Leptospirosis

updateDr.T.V.Rao MD

Dr.T.V.Rao MD 1

Scientific Beginning • It was first described by Adolf Weil

in 1886 when he reported an "acute infectious disease with enlargement of spleen, jaundice and nephritis". Leptospira was first observed in 1907 from a post mortem renal tissue slice.

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Leptospirosis - Zoonosis

• Leptospirosis is an acute arthropod-zoonotic infection of worldwide significance caused by spirochete Leptospira interregna's which has 23 serogroups and >200 serovars. Various factors influencing the animal activity, suitability of the environment for the survival of the organism and behavioural and occupational habits of human beings can be the determinants of incidence and prevalence of the disease.

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What is leptospirosis?

• Leptospirosis, also known as canicola fever, haemorrhagic jaundice, infectious jaundice, mud fever, spirochetal jaundice, swamp fever, swineherd's disease, caver's flu or sewerman's flu, is a bacterial infection resulting from exposure to the Leptospira interrogans bacterium.

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Leptospirosis also called as Weil’s Disease after its inventor

.

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Weil’s disease signifies Leptospirosis

• There is an acute form of human infection known as Weil's disease, where the patient suffers from jaundice, though this term is often (incorrectly) used to describe any case of infection..

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Leptospirosis 2011

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SynonymsMud / Swamp fever

Japanese 7 day fever

Rice Field Fever Spirochete Jaundice

Canicola Fever Leptospiral Jaundice

Autumn Fever Swineherd’s Disease

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The Causative BacteriumOrder Spirochaetales – Treponema, Borrelia, Leptospira

Family – Leptospiraceae, susceptible to heat, cl, acidGenus – Leptospira, 26 serogroups, 250 serovarsinterrogans, biflex, ictero hemorrhagica, hebdomidis

Corkscrew shaped, delicate, flexible spirochete, Gram -ve

6 to 20 long & 0.1 thick, coiled, flagellate, actively motile

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Reservoirs

• Wild and domestic animals rodents, livestock (cattle, horses, sheep, goats, swine), canines, and wild mammals are the reservoir for leptospirosis. Many animals have prolonged leptospiruria without suffering from the disease themselves.

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Classification:

• Phylum: Spirochaetes • Class: Spirochaetes • Order: Spirochaetales• Species: Leptospira • Family: Leptospiraceae

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What causes Leptospirosis

• Leptospirosis is a bacterial disease that affects humans and animals. Leptospira bacteria are found worldwide and there are many different types or serovars capable of causing disease. Disease caused by Leptospira bacteria is most common in temperate or tropical climates and appears to be rare in North America.

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Morphology• The Leptospira appear

tightly coiled thin flexible Spirochetes 5 – 15 microns long.

• Fine spiral of 0.1 – 0.2 microns

• One end appears bent forms a hook.

• Actively motile• Seen best with dark field

Microscopy.

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Greater Understanding with Electron Microscopy

• Electron Microscopy show thin axial filament and a delicate membrane

• In dark field it may appear as chain of miniature cocci.

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Resistance and Disinfection

• Leptospira species can be inactivated by 1% Sodium hypochlorite

• 70%ethanol,• glutaraldehyde,• formaldehyde,• detergents and acid.• This organism is sensitive to moist heat (121 ° C for a

minimum of 15 min))and is also killed by pasteurization.

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Leptospirosis – A Major Zoonotic Infection

• Weil's disease is comparatively rare, though 'mild' cases of leptospirosis happen everywhere there are carriers, and it is believed that leptospirosis is one of the most common zoonotic infections in the world. Millions of people are infected each year, but information and treatment can be limited, especially in the developed world where cases are considered 'rare' by the medical community.

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Animals spread Leptospirosis

Rats, Mice, Wild Rodents, Dogs, Swine, Cattle are principle source of infection

The above animals excrete Leptospira both in active infection and Asymptomatic stage

The Leptospira survive and remain viable for several weeks in stagnant water.

