Epidemiology & Assessment

The Epidemiology and Assessment 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 epi@ochca.com.

Latest News & Health Advisories

Provider Advisory: First West Nile Virus Death of SeasonOctober 6, 2017
The first West Nile Virus (WNV) death of the season has been confirmed in an elderly female resident of Anaheim who had neuroinvasive disease. New cases of WNV continue to be reported throughout Orange County. A total of 26 symptomatic cases and 5 asymptomatic blood donors have been reported so far this season.

Provider Advisory: First Influenza Case 2017-2018 SeasonOctober 6, 2017
The Orange County Health Care Agency (HCA) has confirmed the county’s first case of influenza for the 2017-18 season which began October 1st. The best way to prevent the flu is by getting vaccinated. Anyone who has not already received the flu vaccine should get it now before influenza season peaks.

Provider Advisory: Two New Mumps Cases Indentified in Orange CountySeptember 22, 2017
Two new cases of mumps have been identified in Orange County residents in the past ten days. The two cases are adults in their twenties and have no identified common contacts. Neither has a history of travel or contact with other mumps cases. They had symptom onset dates of September 6 and September 9.
Orange County has had 24 cases of mumps reported this year. This includes 13 cases associated with the Chapman University outbreak which ended in April, and five additional cases who have no history of travel and apparently acquired infection locally.

Provider Advisory: Update Hepatitis A Outbreaks in HomelessSeptember 21, 2017
Outbreaks of Hepatitis A virus (HAV) infection have been identified in homeless and illicit drug user populations in San Diego, Santa Cruz, and Los Angeles Counties. San Diego County has identified 444 cases of HAV infection, including 16 deaths, since early in 2017; Santa Cruz County has had 69 cases since April. Earlier this week, the Los Angeles County Department of Public Health reported an outbreak of HAV infections in their homeless population. Two Los Angeles cases apparently acquired disease in that county; eight more have occurred there after exposure in San Diego or Santa Cruz.

Hepatitis A Outbreaks in Homeless and Illicit Drug User Populations in CaliforniaSeptember 20, 2017
San Diego, Santa Cruz, and Los Angeles Counties are experiencing Hepatitis A outbreaks primarily in their homeless and illicit drug user populations. San Diego County has had 444 cases of Hepatitis A, Santa Cruz County has reported 69, and Los Angeles County has reported 10 cases.