Marker system, in particular for baculovirus-expressed subunit antigens

A method of differentiating a non-vaccinated mammal or bird from a mammal or bird which has received an immunogenic composition comprising the steps of:

• a. obtaining a biological sample from a mammal or bird;
• b. contacting antibodies of the biological sample with a capture reagent, wherein the capture reagent specifically binds antibodies specific for a rhabdovirus antigen and is selected from:
• i. a polypeptide comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs:
• 1 to 8;
• ii. a RNA virus which comprises a polypeptide comprising an amino acid sequence having at least 95% sequence identity with the sequence of SEQ ID NO:
• 1 and/or SEQ ID NO:
• 7;
• and
• iii. a synthetic polypeptide having a sequence selected from the sequences consisting of 5 to 11 consecutive amino residues of SEQ ID NO:
• 1 or SEQ ID NO:
• 7;
• and
• c. detecting for the presence of capture reagent-antibody complexes,
• wherein the presence of capture reagent-antibody complexes indicates that said mammal or bird has received said immunogenic composition, and thus differentiates a vaccinated mammal or bird from a non-vaccinated mammal or bird.