Poliovirus found in sewage samples of five cities

ISLAMABAD: Wild poliovirus is continuously spreading in entire Pakistan as the Regional Reference Laboratory for Polio Eradication at the National Institute of Health (NIH), Islamabad has confirmed the detection of Type-1 Wild Poliovirus (WPV1) in six environmental (sewage) samples collected in November 2023, including two from Quetta and one each from Hub, Peshawar, Tank and Karachi’s Malir.

In Quetta, the environmental sample (Grab) was collected on November 20, 2023 from the ‘Jatak Takhtani’ environmental sample collection site, which is the fourth positive sample from district Quetta this year.

The previous three positive samples were collected on October 3, November 6, and November 13, 2023, the officials said, adding that the isolated virus is classified as YB3A cluster and 99.3 percent genetically linked to the virus detected in an environmental sample in Karachi East Gadap on September 12, 2023.

Another positive environmental sample was collected in Quetta on November 13, 2023 from the ‘Surpul’ environmental sample collection site, which is the fifth positive sample from district Quetta this year.

The officials said previous four positive samples were collected on October 3, November 6, November 13 and November 20, 2023, adding that the isolated virus is classified as YB3A cluster and 99.5 percent genetically linked to the virus detected in an environmental sample in Chaman on October 2, 2023.

In Hub town of Balochistan, the environmental sample (Grab) was collected on November 20, 2023 from the ‘Jumma Khan Bazar Pul’ environmental sample collection site, which is the second positive sample from district Hub this year.

The officials further said the previous positive sample from the district was collected on September 20, 2023, adding that the isolated virus is classified as YB3A cluster and 99.5 percent genetically linked to the virus detected in an environmental sample in Karachi East Gadap on September 12, 2023.

In Peshawar, the environmental sample (Grab) was collected on November 20, 2023 from the ‘Shaheen Town’ environmental sample collection site, which is the 25th positive sample from district Peshawar this year.

The previous 24 positive samples were collected on April 10, May 9, May 16, June 5, July 4, July 17, August 1, August 17, August 22 (n = 2), September 5, September 12, September 20 (n = 2), October 4 (n = 2), October 5 (n = 3), October 23, November 6 and November 7, 2023 (n = 3).

The officials said the isolated virus is classified as YB3A cluster and 98.8 percent genetically linked to the virus detected in an environmental sample in the same district (i.e. Peshawar - Naray Khuwar) on August 22, 2023.

In Tank town of Khyber Pakhtunkhwa, the environmental sample (Grab) was collected on November 20, 2023 from the ‘Gara Kauroo Khan’ environmental sample collection site, which is the first positive sample from district Tank this year.

The previous positive sample from the district was collected on December 3, 2021, the officials said, adding that the isolated virus is classified as YB3A cluster and 99.89 percent genetically linked to the virus detected in an environmental sample in Karachi Central on September 7, 2023.

In Karachi’s Malir area, the environmental sample (BMFS) was collected on November 20, 2023 from the ‘Landhi Bakhtawar’ environmental sample collection site, which is the first positive sample from district Malir this year.

The previous positive sample from the district was collected on August 23, 2022, the officials said, adding that the isolated virus is classified as YB3A cluster and 99.6 percent genetically linked to the virus detected in an environmental sample in Karachi Central on September 7, 2023.

These new detections take the total number of positive environmental (sewage) samples in Pakistan in 2023 to 90. Moreover, the number of human polio cases in Pakistan in 2023 is six.