Leptospira bacteria cause leptospirosis, a disease primarily affecting mammals that can lead to severe human health complications, including liver and kidney failure. The illness presents in two phases, starting with acute symptoms such as fever and muscle pain, followed by a possible immune response phase. Diagnosis is challenging due to variable symptoms, and control measures include reducing animal reservoirs and using antibiotics for treatment.

1. Leptospira
Causes leptospirosis (എലിപ്പനി), a
usually mild febrile illness that may result
in liver or kidney failure.
Attribution-NonCommercial-ShareAlike
4.0 International (CC BY-NC-SA 4.0)

2. Spirochete
• Spirochete, (order Spirochaetales) any of a group of spiral-shaped bacteria, some of which are serious
pathogens for humans, causing diseases such as syphilis, yaws, Lyme disease, and relapsing fever.
• Examples of genera of spirochetes include Spirochaeta, Treponema, Borrelia, and Leptospira
• Spirochetes are gram-negative, motile, spiral bacteria, from 3 to 500 m (1 m = 0.001 mm) long
• Spirochetes are unique in that they have endocellular flagella (axial fibrils, or axial filaments), which number
between 2 and more than 100 per organism, depending upon the species
• Each axial fibril attaches at an opposite end and winds around the cell body, which is enclosed by an
envelope
• Spirochetes are characteristically found in a liquid environment (e.g., mud and water, blood and lymph).

3. Spirochete
• Treponema includes the agents of syphilis (T. pallidum pallidum) and yaws (T. pallidum pertenue)
• Borrelia includes several species transmitted by lice and ticks and causing relapsing fever (B. recurrentis and
others) and Lyme disease (B. burgdorferi) in humans.
• Spirochaeta are free-living nonpathogenic inhabitants of mud and water, typically thriving in anaerobic
(oxygen-deprived) environments
• Leptospirosis, caused by Leptospira, is principally a disease of domestic and wild mammals and is a
secondary infection of humans.

4. Leptospira
• Leptospira organisms are very thin, tightly coiled, obligate aerobic spirochetes characterized by a unique
flexuous type of motility
• The genus is divided into two species: the pathogenic leptospires L interrogans and the free-living leptospire
L biflexa
• Primary hosts for this disease are wild and domestic animals, and the disease is a major cause of economic
loss in the meat and dairy industry
• Humans are accidental hosts in whom this disseminated disease varies in severity from subclinical to fatal
• serotypes of L biflexa exist in water and soil as free-living organisms
• Although L biflexa has been isolated from mammalian hosts on occasion, no pathology has been found

5. Clinical Manifestation
• Clinical manifestations of leptospirosis are associated with a general febrile disease and are not sufficiently
characteristic for diagnosis
• leptospirosis often is initially misdiagnosed as meningitis or hepatitis
• the disease is biphasic, which an acute leptospiremic phase followed by the immune leptospiruric phase

6. Clinical Manifestation
Leptospirosis
Acute phase Immune phase
• After an average incubation period of 7 to 14 days
• abrupt onset of fever, severe headache, muscle pain,
and nausea for approx. 7 days
• Jaundice may occur
• With the appearance of antileptospiral antibodies, the
acute phase of the disease subsides
• leptospires can no longer be isolated from the blood
• The immune phase occurs after an
asymptomatic period of several days
• a fever of shorter duration and central nervous
system involvement :- meningitis
• Leptospires appear in the urine during this
phase

7. Clinical Manifestation
In humans, Leptospirosis can cause a wide range of
symptoms, including:
• High fever
• Headache
• Chills
• Muscle aches
• Vomiting
• Jaundice (yellow skin and eyes)
• Red eyes
• Abdominal pain
• Diarrhea
• Rash
• Meningeal Involvent
• Hemorrhagic manifestation (intestines, lung)

8. Structure, Classification, and Antigenic Types
• The cell is encased in a three- to five-layer outer membrane or envelope
• Beneath this outer membrane are the flexible, helical peptidoglycan layer and the cytoplasmic membrane;
these encompass the cytoplasmic contents of the cell.

9. Structure, Classification, and Antigenic Types
• The structures surrounded by the outer membrane are collectively called the protoplasmic cylinder
• An unusual feature of the spirochetes is the location of the flagella, which lie between the outer membrane
and the peptidoglycan layer
• They are referred to as periplasmic flagella
• The periplasmic flagella are attached to the protoplasmic cylinder subterminally at each end and extend
toward the center of the cell, have two periplasmic flagella, one originating at each end of the cell.
• The number of periplasmic flagella per cell varies among the spirochetes
• The motility of bacteria with external flagella is impeded in viscous environments, but that of spirochetes is
enhanced
• They do not stain well with aniline dyes

10. Structure, Classification, and Antigenic Types
• The two species, L interrogans and L biflexa
• further divided into serotypes based on their antigenic composition
• More than 200 serotypes have been identified in L interrogans.

