza virus | Acute onset fever, chills, myalgias, and cough during influenza season or in patients with known exposure or recent travel |
| Bordetella pertussis | Cough lasting ≥2 weeks without an apparent cause, with one of the following symptoms: paroxysms of coughing, inspiratory whoop, or post-tussive emesis, particularly during outbreaks or in patients with known exposures |
| Bordetella bronchiseptica | Pertussis-like syndrome in a patient with animal exposure, particularly if immunocompromised |
| Mycoplasma pneumoniae | No distinguishing clinical features, although outbreaks reported across large geographic regions and among families or persons living in close quarters |
| Chlamydia pneumoniae | No distinguishing clinical features, although outbreaks reported in persons living in close quarters |
| Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) | Common features include cough, myalgias, and headache; diarrhea, sore throat, and smell or taste abnormalities are frequently reported |
