A recombinant, refolded non-fusion polypeptide expressed from a truncated r56 gene of the causative agent of scrub typhus, Orientia tsutsugamushi for the Karp, Kato and Gilliam strains has been produced. The invention is useful for detecting prior exposure to scrub typhus, screening for and/or identification of at least one infectious strain-similarity (i.e. a Karp-like, Kato-like or Gilliam-like strain) based on its strength of reaction toward a truncated protein and as a component in vaccine formulations and production of immune globulins for passive prophylaxis and immunity in subjects.