However, Nigeria has a very low immunization rate to fight the crippling disease because of its weak health system. Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease that is highly contagious and spreads easily from human-to-human contact. In endemic areas, wild polioviruses can infect virtually the entire human population.
According to figures released by the World Health Organization last week, Nigeria had 54 reported cases in 2007 caused by wild polio virus. Nearly 106 new cases of polio have been recorded so far in 2008.
Oral polio vaccine (OPV) is also linked to the spread of the disease. The OPV contains a weakened virus, which passes through children who have not been immunized. In some cases it changes into a form that can turn into deadly outbreaks. The vaccine-linked outbreak has struck more than 100 children so far, including eight this year.
Two polio vaccines are used throughout the world to combat polio. The first, developed by Jonas Salk, consists of an injected dose of inactivated (dead) poliovirus.
The second is an oral vaccine developed by Albert Sabin using weakened poliovirus.
The two vaccines have eradicated polio from most of the countries in the world and reduced the worldwide incidence from an estimated 350,000 cases in 1988 to just over 1000 cases in 2007.
