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, you can also email us at

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Latest News & Health Advisories

CD Health Alert: First West Nile Virus Positive Mosquito Samples Have Been Identified in Orange CountyJuly 13, 2020
Orange County's first West Nile Virus (WNV) positive mosquito samples of the season were identified last week in Cypress, Anaheim, and Garden Grove through routine trapping and testing by the Orange County Mosquito and Vector Control District. The first WNV positive dead bird of the season was also collected in Irvine.

CD Health Alert: COVID-19 Update for Orange County ProvidersJuly 7, 2020
COVID-19 daily case counts and the number of those hospitalized with the disease have increased in Orange County in recent weeks. Over 14,000 cases have been reported in Orange County, with over 340 deaths. Approximately half of all county deaths have occurred in residents of skilled nursing facilities.

CD Health Alert: 2019 Novel Coronavirus: Orange County Update for Long Term Care Facilities (LTCFs)May 14, 2020
Fifteen COVID-19 outbreaks have been identified in Orange County LTCFs over the past 4 weeks. These outbreaks have occurred despite good compliance with temperature and symptom screening of both staff and residents. Outbreaks can spread rapidly among residents and staff, and responding to and testing for these outbreaks strains resources.

CD Health Alert: 2019 Novel Coronavirus: Orange County UpdateMarch 23, 2020
Orange County has now had over 125 cases of Novel Coronavirus 2019 (COVID-19) reported. There has been a rapid increase in daily reports of COVID-19 cases over the last several days and community transmission is becoming more widespread. At this point the Orange County Health Care Agency (OCHCA) will only be conducting investigations of cases identified in hospitalized patients, health care workers, and residents of congregate living facilities. Providers should inform their patients of test results and give them education on disease prevention and monitoring for worsening disease.


CD Health Alert: 2019 Novel Coronavirus: Orange County UpdatesMarch 17, 2020
Orange County now has 22 cases of 2019 Novel Coronavirus Disease (COVID-19) reported; case numbers are increasingly rapidly and a number of cases resulting from community transmission have been reported.