(Santa Ana, CA) –Temperatures in Coastal Orange County are expected to reach 95°F, with Inland areas ranging from the mid‑90s up to 105°F through Friday, August 28.

High temperatures increase the risk of heat-related illnesses like heat exhaustion and heatstroke for those at higher risk for heat illness, including people who work outdoors, infants, children, pregnant people, ages 65 or older, and people with chronic conditions.

Prolonged exposure to excessive temperatures may cause serious conditions like heat cramps or heatstroke and can even be fatal. Symptoms of heat exhaustion include heavy sweating, muscle cramps, weakness, headache, nausea or vomiting and dizziness. Warning signs of heat stroke include an extremely high body temperature, unconsciousness, confusion, hot and dry skin (no sweating), a rapid pulse, and a throbbing headache.

If symptoms of heat stroke occur, immediately call for medical assistance. Move the person to a shady area and begin cooling their body with cool water.

Recommended precautions to prevent heat-related illnesses include the following:

• Drink plenty of water; don’t wait until you are thirsty.
•  Wear light, loose-fitting clothing.
• Stay out of the sun if possible, and when in the sun wear a wide brim hat and use sunscreen.
• Avoid strenuous activities if you are outside or in non-air-conditioned buildings. If you are working outdoors, take frequent rest and refreshment breaks in a shaded area.
• Never leave children, elderly people or pets unattended in closed cars or other vehicles.
• Check on those, like neighbors, who are at high risk to make sure they are staying cool – including seniors who live alone, people with heart or lung disease, and young children.
• Stay cool indoors – if your home is not air conditioned, visit public facilities such as shopping malls and libraries to stay cool. To find a cooling center near you, visit Cooling Centers | Orange County (ocgov.com).

Since temperatures and conditions can vary widely throughout the county, local schools, child care facilities, and organizations working with children are encouraged to visit the State of California Office of School Health Hub for heat planning guidance and sports and activities recommendations to protect students and youth during these high temperature alert periods.

For more information on heat-related illnesses, visit Health Corner - Heat Stroke Is No Joke And It Can Strike Anyone, CDPH Be Informed Extreme Heat and California HeatReadyCA.com.

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The OC Health Care Agency (HCA) is a regional interdisciplinary health jurisdiction and an accredited health department, charged with protecting and promoting individual, family and community health through partnership and coordination of public and private sector resources. Visit www.ochealthinfo.com to learn more about services and resources.

Source

(Santa Ana, CA) – The OC Health Care Agency (HCA) received confirmation of a measles case in an adult which was locally acquired from a known exposure. The individual visited several public locations during the infectious period including the following:
 
         8/11/26 – 5 p.m. - 10 p.m. – Anaheim Packing District
         8/14/26 – 5 p.m. - 8 p.m. – Fire and Ice restaurant, Anaheim
         8/14/26 – 10 p.m. - 12 midnight – BJ’s restaurant, Orange
         8/14/26 – 8 p.m. - 11 p.m. – The Escape Game Orange
         8/11/26 and 8/14/26 – 10:40 a.m. - 12 noon – UCI Health Fountain Valley Cafeteria
 
People who were in the locations above around the same time(s) should:

• Review whether they are immune to measles or not. People who are not fully immunized against measles or who don’t know if they are immune to measles already, should talk with a health care provider about receiving the measles, mumps and rubella (MMR) vaccine.
• Monitor themselves for illness with fever and/or an unexplained rash from 7 days to 21 days after their exposure (the time period when symptoms may develop); if symptoms develop, stay at home and call a health care provider immediately for guidance.
• Anyone who suspects they may have measles should call their medical provider before arriving at the medical office to avoid exposing others.
• Clinicians should immediately report any suspected measles cases to the OC Health Care Agency for guidance and testing coordination.

“Measles is highly contagious. Everyone 12 months and older should receive two doses of MMR vaccine (measles, mumps and rubella). Infants less than a year old who are traveling internationally should receive one dose of MMR vaccine. Adults and others who are not immune remain at risk, especially as outbreaks continue across the country and worldwide,” said Dr. Anissa Davis, Deputy County Health Officer. “Vaccination is the best protection.”
 
According to the Centers for Disease Control and Prevention (CDC), there have already been 2,566 confirmed measles cases in the United States in 2026. This marks the highest annual case count since measles was declared eliminated in the US in 2000, surpassing the 2,289 cases reported during the full year of 2025.  
 
Common symptoms include fever, cough, red watery eyes, and a rash that typically begins on the head before spreading to the rest of the body. Measles is the most contagious disease known, and it spreads very easily through the air and by direct contact with an infected person. People are contagious from approximately four days before the rash begins through four days after the rash appears.
 
Vaccination remains the most effective way to prevent measles. About measles immunization:

• Immunizing household members, including children, adolescents, and adults, is the best way to protect infants who are too young to receive the MMR vaccine.
• Infants should receive their first MMR vaccine at 12-15 months of age. The second dose of MMR is given between 4 and 6 years of age, before starting school.
• Measles is found in many parts of the world, including Europe, Asia, Africa, the Middle East, and the Americas.
• Children 6 to 12 months of age who are traveling internationally are recommended to receive a dose of the MMR vaccine prior to travel, to decrease their risk of infection. Before travel to domestic measles outbreak areas, talk to a healthcare provider about following immunization recommendations for international travel.
• Children 12 months and older, as well as adults, should receive two doses, at least 28 days apart, before travel, if not already vaccinated.

 
For more information about measles, visit California Department of Public Health - Measles or OC Health Care Agency - Measles.
 
