2. INTRODUCTION
ā¢ Leptospirosis is a blood infection caused by the bacteria Leptospira.
ā¢ It affects both humans and animals.
ā¢ It can pass from animals to humans and vice versa.
ā¢ In humans, it can cause a wide range of symptoms, some of which may be
mistaken for other diseases. Some infected persons, however, may have no
symptoms at all.
ā¢ 7-10 millions are affected annually.
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3. HISTORY
ā¢ Adolf Weil described the first case of leptospirosis in man in 1886.
ā¢ Stimson demonstrated by silver staining the presence of clumps of
spirochetes in the kidney tubules of a patient who reportedly died of yellow
fever in 1907.
ā¢ The causative agent of Weilās disease was isolated by Inada and Ido in 1915.
ā¢ Noguchi proposed the name āLeptospiraā (thin spirals) in 1918.
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4. AETIOLOGY
ā¢ Caused by bacteria of genus-Leptospira (Spirochetes).
ā¢ Many species are present in case of Leptospira.
ā¢ Leptospira has traditionally been divided into three groups
ā¢ The pathogenic - L. interrogans (most imp.), L. borgpetersenii, L. santarosai, L.
noguchii, L. weilli, L. kirschneri and L. alexanderi
ā¢ Intermediates or opportunistic - Leptospira inadai, Leptospira fainei, L. wolffii
ā¢ Free-living non-pathogenic strains - L. biflexa, L. parva
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5. AETIOLOGY
ā¢ The genus Leptospira is divided into 20 species based on DNA hybridization studies.
ā¢ All recognized species of Leptospira interrogans are categorized into 25 serogroups
and 250 serovars based on surface-exposed lipopolysaccharide (LPS).
ā¢ The common Leptospira interrogans serovars are:
ā¢ 1.L.interrogans serovar pomona,
ā¢ 2.L. interrogans serovar hardojobovis,
ā¢ 3.L.interrogans serovar icterohaemorrhagiae,
ā¢ 4.L.interrogans serovar canicola,
ā¢ 5.L.interrogans serovar grippotyphosa,
ā¢ 6.L.interrogans serovar bratislava,
ā¢ 7.L. interrogans serovar tarassovi
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8. EPIDEMIOLOGY
ā¢ Leptospirosis is a worldwide zoonotic infection with a much greater
incidence in tropical regions and has now been identified as one of the
emerging infectious diseases.
ā¢ The epidemiology of leptospirosis has been modified by changes in animal
husbandry, climate, and human behavior.
ā¢ A modeling exercise by the World Health Organization's (WHO's)
Leptospirosis Burden Epidemiology Group estimated that there were
873,000 cases worldwide annually with 48,600 deaths.
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9. MORPHOLOGY
ā¢ Leptospires are actively motile, helically shaped, slender spirochetes possessing large number
of light and fine spirals.
ā¢ Although cytochemically gram-negative, they do not stain well with conventional
bacteriological dyes and are usually visualized using dark-field microscopy.
ā¢ Silver impregnation (Levaditiās stain) staining techniques are used to demonstrate
Leptospira in tissues and Fontana staining for smear on slides.
ā¢ Characteristically, Leptospira have hooked ends and two periplasmic flagella (PF), also
known as axial filament and endoflagella which arise from each end of bacteria.
ā¢ Rotation of the PF results in the distinct spinning mobility of Leptospira.
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10. CULTURAL CHARACTERS
ā¢ They grow very well in media enriched with rabbit plasma (rabbit plasma contain high
concentration of bound vitamin B12).
ā¢ Several liquid and semisolid media are available.
ā¢ Liquid media- Korthofās medium, Stuartās medium, Vertwoortās medium
ā¢ Semi solid medium -Fletcher medium, EMJH, protein free medium, Ellis medium.
ā¢ In semisolid media, growth occurs characteristically 0.5 cm below the surface-.Dingerās
ring/disk.
ā¢ Addition of 5-flurouracil (100 mg/ml) in medium is inhibitory for most of the microorganism
but not for Leptospires
ā¢ Leptospira are highly susceptible to heat, being killed in 10 mts at 50ĀŗC and in 10 sec at 60ĀŗC. .
