Polio on Pakistan—Afghanistan border

[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.