The Senate was told on Friday that Sindh, Northern Areas and Fata had became virtual nurseries of polio posing a serious threat to the country. Holding local governments responsible for the failure of polio eradication programme, Minis-ter for Health Sherry Rehman said during the question hour that vaccines became ineffective because immunisation teams did not keep them at the required temperature. She said that lack of checks along the border with Afghanistan also contributed to a dramatic increase in polio cases. She said the number of polio cases had risen to 41 while it stood at only four after Benazir Bhutto launched a comprehensive programme in 1996. International agencies, she said, had donated Rs132.962 million for polio eradication during 2006-08 and the entire amount had been spent. She said the Sindh health department was activated to some extent after polio cases were found in the province, particularly in Karachi.