Seoul: South Korean health authorities on Friday confirmed the sixth case of Zika virus infection found in a 28-year-old woman who recently came back from the Caribbean island of Dominica. The woman, who had stayed in the Central American country from June 2014, came back to South Korea on June 23 via the US and Taiwan, the Korea Centres for Disease Control and Prevention (KCDC) said. She was confirmed positive with the mosquito-borne virus on Thursday night after developing a rash, joint and muscle pains from Monday, Xinhua news agency reported. It marked the sixth case of the country's Zika virus infection since the fifth one was detected some 50 days ago. Among the total, one came from Brazil, one from Vietnam, one from Dominica and three from the Philippines. The KCDC said the sixth patient is not pregnant, noting that it has been conducting an in-depth epidemiological investigation. Zika is a virus that is primarily spread by mosquito bites, particularly risky for pregnant women as it is thought to be linked to a rare birth defect - microcephaly that causes newborn babies to have unusually small heads and damaged brains. The Zika virus is not spread by ordinary touches between humans, but it can be transmitted through sex and blood transfusion. Cases of sexual transmission from travellers to their sexual partners were reported from the US and Europe.