The novel omp-1 gene cluster encoding twenty one Ehrlichia ewingii (EE) proteins was isolated and sequenced completely. This invention relates to isolated E. ewingii (EE) polypeptides, isolated polynucleotides encoding EE polypeptides, probes, primers, isolated antibodies and methods of their production, immunogenic compositions and vaccines, as well as methods of using the EE polypeptides, antibodies, probes, and primers for the purpose of diagnosis, therapy and production of vaccines against E. ewingii.
