Polio presentation with Structure , Types and Treatment
- 1. Polio Virus Presented to Dr. Alia Erum Written & composed by: M. Milhan Zahid Pharm.D 3rd Semester Regular University of Sargodha Content gathered by: Adeel Haider M. Saeed Presented by: M. Rayan Ali M. Tanawal Ali
- 3. Contents Polio Virus - overview Structure of Polio virus Types of Polio virus Transmission of Polio virus Pathogenesis of Polio virus Mechanism of CNS invasion Clinical manifestation of Polio virus infection Paralytic poliomyelitis Diagnosis of poliomyelitis Immune response to Polio virus Treatment of Polio infection Poliovirus vaccines Global Polio eradication efforts Conclusion
- 4. Polio Virus •Overview: Poliovirus is a highly infectious virus and the causative agent of poliomyelitis, a disease known for its potential to cause severe paralysis and, in some cases, death. •Classification: Member of the Enterovirus genus within the Picornaviridae family. •Relevance: Poliovirus has had significant impacts on public health and remains a key focus in global eradication efforts due to its potential for outbreaks.
- 5. Structure of Polio Virus •Genomic Composition: Poliovirus contains a positive-sense single- stranded RNA genome, approximately 7,500 nucleotides long. •Capsid Structure: Non-enveloped, with an icosahedral capsid made of four main proteins (VP1, VP2, VP3, VP4) that protect its RNA genome. •Unique Features: The virus’s small size (~30 nm) allows it to easily penetrate human cells and establish infection quickly.
- 6. Visual Representation of Structure of Virus
- 7. Types of Polio Virus •Three Serotypes: Poliovirus is classified into serotypes 1, 2, and 3, each with slight genetic and antigenic differences. •Type 1: Most common and responsible for the majority of poliomyelitis cases globally. •Type 2: Was eradicated in 1999, with no wild cases since. •Type 3: Rarely seen and has been declared eradicated in several regions.
- 8. •Primary Mode: Fecal-oral transmission is the main route, facilitated by poor hygiene and sanitation. •Secondary Spread: Through direct person-to-person contact and occasionally respiratory droplets. •Environmental Persistence: Poliovirus is stable in contaminated water, allowing transmission in areas with inadequate water treatment. Transmission of Polio Virus
- 10. Pathogenesis of Poliovirus •Initial Infection: The virus enters through the mouth, replicates in the throat and intestines, and then invades local lymph nodes. •Viremia: Virus spreads through the bloodstream (viremia), which may resolve or progress to infect the central nervous system (CNS). •CNS Invasion: Virus targets motor neurons in the spinal cord and brainstem, which can lead to paralysis.
- 11. Mechanism of CNS Invasion •Entry to CNS: Virus crosses the blood-brain barrier or enters through peripheral nerves. •Target Cells: Poliovirus has a specific affinity for motor neurons, which results in cell death and inflammation. •Paralysis Development: As motor neurons are damaged, muscle function deteriorates, leading to paralysis that can become permanent if neurons are destroyed
- 12. Clinical Manifestations of Poliovirus Infection •Asymptomatic Cases (90-95%): Most infections are mild or symptom-free but still contribute to virus spread. •Abortive Poliomyelitis: A mild, flu-like illness with symptoms such as fever, sore throat, and fatigue. •Nonparalytic Aseptic Meningitis: Includes symptoms like headache, neck stiffness, and back pain, indicating minor CNS involvement. •Paralytic Poliomyelitis: Affects the spinal cord (spinal polio), brainstem (bulbar polio), or both (bulbospinal polio), leading to varying degrees of paralysis.
- 13. •Flaccid Paralysis: Sudden, asymmetric muscle weakness with loss of reflexes, commonly in the legs. •Bulbar Paralysis: Affects cranial nerves, impacting breathing, swallowing, and speaking. •Complications: Respiratory failure in severe cases due to diaphragm and respiratory muscle paralysis. Paralytic Poliomyelitis
- 14. •Clinical Signs: Paralysis onset, history of exposure, and physical symptoms. •Sample Collection: Stool and throat swabs for virus culture. •Molecular Techniques: PCR to detect poliovirus RNA; provides rapid, specific results. •Serological Testing: Used in some cases to identify poliovirus antibodies in blood. Diagnosis of Poliomyelitis
- 15. •Antibody Production: IgM appears first, followed by IgG, which provides long-term immunity. •Mucosal Immunity: IgA antibodies in the gut prevent reinfection and are stimulated by OPV. •Long-lasting Immunity: Recovery from infection or vaccination generally results in life-long immunity to that serotype Immune Response to Polio Virus
- 16. Treatment of Polio infection •Supportive Care: No cure for polio; treatment focuses on symptom relief and supportive measures. •Respiratory Support: Ventilators and iron lungs used for bulbar polio cases affecting breathing. •Physical Therapy: Helps improve mobility and prevent muscle atrophy in affected limbs.
- 17. Poliovirus Vaccines •Oral Polio Vaccine (OPV): Live, attenuated; easy to administer, induces mucosal immunity, but carries a small risk of vaccine-associated paralytic poliomyelitis (VAPP). •Inactivated Polio Vaccine (IPV): Injected and contains inactivated virus, excellent for immunity without VAPP risk; requires higher coverage for herd immunity.
- 18. Global Polio Eradication Efforts •WHO and GPEI: Aim to eliminate polio through widespread vaccination and surveillance. •Successes: Significant reduction in polio cases globally; type 2 and type 3 eradicated in many areas. •Challenges: Persisting outbreaks in areas with limited vaccine access, like Afghanistan and Pakistan.
- 19. Conclusion •Summary: Poliovirus remains a significant public health focus due to its potential for severe neurological impact. •Vaccination Impact: Vaccines have drastically reduced global cases, and eradication is within reach. •Global Effort: Continued commitment to immunization, surveillance, and public health strategies will bring the goal of eradication closer.