LOCALIZATION OF THE VIRUS AND PATHOGENESIS OF EPIDEMIC POLIOMYELITIS

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Poliomyelitis virus can reach central nervous organs without apparent retinal injury.
• The virus initially targets spleen and bone marrow after blood injection, not kidneys, spinal cord, or brain.

Purpose of the Study:

• To investigate the pathway of poliomyelitis virus entry into the central nervous system.
• To understand the role of inflammation and immune response in poliomyelitis infection.
• To determine the origin of histological lesions in human poliomyelitis.

Main Methods:

• Intravenous and intraspinous injections of poliomyelitis virus in animal models.
• Induction of aseptic inflammation using horse serum.
• Administration of immune serum via intraspinous injection.
• Histological examination of nervous tissues and choroid plexus.
• Introduction of carmine pigment to study cellular uptake.

Main Results:

• Nervous tissues do not remove the virus from blood until choroid plexus and blood vessels are injured.
• Intervertebral ganglia remove the virus from blood before the spinal cord and brain.
• Aseptic inflammation facilitates virus passage to the central nervous organs, increasing paralysis risk.
• Virus in blood inconsistently enters the spinal cord and brain; if unsuccessful, it's destroyed, reducing virulence.
• Virus entry into the central nervous system involves lymphatic invasion of the choroid plexus and perivascular infiltration.
• Histological lesions in human poliomyelitis resemble those from intraneural infection in monkeys.
• Intraspinous immune serum neutralizes the virus in cerebrospinal fluid, preventing paralysis.
• Pre-existing inflammation or virus injury enhances ependymal cell uptake of introduced substances.

Conclusions:

• Poliomyelitis infection in humans is likely local and neural, entering via lymphatics from the upper respiratory tract, not through the bloodstream.
• The study supports a neural, lymphatic route of infection, challenging a purely hematogenous spread theory.
• Therapeutic strategies targeting lymphatic pathways and enhancing immune response in the central nervous system may be crucial for poliomyelitis treatment.