<prompt> A patient presented with fever, jaundice some neuro- logical symptoms in the rainy season, most probable diagnosis isLeptospirosisDengue feverBrucellosisLyme disease  <response>: Ans a. Leptospirosis. Ref. Harrison, Medicine, 18thCh. 171LeptospirosisCausative organism isLeptospira interrogans.Exposure to water contaminated with animal urine. Maculopapular eruption; conjunctivitis; scleral hemorrhage in some cases. Fever, haemorrhages, jaundice, renal failure, conjunctival congestion, purpura, large bruising, hematemesis, malena, bleeding into cavities, thrombocytopenia, hepatomegaly, myocarditis, encephalitis and aseptic meningitis can occur - fulminant form: icterohemorrhagic fever Weils disease.LEPTOSPIROSIS Leptospira enters human skin, mucous membrane, facilitated by cuts and water immersion. It is associated with 3 R epidemiological trends r- Rats- Rainfall Floods- Rice-fields Four clinical syndromes are known:- Bacteremia- Aseptic meningitis- Pulmonary syndrome- Icteric leptospirosis Weils disease Treatment of leptospirosis:Rx of leptospirosisMild leptospirosisDoxycycline, 100 mg orally bid orAmpicillin, 500-750 mg orally qid orAmoxicillin, 500 mg orally qid.Moderatesevere leptospirosisPenicillin G, 1.5 million units IV qid orAmpicillin, 1 g IV qid orAmoxicillin, 1 g IV qid orErythromycin, 500 mg IV qid.ChemoprophylaxisDoxycycline, 200 mg orally once a week. 