WASHINGTON, Jan. 20 (UPI) -- As more cases of pregnant women with Zika virus are confirmed in the United States, the Centers for Disease Control and Prevention has issued new guidelines for pregnant women who have traveled to countries where the mosquito-borne virus is spreading.
In the last month, two pregnant women in Illinois and three people in Florida have been confirmed to have the virus. CDC officials also reported the first case of an infant born in the United States with microcephaly, a developmental defect resulting in a smaller-than-normal head or brain, which has been linked to the virus.
There is no vaccine or medication to prevent or cure Zika virus infection, or to prevent microcephaly, prompting the agency to advise women take extreme precaution when traveling, or anywhere they could get bit by mosquitoes.
Zika virus is spread by the same types of mosquitoes that transmit dengue and chikungunya and are found in the Americas, including the United States. Hospitalizations and fatalities are rare, with symptoms such as rash and fever lasting from a few days to one week.
The virus has been linked to an epidemic of microcephaly in Brazil, and the birth defect has been found in other children where the Zika virus has been confirmed. The first case of Zika in the United States was confirmed in Puerto Rico on January 1, with the first baby with microcephaly born in Hawaii two weeks later.
On January 14, the CDC issued travel warnings for pregnant women going to the Caribbean, Central or South America, Mexico, Puerto Rico, or other countries where Zika has been confirmed to take precaution against mosquito bites.
The agency on January 19 added care guidelines for pregnant women traveling to the same areas, including treatment advice for women confirmed to have Zika.
Pregnant women traveling to areas where Zika is known to have been transmitted, the CDC suggests women wear long-sleeve shirts and long pants, use insect repellents, and stay and sleep in screened-in or air-conditioned rooms. Insect repellents containing DEET, picaridin, and IR355 are considered safe for pregnant women, according to the CDC.
In addition to advising doctors to ask all pregnant women about their recent travel history, women who have traveled to any of the areas are advised to be tested for the virus. Testing should include both the mother and fetus, the agency said. If a fetus tests positive for the virus, the agency warns they're unsure if a positive test also predicts microcephaly.
For women who test positive, treatment is advised to be "generally supportive" and should include rest, fluids and analgesics. Dengue fever, which can appear similar to Zika and is also spread by mosquitoes, should be ruled out before aspirin or other nonsteroidal anti-inflammatory drugs are used.
At least one species of mosquito common in Florida and the Gulf Coast, Aedes aegypti, can spread Zika, but it's not known whether other mosquitoes ranging farther north in the country can also transmit the virus.
"We believe this is a fairly serious problem," Dr. Lyle R. Petersen, chief of vector-borne diseases for the Centers for Disease Control and Prevention, told the New York Times. "This virus is spreading throughout the Americas. We didn't feel we could wait."