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Leptospirosis

Leptospirosis. Synonyms. Over View. Most common, underdiagnosed zoonosis India - cases are reported from Kerala, Tamil Nadu, AP, Karnataka , Maharashtra, Gujarat & Andamans. Source - Animals (rodents and domestic animals) Epidemiological factors Contaminated environment, Rainfall

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Leptospirosis

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  1. Leptospirosis

  2. Synonyms

  3. Over View • Most common, underdiagnosed zoonosis • India - cases are reported from Kerala, Tamil Nadu, AP, Karnataka, Maharashtra, Gujarat & Andamans. • Source - Animals (rodents and domestic animals) Epidemiological factors • Contaminated environment, Rainfall • High risk groups, endemic in all states of India • First description by Weil in 1886

  4. Over View continued • Rural > Urban • Male > Female (10 : 1) • Clinical Features –mild to severe life threatening • Mimics many common febrile illnesses • Diagnosis - difficult to confirm • Treatment – effective, if started early (<5 days) • Not to be confused with rat bite fever (SM)

  5. The Causative Bacterium

  6. Leptospira under the Microscope Dark Field Microscopy FL Long, Thin, Highly Coiled

  7. Silver Stain of Leptospira interrogans serotype icterohaemorrhagiae • Obligate aerobes • Characteristic hooked ends (like a question mark, thus the species– interrogans)

  8. Epidemiology • Rainfall; Contaminated environment • Poor Sanitation; Inadequate drainage facilities • Presence of rodents, cattle & stray dogs • Walking/ working bare foot poses high risk • Any person can get infected, if exposed to contaminated and environment

  9. Risk Groups Occupational exposure • Farmers – Rice, Sugarcane, Vegetables, Cattle, Pigs • Sewerage workers; Abattoirs, Butchers • Vetenarians, Lab staff, Miners, Soldiers • Fishermen – Inland (not on the sea) Recreational activities • Swimming, Sailing, Marathon runners, Gardening

  10. Reservoirs of Infection • Rodents • (Rattus rattus, Rattus norvegicus, Mus musculus) • Dogs • Wild animals • Domesticated animals • Caged game animals • Leptospira are excreted in the urine

  11. Modes of Transmission 1. Direct contact with urine or tissue of infected animal Through skin abrasions, intact mucus membrane 2. Indirect contact Broken skin with infected soil, water or vegetation Ingestion of contaminated food & water 3. Droplet infection Inhalation of droplets of infected urine

  12. Transmission Human infection is accidental No human to human transmission

  13. Natural History

  14. Pathogenesis of Severe Disease Vasculitis Damage to small blood vessels Leptospira Massive migration of fluid from Intravascular to interstitial compartment Direct cytotoxic injury Immunological injury Renal dysfunction, vascular Injury to internal organs

  15. Clinical Illnesses

  16. Clinical Presentation

  17. Clinical Progression of Icteric (Weil’s Disease) and Anicteric Leptospirosis (pigmented part of eye)

  18. Anicteric Presentation Initial Subsequent

  19. Icteric Leptospirosis

  20. Icteric Leptospirosis KIDNEYS – Mild to Severe Urinalysis : Hematuria / Pyuria / Proteinuria Renal Failure: Pre renal azotemia, ATN / AIN Oliguric / Non Oliguric Mechanism Nephrotoxicity – Endotoxin, (Direct ) Bacterial migration, Toxic Metabolites Hypoperfusion – Hypotension, Fluid loss/ Fluid shift G.I. Bleed, Myocarditis

  21. Hemorrhagic Manifestations Hemorrhagic Fever - Vascular injury • Respiratory, Alimentary, Renal & Genital tracts • More common in Icteric & with Renal Failure Hemorrhagic Pneumonitis • Hemoptysis / Respiratory failure • CXR : Single/ Multiple ill defined opacities • Occurs in 2nd week (as early as 24-48 hours)

  22. Cardiac Form Cardiac manifestations • Hemorrhagic Myocarditis • Cardiomyopathy / Cardiac failure • Arrhythmias, Hypotension / Death

  23. Other Manifestations Aseptic Meningo-encephalitis • It is rare; It occurs in the Immune phase • CSF –­ proteins , ­lymphocytes  • Convulsions, Encephalitis, Myelitis & Polyneuropathy Ocular manifestations • Late complication; Conjunctival hemorrhage • Anterior uveitis, Iritis, Iridocyclitis, • Occurs in 2 weeks to 1 yr

  24. Laboratory Tests • TC / DC / ESR / Hb / Platelet count • Serum Bilirubin / SGOT/ SGPT • Tests for diagnosis of Leptospirosis • Dark Ground Microscopy: Blood • Culture Blood for Leptospira: Positive • MAT; Seroconversion or 4 fold rise/ high titer • ELISA / MSAT : positive • MAT: Microscopic agglutination test • (M)SAT: Microscopic slide agglutination Test

  25. Interpretation of Tests

  26. Comparison of Diagnostic Tests for Leptospirosis

  27. Prevention

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