Pakistani authorities have detected the crippling poliovirus in the environmental samples in three more cities of Punjab and Khyber Pakhtunkhwa provinces.
According to the Ministry of Health, wild poliovirus was detected in the environmental samples of Peshawar, Bannu, and Lahore, Geo News reported.
The officials also confirmed the detection of the virus in sewage samples taken from Rawalpindi, Sialkot, and Bahawalpur.
In August, poliovirus was detected in four cities of Punjab and two cities of Khyber Pakhtunkhwa. The poliovirus has been detected six times in samples taken from Bannu while in Peshawar and Lahore it was found twice.
Despite the ongoing anti-polio vaccination drives, Pakistan has confirmed 14 wild polio-I cases so far this year.
Wild polio-I has been confirmed in 17 environmental samples taken, officials said, adding that the extent of the spread cannot be estimated due to relentless rains in Sindh and Balochistan.
Pakistan is one of the two polio-endemic countries in the world along with its neighbour Afghanistan.
Attempts to eradicate the crippling disease in Pakistan have been seriously hampered by deadly targeting of vaccination teams in recent years by militants, who oppose the drives, claiming that the polio drops cause infertility.