Diagnostic Systems for Viral Hemorrhagic Fevers and Emerging Viral Infections Prepared in the National Institute of Infectious Diseases
Given the real possibility of hemorrhagic fever viruses such as ebola (EBOV), Marburg (MARV), Crimean-Congo hemorrhagic fever (CCHFV), and Lassa (LASV) viruses being introduced into virus-free nations such as Japan, the need arises for concomitant diagnostics even where such diseases are not endemic. Hemorrhagic fever viruses classified as biosafety level-4 (BSL-4) pathogens can only be manipulated in BSL-4 laboratories, making it difficult for nations such as Japan, having no BSL-4 laboratories, to develop required diagnostic assays. To circumvent this problem, diagnostic assays with recombinant viral antigens have been developed at the National Institute of Infectious Diseases, Tokyo, Japan (NIID). Diagnostics such as enzyme immunoassays for detecting viral hemorrhagic antibodies and antigens were developed using recombinant nucleoproteins (rNPs) of EBOV, MARV, CCHFV, and LASV for use as antigens. Immunoglobulin-G (IgG)-linked immunosorbent assay (ELISA) and indirect immunofluorescence assay using rNPs were confirmed to be highly sensitive and specific in detecting these antibodies. Sandwich antigen (Ag) capture ELISA was also developed for detecting these antigens. The sections that follow detail diagnostics developed at the NIID.