poliovirusc : Phases of infection

• • Alimentary phase :
  • • • primary replication in oropharyngeal and intestinal mucosa
  • Lymphatic phase :
  • • • Abundant replication: virus spreads to tonsils and peyer's patches of ileum and to deep cervical and mesenteric nodes
  • Viremic phase :
  • • • Virus spreads to bloodstream and from there to internal orgnas and regional lymph nods. Mostly stops here with symptoms of fever, malaise, headache, nausea, GI disturbance, sore throat
  • In rare cases :
  • • • progression to neurologic phase by hematogenous routes to spinal cord or brain stem (or both)