By Kim Hyun-cheol
Staff Reporter

Larvae of a kind of mosquito that transmits dengue fever, a life-threatening disease that widely occurs in the tropics, have been found on Jeju Island.

A research team led by Professor Lee Keun-hwa of Jeju National University said Monday that Korea is turning into a subtropical climate and faces the risk of tropical diseases.

Asian tiger mosquitoes have been confirmed to be inhabiting the island since 1998, but their larvae were found there for the first time last December, Lee said at a forum on Jeju. The case was reported to the Korea Center for Disease Control and Prevention (KCDC), he added.

A bite of the virus-containing pest could lead to a sudden onset of symptoms such as fever, severe headache, muscle pain and a rash. Patients with dengue fever might be exposed to a severe case of the disease, dengue shock syndrome, which has a high rate of mortality.

Currently, about 2.5 billion people are at risk from dengue fever, according to the World Health Organization (WHO). It is estimated that there may be 50 million cases every year of dengue infection, which is an endemic in more than 100 countries.

No case of the hemorrhagic disease has been reported in South Korea, although the country has 60 to 70 dengue patients per year who are infected while traveling in Southeast Asia.

The detection of the larvae on Jeju, however, has raised concerns among local medical experts regarding the disease.

Normally, Asian tiger mosquitoes are fertile in temperature above 20 degrees centigrade. When it's 14.5 degrees or below, no eggs or larvae have been found.

Since the discovery took place in the winter, fears are growing that it means the species has successfully colonized Korea.

Some even suspect there might have already been unreported indigenous dengue cases in the region.

The KCDC plans to team up with Jeju National University to run a center on the island to monitor possible outbreaks of tropical diseases, including dengue fever.

The spread of such diseases is emerging as a growing problem here. Korea was declared malaria free by the WHO in 1979, but the disease came back after 14 years, when a soldier was diagnosed with vivax malaria in 1993.

As the number of cases continued to rise over the following years, the government started a 10-year program to eradicate malaria by 2010. Victims were tallied at 1,354 nationwide last year, up 27.8 percent from 2008 amid global climate abnormalities.

"Jeju Island is already labeled as a subtropical region. Active disease control against outbreaks of tropical diseases and waterborne epidemics is necessary as the whole of South Korea is forecast to follow suit in the future," Lee said.

hckim@koreatimes.co.kr