Poliomyelitis - Risk Factors

Risk factors

Humans are natural host for poliovirus. There are a number of factors which influence its infection.

The poliovirus attaches effectively on to the epithelial cells lining the alimentary tract and on to the cells of the central nervous system. They attach to a specific receptor on these cells, which in humans is encoded by a gene on chromosome 19.

The outcome of poliovirus infection is influenced by the following factors:

1. Virulence of the infecting strain
2. Size of the infecting dose
3. Immune status of the host

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Other factors which predisposes an individual includes:

1.  Recent or previous tonsillectomy. Removing the immunologically- active tonsils exposes nerve endings to the virus.
2.  Histocompatibility antigens HLA-3 and HLA-7 maybe associated with an increased risk of paralysis