Skip Navigation LinksNR23-021

office of communications

Contact :

Office of Communications

Record Rai​​nfall Raises Risk of Mosquito-borne Diseases

Date: June 29, 2023
Number: NR23-021

​​​Californians should take precautions, including applying repellent, wearing protective clothing, and draining standing water, where mosquitoes breed

SACRAMENTO – This summer, the California Department of Public Health (CDPH) reminds Californians to take extra precautions to protect themselves from mosquitoes and mosquito-borne diseases during outdoor activities. Due to heavy rains this past winter, mosquito populations have increased across the state, posing a greater risk for mosquito-borne diseases. 


“Many of us enjoy spending time outdoors, especially during the summer months, and this year it is particularly important to take extra precautions against mosquitoes," said CDPH Director and State Public Health Officer Dr. Tomás Aragón. “The best way to prevent diseases that are spread by mosquitoes is to protect yourself, your family, and pets from mosquito bites."


PREVENT YOUR EXPSOURE: CDPH recommends individuals prevent exposure to mosquito bites and vector-borne diseases by practicing the “Three Ds": 

  • DEET – Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting you. DEET can be used safely on infants and children 2 months of age and older.  
  • DAWN AND DUSK – Mosquitoes are more active in the early morning and evening so it is important to wear protective clothing and repellent if outside during these times. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.  
  • DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including flowerpots, old car tires, and buckets. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito and vector control agency. 

Recently, malaria, a mosquito-borne disease, has been making headlines in other states. There are no reported cases of malaria in California to date. And while no human cases of West Nile virus or St. Louis encephalitis virus have been reported in California so far this year, West Nile has been detected in mosquito samples or dead birds in 11 counties and St. Louis encephalitis has been detected in four counties. CDPH monitors avian deaths as a way of predicting when and where people may be at greater risk. The state continues to work closely with local agencies to reinforce prevention tips and control mosquito populations and the diseases they spread. 


RESOURCES FOR CALIFORNIANS: California's West Nile vi​rus website includes the latest information on West Nile activity in the state. Californians are encouraged to report dead birds on the website or by calling toll-free 1-877-WNV-BIRD (877-968-2473). To learn more about how you can protect your health and the health of your loved ones from diseases carried by insects and other animals such as WNV, SLEV, malaria, Lyme disease, and other tick-borne and mosquito-borne diseases, visit the CDPH website

Page Last Updated :