Polio Virus
Polio virus causes poliomyelitis in children.
Polio virus is member of enterovirus genus, family Picornaviridae.
Poliomyelitis is inflammation of grey matter of spinal cord and brain.
Structure of Poliovirus
Poliovirus is non enveloped virus.
It contains positive sense RNA in nucleoprotein core.
Size; Spherical and 10nm in diameter.
Source and mode of Transmission
Reservoir host of infection is human.
Transmitted through;
Feco-oral route
Ingestion of contaminated food or water
Oral intestinal route
Respiratory route
Feces in Infected individual
Transmitted by nose
Throat discharges
Pathogenesis
Virus multiplies in alimentary canal and lymphatic tissue where virus enter in blood.
Through blood stream, Virus enter to spinal cord and brain, they destroy motor neurons cause flaccid paralysis.
Laboratory Diagnosis
Specimen collection
Neutralization test; identify type of Poliovirus
Fecal test
Prophylaxis and Treatment
1. Killed (Salk vaccine); Intramuscular vaccines
Prevent poliovirus in blood stream from reaching spinal cord and prevent paralysis.
2. Live oral attenuated vaccine (Sabin)
It kill virus both in blood and alimentary canal.
Types of Polio vaccine
There are two types of polio vaccines;
1. A killed vaccine given by injection
Salk vaccine/ inactivated polio vaccine (IPV)
2. A live attenuated vaccine
Given orally
Sabin vaccine/ oral polio vaccine (OPV)
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