Epidemiology & Assessment

Orange County Continues to Experience West Nile Virus ActivitySeptember 26, 2014
Orange County continues to see West Nile Virus activity, with a total of 159 human infections reported to date. The County's previous high for a season was 79 cases in 2008. Santa Ana has had the highest number of infections of any city, but cases are now being reported throughout the county.


Enterovirus D68 Identified in San Diego and Ventura Counties

September 19, 2014
The California Department of Public Health (CDPH) has confirmed four enterovirus D68 (EV-D68) cases in patients in San Diego (3) and Ventura (1) counties. No cases of enterovirus D68 have been identified in Orange County. However, additional cases are likely to be reported in California, and cases may be identified in Orange County in the near future.


Orange County Reports West Nile Virus Related FatalityWest Nile Virus Activity throughout the Cunty is Increasing
August 26, 2014
A Seal Beach resident in her 80s with underlying medical conditions died last week with complications of West Nile Virus (WNV) infection. Test results received this week confirmed WNV infection; of which she had the more severe form, West Nile Neuroinvasive Disease. Orange County currently leads the state in number of WNV infections this year with 40 to date, compared to fewer than 5 infections around this time in the previous four years.


Certain communicable diseases are required to be reported to the local health department (see List of Reportable Diseases) as per the State of California Code of Regulations. Epidemiology and Assessment (E&A) unit's medical directors, public health nurses, and epidemiologists investigate individual cases and outbreaks of reported communicable diseases. We monitor disease trends, and often provide current statistics and other information to doctors, hospitals, the public and news media. We may also provide education or preventive treatment in some circumstances. Although other units handle reports of HIV/AIDS, tuberculosis (TB) or sexually transmitted diseases (STDs), we do monitor their trends in Orange County.

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