The enzyme-linked immunosorbent assay (ELISA) for the diagnosis of a serum antibody to the Nipah and Hendra virus developed in the Australia Animal Health Laboratory (AAHL) was studied in Japan for its practical application as an actual diagnostic method. The protocol and positive result were different in the method used for the Nipah virus than when the method was used for the Hendra virus. The method for the Nipah virus was developed as a means of detecting an antibody in swine sera, but the method for the Hendra virus was developed as a means of detecting an antibody in horse sera. The preprocessing of the serum was done according to the method for the Nipah virus, but this preprocessing was not necessary for the horse sera because a non-specific reaction was not observed in the horse sera. The cross reaction between the Nipah virus antibody and the Hendra virus antibody in ELISA was studied; the homo reaction showed an OD (450 nm) twice as high as obtained from the hetero reaction. The standard for a positive result in the case of the Hendra virus with ELISA depended only on the OD in ELISA, but this result was easily influenced by the dilution condition of the virus antigen. For the diagnosis of both the henipavirus and the emerging paramixovirus infection in horses, we propose a new standard for a positive result based on the ELISA standard used with the Nipah virus.
(Research Team for Zoonotic Diseases, TEL +81-42-321-1441)
