Why polio in Brazil is as scary as Ebola in West Africa

Children disabled by polio begging in Abuja, Nigeria (Credit: Mike Urban)

The polio virus has been detected in the sewage of Sao Paulo, reports the World Health Organization, the first time the virus has shown up in Brazil in 20 years.

Genetic testing of the virus, WHO says, indicates it most likely came from Equatorial Guinea – the same general area in West Africa where health officials and humanitarian groups are battling one of the biggest outbreaks of the Ebola virus with something like 350 deaths so far.  As Humanosphere and others are reporting:

CNN Ebola epidemic out of control

Guardian West Africa Ebola epidemic is out of control

Reuters Aid group warns Ebola ‘out of control’ 

While the deadly and immediate threat posed by this latest Ebola outbreak deserves an aggressive response, it is perhaps worth comparing it to the global polio outbreak – which is arguably even more ‘out of control’ but much less likely to inspire the same drama or sense of urgency.

Yet polio is, from a public health perspective, perhaps more of the canary in a coal mine.

The way the two viruses operate explains, at least from a brain scientist’s perspective, why Ebola excites and polio is a yawner. We are wired to respond to immediate threats we can see. Ebola spreads quite visibly and horribly, rapidly killing the majority of those infected. The polio virus, in contrast, spreads quietly, slowly and mostly invisibly (most of those infected show no symptoms). Polio only kills something like one in 15 of those who fall ill.

Ebola, first discovered in the mid-1970s, is a made-for-Hollywood thriller of an infectious disease. Polio is an old problem, a tired rerun on black-and-white TV.  Yet the implications of polio’s current global expansion are potentially much more dire than any threat Ebola poses.

The Ebola virus doesn’t spread that easily, requiring direct contact with the bodily fluids of someone who is infected. Ebola kills fast and furiously. But Ebola also tends to ‘burn itself out’ fairly quickly, though the recent outbreak in West Africa is larger and more persistent than most. Some are concerned this may be due to the virus adapting, while others say it is probably just poor hygiene practices in the communities dealing with the disease making it hard to contain.

The polio virus, which is much more highly contagious, operates according to stealth strategy, with diagnosed diseases or detection of the virus in sewage offering only a hint of what may be a much bigger presence.

Statistically, there are at least a hundred other people infected with polio for every person who falls ill with the paralytic disease. The WHO emphasized in its report on discovering the polio virus in San Paulo sewage that, technically, Brazil remains (as it has been since the late 1980s) polio free because this involves no indigenous cases of disease.

But that’s what WHO said when polio was detected in sewage in Egypt in 2013. Egypt, technically, has remained free of polio cases since 2004. But what that finding in the sewers of Cairo foretold was the spread of polio beyond its traditional confines in what had been the last three countries with endemic disease – Pakistan, Afghanistan and Nigeria.

Today, as the Global Polio Eradication Initiative reports, there have been new polio cases in Syria, Iraq and other countries in sub-Saharan Africa. China and Israel have reported a return of the virus over the past few years. In conflict areas, like Syria or Somalia, the case count is probably pretty unreliable. And now, polio has returned to the Western Hemisphere.

Last month, the WHO declared the global resurgence of polio an emergency.

Ebola spreads because it’s fast and we lack a basic tool, the vaccine, of prevention. We have the tools to stop and even eradicate polio, yet it is again gaining ground. The spread of polio is fueled by instability, lack of basic health care services (like vaccination), dirty water and inadequate sanitation. It’s fueled by poverty, inequity. An Ebola outbreak is a human tragedy; but today’s global polio epidemic is a systems failure that reveals fundamental gaps in global health and the fight against poverty.

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About Author

Tom Paulson

Tom Paulson is founder and lead journalist at Humanosphere. Prior to operating this online news site, he reported on science,  medicine, health policy, aid and development for the Seattle Post-Intelligencer. Contact him at tom[at]humanosphere.org or follow him on Twitter @tompaulson.