11. Pathogenesis
• The mucosa and broken skin are the most likely sites of entry for the pathogenic leptospires
• no lesion develops at the site of entry
• Bacteremia occurs during the acute phase of the disease
• The leptospires are rapidly eliminated from all host tissues except the brain, eyes, and kidneys
• Leptospires surviving in the brain and eyes multiply slowly
• however, in the kidneys they multiply in the convoluted tubules and are shed in the urine
• The leptospires may persist in the host for weeks to months; in rodents they may be shed in the urine for
the lifetime of the animal
• Leptospiruric urine is the vehicle of transmission of this disease.

12. Pathogenesis
• No endotoxin nor exotoxins have been associated with them
• The most notable feature of severe leptospirosis is the progressive impairment of hepatic and renal
function
• Renal failure is the most common cause of death
• The host's immunologic response to leptospirosis is thought to be responsible for lesions associated with the
late phase of this disease

13. Ocular manifestation
• Red eye can be the initial manifestation
• a mild anterior uveitis and panuveitis
• Vitreous inflammatory cells aggregate to form
vitreous exudates floating in vitreous: Hypopyon
• Retinal Vasculitis
Subconjuctival haemorrhage in a patient
with leptospirosis

14. Diagnosis
• Because clinical manifestations of leptospirosis are too variable and nonspecific
• microscopic demonstration of the organisms, serologic tests, or both are used in diagnosis
• The microscopic agglutination test is most frequently used for serodiagnosis
• The organisms can be isolated from blood or urine on commercially available media
• Isolation of the organisms confirms the diagnosis
• CSF sample and urine samples are used. Blood samples are useful only during initial days

15. Control
• Human leptospirosis can be controlled by reducing its prevalence in wild and domestic animals
• Leptospirosis is treated with antibiotics, such as doxycycline or penicillin, which should be given early in the
course of the disease
• Intravenous antibiotics may be required for persons with more severe symptoms. Persons with symptoms
suggestive of leptospirosis should contact a health care provider
• The risk of acquiring leptospirosis can be greatly reduced by not swimming or wading in water that might be
contaminated with animal urine, or eliminating contact with potentially infected animals.
• Protective clothing or footwear should be worn by those exposed to contaminated water or soil because of
their job or recreational activities.

16. National Centre for Disease Control guidelines
• Leptospirosis is usually a seasonal disease that starts at the onset of the rainy season and
declines as the rains recede. Sporadic cases may occur throughout the year. In India the disease
has been found more commonly associated during post-monsoon period. In natural disasters
such as foods it may assume epidemic potential
• Agricultural workers such as rice field planters, sugar cane and pineapple field
harvesters,labourers engaged in canal cleaning operations and livestock handlers are subjected
to exposure with leptospires.
• Fishermen, sewer workers and all those persons who are liable to work in rodent infested
environment. Lorry drivers as they may use contaminated water to wash their vehicles and
masons, who may come in contact with the organisms while preparing the cement and sand
mixture for construction work with contaminated water

17. National Centre for Disease Control guidelines
Chemoprophylaxis:
• During the peak transmission season Doxycycline 200 mg, once a week, may be given to agricultural workers
(eg. paddy field workers, canal cleaning workers in endemic areas) from where clustering of cases has been
reported
• The chemoprophylaxis should be for six weeks and never to be extended for more than eight weeks

18. National Centre for Disease Control guidelines
Rodent control
• It is established beyond doubt that rodents are the major reservoirs of bacterium Leptospirainterogans
• Four species of rodents Rattusrattus(House rat), Rattusnorvegicus(Norway rat), Bandicotabengalensis
(Lesser bandicoot) and Bandicotaindica(Larger bandicoot) are so far found to be reservoirs for this bacterium
in India
• Hence controlling these reservoir species with proper strategy planning and management planning will
reduce the incidence of the disease in the affected areas

19. National Centre for Disease Control guidelines
Rodent control
The strategy planning should cover the following
1. Identifying the reservoir species of affected area
2. Delineating areas for anti rodent activities
3. Limiting the operations to pre monsoon months.
4. Adopting appropriate technology for anti rodent operations. This includes
correct inputs and appropriate application technology.
5. Capacity building among all involved personnel and
6. Awareness creation among public to bring community involvement