Imported Dengue Cases
Dengue viruses are transmitted by infected mosquitoes, mainly Aedes aegypti and A. albopictus[3,4]. The clinical manifestations of dengue virus infections range from asymptomatic infection to dengue fever and dengue hemorrhagic fever[5]. Dengue epidemics caused by dengue virus type 1 occurred in Nagasaki, Osaka, Kobe, and Hiroshima from 1942 to 1945[6,7]. No outbreaks of dengue virus infection have been reported since then in Japan, and no domestic dengue virus infections have been identified. However, during this period there have been imported dengue cases[8,9] in persons who visited dengue epidemic areas, were infected with dengue viruses, and became ill after returning to Japan. In addition, some foreign visitors who were infected in their own countries became ill with dengue while in Japan.
Dengue virus infections were diagnosed in serum specimens of suspected dengue cases submitted from hospitals and clinics by IgM-capture enzyme-linked immunosorbent assay, hemagglutination inhibition tests, and reverse transcriptase-polymerase chain reaction. Neutralization tests and virus isolation were also performed for some specimens. Dengue cases were confirmed by these laboratory tests at the National Institute of Infectious Diseases, Japan, from 1985 to 1999 (Table). The number of imported dengue cases has recently increased. Only two dengue hemorrhagic fever cases were identified, one each in 1990 and 1991; all the other cases were dengue fever. Most of these Japanese dengue patients became infected in Southeast Asia (Thailand, India, Philippines, and Indonesia), although some patients became infected in Central America and Africa in recent years. We believe that these dengue cases account for only a fraction of the total imported cases, although the exact number of imported cases is not known. Under a new infectious disease control law, which took effect on April 1, 1999, dengue fever/dengue hemorrhagic fever is a reportable disease. Thus, an accurate annual number of imported dengue cases will be known in the near future.
Emerging Infectious Diseases. 2000;6(6) © 2000 Centers for Disease Control and Prevention (CDC)
Cite this: Trends in Flavivirus Infections in Japan - Medscape - Nov 01, 2000.
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