title: The preliminary differentiation with factor sera of Leptospira interrogans serovars hardjo and balcanica.
mesh_terms: D000818:Animals; D002417:Cattle / Q000276:immunology*; D007919:Leptospira / Q000276:immunology*; D007921:Leptospira interrogans / Q000276:immunology*; D009893:Opossums / Q000276:immunology*; D012698:Serologic Tests