vibrio cholera and all about it

microbiology

1. VIBRIO CHOLERA MAN BAHADUR RANA,BPH

2. History

3. Contd....

4. Contd...

5. Contd.....

6. MORPHOLOGY

7. Contd....

8. Contd...

9. CONTD...

10. Contd...

11. Contd...

12. Contd...

13. CONTD....

14. CONTD....

15. CONTD...

16. PATHOGENESIS - V. cholera 01 causes an acute diarrhoeal disease known as cholera. - It occurs only in man. The faeces and vomitus of human cases or carriers are the main source of infection .

17. Contd...

18. Contd... - The human infection occurs by ingestion of contaminated food and drinks.

19. Contd...

20. Contd...

21. Contd...

22. Contd... - After passing the acid barrier of the stomach, virulent vibrio cholera adhere to the microvilli (brush border) of small intestine mucosa and multiply and secrete cholera toxin. - The cholera toxin (CT) consist of two major non covalently associated regions : ‘ A’ active region (sub unit) and ‘B’ binding sub unit .

23. Contd... - V. cholera 01 protease yield 2 fragments A1 and A2 which remain covalently connected by single disulphide bond. - After the B unit binds to the receptor of the cell membrane , A sub unit dissociates from B sub unit and penetrates the cell membrane. The disulphide bond joining A1 and A2 is broken and the A1 sub unit is activated.

24. Contd... - The A sub unit stimulates cell bound adenylate cyclase and adenyl cyclase activity of the cell increases , this in turn converts ATP to cAMP in the gut epithelial cells. - The increase c AMP level causes hype rsecretion of electrolytes ( Na + , K + ) and water out of the cell and into the lumen of the intestine.

25. Contd... - This leads to an outporing of fluid and contains flakes of mucus and little protein and result in vomiting and profuse watery diarrhoea (rice water stool) . - This result in varying degree of dehydration and electrolyte imblance that can lead to metabolic acidosis, hypokalaemia, shock and death in extreme case.

26. Contd...

27. Contd....

28. Contd....

29. Contd... Clinical Features: - The incubation period is 1-4 days for person who develops symptoms. - Manifest with: . Nausea . Vomiting . Profuse diarrhoea . Abdominal cramps . Rice water stool . Loss of fluids leads to profound dehydration, circulatory collapse and anuria.

30. Contd...

31. LABORATORY DIAGNOSIS

32. CONTD... Transport: If there are the chances of delay, 2-3 gms of faeces are emulsified in 10-15 ml VR(Venkataraman-Ramakrishna) fluid medium or in bile peptone transport medium or in Cary- Blair medium .

33. MICROSCOPY

34. CULTURE

35. Agglutination Test

36. TREATMENT

37. PROPHYLAXIS

38. CONTD....

39. IMMUNISATION

40. CONTD...