Cholera

 

Describe Lab diagnosis of cholera

          1. Dark ground illumination examination of stool for darting motility. Diagnosis is confirmed by adding antiserum to the sample which abolish the motility .

           2. Cultural isolation from stool on tellurite gelatin agar or any other special medium particularly , alkaline peptone water and thiosulphate eitrate bile salt.

            3. By chemical reaction :- Cholera Vibrio ferments glucose , maltose , mannite and sucrose with acid production only.

             4. Cholera Red Reaction :- This is rapid method of diagnosis bacteria grown in peptone water is mixed with 1 drop of Conc Hzso4 media turns red if cholera is present.

              5. GRERG test for hemolysis :- It is done for differentiating cholera from EL – TORS , EL – TOR is haemolytic and cholera is not.

               6. Agglutination Test :- For antigenic classification into oguva , in ova and hikajima.

              7.  Phage typing by phage – 4 :- Cholera is not killed by phage – 4.

              8. String Test :- Bacterial suspension + 0 ˙5 % sodium deoxycholate – Clera the turbidity + mucoid-+ ve.