Featured Topics

Stay informed and prepared with timely public health topics, resources, and updates.

Last reviewed: 8/13/2026

West Nile Virus (WNV) - Updated 8/13/26

Updated 8/13/26

Health Alert Network Health Advisory
The Centers for Disease Control and Prevention (CDC) has issued a 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.

Information about West Nile Virus:

Extreme Heat - Updated 8/3/26

Updated 8/3/2026

Summer heat waves can be dangerous, especially for young children, older adults, people with chronic diseases and disabilities, outdoor workers, people who are unhoused and those who are pregnant. It’s important to protect yourself and your loved ones by checking in on friends and family who may need assistance, monitoring weather forecasts, staying hydrated, limiting time in the heat and staying in or visiting cool spaces.

  • Take precautions:
  • Hydrate with water.
  • If possible, stay in air-conditioned buildings as much as possible.
  • If you must go outside, find shade, wear sunscreen, and take breaks.
  • Never leave children or animals unattended in parked cars.

To learn more about staying safe during a heatwave, visit CDPH's webpage with Tips for Preventing Heat-Related Illness.

Additional Resources:

Cyclospora - Updated 7/21/2026

Updated 7/21/2026

California is not among the states currently experiencing an increase in cyclosporiasis cases. There are no known local outbreaks in California. The California Department of Public Health continues to closely monitor for domestically acquired cases and outbreaks and encourage preventative measures including following safe food and water practices and thoroughly washing produce.

For more information, read the CDPH New Release about cyclosporiasis cases or visit the CDPH cyclosporiasis webpage.

Additional Resources:

Measles

  • Measles is a very contagious virus that spreads easily among unvaccinated people.
  • 1 in 5 unvaccinated children who contract measles can be hospitalized.
  • If you think your family has been exposed to measles or you have measles symptoms, call your healthcare provider and stay home to protect others. Measles begins with a fever and is followed by:
    • A cough
    • Runny nose
    • Pink eyes (conjunctivitis)
    • Rash
  • The measles-mumps-rubella (MMR) vaccine provides the best protection against disease and serious illness.

For more information, visit the CDPH Measles Information website or read Answers to Parents' Top Immunization Questions.

Hantavirus

Pandemic Influenza

Pandemic influenza, or pandemic flu, is a worldwide outbreak of a new flu virus for which there is little or no immunity (protection) in the human population. As the new virus spreads through populations, mutations to the virus could occur and cause illness to become more serious.

The links below provide information to help you and your family be prepared: 

Back to top