Detection of MEF1 poliovirus strain in India

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Detection of MEF-1 poliovirus strain in India

• Javier Martin

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MEF-1 wild type 2 poliovirus

• Isolated in 1942 polio outbreak in British Middle
  Eastern Forces in Egypt
• MEF-1 contains two closely related components
• Currently used to prepare IPV
• Commonly used as a laboratory reference strain
• Associated with AFP cases in India in 2000 (2)
  and 2002/3 (7)

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Nucleotide sequence of type 2 MEF-1-like strains
from India
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Nucleotide sequence of MEF-1 strains at key VP1
positions
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Tested at NIBSC

• Both monovalent bulks and finished OPV product of
  vaccines that were found to be temporally and
  geographically associated with the poliomyelitis
  cases were tested for the presence of MEF-1 virus

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Biological test temperature sensitivity
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Molecular test RT-PCR
2 Agarose gel in 0.5xTAE Lane M DNA molecular
weight marker (Promega 100bp DNA ladder). Lanes 1
to 7 represent the RT-PCR product of 10-fold
serial dilutions of MEF-1 in a solution
containing OPV with standard virus concentration
(6.0, 5.0 and 5.8 log TCID50/100ul for each of
the three serotypes, respectively). RNA from
these dilutions was purified using the MagNA Pure
procedure (Roche). Lane 8 No MEF-1. Lane - No
virus. Lane S2 Sabin 2.
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OPV batch positive for MEF-1 virus!!!!
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Nucleotide sequence of MEF-1 strains at key VP1
positions
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Molecular test RFLP
DdeI
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Nucleotide mixtures in VP1
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Nucleotide sequence of MEF-1 strains at key VP1
positions