HYDERABAD: An environmental sample collected in Hyderabad has been tested positive for poliovirus. It appeared to the first after 29 months as the last one had turned out to be positive in July 2021. Such a sample is also tested positive in Jamshoro district.

Hyderabad has been showing consistently positive poliovirus presence in sewerage sample since 2020. It was only in the April-October 2020 period when it remained negative while the rest of the year it was otherwise.

This year’s October sample has been tested positive. “We collected sample from the Qasimabad pumping station which is a new site for sample collection, considering the fact that the designated site of Jacob Lines had stagnant water so it had to be changed,” said Hyderabad District Health Officer Dr Lala Jaffar. That site also received sewage from Jamshoro and the latter also reported positive poliovirus presence, he added.

A sample was collected on Nov 8 in Hyderabad and Jamshoro districts. “For Hyderabad, the isolated virus is classified as YB3A cluster and 99.6pc genetically linked to the virus detected in an environmental sample in Karachi East district (Sohrab Goth) on Sept 12,” said an administration official. In case of Jamshoro, said the official, the cluster remained the same and it was linked to the virus detected in Karachi Central district on Sept 7. The samples were tested at the National Institute of Health.

Two poliovirus cases, both girls, were reported in Hyderabad in 2019 after seven-and-a-half years when the last positive case was reported in Jan 2012. Environmental samples were collected through ‘grab’ and advanced method of “Bag Mediated Filtration System (BMFS)” from the designated sites. Sindh has 17 designated sites for collection of samples. Of them, 11 were located in Karachi.

“We will try our level best to make sure that the next sample collection results remain negative for our city,” pledged DHO Dr Jaffar. He said Hyderabad had successfully controlled poliovirus and it was only in 2019 when polio cases were reported. He said that 383,610 children of five years of age were to be covered for vaccination in seven days of the National Immunisation Drive in Hyderabad district.

The virus survived, according to officials, in human body and chances of its multiplication got increased in the areas having population density like Karachi and Hyderabad because human population movement remained uncontrolled. They believed that poliovirus remained present in environment. It was due to the city’s broken sewerage system where lines were mixed with drinking water supply lines, thus it considered to be a potential source of the virus spread.

Published in Dawn, December 4th, 2023