| Clinical
Features |
Pneumonia or bronchitis, gradual
onset of cough with little or no fever. Less common presentations
are pharyngitis, laryngitis, and sinusitis. The spectrum of
illness can range from asymptomatic infection to severe disease. |
| Etiologic
Agent |
Chlamydia pneumoniae, proposed
new name, Chlamydophila pneumoniae. C. pneumoniae
is distinct from other Chlamydia species. |
| Incidence |
The overall incidence is unknown.
Each year, an estimated 2-5 million cases of pneumonia and
500,000 pneumonia-related hospitalizations occur in the United
States. |
| Sequelae |
C. pneumoniae infection may
be associated, by some investigators, with atherosclerotic
vascular disease. Associations with Alzheimer’s disease, asthma,
and reactive arthritis have been proposed. |
| Transmission |
Person-to-person transmission by
respiratory secretions. |
| Risk
Groups |
All ages at risk, but most common
in school-age children. In the United States, about 50% of
adults have evidence of past infection by age 20. Reinfection
throughout life appears to be common. |
| Surveillance |
No national or state surveillance
exists. |
| Trends |
Unknown. Improved diagnostic testing
may lead to improved recognition of infection. |
| Challenges |
There is a lack of standardized
diagnostic methods. Isolation of the etiologic agent is difficult,
so antibody tests using paired acute- and convalescent-phase
sera have been used for diagnosis. There are no known methods
to prevent possible sequelae. The role of C. pneumoniae
in atherosclerotic vascular disease needs further definition. |
| Opportunities |
To apply new laboratory methods
to develop better diagnostic tests and to evaluate association
between C. pneumoniae infection and atherosclerosis,
as well as other chronic diseases. |
|
December 2003
|
