Leptospira is a spirochete bacteria that can cause leptospirosis in humans. There are pathogenic and non-pathogenic strains, with L. interrogans being the primary human pathogen containing 26 serogroups. Infection typically occurs through contact with water contaminated by the urine of infected rodents. Symptoms include fever, jaundice, and hemorrhaging. Laboratory diagnosis involves dark-field microscopy, culture, serological tests, and animal inoculation to identify the infecting serotype. Treatment involves antibiotics like penicillin and tetracycline.

1. Leptospira G.HARIPRASAD M.Sc.,(Med micro),M.phil., Lecturer in Microbiology Department of Microbiology Thoothukudi Govt. Medical College Thoothukudi LEPTOSPIRA

2. Spirochaetes possess numerous closely wound spirals with characteristic hooked ends. Actively motile

3. Classification Non-pathogen– L.biflexa –found in waters. Human Pathogen- L. interrogans

4. L.interrogans has 26 serogroups e.g. - Icterohaemorrhagiae - Canicola - Australis - Hebdomadis - Andamana

5. Leptospira interrogans-Pathogenicity Infection with leptospira – Leptospirosis The primary reservoir is rodents because, once infected, they shed the organisms for life. ANIMAL RESERVOIR FOR LEPTOSPIRA RODENT

6. Humans gets infection by drinking water contaminated with Leptospira…. Leptospires can also enter thro’ abraded skin….. Incubation period – 6-8 days

7. Leptospires enters blood & multiply for 1 wk Then disappear from the blood and enters into the liver, Kidney, spleen and meninges. Persist mainly in kidney and excreted in urine in later stages

8. WEIL’S DISEASE Severe form of leptospirosis Fever, conjunctivitis, albuminurea, jaundice and haemorrhage Implicated group: L.icterrohaemorrhagiae

9. Clinical symptoms

10. Laboratory diagnosis Specimens: 1. Blood – in initial stage 2. Urine – in later stage Blood should be examined during the first week of illness thereafter urine is examined.

11. DARK-GROUND MICROSCOPY Gold standard method for detection of spirochetes including Leptospira

12. FONTANA’S STAIN

13. CULTURE Modified Korthof’s medium Fletcher’s semisolid medium Incubated at 28-32 0 C aerobically Examined every 3 rd day upto 6 weeks before discarding it as negative

14. ANIMAL INOCULATION Intraperitoneal inoculation into young guinea pigs On third day, the peritoneal fluid is examined daily by dark ground illumination.

15. SEROLOGICAL TESTS Useful method of diagnosis Antibodies begin to appear at the end of first week and continue to rise till the fourth week and then begin to decline. Two types Screening tests Serotype specific tests

16. SCREENING TEST Identify genus i.e.Leptospira????? Using antigen: L.biflexa (non-pathogen) Test used: Complement-fixation test Haemagglutination test ELISA Agglutination Indirect immunofluorescence

17. Serotype specific tests Identify exact serotypes Microscopic agglutination test Macroscopic agglutination test

18. TREATMENT: Penicillin Tetracycline Erythromycin PROPHYLAXIS: Rodent control Disinfection of water Wearing of protective clothes No vaccines!!!! Natural immunity develops after infection with corresponding serotype