Diagnosis of oropouche virus infection using a recombinant nucleocapsid protein-based enzyme immunoassay

Oropouche (ORO) virus is an emerging infectious agent that has caused numer ous outbreaks of an acute febrile (dengue-like) illness among humans in Bra zil, Peru, and Panama, Diagnosis of ORO virus infection is based mainly on serology, Two different antigens, hamster serum antigen (HSA) and Vero cell lysate antigen (VCLA), are currently used in enzyme immunoassays (EIAs) in Brazil and Peru, respectively, to investigate the epidemiology of ORO viru s infection. Both antigens involve use of infectious virus, and for this re ason their use is restricted. Consequently, the frequency and distribution of ORO virus infection are largely unexplored in other countries of South A merica. This report describes the use of a bacterially expressed recombinan t nucleocapsid (rN) protein of ORO virus in EIAs for the diagnosis of ORO v irus infection. The data revealed that the purified rN protein is comparabl e to the authentic viral N protein in its antigenic characteristics and is highly sensitive and specific in EIAs. Among 183 serum samples tested, a hi gh degree of concordance was found between rN protein-based EIA and HSA- an d VCLA-based EIAs for the detection of both ORO virus-specific immunoglobul in M (IgM) and IBG antibodies. The high sensitivity, specificity, and safet y of the rN protein-based EIA make it a useful diagnostic technique that ca n be widely used to detect ORO virus infection in South America.