1. ‫بسم ا الرحمن الرحيم‬
LEPTOSPIRA
Prof. Khalifa Sifaw Ghenghesh

2.  Actively motile spiral bacteria, appear straight
and rigid with one or both ends hooked
 Obligate aerobes, Optimum temp. > 28-32oC
 Many types are harmless, others cause
disease in warm-blooded animals (including
domestic) and man (leptospirosis)
 Pathogenic leptospires found in kidneys of
rodents and other small mammals
– Excreted in their urine
 2 species
– L. interrogans
– L. biflexa
>> Parasitic strains
>> Free-saprophytic strains

3. Leptospira species

4. Leptospira species

5. Leptospira interrogans
 Require addition of serum for growth
 Slow growth requires 2-3 weeks
incubation in liquid media
 Can cause
– Benign leptospirosis with mild influenza-like
illness (Canicola fever)
– Severe form of illness characterized by
jaundice and haemorrhages in the eyes, skin
and mucous membranes (Weil’s disease)
 Sometimes fatal
 Usually due to serovar icterohaemorrhagiae

6. LABORATORY DIAGNOSIS
 Specimen
– Blood > after 5-12 days incubation >
leptospiraemia for 7 days
– Urine deposit > leptospires after 2nd week of
illness for 4-6 weeks (intermittently)
 Microscopy
– Dark-ground microscopy
 Culture:
– Blood > Liquid medium
– Urine sediment > Semisolid medium

7.  Serological Examination
– Specific Abs in patients serum > end of 1st
week
– Continue to rise for several weeks and then
decline
– Serum examined early day of illness and at
intervals of 4-5 days thereafter
– Rise in Ab titre is indication of current
infection
– Tests used
 Complement fixation and Haemagglutination
tests, ELISA and Microscopic agglutination test

8. Leptospira bacteria in liver impression
smear (FA stain) of a Patient died of
leptospirosis.

9. Histopathology of leptospirosis, kidney
(Dieterle silver stain)

10. Photomicrograph of leptospiral microscopic
agglutination test with live antigen using
darkfield microscopy technique.

11. TREATMENT AND CONTROL
 Benzylpenicillin (IV) in large
doses (3.6-4.8g) > daily for 7 days
 Alternatives:
– Erythromycin, Streptomycin
 Control: