Detection of Dengue Virus Nonstructural Protein 1 (NS1) by Using ELISA as a Useful Laboratory Diagnostic Method for Dengue Virus Infection of International Travelers


  • Presented in part at the 9th Asia Pacific Travel Health Conference in Conjunction with the 5th Regional Meeting of the International Society of Travel Medicine, Singapore. May 2012; 86th Annual Meeting of the Japanese Association for Infectious Diseases, Nagasaki, Japan. April 2012 (in Japanese).

Corresponding author: Tomohiko Takasaki, MD, PhD, Department of Virology 1, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640, Japan. E-mail:



Dengue virus ( DENV) nonstructural protein 1 ( NS1) has been used as a novel diagnostic marker during the early phase of DENV infection.


Presence of NS1 antigen was examined using 336 serum samples obtained from 276 travelers returning to Japan from Asia, Central and South America, Pacific Islands, and Africa with dengue. Assay specificity was evaluated using 148 non-dengue samples.


Positive rates among four DENV serotypes were 68%–89%. NS1 antigen positive rates were at similar levels between primary infection and secondary infection. NS1 antigen positive rates were 88%–96% on days 1–5, 75%–100% on days 6–10, and 36–60% on ≥day 11. Positive rates using real-time polymerase chain reaction (RT-PCR) were over 70% on days 1–5, but decreased thereafter.


The results indicate that NS1 antigen positive rates were higher than those of RT-PCR during longer period of early phase in DENV infection. Thus, NS1 antigen ELISA is a useful tool for confirming DENV infection in international travelers, when it is used in combination with anti-DENV IgM ELISA.