Leptospirosis is caused by bacteria that can infect humans and animals. It is commonly spread through contact with urine of infected animals like rats. The document discusses the causative agents, symptoms, diagnosis and treatment of the disease. Leptospirosis symptoms include high fever, headache, muscle pain and can potentially lead to liver or kidney damage. Diagnosis involves blood and urine tests or culture. Antibiotics like doxycycline or penicillin are used for treatment. Prevention involves reducing contact with infected animals and their urine.

1. LEPTOSPIROSIS
Name: Purshotam Kumar Sah Kanu
Roll No.: MB 1318/075
Level: M.Sc Microbiology (3rd Sem)
Central Department of Microbiology
Tribhuvan University, Kirtipur
Kathmandu, Nepal

2. INTRODUCTION
• Also known as Weil’s disease, rice field worker’s disease, rat
fever.
• Leptospirosis is a potentially serious illness that can effect
many parts of the body.
• Leptospirosis is commonly caused by Leptospira interrogans,
a corkscrew-shaped bacterium (spirochete).

3. Systemic Classification
Kingdom: Eubacteria
Phylum: Spirochaetes
Class: Spirochaetes
Order: Spirochaetales
Family: Leptospiraceae
Genus: Leptospira
Species: interrogans
biflexa
parva

4. HISTORY
• Leptospira was first described by Adolf Weil in 1886 when he
reported an “acute infectious disease with enlargement of
spleen , jaundice and nephritis”.
• It was first observed in 1907 from a post mortem renal tissue
slice.
• In 1908, Inada and Ito first identified it as the causative
organism and in 1916 noted its presence in rats.

5. DISTRIBUTION
• Leptospirosis occurs worldwide but is most common in
tropical and subtropical areas with high rainfall.
• The disease is found mainly wherever humans come into
contact with the urine of infected animals or a urine-polluted
environment.

6. INCIDENCE
• The number of human cases worldwide is not known precisely.
• Estimated annual incidence (WHO)
-0.1 to 1 per 1,00,000 per year in temperate climates
-10 or more per 1,00,000 per year in the humid tropics
• Estimated case-fatality rates in different parts of the world
have been reported to range from 5-30%
• Seasonal – peak in summer, during rainy/monsoon season

7. Leptospirosis in Nepal
• The first report of a suspected leptospiral infection in Nepal
was in a Nepali soldier in 1981.
• Till date, the frequency, incidence, and prevalence of
Leptospirosis have not been well demonstrated in Nepal.
• In 2014, a seroprevalence rate of 21% acute leptospirosis was
found among febrile patients in Dang .
• In 2017-18, Leptospirosis outbreak was recorded in Foklan
Tapu, Sundarharaicha Municiaplity of Morang district.

8. RESERVOIR
• About 160 mammalian species serve as reservoirs.
• Rodents were the first recognized carriers of leptospirosis and
are a primary source of infection for humans.
• Rodents have a prolonged carrier state, i.e. they can shed
leptospires throughout their lifespan without showing any
clinical symptoms.

9. 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
• Can be Seen with dark field Microscopy.

10. Important species in Leptospirosis
• The genera Leptospira contains three species, namely L.
interrogans, L. biflexa and L. parva. The first includes 23
serogroups and more than 250 serovars and is the principal
cause of leptospirosis in humans and animals.
• Important pathogenic serovars from this species are Canicola
and Icterohaemorrhagiae.
• They reside in alkaline water, alkaline soil- survive in these
area for months or years
• Also could be found in urine

11. Cont…
• Two types of leptospirosis:
1. Anicteric leptospirosis or self-limited illness (85-90% of the
cases)
2. Icteric leptospirosis or weil’s syndrome (5-10%)

12. Cont…

13. Mode of Transmission
• Contact with urine or tissues from infected animals, usually
rodents.
• Contact with surface water, soil or plants contaminated with
the leptospirosis bacteria from the urine of infected animals.
• Via skin abrasions or exposed mucous membranes, the most
common entry point for infection.
• Human-to-human transmission is rare.

