Pakistan launches special anti-polio drive in Islamabad
A special anti-polio drive has been launched in Pakistan after traces of the virus were found in Islamabad's sewage system.
The virus was detected weeks ago, but so far no cases have been reported in the city.
Dr Rana Safdar, who coordinated Pakistan's polio eradication centre, said the three-day vaccination campaign started on Monday.
Dr Safdar says police have taken steps to protect the polio workers.
Islamabad registered its last polio case 10 years ago.
The Taliban and other militants have in the past attacked vaccination centres and health workers because they perceive the vaccination drives as part of a Western conspiracy to sterilise Pakistani children or collect intelligence.
Pakistan is among a few countries in the world where polio is endemic.