CDC issues a travel advisory to Miami, which has 10 new cases of Zika

For the first time, the Zika virus has prompted public health officials to warn pregnant women to avoid traveling to a part of the continental United States. The travel advisory comes in response to a growing outbreak of the mosquito-borne disease in South Florida.

The state on Monday said 10 more people have been infected with the Zika virus who probably contracted it from mosquitoes in Florida, bringing the total number of such cases in the state to 14. All of the cases have surfaced in a densely populated community north of downtown Miami.

Because the virus can have devastating consequences for a fetus, the CDC urged pregnant women to avoid traveling to the area, and for pregnant women who live and work there to make every effort to avoid mosquito bites and to get tested for possible exposure during each prenatal visit. It also advised women to use protection during sex, because the virus can be transmitted sexually.

Further, the CDC is advising that all pregnant women should be asked about travel to Zika-infested areas during routine prenatal visits. Any pregnant women who have traveled to Zika areas - including this area of Florida on or after June 15 - are advised to talk with their health care providers and get tested for Zika.

For couples trying to have a baby, women with Zika virus disease should wait at least eight weeks and men with Zika virus disease should wait at least six months after symptoms begin to attempt conception.

CDC Director Tom Frieden said the agency issued the travel warning because of the additional Zika infections that were identified in the past 48 hours, and because of new information that indicates mosquito control efforts are not working as well as officials would like.

Frieden said it's possible the insects have developed resistance to some of the insecticides being used, or that the mosquitoes are able to continue laying eggs in 'cryptic breeding places,” or that it may simply be that it's very difficult to do mosquito control in this particular area.

He said more infections are likely because four out of five people with Zika don't have symptoms.

The Zika area is a dense, diverse section about one mile square that includes the neighborhood of Wynwood. It now has become the first area in the continental United States with confirmed local spread of the Zika virus. State and federal officials have warned for months that such a transmission was inevitable.