A baby in Hawaii with a brain abnormality is the first in the US to have the untreatable Zika virus

A virus that until this month had never been in the US has been connected to a case of brain abnormality in Hawaii.

A baby born with brain damage at a hospital in Oahu was confirmed to have been infected by the Zika virus, that state's department of health said.

This appears to be the first U.S. case of a baby born with microcephaly, a condition in which the brain is abnormally small, after having a Zika infection.

The mother was believed to have had a Zika infection while living in Brazil in May 2015 and that the baby was likely infected in the womb. Neither baby nor mother are currently infectious, the Hawaii State Department of Health said.

"We are saddened by the events that have affected this mother and her newborn," Dr. Sarah Park, Hawaii state epidemiologist, said in the statement.

An untreatable virus

The Zika virus was originally identified in 1947 in Uganda. It's primarily transmitted by tropical mosquitoes - the same kind known for spreading dengue - that pick up the virus from infected people, according to the CDC. It was relatively unknown until 2007, when there was an outbreak of the virus in Micronesia.

Until 2014, the virus had only broken out in Africa, Southeast Asia, and the Pacific Islands. That year, it spread to Easter Island and Chile. By May 2015, Zika had made its way to Brazil. In the past year, Brazil has seen have been more than 84,000 cases of the virus.

So far, there are no vaccines or treatments for Zika. The only way to prevent the infection is to avoid being bitten by mosquitoes.

Once infected, only about 20% ever show symptoms, which most commonly include fever, rash, joint pain, and red eyes.

Travel warning

Last week, U.S. health officials issued a travel warning for 14 countries and territories in the Caribbean and Latin America where infection with Zika is a risk.

The U.S. Centers for Disease Control and Prevention (CDC) in particular cautioned pregnant women not to travel to those areas as Zika has been linked to serious birth defects.

The travel alert applies to Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, and the U.S. Commonwealth of Puerto Rico.

It also includes advice that women who are trying to become pregnant should consult with their doctor before traveling to those areas.

In the Hawaii case, a doctor recognized the possibility of a Zika infection in the newborn baby and alerted state officials, the health department said. The infection was confirmed by a laboratory test conducted by the U.S. Centers for Disease Control and Prevention.

(Reuters reporting by Dan Whitcomb)