By Alex Jensen

SEOUL

A man in his 40s has become South Korea's first Zika virus patient, according to the Centers for Disease Control and Prevention (CDCP) Tuesday.

A CDCP official told reporters that the 43-year-old was infected after being bitten by a mosquito during a trip to Brazil between the middle of February and the start of this month.

Having been treated upon his return in the southern city of Gwangju, the man's close acquaintances are being tracked.

"He no longer needs to be quarantined, but we will closely watch his condition and carry out a thorough examination on him," added the official quoted by local news agency Yonhap.

South Korea's ability to contain infectious diseases was called into question last summer, when Middle East Respiratory Syndrome claimed dozens of lives as it spread through medical facilities nationwide.

Even before this first Zika case, local concerns were being raised -- especially when China and Japan unveiled cases closer to home than South America and Africa.

Mosquitos are widely dispersed during the warmer months in South Korea, where spring has brought a distinct recent jump in temperatures.

The CDCP is to intensify the monitoring of those mosquitos associated with Zika in case the virus were to enter the local insect populations.

Zika is usually not fatal but it can cause a rash and flu-like symptoms -- the virus has also been linked with the birth defect microcephaly, particularly in Brazil, prompting the World Health Organization (WHO) to declare a public health emergency.

WHO data indicates that local Zika transmission has been documented in at least 55 countries and territories from Jan. 2007 to March 3 this year.