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16. INCUBATION PERIOD
ā¢ The incubation period is usually 5-14 days, with a range of 2-30 days.
ā¢ Animals also the same .
ā¢ Depends on the strain, serovar and the bacterial load and health status.
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20. Human Clinical Signs
ā¢ In humans, Leptospirosis can cause a wide range of symptoms, including:
ā¢ High fever.
ā¢ Headache.
ā¢ Chills.
ā¢ Muscle aches.
ā¢ Vomiting.
ā¢ Jaundice (yellow skin and eyes)
ā¢ Red eyes.
ā¢ Abdominal pain
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24. Cattle, Sheep- Leptospirosis
ā¢ Leptospira interrogans hardjobovis and L. borgpetersenii serovar hardjo is the host-
adapted lepto serovar in cattle and sheep and can infect animals at any age, including young
calves.
ā¢ Infection with this serovar will often produce a carrier state in the kidneys associated with long-
term urinary shedding. In addition, infections with hardjobovis can persist in the reproductive tract.
ā¢ red urine (red water), jaundice
ā¢ Lactating cows produce less milk, and, for a week or more, the milk they produce is thick and
yellow.
ā¢ However, unlike many other udder infections, leptospirosis does not usually cause any firmness
of the udder and it causes Flaccid mastitis.
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25. Equine Leptospirosis
ā¢ The Infection with serovar bratislava, which has been associated with
abortions and stillbirths in horses.
ā¢ Clinical disease most often results from incidental infection with serovar
pomona.
ā¢ Signs include abortion in mares and renal disease in young horses.
An immune-mediated anterior uveitis (periodic ophthalmia, 'moon
blindness') may be a manifestation of chronic leptospirosis in horses.
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26. Canine Leptospirosis
ā¢ Dogs: The acute form of leptospirosis is known as Stuttgart disease.
ā¢ The serovars associated with leptospirosis in dogs are canicola and
icterohaemorrhagiae .
ā¢ Serovar canicola, which is host-adapted for dogs, causes severe renal disease in
pups. In animals which survive the acute phase, a chronic uremic syndrome may
subsequently develop.
ā¢ Nephritis with petechial hemorrhage and degeneration of tubules is the main lesion
in acute form. While in chronic form areas of fibrosis, thickening of Bowmanās
capsule are the main lesions.
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27. Porcine Leptospirosis
ā¢ Acute leptospirosis in pigs is usually caused by rodent adapted serovars such as
icterohaemorrhagiae and copenhagenii .
ā¢ These serovars cause serious, sometimes fatal, disease in young pigs. It causes
hemoglobinuria, jaundice and fever.
ā¢ In many parts of the world, the principal host-adapted serovar is pomona.
ā¢ Pigs also serve as maintenance hosts for serovars tarassovi and bratislava, which may also
cause reproductive failure. Abortion occurs in the last 3rd of pregnancy and stillbirth.
ā¢ Lesions include icterus, petechial hemorrhage of liver, kidney and intestine, grayish white
areas surrounded by zone of congestion in kidneys.
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36. DIAGNOSIS
ā¢ 1.Tentative Diagnosis: Clinical signs with the history of exposure to contaminated urine.
ā¢ 2. Direct microscopy :Leptospires can be demonstrated in blood and CSF (during first 3-7 days),
urine (after 10 days of infection), by darkfield microscopy (DFM), Fontana staining and by FAT.
ā¢ 3.In tissue by Levaditiās staining and FAT.
ā¢ 4. Isolation in culture media
ā¢ 5. Animal inoculation āGuinea pigs
ā¢ 6.Microscopic Agglutination test (MAT), using live organisms- is the gold standard test for
diagnosis and is serovar specific) āGST.
ā¢ 7.ELISA IgM and slide agglutination tests (SAT).
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37. TREATMENT
ā¢ Penicillin G āDrug of Choice.
ā¢ Ampicillin, Doxycycline are also used.
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38. PREVENTION AND CONTROL
ā¢ Proper hygiene measure should be practiced.
ā¢ Urine should be cleaned from sheds.
ā¢ Animals should be taken care of.
ā¢ Proper vaccination practice.
ā¢ Control the rodent population
ā¢ Use of rodenticides.
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