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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

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Transmission

Environment Human

Contam Survive

Urine

Tissue

Feces

Infection

Animal Source

Human infection is accidentalNo human to human transmission

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Pathogenic Strains x Non pathogenic Leptospirosis

• There are several species of Leptospira only few are pathogenic to Humans, rest to some Animals and Many in Nature as saprophytes

• Leptospira Interrogans is Pathogenic there are 200 serovars.

• Leptospira biflexa Non Pathogenic there are 60 serovars

• Further classifications are made on shared antigens

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Genomic based classification

• DNA – DNA hybridization studies proved more specific

• The traditional serologic classification has limitations at Molecular level, but useful at Epidemiological studies.

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Comparative Morphology of Spirochetes

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Culturing of Leptospira• Leptospira grows best

under aerobic conditions at 280 to 300c best demonstrated in Semisolid agar media

• Optimal Media Fletchers Media Stuarts MediaOptimal growth after 1 – 2

weeksDr.T.V.Rao MD 25

Growth requirements• Leptospira derive

energy from oxidation of long chain fatty acids, and cannot use or carbohydrates or amino acids as major energy source.

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Antigenic structure• All isolates of L.inttterogans from different

parts of the world are serologically related and exhibit cross reactions in serologic tests.

• Overlapping of Antigens do occur in different species.

• Outer envelop contains large amount of Lipopolysaccharides ( LPS )

• Antigenic structure varies from one strain to other

• This variation forms the basis of serologic classification

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Genome of Leptospira

• L. interrogans serogroups Icterhaemorrhagiae consists of a 4.33 mega base large chromosome and a 359 kilo base small chromosome, totalling 4,768 predicted genes. A series of genes have been discovered that could potentially be related to adhesion. This genome differs from the two other pathogenic spirochete (Treponema palladium and Borrelia burgdorferi), though some similar genes are visible (CHGC, 2004).

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PATHOGENESIS

• leptospira

• skin,mucosa• Initial stage leptospiremia toxic symptoms• (1~3days) three symptoms:• fever,myalgia,fatigue;• three signs:• conjunctival suffussion;• muscle tenderness;• enlargement of lymphonodes;

• •

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Pathogenesis• Leptospira are present in the water bodies• Enter through breaks in the skin ( cuts and abrasions ) and

mucous membranes• Enters through Mouth – Nose – Conjunctive • Rarely enters though ingestion.• Incubation period 1 – 2 weeks• When multiples blood stream produces fever.• May establish organ involvement in Kidney and Liver,• May produce hemorrhage and necrosis in the tissues

and initiates dysfunction of these organs

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Sequence of Leptospira Infection

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Clinical IllnessesTypes Anicteric (common 95% recover)

Icteric ( Weil’s Syndrome) (rare, fatal)

Hepato-renal syndrome

Hemorrhagic syndrome with ARF

Atypical pneumonia syndrome

Aseptic meningo-encephalitis

Myocarditis, Chronic uveitis

Clinical Presentation

AnictericCommon, mild< 2% Mortality

IctericRare, Severe15% Mortality9

0%

of

Case

s1

0%

of C

ase

s

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May present with

• Jaundice• Hemorrhage• Nitrogen retention• The Illness is Biphasic with initial temperature

when the second phase comes with raise of IgM titers raise

• Aseptic meningitis – initial headache, stiffness of neck, pleocytosis of Cerebro spinal fluid

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Pathogenesis of Severe Disease

Leptospira

Damage to small blood vessels

Vasculitis

Direct cytotoxic injuryImmunological injury

Massive migration of fluid from Intravascular to interstitial compartment

Renal dysfunction, vascularInjury to internal organs

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Presenting with Jaundice is significant and Important, Serious Manifestation

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May present with Major Complications

• Nephritis• Hepatitis.• Manifestations in

eye• Muscular lesions• Many infections are

mild and subclinical

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Weil’s Syndrome• Weil's syndrome is a severe form of

leptospirosis that causes a continuous fever, stupor, and a reduction in the blood's ability to clot, which leads to bleeding within tissues. Blood tests reveal anaemia. By the third to sixth day, signs of kidney damage and liver injury appear. Kidney abnormalities may cause blood in the urine and painful urination. Liver injury tends to be mild and usually heals completely.