14. Pathogenesis
• Infects through mucosa ( conjunctival , oral) or through
punctured or abraded skin
• Proliferate in bloodstream and disseminate hematogenously
• Development of antibodies(5-7 days)
• Organism disappears from blood but remains in organs
including brain , liver, lung, heart and kidneys
• Traverse interstitial spaces of kidney
• Penetrate basement membrane of PCT
• Adhere to proximal tubule epithelial cells
• Excreted in urine

15. Cont…
• Produces endotoxin
• Attach onto the endothelial cells
• Capillary vasculitis (endothelial necrosis and lymphocytic
infiltration)
• Vasculitis and leakage : petechiae , intra parenchymal
bleeding and bleeding along serosa and mucosa
• Loss of fluids into the third space
• Hypovolaemic shock and vascular collapse

16. Clinical signs and symptoms
• 2phases:
• Begins with flu-like symptoms then briefly asymptomatic until
the second phase begins.
• First phase(1 week ): Septicaemic/ Leptospiremia phase
- High, remittent fever(38-40°C)
- Retroorbital headache, chills and rigors
- Myalgia : paraspinal, calf, abdominal muscle
- Conjuctival suffusion
- Maculopapular skin rashes
- Vomitting

17. Cont…
• Second stage - immune or leptospiruric stage
- Lasts 4-30 days
- Disease referable to specific organs is seen.
- These organs include the meninges, liver, eyes, and kidney.
- Nonspecific symptoms, i.e. fever and myalgia, less severe
than in the first stage and last a few days to a few weeks.
- Aseptic meningitis is the most important clinical syndrome
observed in the immune anicteric stage.
-lasts a few days but occasionally lasts 1-2 weeks.
-Meningeal symptoms develop in 50% of patients.
-Mild delirium may also be seen.
-Weil’s disease

18. Complications
• Nephritis
• Hepatitis
• Manifestations in eye
• Muscular lesions

19. CASE CLASSIFICATION

20. Cont…

21. Laboratory Diagnosis
 Sample
- Blood, CSF, urine, serum, body fluids, tissues
• Specimen collection
- Blood : citrate, heparin, or oxalate anticoagulants
- Urine : no preservatives
- Transported at room temperature and inoculated for culture
within 24 hours.

22. Cont…
• Direct detection
- centrifuging at 1500×g for 30 minutes
- sodium oxalate or heparin-treated blood at 500×
g for 15 minutes
• Culture
- Semisolid medium (Fletcher’s or Stuart’s)
- Blood : inoculated into tubes
- Urine : undiluted+ diluted , addition of 200 μg/ml
of 5-fluorouracil

23. Cont…
• Serology
1. Microscopic Agglutination Test ( gold standard)
- 4X rise in titres between acute and convalescent-phase
- A single titer of >1:800 is strong evidence of current or
recent infection with leptospira

24. Cont…
2. Genus specific or rapid tests
- ELISA
- Macroscopic slide agglutination test (MSAT)
- Latex agglutination test
- Dipstick tests ( Lepto dipstick, Lepto Tek lateral flow)
- Lepto Tek Dri-Dot test
- Indirect hemagglutination
- They detect specific IgM antibodies, using saphrophytic
leptospira as antigens

25. Cont…
• Molecular diagnosis
- PCR : Detection of pathogenic Leptospira DNA from a clinical
specimen.

26. Cont…

27. Treatment
• Mild/outpatient :
- Doxycycline 100mg BD X 1/52 (2mg/kg/day) or
- Ampicillin 500-750mg 6hourly X 1/52 or
- Amoxicillin 500mg 6hrly X 1/52
• Severe Disease:
- IV penicillin G 1.5MU 6hourly X 1/52 or
- IV Ceftriaxone 1g OD X 1/52 or
- IV Cefotaxime 1g 6 hourly

28. Prevention and control
• The infection source can be controlled by general measures
including:
• reduction of animal reservoir populations, such as rats;
• immunization of dogs and livestock;
• removal of rubbish and ensuring areas in and around homes
are clean.

29. Cont…
Individuals
• Avoid contact with animal urine, infected animals or an
infected environment e.g. waterlogged places where infected
animals may have urinated.
• Wear protective clothing and cover wounds with waterproof
dressings to reduce the chance of infection if exposure is
likely, e.g. occupational or recreational exposure.
• Do not swim in lakes or rivers that might be contaminated
with animal urine.

30. Cont…
• Drink only safe or boiled water during the rainy season,
especially in flood-prone areas.
• Practise good personal hygiene, washing hands before eating
and after defecating.
• Consult a physician for prophylactic use of antibiotics during
flooding times.
• Protect the water supply from animal contamination.
• Drain wet ground.

31. Prophylaxis

32. BIBLIOGRAPHY
• Regmi, L., et al. (2017). "Sero-epidemiology study of
leptospirosis in febrile patients from Terai region of Nepal."
BMC Infectious Diseases 17(1): 628.
• http://nhrc.gov.np/wp content/uploads/2019/04/pdfresizer.com-
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