The centers for Disease Control and Prevention has issued a travel alert to Americans considering travel to regions south of the border as more infections from the Zika virus are reported.

The Zika virus is an infection transmitted to humans through mosquito bites. Most infected people have no symptoms. If symptoms do develop, the most common are fever, rash, joint pain, and/or red eyes. Symptoms usually begin three to seven days after a person is bitten by an infected mosquito and last several days to a week. The illness is usually mild, and severe disease requiring hospitalization is uncommon. There is no specific treatment for Zika virus disease. The only treatment option available is the provision of supportive care including rest, fluids, and use of analgesics and antipyretics.

However, the virus has been linked to birth deformities and miscarriages. The CDC alert follows reports in Brazil of increased numbers of newborns born with microcephaly, which is a condition marked by a much smaller than expected head size, and fetal losses among mothers who were infected with Zika virus while pregnant.

The CDC issued the travel alert for Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, and the Commonwealth of Puerto Rico.

The World Health Organization is predicting the virus could reach up to 4 million cases in the next year in the Americas.

Thus far in California, Zika infections have been documented only in persons who were infected while traveling outside the United States. While the risk for transmission of Zika, chikungunya, or dengue viruses is still low in California, infected travelers coming back to California can transmit these viruses to mosquitoes that bite them. This may lead to additional people becoming infected if they are then bitten by those mosquitoes. To date no local transmission of Zika infections has occurred in California.

The number of U.S. travelers infected with the virus while traveling is at 31, according to the CDC.

The California Department of Public Health recommends special travel precautions for pregnant women and women trying to become pregnant:

· Pregnant women in any trimester should consider postponing travel to areas where Zika virus transmission is ongoing. Pregnant women who must travel to one of these areas should talk to their healthcare provider first and strictly follow steps to avoid mosquito bites during the trip.

· Women trying to become pregnant should consult with their healthcare provider before traveling to these areas and strictly follow steps to avoid mosquito bites.

· Pregnant women who traveled to an area with ongoing Zika virus transmission during pregnancy should be evaluated for Zika virus infection if they had any symptoms suggestive of Zika or if their baby has evidence of microcephaly or brain calcifications. Dengue and chikungunya virus infection should be ruled out in these patients.

There are no vaccines to prevent Zika infection. Preventing mosquito bites is the only way to avoid becoming infected.

· Use insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol for long lasting protection. If you use both sunscreen and insect repellent, apply the sunscreen first and then the repellent.

· Using insect repellent is safe and effective. Pregnant women and women who are breastfeeding can and should choose an EPA-registered insect repellent and use it according to the product label.

· When weather permits, 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 inside your home or hotel, sleep under a mosquito bed net.

· Help reduce the number of mosquitoes outside your home or hotel room by emptying standing water from containers such as flowerpots or buckets.