Psittacosis Surveillance and Trends

Key points

  • CDC tracks psittacosis cases using a national surveillance system.
  • Psittacosis is an uncommon disease in the United States.
  • Outbreaks of psittacosis are known to occur.
An illustration of generic data

Data system

A map of the United States to show the National Notifiable Diseases Surveillance System monitors disease at a national level.
NNDSS collects information on psittacosis cases.

National Notifiable Diseases Surveillance System

Psittacosis is a reportable condition in most states.

CDC collects national information about psittacosis cases through the National Notifiable Diseases Surveillance System (NNDSS). CDC publishes updated NNDSS data each week.

How the data are interpreted

Disease trends

Between 1988 and 2010, the number of reported psittacosis cases decreased. This decline may be the result of improved diagnostic tests that distinguish Chlamydia psittaci from more common C. pneumoniae infections.

The number of cases can vary widely from year to year because of periodic outbreaks. For example, poultry processing plants have reported psittacosis outbreaks. In 2018, a multistate psittacosis outbreak among poultry plant workers had 13 laboratory confirmed cases.

Data reporting

Since 2010, CDC has typically received reports of fewer than 10 cases in the United States each year. However, experts believe the disease is potentially underreported and underdiagnosed.

View NNDSS infectious disease data tables.

Data definitions

The Council of State and Territorial Epidemiologists (CSTE) released the most recent case definition for psittacosis in 2010.