Estimating Frequency of Probable Autochthonous Cases of Dengue, Japan.

Akiyoshi Senda,Shinako Inaida,Richard E Paul,Anavaj Sakuntabhai,Fumihiko Matsuda,Yoann Teissier

doi:10.3201/eid2409.170408

Akiyoshi Senda, Shinako Inaida + Show 4 more

Open Access

https://doi.org/10.3201/eid2409.170408

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Abstract

Imported dengue into naive areas is a recognized but unquantified threat. Differentiating imported and autochthonous cases remains problematic. A threshold approach applied to Japan identified several aberrant incidences of dengue. Despite these alerts, no epidemics occurred other than 1 in Yoyogi Park in Tokyo, which was probably an unusual event.

Highlights

Imported dengue into naive areas is a recognized but unquantified threat
The potential threat of dengue virus (DENV) invasion into naive areas is illustrated by autochthonous dengue cases in France and the United States [3,4] and unprecedented epidemics in the Madeira Islands of Portugal and Tokyo, Japan [5,6]
Most human DENV infections are asymptomatic [7], but the virus can still be transmitted to mosquitoes [8], so repeated “silent” DENV invasion will probably become increasingly frequent

Summary

Introduction

Imported dengue into naive areas is a recognized but unquantified threat. Differentiating imported and autochthonous cases remains problematic. The potential threat of DENV invasion into naive areas is illustrated by autochthonous dengue cases in France and the United States [3,4] and unprecedented epidemics in the Madeira Islands of Portugal and Tokyo, Japan [5,6]. The definition of an imported case is DENV infection in a patient who had traveled to a dengue-infected area within 2 weeks before symptom onset; all other cases are defined as autochthonous.

Results

Conclusion