July 22, 2014 |

If polio is on the run, why do we need new tools to help prevent it?

We're close to wiping out polio, but we still need ways to find the virus and diagnose the disease. Here's why.
A baby held on mother's lap opens mouth to receive a drop of polio vaccine.
An infant receives oral polio vaccine in India, which was declared polio-free earlier this year. Photo: PATH/Gabe Bienczycki.

In the past 25 years, global immunization efforts have eliminated polio from most regions of the world. Over the last two decades, the number of cases has dropped by more than 99 percent, bringing in sight the goal of eradication—no one with polio, anywhere.

This week, PATH and our partners announced a new contribution to this effort. A grant from the Paul G. Allen Family Foundation will help expand use of two new polio detection tools: a system to make it easier to check for polio in waste water and a simplified diagnostic test to find the virus in people.

Why do we need new tools when we’re already so close to wiping out polio? Dr. David Boyle, a PATH senior researcher, explains.

Not missing the poliovirus—anywhere

Especially now, when eradication is within sight, we need to be sure we’re not missing the virus anywhere. Polio is very contagious, so a new epidemic can start with just one infection. Just this May, the World Health Organization (WHO) issued a formal warning that the virus is spreading internationally from Cameroon, Pakistan, and Syria, where conflict and other factors have interfered with elimination efforts. That puts progress at risk: it could spark new epidemics if leaders don’t step up to stop polio.

Aggressively looking for the virus allows us to adjust our strategy, catch outbreaks early, and respond quickly. It also tells us whether immunization strategies are working. Basically, we’re always asking, “Is the virus really not here or are we just not seeing it?” There’s no way to treat polio, so it’s important to keep people from getting it in the first place.

Rooting out polio

A slender tripod set up on a dock with boats in the background holds a bright yellow bag filled with water.
Waste water collection and filtration system, assembled near the University of Washington campus. Photo: University of Washington/Christine Fagnant.

Because poliovirus spreads through human waste, it usually shows up in sewage and waste water. So to find polio, workers collect and test water samples. That can be unhygienic and difficult work, and it’s where our first tool comes in. We’re working with the University of Washington to advance an improved waste water collection and filtering system. The all-in-one sampling kit allows workers to gather and filter much more fluid than other commonly used systems and increases their chance of finding the virus if it’s present. It is also easier to transport and store and is more hygienic to use.

Our second tool, a fast, inexpensive polio diagnostic test, can help health workers test people who have symptoms that could be the disease. The test won’t require expensive equipment, so it has the potential to complement existing, more complex tests. For example, local laboratory workers can use the test as backup in areas where political unrest makes it difficult to ship samples to regional laboratories for testing.

Until it’s really gone

We’re in the last mile on eradicating polio, but to be confident in the success of our strategy and to continue to target our efforts quickly and efficiently, we need to be confident that when we don’t see the virus, it’s really gone. We need to keep the floodlights on polio, everywhere in the world, to root it out for good.

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