Polio disease

Poliomyelitis, also known as polio or infantile paralysis, is a vaccine-preventable systemic viral infection affecting the motor neurons of the central nervous system (CNS). Historically, it has been a major cause of mortality, acute paralysis and lifelong disabilities, but large scale immunisation programmes have eliminated polio from most areas of the world. The disease is now confined to a few endemic areas and attempts are being made to globally eradicate the wild polio virus (WPV). The last WPV infection in Europe was in 1998 and the World Health Organization (WHO) declared the European Region polio-free in 2002. The pathogen • Polioviruses are small single-stranded RNA viruses that belong to the Enterovirus subgroup of the family Picornaviridae. Humans are the only reservoir for polio virus. • There are three distinct serotypes of wild polio virus (WPV), types 1, 2 and 3, and infection or immunisation with one serotype does not induce immunity against the other two serotypes. • Poliovirus type 1 has historically been the predominant cause of poliomyelitis worldwide and continues to be transmitted in endemic areas. Transmission of both WPV2 and WPV3 have been successfully interrupted globally and cases were last reported in 1999 and 2012, respectively. • Oral polio vaccine (OPV) is produced from live attenuated WPV. On very rare occasions, if a population is seriously under-immunised, the virus can transform into pathogenic strains, known as vaccine derived poliomyeli...