Four more sewage samples tested positive for poliovirus.

The number of environmental samples this year that have been tested for wild poliovirus type 1 (WPV1) has reached 112. This is according to the Regional Reference Laboratory for Polio Eradication at the National Institutes of Health. Four additional sewage samples were obtained from previously afflicted districts.

The notification stated that one sample from Pishin and three samples taken from various Karachi areas had shown positive results.

The imported YB3A cluster of WPV1 was genetically associated with the samples.

The two human cases this year and all positive samples include the YB3A cluster, which vanished from the nation in 2021 but persisted in circulation in Afghanistan before being reintroduced through cross-border transmission last year, the official stated.

A lab official reported that so far this year, the virus has been detected in sewage samples from 33 different areas.