One of the most important aspects of the fight to eradicate polio is detection. This requires continuous surveillance that is complicated and costly. Polio surveillance consists of two parts. First, doctors and community health workers monitor children for acute flaccid paralysis. The second part of the process involves local authorities collecting samples from sewage systems or in places that don’t have adequate sanitation facilities, including rivers or bodies of water near a large group of residents.
Ninety percent of people infected with the virus show no symptoms, and those who do usually have mild symptoms such as fever, fatigue, and headaches. Only one in every 200 cases of the illness results in paralysis, which means that for every child who is paralyzed, several hundred are carrying the disease and may not show it.
And not every case of paralysis is caused by polio. Other viruses that can cause the polio-like symptoms known as acute flaccid paralysis include Japanese encephalitis, West Nile, and Zika. To determine if a patient has polio, health workers must collect two stool specimens 14 days apart and send them to a lab for testing.
- 145.00 labs
monitor polio around the world
- 72.00 countries
are being monitored for polio
To find the patients who don’t present symptoms or don’t make it to a clinic, Rotary and its partners in the Global Polio Eradication Initiative (GPEI) — composed of the World Health Organization, the U.S. Centers for Disease Control and Prevention (CDC), UNICEF, and the Bill & Melinda Gates Foundation — have set up environmental sampling sites in the areas that are most susceptible to the disease.
Fifteen to 20 countries are still at high risk despite having eradicated the illness. Because the poliovirus is most easily detected, and most easily contracted, through stool, researchers take samples from sewage systems and, in places that don’t have sewer infrastructure, from rivers and open gutters.
GPEI has developed a network of 145 laboratories around the world that can identify the disease, and Rotary has played a leading role in supporting these facilities.
But regular environmental surveillance is “logistically not so easy to do and it’s relatively expensive. It adds a considerable burden to the labs to process the sewage samples,” says Stephen Cochi, senior adviser to the director, Global Immunization Division, at the CDC. “It costs real money to keep that network operational, and this lab network is the most highly sophisticated, state-of-the-art infectious-disease network in the world. Rotarians should be proud of that — it’s the No. 1 network, bar none.”
As part of this system of labs, Rotary has helped fund small, sophisticated local laboratories to track genetic variations of the disease. All viruses mutate to confuse the human immune system, but the poliovirus is notorious for doing so at a rapid rate.
One of these labs allowed Brazilian authorities to trace the virus at São Paulo airport to Equatorial Guinea more than 6,400 kilometers (4,000 miles) away.
Vigilance is key to successful surveillance, says Michel Zaffran, director of polio eradication at WHO. “This is a hidden cost to the program that people don’t realize is absolutely necessary to maintain,” he said.
The GPEI is providing surveillance in about 72 countries, RI President John F. Germ said at Rotary’s World Polio Day event on 24 October 2016. “It’s an expensive fight,” he said.