Dengue hemorrhagic fever in a Japanese traveler who had preexisting Japanese encephalitis virus antibody

抄録

A patient, an adult Japanese traveler who had just returned from Thailand, had developed dengue hemorrhagic fever (DHF). A primary infection of dengue virus (DENV) was confirmed, in particular, DENV serotype 2 (DENV-2) via the detection of the virus genome, a significant increase in its specific neutralizing antibody and the isolation of DENV-2. DHF is often observed following a secondary infection from another serotype of dengue virus, particularly in children, but this case was a primary infection of DENV. Japan is a non-endemic country of dengue disease. Instead, only Japanese encephalitis (JE) is known to be an endemic flavivirus family. In this study, IgG antibody against Japanese encephalitis virus (JEV) was detected. JEV belongs to the family of dengue virus and prevails in Japan, particularly in Kyushu. Among many risk factors for the occurrence of DHF, a plausible candidate could be a cross-reactive antibody-dependent enhancement (ADE) mechanism by JEV antibody. This indicates that most Japanese travelers, who live in non-endemic areas of dengue, particularly in Kyushu, should pay attention to the occurrence of DHF.