An elder brother of a 20-year-old South Korean man who was confirmed to be the country’s second case of Zika virus infection has also contracted the mosquito-borne virus.

The Korea Centers for Disease Control and Prevention(KCDC) said Friday that the elder brother’s urine and saliva samples tested positive for the Zika virus by reverse transcription polymerase chain reaction(RT-PCR) testing.

The KCDC, however, said the elder brother has no symptoms of illness and is not classified as a confirmed Zika case.

The two brothers went on a four-day trip to Kalibo and Boracay in the Philippines from April tenth to the 14th.

After returning from the trip, the younger brother went to a medical clinic in Nowon District, Seoul on April 20th, reporting cold symptoms. 

He later developed a fever, and went to Inje University Sanggye Paik Hospital in the same district, where he was referred to the KCDC as a person suspected of contracting Zika. He was confirmed as a Zika patient on Wednesday.