Islamabad, April 13 : Poliovirus has been detected in sewage samples from 20 districts across Pakistan, according to test results from the Regional Reference Laboratory for Polio Eradication at the National Institute of Health (NIH).

In a statement issued on Sunday, the Pakistan Polio Eradication Program said the environmental samples were collected between March 5 and March 19, confirming the presence of wild poliovirus type 1 (WPV1) in multiple areas, Xinhua news agency reported.

"A total of 60 environmental samples were collected from 51 districts during this period. Of these, 25 samples tested positive for poliovirus, while 35 were declared negative," the statement said.

The statement added that while the detection of poliovirus in sewage remains a concern, the number of positive samples has declined, indicating a reduction in virus circulation in several areas.

The samples that confirmed the presence of wild poliovirus type 1 (WPV1) came from districts including Dukki, Kech, Khuzdar, Lasbela, Loralai, Nasirabad, Pishin, Quetta, Usta Muhammad, Bannu, Kohat, Lakki Marwat, Peshawar, South Waziristan Lower, Bahawalpur, Bahawalnagar, Dera Ghazi Khan, Lahore, Multan, and Rahim Yar Khan.

Meanwhile, samples from cities such as Islamabad, Gilgit, Rawalpindi, Swat, Sahiwal, Nowshera, and others tested negative, pointing to improved control measures in several areas.

"The trend shows a decline in positive samples and a reduction in virus circulation in many areas," an NIH official said.

A new nationwide polio campaign is set to begin on April 21, targeting 45.4 million children under the age of five. Authorities have urged parents to ensure their children receive the vaccine each time it is offered.

"Repeated vaccination strengthens immunity and helps stop the spread," the official added.

"No child should be left behind -- protecting them from polio is a collective responsibility."

Pakistan has reported only six polio cases so far in 2025, down from 74 in 2024. Officials credit improved immunisation drives since September last year.

According to the programme, Pakistan has reported six new poliovirus cases since the start of 2025.

The next nationwide anti-polio campaign is scheduled to run from April 21 to 27, aiming to vaccinate more than 45 million children under the age of five across the country.

/IANS