Method for the diagnosis or the screening of an arbovirus infection and preferably a flaviviridae infection and more preferably a flavivirus infection, reagents useful in said method and their applications. Said method comprises: (i) contacting a sample from the subject or animal with a solid support sensitized with an Ig binding protein which is directed against a specific class of Ig molecules of the subject or animal species under consideration and (ii) incubating the immunocomplex formed in (i) with a detector molecule consisting of a hybrid protein comprising at least an arboviral ED3 domain and an alkaline phosphatase (PhoA), the detection of said immunocomplex being the sign of the presence of an arbovirus in said sample.