Polio Virus

Poliomyeliti s Dr. Mejbah Uddin Ahmed

• Caused by poliovirus • Destroys nervous system  paralysis

Poliovirus • Nonenveloped, ssRNA virus of the Picornavirus family and Enterovirus group • Nonenveloped, ssRNA. • Three serotypes: type-1, type-2, type-3 • Reservoir: humans only • Transmitted through fecal-oral route.

Transmission& pathogenesis • Entry into mouth • Replication in pharynx & GI tract in local lymphoid tissue • Hematogenus spread to central nervous system • Virus can also spread along nerve fibers • Virus replicates in the anterior horn cells of spinal cord • Destruction of motor neurons & alos affect brainstem

Polio Infection An acute infection, ranging from: - Asymptomatic infection - Abortive poliomyelitis - Non-paralytic (aseptic meningitis) - Paralytic poliomyelitis

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Paralytic poliomyelitis • Initial constitutional symptoms followed by paralysis. • Three types: – Spinal polio – Bulbar polio – Bulbospinal polio

Paralytic poliomyelitis • Spinal polio: Flaccid type paralysis of muscles occur. • Bulbar polio: Life threatening respiratory paralysis occur. • Bulbospinal polio.

Spinal Polio

Lab Diagnosis • Definitive diagnosis is made by isolation of the virus from stool, CFS, oropharyngeal secretions • Detection of antibody By: • ELISA • IFA • CFT

Prevention • Both oral polio vaccine( OPV live, attenuated ， Sabin, 1957) • and inactivated poliovirus are avilable.

Prevention • Active: • Killed vaccine (IPV ， Salk) • Live attenuated vaccine (OPV ， Sabin) **Current version of IPV is eIPV. • Passive: Immunoglobulin is available.