Health officials on Friday, advised pregnant women to avoid travelling to Latin America and Caribbean countries that have outbreaks of a tropical illness, caused by Zika virus. The illness is linked to birth defects, causes only a mild symptoms in most people, and spreads through mosquito bites.

U.S health officials reported that a baby born in Hawaii had tested positive for the virus.the mother was likely to be infected in Brazil, they added. The illness has been spreading around the world, and there is growing evidence that it is linked to birth defects, especially in Brazil. Brazil reported its first case in the Americas while Puerto Rico confirmed its first case in December.

On Friday, U.S health officials urged pregnant women consider postponing trips to 14 destinations — Brazil, Columbia, El Salvador, Puerto Rico, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, French Guiana, Suriname and Venezuela. Officials have also advised women who are trying to get pregnant or thinking to get pregnant, to consult their doctor, before travelling to those areas. They also have to take extra precautions to avoid mosquito bites.

Zika virus was discovered in a monkey in the Zika forest of Uganda in 1947. The illness spreads through mosquitoes, similar to other tropical diseases, like dengue fever and chikungunya. Experts believe that only one in five people infected with the virus develop symptoms, such as fever, rash, red eyes and joint pain. There is no medicine or vaccine for the virus and hospitalizations are rare.

However, there is a mounting evidence that the virus is linked to a rare condition called microcephaly in pregnant women, where the baby’s head is smaller than normal and brain is not developed properly. Since 2007, about 27 Americans have been diagnosed with the Zika virus. Though all of them are believed to have caught the virus overseas, a person in Puerto Rico, who had not traveled was diagnosed with the illness last month.