ISLAMABAD: Environmental samples collected from 21 districts have tested positive for the presence of polio virus, according to an official of the nationalpolioprogramme.

As poliovirus surveillance continued in Pakistan, 38 environmental (sewage) samples collected from 30 districts were tested at the Regional Reference Laboratory for Polio Eradication at the National Institute of Health Islamabad.

The wild poliovirus type 1 (WPV1) was detected in sewage samples collected from Loralai, Quetta, Zhob, Islamabad, Abbottabad, Bannu, D.I. Khan, Peshawar, Tank, North Waziristan, Lahore, Rawalpindi, Badin, Jamshoro, Hyderabad, Kashmore, Karachi East, Karachi Malir, Karachi Korangi, Karachi South and Sukkur.

Samples collected from Noshki, Sibi, Charsadda, Lower Dir, Mansehra, Swat, Faisalabad, Gujranwala and Rajanpur tested negative, the official said.

This year, the country hasreported eightcasesof poliovirus. Two of the cases were reported in three days last month.

Officials have said Pakistan may report frequent cases during the coming weeks and months as the high transmission season has just started.

The virus becomes active in high temperatures.

The polio programme is implementing a rigorous vaccination campaign to protect children from paralytic polio and interrupt virus transmission, an official said.

`Due to high-quality campaigns since September 2024, polio cases nationwide have declined.

The next nationwide campaign is scheduled from May 26 to June 1, aiming to vaccinate 45.4 million children under the age of five across the country.