Leptospirosis(alsoknownasWeil"ssyndrome)isprobablythemostwidespreadzoonosisintheworld.ItiscausedbyinfectionwithspiRochetebacteriaofthegenusLeptospiraandaffectshumansaswellasabroadspectrumofanimalhosts.Theincidenceissignificantlyhigherinwarmclimatecountriesthanintemperateregions.Thediseaseisseasonal,withpeakincidenceoccurringinsummerorfallintemperateregions,wheretemperatureisthelimitingfactorinsurvivalofleptospires,andduringrainyseasonsinwarmclimateregions,whererapiddesiccationwouldotherwisepreventsurvival.NaturalreservoirsforthepathogenicLeptospirainterrogansincluderodentsaswellasalargevarietyofdomesticatedmammals(e.g.pigs,cattleanddogs).Leptospiresoccupythelumenofnephritictubulesintheirnaturalhostandareshedintotheurine.Transmissioncanoccurwhenhumansaredirectlyorindirectlyexposedtotheurineofinfectedanimalsoraurine-pollutedenvironment.Leptospiresgainentryintothehumanbloodstreamviacuts,skinabrasionsormucousmembranesthroughcontactwithmoistsoil,vegetation,andcontaminatedwaters;handlinginfectedanimaltissues;andingestionoffoodandwater.Leptospiresarerarelytransmittedfromhumantohuman.Theincubationperiodisusually5-14days,witharangeof2-30days.Thespectrumofclinicalsymptomsisextremelywide.ThevastmajorityofleptospiralinfectionsareeithersubclinicalorresultinverymildillnessandrecoverwithoutanycomplicationsClinicalmanifestationsofleptospirosisrangefrommildinfluenza-likesymptomstoseverelife-threateningdiseaseforms,characterizedbyjaundice,renalfailure,bleedingandseverepulmonaryhemorrhage.Theclinicalpresentationofleptospirosisisbiphasic,withtheacuteorsepticemicphaselastingaboutaweek,followedbytheimmunephase,characterizedbyantibodyproductionandexcretionofleptospiresintheurine.Mostofthecomplicationsofleptospirosisareassociatedwithlocalizationofleptospireswithinthetissuesduringtheimmunephaseandthusoccurduringthesecondweekoftheillness.TheclassicalsyndromeofWeil’sdiseaserepresentsonlythemostseverepresentation.Itischaracterizedbyjaundice,renalfailure,hemorrhageandmyocarditiswitharrhythmias.

Thepresenceofpathogenresp.infectionmaybeidentifiedby

•Pathogendetection:dark-fieldmicroscopy,culturefromblood,urine,cerebrospinalfluidortissues
•PCR
•SEROlogy:microscopicagglutination(MAT)test,ELISA