The Korea Centre for Disease Control and Prevention (KCDC) on Friday said the third case of the Zika virus was detected in South Korea from a man having traveled to the Philippines.
The 21-year-old man, who had made a trip to the Southeast Asian country for five days through April 14, tested positive for the mosquito-borne virus.
The virus was detected from his saliva and urine, but he did not show any symptoms of the virus such as rash and muscle pain.
According to the KCDC, he was not classified as a confirmed patient.
The man’s 20-year-old brother, the second Zika case who had traveled to the Philippines together with the man, was classified as a confirmed patient on Wednesday.
The younger brother developed symptoms of flu from April 20 and started to show rash in his body on April 22.
He was discharged from a hospital on Thursday as he recovered from the viral disease.
The first South Korean Zika case was found from a 43-year-old man on March 22.
Zika is a virus that is primarily spread by mosquito bites.
The bite is 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 believed not to be spread by ordinary touches between humans, but it can be transmitted through sex and blood transfusion.
Cases of sexual transmission from travelers to their sexual partners had been reported from the U.S. and Europe.
The KCDC advised pregnant women not to travel to Zika-infected countries, while recommending fertile women delay pregnancy for at least two months after returning from those countries.
Zika was first found in Africa and spread to Asia and Lain America.
The virus is spreading rapidly in Latin America, while Thailand and the Philippines are the most Zika-infected countries in Asia.