Dengue virus infection in aedes albopictus during the 2014 autochthonous dengue outbreak in Tokyo Metropolis, Japan

Daisuke Kobayashi, Katsunori Murota, Ryosuke Fujita, Kentaro Itokawa, Akira Kotaki, Meng Ling Moi, Hiroko Ejiri, Yoshihide Maekawa, Kohei Ogawa, Yoshio Tsuda, Toshinori Sasaki, Mutsuo Kobayashi, Tomohiko Takasaki, Haruhiko Isawa, Kyoko Sawabe

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26 Citations (Scopus)


In 2014 in Japan, 162 autochthonous dengue cases were reported for the first time in nearly 70 years. Here, we report the results of the detection and isolation of dengue virus (DENV) from mosquitoes collected in Tokyo Metropolis in 2014 and 2015. The phylogenetic relationship among DENV isolates from mosquitoes and from patients based on both the entire envelope gene and whole coding sequences was evaluated. Herein, 2,298 female and 956 male Aedes albopictus mosquitoes were collected at six suspected locations of DENV infection in Tokyo Metropolis from August to October in 2014 and grouped into 124 and 35 pools, respectively, for viral genome detection and DENV isolation. Dengue virus RNA was detected using reverse transcription polymerase chain reaction and TaqMan assays from 49 female pools; 16 isolates were obtained using C6/36 and Vero cells. High minimum infection rates (11.2–66.7) persisted until mid-September. All DENV isolates belonged to the genotype I in serotype 1 (DENV-1), and its sequences demonstrated > 99% homology to the sequence of the DENV isolated from a patient in the vicinity of Tokyo Metropolis in 2014. Therefore, Ae. albopictus was a major DENV vector, and a single DENV-1 strain circulated in Tokyo Metropolis in 2014. Dengue virus was not detected from male mosquitoes in 2014 and wild larvae in April 2015. Thus, the possibility of both vertical transmission and overwintering of DENV was extremely low, even in dengue-epidemic areas. This study reports the first entomological information on a dengue outbreak in a temperate region, where no Aedes aegypti mosquitoes are distributed.

Original languageEnglish
Pages (from-to)1460-1468
Number of pages9
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number5
Publication statusPublished - 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Parasitology
  • Virology
  • Infectious Diseases


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