Poliovirus Pathogenesis

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Pathogenesis In 99% of poliovirus infections, alpha and beta interferons limit replication of the poliovirus in nonneural tissues, which causes the infection to end (Racaniello, 2005). There are 1-2% of poliovirus infections where the interferons do not work as well, and the virus spreads to extraneural sites and then to the central nervous system causing poliomyelitis (Racaniello, 2005). Infection with poliovirus causes the inhibition of host cap-dependent translation, DNA- dependent RNA synthesis, cellular protein secretion of cytokines and antigen presentation, nuclear export, and the suppression of the nuclear factor kappa-light-chain-enhancer of activated B cells (Racaniello, 2005). Paralysis of the legs due to an infection of …show more content…

Viral replication in the spinal cord is what leads to muscle paralysis and poliomyelitis (Racaniello, 2005). Old world monkeys and chimpanzees can be experimentally infected, and humans are the natural hosts for poliovirus, because these species have suitable environments and receptors for the survival of poliovirus, but other species such as mice do not have suitable environments for poliovirus unless the mice have been experimentally altered to express CD155 (Racaniello, 2005). Some strains of the poliovirus have been able to replicate in mice due to a process of adaptation, and some strains of the virus are naturally virulent in the mice (Racaniello, 2005). Scientists were able to substitute a six amino acid sequence of the P1/Mahoney strain, which is in the VP1 capsid protein and located near the CD155 binding site, with the corresponding sequence in P2/Lansing strain (Racaniello, 2005). This caused the mice to have neurovirulence to the poliovirus (Racaniello, 2005). In humans, they have taken samples of tonsillopharyngeal tissue, the wall of the ileum and mesenteric lymph nodes and been able to isolate poliovirus from each of the samples, but even with the removal of the tonsils and adenoids there continues to be a multiplication of the poliovirus in the throat (Racaniello, 2005). CD155 RNA is produced in high levels in human epithelial cells, and CD155 protein is

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