New tools for polio surveillance could aid eradication efforts
Kate Cheney Davidson, PATH, firstname.lastname@example.org.
Seattle, July 22, 2014–With grant funding made possible by the Paul G. Allen Family Foundation, two new tools to help detect the poliovirus may soon strengthen global efforts to eradicate the disease. The foundation will invest up to US$5.3 million dollars in support of this goal.
The tools, a system to improve environmental surveillance and a simplified diagnostic test, were developed by PATH, a leading international health organization, and researchers at the University of Washington (UW). They have the potential to help workers identify and stop polio by making it easier to find the virus in sewage and among people. Although polio spreads very quickly and can be devastating, many people will never show symptoms–making early detection and response crucial for controlling the spread of disease.
The grant announcement, made today by PATH and UW, comes at a time of heightened attention to the spread of polio worldwide. In early May, the World Health Organization (WHO) declared it a Public Health Emergency of International Concern, warning that the recent spread of the virus from Pakistan, Syria, and Cameroon to neighboring countries could spark widespread epidemics if leaders do not take action.
The initial $2.4 million of the grant, administered in partnership with the Bill & Melinda Gates Foundation, will allow the PATH/UW team to accelerate development, evaluation, and introduction of the tools in coordination with global polio eradication partners. Additional technical and administrative support will be provided by the Gates Foundation as part of its longstanding support for eradication. PATH and UW will seek additional technical advice from the US Centers for Disease Control and Prevention (CDC) and WHO.
A persistent foe
Over the past 25 years, global immunization efforts have eliminated the poliovirus from most regions of the world. In the last two decades, the number of polio cases globally has dropped by more than 99 percent, bringing eradication within sight.
This success demonstrates that a coordinated global vaccination strategy can stop polio. Yet the recent WHO declaration, and periodic outbreaks, point to the importance of strong surveillance. The poliovirus can spread quickly, facilitated by sewage-contaminated floodwaters, travelers with the infection, and gaps in immunization coverage.
"As the world reaches a place where polio eradication is within view, we need to increase our efforts to be sure we're not missing the virus anywhere," explains project director Dr. David Boyle, a senior researcher at PATH. "Resurgence remains a risk. So we're always asking, 'Is the virus really no longer there, or are we just not seeing it?' It's also important for us to know when immunization is working. Good surveillance is crucial to monitor this approach and push the global eradication strategy forward."
Today, the CDC and WHO lead a coordinated, state-of-the art global surveillance program. This includes the Global Polio Laboratory Network (GPLN), a web of facilities that monitor and test for the virus worldwide. Although this program is bringing eradication within reach, enhanced surveillance methods are still needed. If effective, the PATH/UW tools, which are designed specifically for use in low-resource settings, can significantly expand efforts.
No place for polio to hide
Poliovirus is highly contagious, but only about 1 out of every 200 infected people will experience clinical symptoms, which can lead to paralysis and, in rare cases, death. By the time symptoms appear, the virus may have already spread throughout, or even beyond, a community. This makes surveillance and early detection particularly important.
To detect polio as early as possible, health workers monitor the virus by collecting and testing water samples (environmental surveillance) and by testing individuals who have symptoms that suggest polio infection. Together, the PATH/UW technologies support both approaches.
An improved sample collection system. Because poliovirus is carried in human feces, sewage is an ideal place to look for the virus and can be used to track the infection in a population. Today, most environmental surveillance methods require workers to collect waste or standing water and transport it to a laboratory, where it is processed and prepared for testing. Since 2012, UW researchers, with support from PATH through the Gates Foundation, have been developing a new device to improve this process. The bag-mediated filtration system is a simple, affordable, and effective all-in-one sample kit. It allows workers to gather and filter much more fluid, dramatically increasing their chance of finding any poliovirus present in an environment. In addition, it is easier to transport and store and is more hygienic to use.
"Everyone wants to increase the amount of surveillance to pin down where transmission is occurring," says Dr. Scott Meschke, an associate professor of environmental and occupational health sciences in the School of Public Health at UW. "If a bottleneck in the laboratory is hindering those efforts, then that's a real problem. That's a key rationale behind this project: to minimize that bottleneck."
The improved system could decrease the time required to process an environmental sample from one month to two days.
A simplified diagnostic. Tracking polio also requires tests that can quickly identify the virus in individuals. Although polio can't be cured, the most identifiable symptom, paralysis, can be caused by a variety of conditions. Testing rules the virus out–or signals that a community is at risk of a polio outbreak. It is also useful among nomadic communities and small groups, in conflict zones, or in contexts where environmental testing may not be appropriate.
Although effective diagnostic tests exist, they often require samples to be shipped to highly equipped laboratories for preparation and testing by trained staff. An inexpensive, easier-to-use test has the potential to complement existing options. PATH is developing a simplified diagnostic tool to detect the poliovirus that is fast, reliable, and can be used in local laboratories without complex equipment. It can also test a relatively large sample volume, increasing health workers' chance of finding even small amounts of virus. In areas where political unrest makes it difficult to ship samples to a GPLN laboratory, local testing could provide a crucial backup. In addition, the test may soon allow workers to identify different types of the virus, helping workers monitor and hone eradication efforts.
Innovation to bring eradication closer
Together, the bag-mediated filtration system and poliovirus diagnostic tool provide a good example of PATH's work to push innovative health solutions to scale. Over the next several years, PATH and UW will focus on bringing the technologies to markets worldwide.
"These new tools demonstrate PATH's commitment to partnering with leading innovators to drive smart technologies forward to improve health and save lives worldwide," says Steve Davis, PATH president and CEO. "The Paul G. Allen Foundation's generous support is opening the door for us to move these devices from promising prototypes to powerful, effective tools in the fight to eradicate polio."
About the University of Washington Department of Environmental and Occupational Health Sciences
Researchers in the Department of Environmental and Occupational Health Sciences (DEOHS) study how environmental factors affect susceptibility to disease and how to identify, prevent and control their effects. The department's goal–through research, teaching, and service–is prevention and protection. DEOHS is part of the University of Washington School of Public Health, which was founded in 1970 and is one of 40 accredited schools of public health in the nation and the only one in the Northwest. Learn more at http://deohs.washington.edu.