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May present as Atypical Pneumonia

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Hepatitis - Leptospirosis• Hepatitis is the frequent

complication• Elevation of serum

creatine phospholipase enzyme raise differentiates from Viral hepatitis where the enzyme is not raised

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Nephritis - Leptospirosis• Kidney involvement in

animals produce chronic disease of the kidney and the infected animal starts shedding large number of Leptospira and main source of environmental contamination of bacteria and results I human infections

• Human urine also contain Spirochetes in the second and third week of infection

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Complications• Azotemia• Oliguria• Hemorrhage• Purpura• Hemolysis• Gastrointestinal bleeding• Hypoprothrombinemia and

Thrombocytopenia

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Fever

Viral fever, Malaria, Typhus

Jaundice

Malaria, Viral hepatitis, Sepsis

Renal Failure

Malaria, Hanta virus, Sepsis

Meningitis

Bacterial / Viral causes

Hemorrhagic Fever

Dengue, Hanta virus, Typhus

Diff

eren

tial D

iagn

osis

Early and Prompt Diagnosis is Highly Essential

• The development of simpler, rapid assays for diagnosis has been based largely on the recognition that early initiation of antibiotic therapy is important in acute disease but also on the need for assays which can be used more widely.

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Laboratory Tests• TC / DC / ESR / Hb / Platelet count• Serum Bilirubin / SGOT/ SGPT• Blood Urea, Creatinine & Electrolytes• Chest X-Ray; ECG• Tests for diagnosis of Leptospirosis

– Culture for Leptospira: Positive– MAT; Sero conversion or 4 fold rise/

high titer– ELISA / MSAT : positive

• MAT: Microscopic agglutination test• (M)SAT: Microscopic slide agglutination

Test

Approach to DiagnosisClinical Features

Leptospiremic phase < 7days

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Laboratory Diagnosis Specimens

1 Blood to be collected in a heparin tube

2 CSF, Tissues Microscopic examination 3 Urine to be collected

with great care to avoid contamination

4 Serum for agglutination tests

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Leptospira under the Microscope

Long, Thin, Highly Coiled

Dark Field Microscopy FL

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Culturing Leptospira Blood and Urine be

cultured in Fletcher’s semisolid agar or other media chemically defined protein-free media for the growth of leptospires have been proposed.

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Time Relationship of Tests

1 week 1 month 2 months 1 year 5 years

ELISA or SAT

MAT

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WHO Guide - Faine’s Criteria• Headache2

• Fever2

• Temp > 39 F2

• Conjn. suffusion4

• Meningism4

• Muscle pain4

• Jaundice1

• Alb, creatinine1

• Rain fall5• Contaminate

H204

• Animal contact1

• ELISA IgM + ve15

• SAT positive15

• MAT high titer15

• MAT rising titer25

• Culture positiveDefinite

Score of 25 or more – Presumptive DiagnosisScore of 20 to 25 – Possible case of leptospirosis

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Serology based Testing

• Variety of serological tests other than MAT have been developed for the diagnosis of leptospirosis. Among them are the complement fixation test , several enzyme-linked Immuno-Sorbant assay formats , the macroscopic slide agglutination test , the microcapsule agglutination test , the indirect Haemagglutination assay , the dipstick assay , and other methods . Each assay has its own advantages, drawbacks, and limitations

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Serology• Agglutinating

antibodies raise to very high titers

1 : 10,000 or higher

occurs 5 – 10 weeks after onset of infection

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What is MAT Testing• Each serum sample was tested against 21 or as

specified different serovars by MAT by the standard procedure . Agglutination was examined by dark-field microscopy at a magnification of ×100. The reported titer was calculated as the reciprocal of the highest dilution of serum that agglutinated at least 50% of the cells for each serovar used.

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What is MAT Confirmed Test

• A MAT-confirmed case was defined as a fourfold increase in antibody titer or a single titer ≥1:200, according to the case definition of the Centres for Disease Control and Prevention

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Serology - ELISA• Several

Immunoassays are available as commercial kits

• Detection of IgM and razing titers of IgG will guide in association with clinical history will help in Diagnosis Dr.T.V.Rao MD 56

Newer and Rapid Methods in Diagnosis

• Several rapid tests are evolved for the• diagnosis of leptospirosis. They are easy

to perform and read, although needs to be scientifically evaluated with respect to sensitivity and specificity.

