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Public Health Reports First Confirmed Zika Virus Case Acquired Through Sexual Transmission in California 

Date: 3/25/2016 

Number: 16-016 

Contact: Orville Thomas (916) 440-7259 


California Department of Public Health (CDPH) Director and State Public Health Officer Dr. Karen Smith today announced the first confirmed case of Zika virus acquired in California. This case involves transmission of Zika virus through sexual contact with a Zika infected partner who returned from a country where Zika virus was circulating, not from a mosquito bite. The woman who was infected was not pregnant and had not traveled out of the country. She and her partner have fully recovered.

“This is the first confirmed case in California where Zika virus was transmitted sexually,” said Dr. Smith. “If your partner has traveled to an area where Zika is present, protecting yourself by abstaining from sex or using condoms during sex is the best way to prevent sexual transmission of the Zika virus.”

A man infected with Zika virus can spread it to his sexual partners. It is not known how long after infection a man can spread Zika virus to sexual partners. At this time, there is no evidence that women can transmit Zika virus to their sexual partners.

CDPH recommends that if men have traveled to an area where Zika virus is circulating, they abstain from sex or diligently use condoms with a partner who is pregnant or trying to become pregnant for the duration of the pregnancy. These cautions apply to vaginal, anal or oral sex.

Women who want to get pregnant, whose partner has had exposure to Zika virus, should discuss with their health care provider any potential risk of Zika virus during pregnancy. The virus can spread from a woman to her child during pregnancy and the infection is believed to lead to neurologic complications in the infant, including microcephaly, which is a birth defect in which the baby is born with a smaller-than-normal head due to abnormal brain development.

Most people infected with Zika virus will not develop symptoms. If symptoms do develop, they are usually mild and include fever, rash, joint pain and eye redness. If you have returned from an affected country and you have fever with rash, joint pain, and eye redness within two weeks, or any other symptoms following your return, please contact your medical provider and tell the doctor where you have traveled. While there is no specific treatment for Zika virus disease, the best recommendations are supportive care, rest, fluids and medications for relief of fever. 

Zika virus is primarily transmitted to people by mosquitoes known as Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asian tiger mosquito), which are the same type of mosquitoes that transmit dengue and chikungunya viruses. These types of mosquitoes have been detected in 12 California counties. To date, there have been 22 travel-associated cases of Zika virus reported in California in 2015-2016. There has been no local mosquito-borne transmission of Zika virus in California.

People who are traveling to areas with known Zika virus risk should take steps to avoid being bitten by mosquitoes, including:

  • Use insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol for long-lasting protection. If you use sunscreen and insect repellent, apply the sunscreen first and then the repellent. Pregnant women and women who are breastfeeding should choose an EPA-registered insect repellent and use it according to the product label.
  • Wear long-sleeved shirts and long pants.
  • Use air conditioning or window/door screens to keep mosquitoes outside. If you are not able to protect yourself from mosquitoes indoors, sleep under a mosquito bed net.
  • Help reduce the number of mosquitoes outside by emptying standing water from containers, such as flowerpots or buckets.

For more information on Zika virus disease and other mosquito-borne illnesses, please visit the CDPH Zika virus information Web page.

Last modified on: 3/25/2016 1:22 PM