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Epidemiology of Poliomyelitis. Dr Akshaya K M Department of Community Medicine Yenepoya Medical College, Mangaluru. Learning objectives. At the end of the class, the student shall Define poliomyelitis Enlist the countries endemic for poliomyelitis in 2018
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Epidemiology of Poliomyelitis Dr Akshaya K M Department of Community Medicine Yenepoya Medical College, Mangaluru
Learning objectives At the end of the class, the student shall • Define poliomyelitis • Enlist the countries endemic for poliomyelitis in 2018 • Explain the epidemiological triad of poliomyelitis • Explain vDPV • Enumerate the types in the clinical spectrum of poliomyelitis
Introduction Acute Viral Infection Caused by RNA virus Mainly affects human alimentary tract Affects CNS and causes paralysis in 1% cases One of the disease considered for eradication
Current global situation Source: http://polioeradication.org/polio-today/polio-now/this-week/
Wild poliovirus cases, India 1934 No WPV case since January 2011 1600 P2 wild P1 wild P3 wild * data as on 6 July 2018
WPV2 24/10/1999 Aligarh (UP) WPV3 22/10/2010 Pakur (JH) WPV1 13/01/2011 Howrah (WB) Last wild poliovirus cases by type, India
Agent • Polio Virus: 3 sero types • Outbreaks: Type 1 virus • Infects only human beings, no animal reservoir • Transmission: Person to person via feaco-oral route • Infectious material: Faces and oropharyngeal secretions • Communicability: High; 7 to 10 days before and after onset of symptoms
Vaccine Derived Polio Virus >10 billion doses of OPV to 3 billion children worldwide since 2000 Genetically changed from the original strain contained in OPV (cVDPV) Reason: Low vaccination coverage cVDPVs are extremely rare (24 outbreaks in 21 countries and 750 cases)
Host Disease of infancy and childhood Vulnerable age: 6 months and 3 years 3 Males:1 Female Risk factors Immunity: Immunization or Natural Infection (Life long)
Environment More common in rainy season Source of infection: Contaminated food and flies Survives long in the cold environment Overcrowding and poor sanitation IP: 7-14 Days
Clinical Spectrum • Inapparent/ Subclinical infection: 91-96% • Abortive polio or minor illness: 6-8% • Non-Paralytic polio: 1% • Paralytic polio: <1% • Asymmetrical patchy paralysis • Tripod sign • Proximal muscle involvement • No sensory loss