• Dri-Dot test gave considerable sensitivity (67.7%)along with good specificity (78%)by Ig M ELISA.

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Treatment

• Antibiotic of choice is Benzyl Penicillin given by injection in doses of 5 mega units in a day, for 5 days.

• If the patients are genuinely hypertensive to Penicillin opted with Erythromycin 250mgs four times a day for a period of 5 days.

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Preferred treatment • Penicillin 6 million units

daily I.V (10-14 days)• Amoxicillin,

Erythromycin, & Doxycycline

• Patients with MOF(Multi organ failure) to be observed and treated in intensive care unit

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Treatment - Other alternatives

• The leptospirosis can be effectively treated with

Doxycycline Ampicillin AmoxicillinSevere patients need administration

Intravenous Penicillin or Amoxicillin

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Epidemiology• Rainfall; Contaminated

environment

• Poor Sanitation; Inadequate drainage facilities

• Presence of rodents, cattle & stray dogs

• Walking/ working bare foot poses high risk

• Difficult to pinpoint the source of infection

• Any person can get infected, if exposed to contaminated and environment

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Epidemiology

• Leptospirosis causes several animal infections• Most wide spread zoonotic infection in Nature• Human infections are accidental associated with

contamination of water, other materials contaminated with excreta and animal flesh.

• Animal carriers often excrete upto 100million leptospirosis per ml of urine

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Epidemiology - Occupation

Certain occupational

groups such as agriculture

workers in rice and cane fields,

miners and sever cleaners are potential

victims Dr.T.V.Rao MD 63

Leptospirosis – India’s Concern• The first of its kind in India was reported in the 1920s from

Andaman and Nicobar Islands. • In 1993, a serosurvey of conservancy workers in Madras

(using MAT) revealed a prevalence rate of 32.9%. • In 1994, an increase in the number of individuals with uveitis

was noted at Aravind Eye hospital, Madurai, India after an epidemic of leptospirosis in South India; the epidemic followed severe flooding of the Tamil Nadu District in the autumn of 1993

• In 1995, a seroprevalence rate of 12% leptospirosis was found among febrile and jaundice patients in Pondicherry

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How Man gets Infected• Water the great source Drinking Swimming Bathing, as the urine of

Rodents chronically infected contaminate water sources

Children get infected when

in contact with infected Dogs

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Control of Leptospirosis

• Rodent control is most important.

• Human’s should avoid contact with water contaminated with animal contact.

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Chemoprophylaxis

Doxycycline 200 mg orally once a week is

simple effective measure.

When heavy exposure is anticipated

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Vaccination in humans

• Vaccination for humans is justified where they cannot be separated from animal sources or where the animals cannot be immunized successfully

• Necessity of human vaccinated will arise where people live and work in proximity to rodents in wet, tropical conditions, in wet rice planting and harvesting, in military operations, or working in sewers.

• Yet no universally accepted vaccine is available for humans

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Vaccination of Animals

Vaccinating animals have a dual purpose 1 Protecting animals

2 Protecting humans who may contract leptospirosis from them

It is probably true as that immunization of animals will prevent leptospirosis in people in contact

with them. It proved true in 1980 when extensive vaccination

of dairy cows in New Zealand lead to marked decreased incidence in Humans.

Animals immunized experimentally with polysaccharide derived from Leptospira LPS linked to diphtheria Toxoid were protected

against challenges Several other vaccines in use to suit local needs.

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New Vaccine trails - Leptospira

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Walking in Flood Waters can Infect

• With the rats comes the threat of illnesses such as Weil's Disease, which is transmitted to humans via contaminated water and is carried by up to 30 per cent of the rodent population.

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PreventionPrevention is difficult due to wild animal infection

Good sanitation, Immunization of live stock

Personal hygiene, PPE, Water treatment

No useful human vaccines – multiple serovars

Doxycycline 200 mg weekly for at risk groups

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Created for Health Awareness on Leptospirosis

Email

doctortvrao@gmail.com

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