Korea was an endemic area for lymphatic filariasis (LF), caused by the nematode parasite Brugia malayi, until the 1970s. The World Health Organization recognized Korea as LF-free in June 2008. However, it is necessary to confirm that patients that have had LF in the past still test negative, to prevent the re-emergence of LF in Korea.

We followed up a total of 83 patients who had been diagnosed with LF between 2002 and 2010 in endemic LF areas.

Fifty-two of the 83 subjects were negative for LF, whereas 31 subjects had re-located to a different city or province, were dead, or were unaccounted for. Most subjects with negative test results still exhibited edema in the legs or the arms, and some complained of redness and swelling in the legs or ankle joints. However, we found that these symptoms were due to diseases other than LF.

In this follow-up study, we did not find any evidence indicating the potential re-emergence of LF in Korea.