ISLAMABAD: Environmental samples collected from 18 districts have been found positive for poliovirus, indicating the presence of the virus in these areas.

An official of the Regional Reference Laboratory for Polio Eradication at the National Institute of Health said environmental (sewage) samples were collected from 22 districts.

The wild poliovirus type 1 (WPV1) has been detected in sewage samples of Chaman; Islamabad; South Waziristan Lower; South Waziristan Upper; Lahore; D.G. Khan; Badin; Dadu; Hyderabad; Jacobabad; Kambar; Karachi East, Central, Keamari and West; Shaheed Benazirabad; Sujawal and Sukkur.

Meanwhile, samples from Zhob, Sialkot, Multan and Rahim Yar Khan tested negative for the virus.

A sewage sample from an area is the basic parameter used to identify the presence of the virus in an area.

It determines if polio vaccination campaigns were resulting in the desired immunity among children.

The official said the Pakistan Polio Eradication Programme has expanded its environmental surveillance sites from 65 in 2021 to 127 in 2025.

Its efficiency in detecting poliovirus in sewage and cases ensures no transmission goes unnoticed, even in remote areas.

The programme is also implementing rigorous vaccination campaigns to protect children from paralytic polio and interrupt virus transmission.

The next nationwide campaign is scheduled from April 21 to 27, aiming to vaccinate 45.4 million children under the age of five across the country, the official said.

Pakistan has already reported six cases of poliovirus from Punjab, Sindh and Khyber Pakhtunkhwa in the first three months of 2025. Last year, the country reported 74 cases, according to the polio programme.

Published in Dawn, March 24th, 2025