Despite mass vaccination, polio is making a comeback. Sewage could become a critical early warning system.

Human excrement, much maligned as a carrier of disease, flexes its public health credentials as a weapon against polio in a study published in Science Translational Medicine.

The research, led by Yakir Berchenko of the Ben-Gurion University of the Negev in Israel, analysed polio virus in sewage collected during a 2013 outbreak of the disease centred on the Bedouin town of Rahat in the south of the country.

The result, the authors report, is a more accurate way of spotting a “silent epidemic” of polio. This could prompt early deployment of vaccines to halt the disease’s devastating effects.

Polio destroys nerves as they exit the spinal cord, leaving its victims, mostly children under five, paralysed. In severe cases the breathing muscles are disabled, leading to the searing images of rows of children in iron lungs that became familiar during the polio outbreaks of the mid twentieth century.

But polio has been a showcase of vaccination success, with the toll reduced from 350,000 cases in 1988, when the World Health Organisation launched its Global Polio Eradication Initiative, to just 74 in 2015.

The virus is, however, fighting back. It reared its head in 2013 across four regions previously declared disease-free – Egypt, Syria, the Horn of Africa and Israel – in a resurgence that presents something of a Gordian knot for vaccine policymakers.

Read the full article in Cosmos magazine here