The CDC also reported 40 locally acquired cases of the virus in U.S. territories. Thirty-five are in Puerto Rico, four are in American Samoa, and one is in the U.S. Virgin Islands.
Not included in that count are an additional 117 diagnosed cases of the virus in Puerto Rico that were reported to the CDC after they totaled the above numbers.
The agency also said pregnant women should consider not traveling to the Summer Olympics
in Brazil, calling the situation with the virus there "dynamic." This is in line with existing recommendations for pregnant women to postpone travel to areas where the virus is being transmitted.
Nine confirmed pregnant returning travelers with Zika
There are nine cases of the Zika virus among pregnant women in the United States who have returned from travel to Zika-infected areas, the CDC said. The agency is investigating 10 more reports of the virus in pregnant women who have returned from infected destinations.
Details of these cases were published online in the CDC's MMWR
Of the nine confirmed cases, all the women experienced at least one of the four most common symptoms of the virus: fever, rash, red eyes (or conjunctivitis), and joint pain. Most of the women reported having a rash and most had two symptoms. None of the women were hospitalized.
Six of the women reported their symptoms during the first trimester of their pregnancy. Two women had miscarriages.
"It's important to note that 10-20% of all pregnancies end in a spontaneous miscarriage, so the fact that (Zika is) present doesn't necessarily mean that it caused them. However, its presence in the placenta is certainly suggestive that it may have," Frieden said.
Two women chose to terminate their pregnancies. No information was available for one of those cases. As for the other, "We don't have information about how that personal decision was made. However, there were brain abnormalities noted on ultrasound and on MRI," said Dr. Denise Jamieson, a medical officer with the CDC division of reproductive medicine and part of the Zika response team.
One baby was born with severe microcephaly. The CDC has not released the location or identification of this family but the Hawaii Department of Health reported
a case of a baby born in Oahu with microcephaly in January.
"We did not expect to see these brain abnormalities in this small case series of U.S. pregnant travelers, so it is unexpected and greater than we would have expected," Jamieson said.
Two women experienced the virus during their second trimester of pregnancy. One of them delivered a seemingly healthy baby and the other is continuing her pregnancy without complications.
One pregnant woman experienced the virus during her third trimester and delivered a seemingly healthy baby.
These details may help determine conclusively if Zika virus causes microcephaly and what other contributing factors there are, such as phase of pregnancy during infection or whether the mother-to-be experiences symptoms.
Emergency Use for new Zika test
The FDA granted emergency use of a new CDC test for the Zika virus. "The Zika MAC-ELISA can help determine whether a person has been recently infected with the virus," said Julie Villanueva, who is with the agency's Zika response team.
The blood test is for people with symptoms of Zika who have traveled to areas where the virus is being transmitted or otherwise meet requirements for testing. It detects antibodies in the blood from four days to 12 weeks after symptoms begin.
The test can result in false positives if the person is infected with another related virus such as dengue fever. Therefore, positive or inconclusive tests should be followed up with additional screening to confirm a Zika diagnosis. A false negative can result when a person does not have enough virus proteins to be detected, which could be the case when someone is nearly recovered.
The test can be performed at laboratories across the country through the CDC's laboratory response network and will become available in about two weeks.
"This is a test that was developed over years in the CDC laboratory and in over a question of just weeks we've been able to scale up production," Frieden said, adding while the test is not yet widely available, it is a step forward.
Sexually transmitted cases of Zika
A new report on sexually transmitted cases of the Zika virus says two confirmed and four probable cases included "condomless vaginal intercourse and occurred when the male partner was symptomatic or shortly after symptoms resolved," according to the CDC. It is not yet known how long the virus remains in semen.
The infected individuals were between the ages of 19 and 55 and "several" of the women were pregnant. All the cases were reported to the CDC between February 6 and February 22.
The new report
was published online in the CDC's MMWR Friday.
The CDC announced Tuesday
it was investigating 14 new reports of sexual transmission of the virus.
These cases are from multiple unidentified states. However, the Oregon Health Authority said Friday
it has one case in the state.
This report emphasizes the importance of condom use or abstinence, as previously advised by the CDC for pregnant women whose male sexual partners have traveled to Zika-infected areas.
"We did not expect to see this many sexually transmitted cases," Frieden told reporters Friday.