A woman supports her child who has leg paralysis resulting from polio. Polio, or poliomyelitis, also known as infantile paralysis, is a childhood disease caused by a virus. Polio epidemics in the early 20th century left thousands paralysed. Vaccines were developed in the 1950s and 1960s, and the disease has been eradicated in many countries. In Nigeria in 2003 religious groups spread disinformation about polio vaccination, resulting in the reappearance and spread of the disease. Photographed in Katsina State, Nigeria, 2009.