<prompt> Causative organism of Weil disease is:Leptospira interrogansLeptospira biflexaLeptospira wolhachiiLeptospira inadai  <response>: Ref: Ananthanarayan, Paniker CJ. Textbook of Microbiology. 6th Ed. London: John Wiley Sons; 2000. Gillespie SH, Hawkey PM. Principles and Practice of Clinical Bacteriology. 2nd Ed. London: John Wiley Sons; 2006.Explanation:Leptospira interrogans, comprises all pathogenic strains such as Icterohaemorrahgiaea, Canicola. Pomonaa. Australisa, Autumnalisa, Pyrogenesa. Grippotyphosaa.All the serovars mentioned above are capable of causing Weils disease.L. biflexa, L. inadai and L. wolhachii are non- pathogenic and do not result in Weils diseaseWeils syndromeJaundice ProfoundRenal dysfunction II wk onwardshemorrhagic diathesisLab DiagnosisBlood- Early disease. Urine- Late disease, CSF- Late disease. Serum AntibodiesMicroscopy - silver stainingDark Ground Microscopy - Blood UrineCulture - EMJH medium -Ellinghausen. McCullough, Jhonson HarrisSerologyELISA - IgM IgGMAT - Microscopic agglutination Test Gold StandardTreatment - Doxycyclin, Penicillin G or Ceftriaxone 