Serologic and Virologic Studies of an Imported Dengue Case Occurring in 2014 in Okinawa, Japan

Abstract

SUMMARY: After returning from Bali, Indonesia, in February 2014, a 72-year-old man was hospitalized in Okinawa owing to a high fever and rash. Dengue was clinically suspected, and the patient tested positive for IgM against dengue using a commercial kit. Serologically, the patient showed secondary seroreactivity. Significant increases in neutralization titers (N-titers) against all 4 serotypes of dengue virus (DENV) and Japanese encephalitis virus (JEV) strains were recognized in convalescent-phase sera comparing to acute phase sera. The N-titer against DENV serotype 1 (DENV-1) was the highest among all DENV serotypes. Interestingly, the N-titers against JEV strains were significantly higher than those against all types of DENV comparing to acute phase sera. The virus was isolated from the acute-phase serum and identified as DENV-1 and designated RD14/Okinawa. The patient's symptoms were due to DENV-1 infection. Phylogenetic sequencing analysis indicated that the isolate RD14/Okinawa belonged to genotype I of DENV-1, which is closely related to the Southeast Asian strains and isolates found during the dengue outbreak in Japan in 2014. We should undertake control measures against dengue in Okinawa, which is a subtropical area with Aedes albopictus activity throughout year.

Dengue viruses circulating in Indonesia: A systematic review and phylogenetic analysis of data from five decades

“…DENV‐1 Genotype I was first isolated in Indonesia in 2006 and quickly became the most frequently isolated DENVs in Indonesia. Genotype I viruses have been sampled over a wide geographical range, not only in regions of Java Island, but also in Bali, Jambi, Makassar, and Manado . Since its first detection in Indonesia, Genotype I has frequently been reported to cocirculate with Genotype IV in several regions in the country …”

“…Although introduction of this genotype occurred relative recently, the viruses of this genotype were the most frequently isolated virus within DENV‐1 in Indonesia. This genotype has been isolated in almost all Indonesian main islands, suggesting that this virus may be more efficiently transmitted and is better at adapting to new ecological niches.…”

“…Our group has previously conducted studies relating to the molecular epidemiology of dengue in several major Indonesian cities, including Bali, Jakarta, Jambi, Makassar, Semarang, Sukabumi, Surabaya, and Purwokerto . Similar studies have also been conducted in other regions of Indonesia, with local inhabitants or travellers returning from Indonesia . Although these studies have been important for determining DENV serotypes, genotypes, and lineages circulating in Indonesia, the data reported represent only single cities or sites at a particular time and fail to provide a comprehensive picture of circulating DENV throughout Indonesia over time.…”

Dengue in Bali: Clinical characteristics and genetic diversity of circulating dengue viruses

“…Phylogenetic analysis revealed that all of the 10 DENV -1 isolates were grouped into Genotype I (Fig 1). The isolates were closely related to Bali strains from imported cases to Australia in 2010 [9] and 2011 [8] and Japan [10] and strains from other cities in Indonesia i.e. Makassar [18] and Surabaya [29].…”

“…This transmission created substantial DENV diversity and serve as a hub for dengue transmission and mixing in Bali [8]. Most of the reports of dengue in travelers returning from Indonesia have implicated Bali as the source of importation [8–10]. All four DENV serotypes were detected from travelers entering Western Australia between 2010–2012, mostly from Bali [8].…”