2. Introduction
Most common, underreported and under
diagnosed zoonosis.
India - Cases reported from Maharashtra,
Gujarat , Kerala, Tamil Nadu, Karnataka,
Andaman.
Source –Animals ( rodents and domestic
animals) or an environment contaminated by
their urine
Causative org. can survive for months in water
& damp soil
3. Organism
Order-Spirochaetales
Family-Leptospiraceae
Genus-Leptospira
Species-17(11 pathogenic-L. interrogans sensu lato)
& (6 non-pathogenic-L. biflexa sensu lato)
Pathogenic leptospira divided into ›26 serogroups & ›250
serovars.
Leptospires are coiled thin highly motile organisms, 6-
20µm long and ~0.1µm wide, obligate aerobes
Stain poorly… but seen by dark-field microscopy & by
silver impregnation tech.
Culture media- EMJH, Fletcher, Korthof
5. Epidemiology
Etiology: L interrogans
Most widespread zoonosis in the world
Peak incidence during rainy season
Occupational & recreational exposures
Source of infection in humans: direct or
indirect contact with the urine of an infected
animal
Portal of entry: abrasions or cuts on skin,
conjunctiva & other mucous membranes.
Inc. period: 2-30 days(commonly 5-14 days)
6. Epidemiology
Rainfall
Contaminated environment
Poor Sanitation
Inadequate drainage facilities
Presence of Rodents, cattle& stray dogs
Walking bare foot
Specific source of infection cannot be
pinpointed with certainty.
Males>Females… more chance of exposure
8. PATHOGENESIS
Pathogenesis not completely understood
1. Leptospiremia...multiplication in blood, tissues.
2. Vasculitis– responsible for most of the
manifestations… LOS TNF-α
3. Kidneys- interstitial nephritis, tubular injury
4. Liver- centrilobular necrosis(usually not
extensive)
5. Lungs- involvement due to hemorrhage, not to
inflammation
6. Microcirculation damage, increased vascular
permeability….hypovolemia
7. Skeletal muscles-necrosis
9. Clinical Features
Biphasic clinical presentation
Acute or bacteremic phase lasting ~1 week
Immune phase, characterized by antibody production and
leptospiruria
Anicteric Leptospirosis
Abrupt onset of fever, chills, headache, myalgia,
abdominal pain, conjunctival suffusion, transient
skin rash, Aseptic Meningoencephalitis
Icteric Leptospirosis (Weil’s disease) 5-10%
Occurs in 5-15% of patients
Jaundice, Proteinuria, hematuria, oliguria and/or anuria
Pulmonary hemorrhages, ARDS
Myocarditis
Aseptic Meningoencephalitis
10. Icteric Leptospirosis- LIVER
Jaundice -Occurs 4-6 days (2 - 9 days)
Sr.Bilirubin –Markedly increased- (20-40
mg/dl) Conjugated bilirubin rise
SGOT / SGPT -Mild elevation
ALP- moderately elevated
Hepatocellular necrosis / Intra hepatic
cholestasis
Death - Not due to Liver Disease…if no
predisposing factors present
11. Icteric Leptospirosis- G. I. tract
Massive spontaneous G. I.
bleeding(major cause of death)
Pancreatitis
Severe abdominal wall tenderness
mimicking acute abdomen
12. Icteric Leptospirosis- Lungs
Frequently involved with varying
severity
Cough, dyspnoea, chest pain, blood
stained sputum, hemoptysis
Severe pulmonary hemorrhage causing
Acute Respiratory Distress Syndrome
May cause diffuse or focal interstitial
pneumonitis and pneumonia
CXR- lesions seen are more extensive
than clinical findings, develop ›3-9 days
14. Hematological disturbances
Severe thrombocytopenia…bleeding
Anemia- d/t bloodloss, &/or hemolysis
Petechiae, purpura, ecchymoses
common
PT & PTTK time may be normal to
moderately elevated…can be corrected
with Vit K supplementation.
D.I.C.-rare as compared to Gm(-) sepsis
Jarisch-Herxheimer reaction- rare
15. Icteric Leptospirosis- Kidneys
Invariably involved --Mild to Severe
Urinalysis : Hematuria / Pyuria /Proteinuria
Renal Failure: initially non-oliguric with K+
wasting….may become oliguric
Prerenal ATN
Hypotension
Endotoxins
Fluid loss/ Fluid shift
Toxic Metabolites
Myocarditis
16. Icteric Leptospirosis- Heart
Hemorrhagic Myocarditis- Arrhythmias
,Cardiac failure, Hypotension / Death
Arrhythmias- Atrial fibrillation / Conduction
defects (seen in 20-40%)
ECG changes- Non Specific ST-T changes, Low
voltage complexes
22. Chest radiograph
Three radiographic patterns:
1.small nodular densities (50-60%);
2.confluent areas of consolidation (10-20%); and
3.diffuse, ill-defined, ground-glass density (20-
30%).
Serial radiographs may show a tendency for the
nodular pattern to be followed by confluent
consolidation and/or ground-glass density.
Abnormalities are bilateral, non-lobar in all
cases, and have a marked tendency toward
peripheral predominance
24. Specific investigations
Dark-field microscopy –blood, CSF,
urine(Low Sensitivity & Specificity)
Culture- blood, CSF, urine…takes up
to 4 weeks for diagnosis
Serological tests- MAT, ELISA
Rapid tests- latex agglutination,
ELISA
Polymerase Chain Reaction Test
25. Microscopic Agglutination Test(MAT)
Gold Standard, Complicated
Titres rise late, but persist longer
Valuable in epidemiologic studies
Less sensitive for current diagnosis
Positive- Seroconversion / 4 fold rise
in the titre, High titre(>1:100).
Will stay positive for long time after
recovery
26. IgM ELISA and other rapid
Tests
Useful for providing presumptive diagnosis in current
infection
Sensitivity is low- 39-72% during acute phase illness
Repeat sample after 3-4 days.
27. Polymerase Chain Reaction Test
Highly valuable during acute illness(<7
days)
Sensitivity decreases as bacteria is cleared
from blood
Can detect even <10 bacteria in any given
sample
Primers should cover all prevalent species
in given area
Recent data - urine sample has more
sensitivity then blood sample after 7 days
Use limited by less availability
28. Approach to Diagnosis
Clinical features suggestive of current leptospirosis
Leptospiremic phase < Immune phase > 7 days
7days
Blood culture ELISA / Rapid IgM
PCR Positive Negative
MAT(if Repeat >3-4
available) days
29. Biphasic nature of leptospirosis and relevant investigations
at different stages of disease
Clin Microbiol Rev. 2001 Apr;14(2):296-326
30. Management(severe
leptospirosis)
Prompt triage of high-risk patients and
early supportive treatment
General management and supportive
therapy
Specific treatment of various organ
system failure
Hemat
RS
Renal
Liver
31. Contd…
Antibiotic therapy
Shortens fever clearance time,
leptospiruria
mortality
Antibiotic regimes
Inj. Penicillin G 1.5 million U Q6H (iv) x 7
days(used to be DOC)
Inj. Ceftriaxone 1 Gm OD (iv) x 7 days
Inj. Cefotaxime 1 Gm Q6H (iv) x 7 days
Other agents- Macrolides,
fluoroquinolones