A Case of Dengue Fever Imported from Burkina Faso to Japan in October 2016.

Dengue fever remains underreported in Africa due to a lack of awareness among healthcare providers, the presence of other febrile illnesses, and insufficient laboratory testing. We present a case of dengue fever imported from Burkina Faso to Japan, where an outbreak of dengue was reported on October 18, 2016. Phylogenetic analysis revealed that the isolate from our patient belonged to a distinct cluster of sylvatic dengue viruses, suggesting that dengue viruses have been maintained in mosquitoes and human cycles in Burkina Faso for more than 30 years.