Chimeric reporter West Nile/dengue viruses and their use

A chimeric flavivirus nucleic acid molecule comprising in the 5′ to 3′ direction:

• (i) a 5′ non-coding region from a West Nile virus (WNV) genome;
• (ii) a nucleic acid encoding amino acid residues 1-35 of a capsid (C) protein of the WNV, wherein residues 1-35 of the C protein correspond to residues 289-323 of the polyprotein of SEQ ID NO:
• 2;
• (iii) a reporter gene;
• (iv) a nucleic acid encoding a 2A proteolytic site;
• (v) a nucleic acid encoding a flavivirus C protein, comprising:
• (a) a 5′ portion encoding amino acid residues 1-35 of a C protein of the WNV,
• wherein residues 1-35 of the C protein correspond to residues 289-323 of the polyprotein of SEQ ID NO:
• 2, and wherein the 5′ portion comprises at least one silent mutation;
• and
• (b) a 3′ portion encoding amino acid residue 36 to the C-terminal most amino acid residue of the flavivirus C protein, wherein residue 36 corresponds to residue 324 of the polyprotein of SEQ ID NO:
• 2, and wherein the 3′ portion comprises a WNV premembrane (prM) signal sequence, a DENV prM signal sequence or a chimeric WNV/DENV prM signal sequence;
• (vi) a nucleic acid encoding a prM protein and an envelope (E) protein from the DENV;
• (vii) a nucleic acid encoding non-structural proteins NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5 from the WNV;
• and
• (viii) a 3′ non-coding region from the WNV genome.