It
has zoonotic importance. It is caused by Leptospira interrogans and
Leptospira biflexa. Different strains as Leptospira Hardjo in
cattle, Leptospira pamma and Leptospira canicola in humans. It causes abortion, still birth and leads to
infertility. It changes all reproductive parameters.
Spread:
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Through carrier animals. It may be rodents and non rodents as
rabbits, fox, and cattle. Occurrence is high in wild animals.
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Disease also spreads through contaminated food and water.
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Disease is high in tropical areas.
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Bacteria can live in water for years specially in stagnant
water.
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Flood after heavy rains is also a source of spread.
Pathogenesis and Symptoms:
Entry of organism is through skin lesions, through mucosa, direct
ingestion of contaminated food and water. After ingestion bacteremia
develops and antibodies are produced. Then organism is localized in
different organs specially in kidney, stomach, lungs, uterus, and in
pregnant animals cross the placental barrier.
In
kidney it causes nephritis and hemolysis. If hemolysis occurs, it
will lead to hemoglobin urea and then renal failure.
In
uterus there will be placentitis and cotylodinitis, and it will lead
to abortion.
In
liver there are two types of diseases which appear after damaging
liver as an-icteric form and icteric form. An-icteric form is 90-95
% while icteric form is 5-10 % where symptoms of jaundice appear. In
cattle there is spontaneous abortion (without showing symptoms) from
forth month of gestation and there will be Leptospiral mastitis.
There will be appearance of udder like flabby bag. There will be
sudden drop in milk production. Milk will be like colostrums. Even
there will be presence of blood in milk.
Factor for Persistence of Disease:
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Carriers as rodents and non rodents
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Drainage congestion specially after heavy rain; stagnant water,
contaminated lakes
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If salinity in soil, organism can survive for years.
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Soil temperature (50 cm in soil) if remains nearly 22 oC,
it provides suitable environment.
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Seasonal variation as high occurrence in rainy season
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Age and sex: slightly more in male, in younger animals of upto
3-8 years and in between 20-30 years in human.
Diagnosis:
For isolation placenta and fetus in case of aborted fetus. From
fetus particularly abomasum part. Placenta is leathery in
brucellosis but specific lesions are absent in leptospirosis. If due
to Aspergillus, there will be white lesions. Kidney, lung, liver,
and stomach can also be used for sample |