An outbreak of head deformities in Brazil is linked to a mosquito-borne virus, the Health Ministry says. The government said Saturday there is a connection between cases of microcephaly, meaning small head, in babies and the Zika virus, which is transmitted by mosquitoes that spread dengue, Agence France-Presse reported.

The outbreak in northeastern Brazil "is a unique situation in global scientific research," the agency said in a statement.

Scientists at the Evandro Chagas Institute established the link by finding the virus in the body of a baby in Ceara state who had been born with microcephaly and other genetic diseases. The congenital disease results in the formation of a smaller skull and impairs intellectual development.

Brazilian health officials believe pregnant women are more vulnerable to developing fetuses with microcephaly if they are infected with Zika in their first trimester, the Associated Press reported.  The U.S. Centers for Disease Control and Prevention said it will send scientists soon to Brazil at the government’s request to study the link between the rare neurological condition and the virus.

A total of 739 suspected cases have already been identified throughout Brazil so far this year, compared to 147 diagnosed cases in 2014, according to official figures.

The government also reported the deaths of an adult and a teenager in what would mark the first non-infant deaths ever linked to Zika. One case was a man from São Luís, Maranhão state, with lupus and chronic steroid usage and the second was a 16-year-old girl from Bala, Outbreak News Today reported

The virus, described as a mild version of dengue, has been detected in 18 of Brazil's 26 states this year. Outbreaks of Zika have occurred in Africa, Southeast Asia and the Pacific Islands. The virus isn’t found in the U.S., but cases of Zika have been reported in returning travelers, according to the CDC.