The Zika virus, a mosquito-borne pathogen that has been linked to a rise of birth defects in Brazil, has been found in at least five people this month in the U.S., prompting the Centers for Disease Control and Prevention to release new guidelines for pregnant women.

The new interim guidelines issued by the CDC on Tuesday advise doctors to ask all pregnant women if they have recently traveled to a country where the a Zika virus outbreak is ongoing. The CDC has also advised any pregnant women who have traveled to countries with the Zika virus to get tested for the virus if they are have two or more symptoms of the virus.

The illness often results in fever, joint pain and rash, health officials said. There is no cure or vaccine for the virus besides supportive care.

The guideline announcement came as two pregnant women in Illinois were reported on Tuesday to have contracted the disease, according to the Illinois Department of Public Health. Both of those women were believed to have been infected while out of the country.

Three other people in Florida were also diagnosed with the illness, officials said today. All of the infected people in Florida contracted the virus while out of the country — in either Colombia or Venezuela. 

Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, said the increase in the cases reported in the U.S. may not be the result of more cases arriving in the U.S.

“I think this is likely to be increasing awareness on part of both the public [and] for women who are pregnant,” said Schaffner, who explained pregnant women were already likely asking to be tested if they visited a country with a Zika virus outbreak.

Schaffner said the new guidelines will be helpful in stopping the virus from spreading in the U.S., but there is no treatment or vaccine for the virus.

“It will provoke a fair amount of anxiety in the pregnant women and their partner,” Schaffner said. “I empathize with them as well as my colleagues in obstetrics. … They don’t have anything to offer except compassionate care.”

On Friday, officials reported of the first case of a U.S. baby born with a birth defect likely linked to the virus. A Hawaii infant was born with microcephaly, an abnormally small head, which was likely caused when the infant’s mother contracting Zika virus while pregnant, according to CDC officials, who also noted that the woman was likely exposed to the virus while living in Brazil last May.

The CDC issued guidelines last week advising pregnant woman to consider postponing travel to any country where the virus is being transmitted or to take extra precautions against mosquito bites if they are in that area.

The virus has been a problem in tropical settings in Africa, Southeast Asia and the Pacific Islands for years, but it’s suspected link to birth defects was found late last year. It does not spread person to person, and the symptoms usually don’t last more than a week, according to the CDC.