As of Dec. 1, there have been 619 cases in California, with 10 just this month, according to the Stanislaus County Health Services Agency. So far in California, Zika virus infections have been documented only in people who were infected while traveling to areas with ongoing Zika transmission, through sexual contact with an infected traveler, or through maternal-fetal transmission during pregnancy.
Zika is carried by the Aedes aegypti mosquito, which is known to be in the San Joaquin Valley. The Centers for Disease Control and Prevention says this type of mosquito is an aggressive day biter, but also known to bite at night. An Aedes mosquito can only transmit Zika virus after it bites a person who has this virus in their blood.
Most people testing positive for Zika will have mild to no symptoms. The most common symptoms include fever, rash, conjunctivitis (red eyes), and joint pain and begin three to seven days after being bitten.
Severe illness requires supportive care at a hospital. There is no vaccine or cure for Zika.
The virus is of most concern to pregnant women or women considering getting pregnant in the near future. Zika virus during pregnancy can cause microcephaly and other severe brain defects in infants. Additionally, there is an association between Zika and Guillain-Barré Syndrome, a disease affecting the nervous system.
Zika virus can also be transmitted to sexual partners by both males and females. Both men and women of childbearing age should take precautions if they have recently traveled, or plan to travel, to a location where Zika is spreading. The virus can live in men for up to six months and up to eight weeks in women.
Sexually active adults who travel to areas with Zika transmission should use condoms or other barriers in order to avoid getting or passing Zika during sex. Couples planning pregnancy should speak with a health care provider about a safe time to wait before trying to get pregnant.