WPV1 detected in sewage samples from Balochistan and Sindh districts; genetic link to Afghan cluster.

ISLAMABAD: The presence of wild poliovirus type 1 (WPV1) has been confirmed in sewage samples obtained from two districts in Balochistan and one district in Sindh, in Pakistan, Dawn reported. According to the National Institute of Health, sewage samples collected from Quetta, Chaman, and Hyderabad have tested positive for WPV1.

These samples contain a virus genetically linked to the imported YB3A genetic cluster of WPV1. This particular cluster vanished from Pakistan in 2021 but persisted in circulation in neighbouring Afghanistan. It was reintroduced into Pakistan through cross-border transmission last year. All positive samples and the two reported polio cases this year are associated with this virus. WPV1 has been detected in a total of 38 districts so far this year, according to Dawn.

The Pakistan Polio Programme has conducted four polio vaccination campaigns this year, including two nationwide campaigns that reached over 43 million children under the age of five in January and February. The next vaccination campaign is scheduled for the first week of June. In Hyderabad, samples were collected from the Tulsidas Pumping Station.

Interestingly, the five preceding samples from this site also tested positive. The sample from Chaman was obtained from the Army Kaziba site, marking the ninth positive sample from the district this year. A source within the National Institute of Health disclosed that in Quetta, the sample was collected from the Railway Pul site, marking the eighteenth positive sample from Quetta district this year, Dawn reported.