Communicable Disease Control

The Communicable Disease Control unit’s medical directors, public health nurses, and epidemiologists investigate individual cases and outbreaks of reported communicable disease (see List of Reportable Diseases) per the State of California Code of Regulations. We monitor disease trends, and often provide current statistics and other information to doctors, hospitals, the public and news media. For more information or CD reporting 24/7 call 714-834-8180.

For questions or comments, please email

Latest News & Health Advisories

CD Health Alert: Orange County’s First West Nile Virus Human Infection of the Season ReportedAugust 19, 2019
A Tustin woman in her 50s was diagnosed last week with West Nile Virus (WNV) fever. This is the first human WNV infection identified in Orange County this season. Human infections have already been reported this season in the surrounding counties of Los Angeles and San Bernardino.

CD Health Alert: First West Nile Virus Positive Mosquito Sample has been Identified in Orange CountyAugust 5, 2019
Orange County’s first West Nile Virus (WNV) positive mosquito sample of the season was identified last week in the city of Orange through routine trapping and testing by the Orange County Mosquito and Vector Control District (OCMVCD). No human infections have been identified so far this season in Orange County.

CD Health Alert: Consider MERS in Returning Travelers from the Arabian PeninsulaAugust 2, 2019
With the annual Hajj pilgrimage occurring from August 9 to 14, 2019, thousands of Americans will be joining approximately two million Muslims in Mecca, Saudi Arabia. Crowded conditions increase the risk of communicable diseases, including respiratory and diarrheal illnesses.

Eye on Influenza 2018-19 Season SummaryJuly 24, 2019
Each influenza season, Orange County Health Care Agency partners with local hospitals, primary care providers, universities, and colleges to conduct influenza surveillance.

CD Health Alert: Ongoing Ebola Outbreak in the Democratic Republic of CongoJuly 22, 2019
An outbreak of Ebola Virus Disease (EVD) in the Democratic Republic of Congo (DRC) was declared on August 1, 2018. The outbreak has been ongoing since then, with 2,578 confirmed and probable EVD cases and 1,737 deaths reported as of July 20, 2019.