1. بسم الله 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. > 28-32 o C   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>> Parasitic strains – –L. biflexa>> Free-saprophytic strains

3. 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 2 nd 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 1 st 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: