Poliovirus detected in sewage of nine cities

KARACHI: 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 nine (09) environmental samples collected in October including four from Karachi, two from Chaman and one each from Peshawar, Kohat and Nowshera, officials said on Thursday.

In Karachi, poliovirus was detected in two environmental samples from Karachi South including Manzoor Colony Nala and Hijrat Colony sites, and Sohrab Goth and Machar Colony Environmental sites in Karachi East, officials said. They said the poliovirus found in Karachi South from Manzoor Colony Nala is classified as a YB3A cluster and 99.66pc genetically linked to the virus detected in an environmental sample in Karachi East Gadap on September 12. Similarly, the poliovirus found in the environmental sample in the Hijrat Colony site is classified as YB3A cluster and 99.33pc genetically linked to the virus detected in an environmental sample in Lahore (Out Fall station-2) on 15th August 2023.

The poliovirus found in the environmental sample in the Sohrab Goth in Karachi East is classified as a YB3A cluster and 99.89% genetically linked to the virus detected in an environmental sample in the same district (i.e. Karachi East) on September 12. Similarly, the poliovirus found in the environmental sample in Machar Colony in District East Karachi is classified as a YB3A cluster and 99.77pc genetically linked to the virus detected in an environmental sample in the same district (i.e. Karachi East) on 6th October 2023.

In Chaman, an environmental sample was collected on October 16 from the ‘Hadi Packet’ environmental sample collection site, officials said adding that this is the third positive sample from district Chaman this year. The previous two positive samples were collected on October 2 (n = 2). The isolated virus is classified as a YB3A cluster and 99.89pc genetically linked to the virus detected in an environmental sample in the same district (i.e. Chaman - Hadi Packet) on 2nd October 2023, they added.

Another environmental sample (Grab) was collected on October 16 from the ‘Army Kaziba’ environmental sample collection site in Chaman, which is the fourth positive sample from District Chaman this year. The previous three positive samples were collected on 2nd October (n = 2) and 16th October 2023. The isolated virus is classified as a YB3A cluster and 99.55% genetically linked to the virus detected in an environmental sample in the same district (i.e. Chaman - Hadi Packet) on 2nd October 2023, they added.

In Peshawar, the environmental sample (Grab) was collected on 23rd October 2023 from the ‘Shaheen Town’ environmental sample collection site. This is the 20th positive sample from district Peshawar this year. The previous nineteen positive samples were collected on 10th April, 9th May, 16th May, 5th June, 4th July, 17th July, 1st August, 17th August, 22nd August (n = 2), 5th September, 12th September, 20th September (n = 2), 4th October (n = 2), and 5th October 2023 (n = 3). The isolated virus in Peshawar is classified as a YB3A cluster and 99.22% genetically linked to the virus detected in an environmental sample in District Hangu on 6th September 2023.

In Kohat, the environmental sample (Grab) was collected on 20th October 2023 from the ‘Faqeerabad’ environmental sample collection site, officials said adding this is the first positive sample from District Kohat this year. The isolated virus in Kohat is classified as YB3A cluster and 98.67% genetically linked to the virus detected in an environmental sample in Batikot, Nangarhar (Afghanistan) on 1st March 2023.

In Nowshera, the environmental sample (Grab) was collected on 24th October 2023 from the ‘Mill Colony’ environmental sample collection site. This is the first positive sample from district Nowshera this year. The isolated virus is classified as a YB3A cluster and 99.55% genetically linked to the virus detected in an environmental sample in Lahore (Multan Road) on September 26.

These new detections take the total number of positive environmental (sewage) samples in Pakistan in 2023 to 64. Meanwhile, the number of human Polio cases in Pakistan in 2023 remains four.