Intratypic Differentiation on Cell culture positive isolates

1.    Scope

• This SOP explains the algorithm to be followed in ITD lab.

2.    Definition

• rRTPCR- Real Time Reverse Transcriptase PCR  
• SL - Sabin Like
• NSL – Non Sabin Like

• Vaccine virus isolates are subjected to respective VDPV screen. For Example:

o   If P1 SL is identified in rRTPCR of ITD then screen this isolate for VDPV1 rRTPCR.

o   If a mixture of polio viruses is identified then screen this isolate for respective VDPV rRTPCR. (Isolate of P1 SL + P3 SL mixture by ITD screen will be subjected to VDPV1 and VDPV3 screen.)

o   If there is a mixture of wild and vaccine, vaccine strain is subjected to respective VDPV screen while wild is reported and referred to GSL for sequencing.

o   If in VDPV screen, the isolate is positive then it is reported as SL and sent to GSL for Banking.

o   If in VDPV screen, the isolate is negative then it is reported as Discordant and sent to GSL for sequencing within 48 hours.

• Wild isolates are reported and sent for sequencing to GSLwithin 48 hours.

3.    Documentation

• rRT PCR Worksheet File PF-16
• rRT PCR Result Register PR-52

4.    References used to draw SOP

• Manual On Intratypic differentiation of Polioviruses by Real time RT-PCR of CDC
• WHO guidelines