LITTLE ROCK - A ninth case of the Zika virus has been confirmed in Arkansas, the state Health Department said Tuesday.

All nine cases involved people who recently traveled outside of the United States. The most recent case involved a person who had traveled to the Caribbean, department spokeswoman Meg Mirivel said.

The virus’ symptoms are usually mild, but Zika has been identified as a cause of congenital microcephaly and other birth defects. The virus is spread through mosquito bites and sexual contact, according to the U.S. Centers for Disease Control and Prevention.