What is the diagnosis for Rift?

During the early phase of illness in the blood and in postmortem tissue, the virus may be detected by virus isolation in cell culture, antigen-detection ELISA, and molecular techniques (PCR). Antibody testing using enzyme-linked immunoassay (ELISA) can be used to confirm presence of IgM antibodies, which appear as an early, transient response, and IgG antibodies, which persist for several years. Both IgM and IgG antibodies are specific to RVF virus. 

Source: http://www.cdc.gov