For additional resources:
 
OC Health Care Agency - Together We Can Prevent Measles
 
Measles Awareness Infographic: English, Spanish   

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The OC Health Care Agency (HCA) is a regional interdisciplinary health jurisdiction and an accredited health department, charged with protecting and promoting individual, family and community health through partnership and coordination of public and private sector resources. Visit www.ochealthinfo.com to learn more about services and resources.

Source

A case of measles has been confirmed in an adult resident of Orange County. This person is a contact to a known case. This is the 6th case of confirmed measles reported in an OC resident in 2026. In 2025 2 cases of measles were reported.

Key Message

• If measles is in the differential, providers should contact Communicable Disease Control Division (CDCD) immediately at 714-834-8180. We can expedite PCR testing at our public health lab with usual turn around times of 24 hours or less.

Measles is an acute viral illness typically presenting with fever, cough, coryza, and conjunctivitis, followed 3-5 days later by a rash. The maculopapular rash typically begins on the face and spreads down the torso and out to the extremities. The incubation period for measles ranges from 7-21 days after exposure and individuals are infectious from 4 days prior to rash onset until 4 days after rash onset. Measles is highly contagious and spreads via airborne transmission.

Individuals can be presumed to be immune to measles if they were 1) born prior to 1957 OR 2) have received two doses of measles containing vaccine OR 3) have documented positive IgG titer OR 4) documentation of prior disease.

Evidence of immunity should not preclude considering measles in anyone with clinically compatible illness, particularly if they have a history of measles exposure. More info...

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to share information and notify clinicians, public health authorities, and the public about the risk of severe arboviral neuroinvasive disease among patients who are receiving B cell-depleting or B cell-modulating medications, particularly anti-CD20 monoclonal antibodies (mAbs). Patients and their providers should be aware of this risk to help patients protect themselves against the bites of mosquitoes and ticks, which can increase patients’ risk of arboviral disease.

View the full report.

Key Messages

• California Department of Public Health (CDPH) urges clinicians and local health departments to remain vigilant for acute flaccid myelitis (AFM), which presents as sudden limb weakness usually in children and can lead to permanent paralysis.
• Increased summer travel and gatherings may elevate circulation of respiratory pathogens, including enterovirus D68 (EV‑D68), a virus previously associated with AFM surges.
• Although AFM and EV‑D68 activity remain low in 2026, providers should stay alert for potential increases in EV‑D68 respiratory disease and subsequent AFM cases.
• Clinicians should also consider poliovirus in patients with sudden limb weakness and obtain whole‑stool samples, especially when patients are under‑vaccinated or unvaccinated.
• Clinicians who suspect AFM in a patient should notify Communicable Disease Control Division at (714) 834-8180.

Full Advisory: Stay Alert for Acute Flaccid Myelitis in Late Summer and Early Fall

A resident of Anaheim has tested positive for West Nile Virus (WNV), becoming the first human WNV infection in Orange County this year. In 2025, Orange County had three WNV human infections. As of July 31st, the California Department of Public Health reported 11 human infections of West Nile Virus statewide this season. More info...

(Santa Ana, CA) - A resident of Anaheim has tested positive for West Nile virus (WNV) infection, becoming the first human WNV infection in Orange County this year. Since there are no vaccines to prevent or medicines to treat WNV, health officials urge residents to take precautions. 
 
“West Nile virus is endemic in Orange County, recurring every year during the summer months and continuing into the fall,” said Dr. Regina Chinsio-Kwong, County Health Officer. “There have been multiple detections of WNV positive mosquitoes in Orange County, signaling that this could be an intense WNV season. The best way to avoid West Nile virus infection is to take precautionary measures to avoid mosquito bites.”

Recommended WNV precautions include:

• Emptying all standing water on your property to reduce areas in which mosquitoes may breed, including flowerpots and pet bowls.
• Making sure your window and door screens are in good condition.
• Using Environmental Protection Agency (EPA) registered insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or products containing IR3535, always following label directions.
• Limiting outdoor activity at dawn and dusk, when mosquitoes are most active.
• Wearing long-sleeved shirts and long pants when outdoors.

Most people who become infected with WNV do not experience symptoms, but about 20% will develop fever and may have headache, body aches, nausea, tiredness and sometimes a skin rash. More serious symptoms, such as severe headaches, neck stiffness, confusion, muscle weakness, or paralysis, occur more rarely, but people who develop these symptoms should seek medical care immediately. People over 50 years of age and those with certain medical conditions are at increased risk of serious complications from WNV infection.

Information on mosquito control is available on the Orange County Mosquito and Vector Control District website at www.ocvector.org. Other websites with helpful information about WNV include:

• Centers for Disease Control and Prevention: CDC - West Nile Virus
• State of California: California Department of Public Health - West Nile Virus
• State of California WNV Testing: West Nile and St. Louis Encephalitis Viruses in CA: Guidelines for Human Testing, Surveillance, and Reporting
• OC Health Care Agency: West Nile Virus - Epidemiology
• OC Health Care Agency: Mosquitoes More Than Just a Nuisance

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The OC Health Care Agency (HCA) is a regional interdisciplinary health jurisdiction and an accredited health department, charged with protecting and promoting individual, family and community health through partnership and coordination of public and private sector resources. Visit www.ochealthinfo.com to learn more about services and resources.

Source

A case of measles has been confirmed in a pediatric patient residing in Orange County who recently returned from international travel. This is the 5th case of confirmed measles reported in an OC resident in 2026. The majority of these cases are associated with international travel. In 2025 2 cases of measles were reported. More info...