Korean J Aerosp Environ Med.  2011 Apr;21(1):5-9.

Malaria Imported by Travelers: Epidemiological Aspects in Korea and Japan

• Park SH
• Lee MJ
• Rhim KH
• Bang HA
• Lee WC

Abstract

Background
Malaria imported by travelers has been an increasing problem in Korea and Japan recent two decades, representing one of risk for travelers visiting tropical and sub-tropical countries where malaria is endemic. The present study analyzes all of the malaria cases reported in Korea and Japan during 2002∼2009 in order to assess the trend of incidence over time and review the risk factors for travelers visiting malaria endemic countries. Methods: All malaria cases that occurred during 2002∼2009 in Korea and Japan were analyzed. The incidences of exotic malaria in Korea and Japan were calculated by continent and by countries most visited, using data provided by annual reports of exotic malaria in the Web Statistics System, Korea Center for Disease, and Report of Infectious Disease Surveillance Center, Japan. Results: A total of 11,573 domestic cases of malaria occurred between 2002 and 2009 in Korea, and the average incidence rate was 2.99, and that of malaria imported by travelers in the exotic was 0.08 per 100,000 populations. During the same period in Japan, the incidence rate of exotic malaria was 0.05, and its incidence rate in Korea was much higher than Japan’s. All 2002∼2009 case report of imported malaria in Korea was analyzed. A total 40.9% (124 cases) of 277 cases were infected with Plasmodium falciparum, while 36.0% (109 cases) were diagnosed with P. vivax, 3.3% (10 cases) with P. falciparum and P. vivax mixed, 1.3% (4 cases) with P. ovale, 2.3% (7 cases) with P. malariae and 16.2% (49 cases) with unknown causes. In Japan, the percentages of the 529 cases with P. falciparum, P. vivax, P. ovale,P. malariae and unknown cases were 49.9% (264 cases), 40.1% (212 cases), 4.9% (26 cases), 1.9% (10 cases) and 3.2% (17 cases), respectively. The infection rates of P. falciparum and P. ovale in Japan were noted to be higher than those in Korea (P＜0.05 and P＜0.01). A total of 303 cases malaria which was regarded from endemic areas outside Korea was recorded during that time. P. falciparum was predominant in the cases from Africa it forms 80.8% (97 cases) of 120 cases, while P. vivax was the leading protozoa in Asia 73.4% (80 cases) of 109 cases. Moreover, most cases were from Africa, 47.9% (145 cases), followed by Asia, 46.2% (140 cases), Oceania, 4.6% (14 cases), Central and South America, 1.0% (3 cases) and unknown areas, 0.3% (I case), respectively. From 2006 to 2009, a total of 215 cases of exotic malaria were reported in Japan. Among them, P.falciparum and P. vivax were by far the most common infecting malaria, being responsible for 90.2% (194 cases) of the cases. Most cases were from Africa, 56.7% (122 cases), followed by Asia, 26.5% (57 cases), Oceania, 10.2% (22 cases), Central and South America, 3.3% (7 cases) and unknown areas, 3.3% (7 cases), respectively.

Keyword

Exotic malaria; Epidemic aspects; Korea and Japan