TABLE 66-1.
Viral and Bacterial Causes of Acute Bronchitis
| PATHOGEN | SEASONALITY | COMMENTS |
|---|---|---|
| Influenza viruses | Winter | Local epidemics last 6-8 wk during which clinical illness of cough and fever has high predictive value; laboratory diagnosis readily available; early neuraminidase inhibitor therapy effective |
| Rhinoviruses | Fall and spring | Most frequent cause of common cold syndrome; immunity is serotype specific |
| Coronaviruses | Winter to spring | Causes common cold syndrome; newer strains are difficult to culture and require RT-PCR for diagnosis |
| Adenoviruses | Year-round, winter epidemics | High attack rates in closed populations such as persons living in military barracks or college dormitories; serotype-specific immunity |
| Respiratory syncytial virus (RSV) | Late fall to early spring | Attack rates approach 75% in neonates, 3%-5% in adults; associated with wheezing in all age groups; rapid antigen test accurate in children but requires culture or RT-PCR to diagnose in adults |
| Human metapneumovirus (hMPV) | Winter to early spring | Associated with wheezing in adults and in infants; difficult to isolate in tissue culture and often requires RT-PCR |
| Parainfluenza viruses | Fall to winter | Similar to RSV and hMPV, parainfluenza viruses primarily pediatric pathogens but can cause severe acute disease in some adults |
| Measles virus | Year-round | Can cause respiratory disease in malnourished children; illness causes transient immune suppression |
| Mycoplasma pneumoniae | Year-round, fall outbreaks | Long incubation period (10-21 days) results in staggered epidemic pattern in families; nonproductive persistent cough typical; diagnosed by IgM serology; treated with macrolide, quinolone, or tetracycline antibiotics |
| Chlamydia pneumoniae | Year-round | Associated with sinusitis; diagnosis by RT-PCR not readily available |
| Bordetella pertussis | Year-round | Severe illness in nonimmunized children; illness milder in partially immune adults can be associated with prolonged cough; adults often reservoir for epidemics; early therapy with antibiotics can reduce spread |
RT-PCR, reverse-transcriptase polymerase chain reaction.