ISLAMABAD: Researchers have made valuable progress in identifying the genetic structure and transmission patterns of polio strains circulating along the Afghanistan-Pakistan border, one of the remaining global reservoirs of the wild virus.

Virologists from the National Institute of Health in Islamabad screened more than 30,000 people living along the border between 2005 and 2007. They identified and sequenced 111 polioviruses, in an attempt to trace their origins and transmission routes.

The researchers isolated the virus from patients with Acute Flaccid Paralysis, a condition characterised by a sudden onset of muscle weakness, a common sign of polio.

The study, published in the Virology Journal last month (22 February), showed that, despite intense immunisation campaigns and efforts to reduce the number of cases, uncontrolled transmission of wild type1 polioviruses has continued in the region.

Salmaan Sharif, a co-author of the paper based at the NIH, told SciDev.Net the findings would help researchers and officials identify communities that are reservoirs for wild poliovirus, and design more targeted immunisation campaigns.

“Persistent pockets of polio transmission along the border between Afghanistan and Pakistan are key epidemiological challenges owing to insecurity and conflict problems,” the researchers said.

Syed Sohail Zahoor Zaidi, head of the virology department at NIH, said eradication efforts needed to be co-ordinated on both sides of the border, and that “parallel immunisation activities in affected areas of both countries are a must”.

He called for greater monitoring of children and migrating communities in conflict-hit regions through the involvement and training of locals, and for the involvement of religious leaders and military personnel in awareness-raising activities.

Aid agencies operating in the region warned that the ongoing conflict in the region has seriously hampered vaccination efforts.

Cathy Williams, a spokesperson for Unicef's (UN Children's Fund) polio eradication unit in Pakistan, said many WHO and Unicef vaccination staff feared for their lives if they did their jobs, “particularly when some have already lost their lives on duty in the tribal areas”.

Public trust in vaccination staff is also at “its lowest ebb”, according to Hussain A. Gezari, the WHO's envoy on global polio eradication, told SciDev.Net.

Last month an alliance of 200 aid groups wrote to the US Central Intelligence Agency criticising its decision to use a fake polio vaccination scheme in the Pakistani town of Abbottabad, as part of US efforts to find Osama Bin Laden last year.

“Undeniably, the fake polio vaccination drive ... gravely harmed the public trust and put [the continuation of] our polio and other vaccination and immunisation programmes at stake,” Gezari said, adding that some families in north-west Pakistan were refusing to allow their children to be vaccinated, amid fears the medication they were being offered was fake.

“Staff from the UN's different agencies — including Unicef — fear a serious backlash if (we)re-visit these areas,” he said. -- www.scidev.net