The polio virus has been found in the sewers of Cairo, in what is Egypt's first case of polio since 2004.
The World Health Organization (WHO), which has planned a vaccination drive in Cairo for 25 February, believes the virus came from Pakistan.
Health workers are currently searching the districts around the affected sewers for children or adults who may have recently been paralysed.
Along with Afghanistan and Nigeria, Pakistan is one of the last three countries in the world with indigenous poliomyelitis which mainly affects children under five.
Cases of polio have decreased by over 99 per cent since a global effort to eradicate the disease was launched in 1988, when the virus was present in over 125 countries.