11 more environmental samples test positive for poliovirus across Pakistan

• Samples collected from 11 sites in all four provinces.
• In Balochistan, poliovirus found in Pishin, Chaman and Quetta.
• New detections take total number of positive samples in 2023 to 54.

ISLAMABAD: Poliovirus was detected in the environmental samples collected from 11 more sites in all four provinces, officials from the country’s polio eradication programme told The News on Saturday only a day after the infectious disease left the fourth child in the country paralysed.

“The Regional Reference Laboratory for Polio Eradication at the National Institute of Health Islamabad has confirmed the detection of Type-1 Wild Poliovirus (WPV1) in 11 environmental (sewage) samples collected in October 2023 (four from Peshawar, three from Quetta Block, two from Karachi and one each from Bannu & Lahore),” an official associated with the polio programme told The News.

In Balochistan, poliovirus was found in Pishin, Chaman and Quetta, the official said, adding that in Pishin, the environmental sample (Grab) was collected on October 2, 2023 from the ‘Turwa’ environmental sample collection site. This is the second positive sample from District Pishin this year. The isolated virus is classified as YB3A cluster and 99.4% genetically linked to the virus detected in an environmental sample in Kandahar (Afghanistan) on May 21, 2023.

In Chaman, the environmental sample (Grab) was collected on October 2, 2023 from the ‘Army Kaziba’ environmental sample collection site. This is the second positive sample from District Chaman this year. The isolated virus is classified as YB3A cluster and 99.89% genetically linked to the virus detected in an environmental sample in Dera Bugti on September 18, 2023.

The official said that in Quetta, the environmental sample (BMFS) was collected on October 3, 2023 from the ‘Surpul’ environmental sample collection site. This is the first positive sample from District Quetta this year. The isolated virus is classified as YB3A cluster and 99.77% genetically linked to the virus detected in an environmental sample in Dera Bugti on September 18, 2023.

In Khyber Pakhtunkhwa, poliovirus was detected at the ‘Hinjil Noorabad’ environmental sample collection site in Bannu, which is the second positive sample from District Bannu this year. Moreover, three human polio cases have also been reported from District Bannu in the current year. The isolated virus is classified as YB3C cluster and 99.4% genetically linked to the virus detected in an environmental sample in the same district, i.e. Bannu on September 21, 2023.

Similarly, poliovirus was detected at four sites ‘Naray Khuwar’, ‘Hayatabad 1&2’, ‘Yousafabad & Tajabad’ and ‘Gulabad & Chungee’ composite environmental sample collection sites. In Karachi, the environmental sample (Grab) was collected on October 3, 2023 from the ‘Orangi Nala’ environmental sample collection site, which is the third positive sample from Keamari this year. Similarly, in District Karachi Central, the environmental sample (BMFS) was collected on October 4, 2023 from the ‘Haji Mureed Goth’ environmental sample collection site.

"This is the second positive sample from District Karachi Central this year. The isolated virus is classified as YB3A cluster and 99.77% genetically linked to the virus detected in an environmental sample in the same district (Karachi Central) on September 7, 2023," the official said.

In Lahore, the environmental sample (BMFS) was collected on October 2, 2023 from the ‘Gulshan-e-Ravi’ environmental sample collection site, the official said, adding that this was the sixth positive sample from District Lahore this year. “The isolated virus is classified as YB3A cluster and 99.5% genetically linked to the virus detected in an environmental sample in the same district, i.e. Lahore) on August 15, 2023,” the official said.

These new detections take the total number of positive environmental (sewage) samples in Pakistan in 2023 to 54. While the number of human polio cases in Pakistan in 2023 is four.