First Ebola, now Zika: the inconvenient truths about battling emerging diseases

In the second time in as many years, the World Health Organization (WHO) has declared a new global public health emergency. Zika virus is predicted to infect millions in the next few months as it sweeps across the globe. Dr Kevin Bardosh talks more about this emerging disease.

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“Everyone knows that pestilences have a way of recurring in the world, yet somehow we find it hard to believe in ones that crash down on our heads from a blue sky.”

Albert Camus in his novel, The Plague (1928)

Just as Ebola in West Africa is nearly out of the headlines, the media has already pegged 2016 “the year of Zika”.

Like the Chinese lunar calendar, each year seems to have its own deadly, emerging pathogen. But without a soothsayer, it is hard to pick from the over 500 other arthropod-borne viruses out there (not to mention the very many viruses, bacteria, fungi, prions and parasites) that may be already competing for the 2017 title.

If I was a Victorian taxidermist, I would be envious of our modern ‘viral hunters’ (disease biologists and ecologists). They have a vast unseen microbiological frontier open to discovery and cataloguing. The problem for the rest of us is that discovery is only half the story; the messy world of global health and emerging diseases isn’t quite like the laboratory bench.

‘Aedes agypti’: a deadly vector

Like Ebola and the majority of other emerging diseases, Zika has an animal origin – it was first detected in a sick rhesus monkey in 1947 along the shores of Lake Victoria. But while we might be forgiven our ignorance about Zika, it would be a faux pas not to know about its deadly vector, the Aedes agypti mosquito.

The notoriety of this little arthropod started way before Zika, as it journeyed on shipping routes in the 1950s, and began breeding in the burgeoning urban cities of Asia and Latin America where it spread arboviruses causing diseases such as Dengue fever, yellow fever and chikungunya. A recent study estimated that there are nearly 400 million dengue infections every year.

But with increasing cases of microcephaly in South America, Zika seems to be a different, more unpredictable beast. Certainly something to broadcast, understand and to act on… quickly.

But the pandemonium around Zika has little to do with the majority of infections. Emerging on a series of Pacific Island States since 2007, Zika typically leads to mild febrile cases, with most being asymptomatic. In much of the tropics, inadequate diagnostic capacity and health services mean such illnesses are typically undiagnosed, unrecorded and forgotten about. Among local communities there is often a widely repeated, but incorrect, maxim that “every fever is malaria”.

But with increasing cases of microcephaly in South America, Zika seems to be a different, more unpredictable beast. Certainly something to broadcast, understand and to act on… quickly.

And that is exactly what is happening. The crisis narrative, the politics, the media, the uncertainty, the fear and the policy prescriptions and citizen reactions. Science and the biological intermixed with the social and political.

A suite of global challenges

With the summer Olympics a matter of months away, troops have been deployed on to the streets of Rio de Janeiro armed with fumigators, larvicide and information pamphlets. A new “war” against the mosquito has begun. The Health Minister of El Salvador, has been more draconian, and advised women in this deeply Catholic country to forgo pregnancy for the next two years, Women rights activists have lashed out.

It’s a clear sign of desperation, of our limited understanding of how and why this unseen enemy has emerged. The US Centers for Disease Control and Prevention (CDC) have just reported a case of Zika being sexually transmitted in Texas. Zika has also been linked to a severe El Niño year.

We are told that a vaccine is “at least” a decade away, if at all, and vector control will also be an uphill battle. Aedes agypti is incredibly resilient.

We are told that a vaccine is “at least” a decade away, if at all, and vector control will also be an uphill battle. Aedes agypti is incredibly resilient. To add insult to injury, conspiracy theorists have begun crying foul, linking Zika emergence to a biotech experiment gone bad. Fears about GMOs have a new poster child.

It is clear that Zika virus has quickly become inseparable from a suite of other global challenges: unplanned urbanisation, poverty, women’s rights, social services for disabled newborns, climate change and dysfunctional political regimes. Entangled together, tensions mount and influence the different ways we respond.

One Health approach

While differences abound, we have been here before. Many times. HIV/AIDS, Ebola, avian influenza, bovine spongiform encephalopathy (BSE), West Nile, Lyme disease, and the list goes on – albeit the characters and script are different.

The past has told us is that we need to take a new approach to these recurring pestilences, that we should not be taken by surprise but plan for the inevitable. Paradoxically, that ‘inevitable’ is also uncertain and complex.

We need a “One Health” approach that integrates human, animal and ecosystems health.

This is the central point of the huge body of post-Ebola literature that lays out clearly how we need to strengthen global surveillance, response and preparedness systems to better handle emerging diseases. We need a “One Health” approach that integrates human, animal and ecosystems health.

While this is all great and good, major disciplinary and socio-political divides remain that may bar these aspirations. Once the dust settles and the news cameras leave, international pledges and lofty rhetoric to deal with the underlining ecological and social roots of these diseases tend to evaporate.

Power and politics

When social scientists talk about ‘political’ and ‘social’ dynamics we are not necessarily talking about exotic cultural practices. Power and politics are interwoven as much into the Vodou ritual dance as into the culture of global disease surveillance and response. This is becoming more and more accepted in public health circles, often under the rubric of “implementation science”.

Thinking about a more resilient and ultimately effective approach to emerging diseases requires asking difficult, sometimes uncomfortable, questions about priorities and the structure of science and intervention. It demands delving into the complex relationships (and tensions) between global and local systems, policy and practice, science, technology and citizen participation, and different forms of knowledge and expertise.

But attention to social and political relationships is, again, only half the story. Social scientists themselves need to get out of their ivory tower. If the future is anything like the past, preventing and responding to future global health disasters will demand teamwork and self-reflection – the ability to work across multiple divides with creativity, political acumen and a dedication to social justice.

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One Comment

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Laura

I found this blog to be enlightening about Ebola and Zika and the other emerging diseases. As stated each few year it seems like we have a new global disease that our media cannot stop talking about. The history of Zika seems to be like various other emerging diseases. The problem with Zika and numerous other emerging diseases is that the symptoms are common everyday symptoms, for example mild fever, that can be overlooked for an ordinary cold and therefore not properly diagnosis or treated. If not accurately diagnosis and treated in an appropriate fashion the illness can spread thus become global. With that being said it is essential that we develop a system for diagnosing and treating Zika and other further or past emerging diseases in order to prevent them from being a global issue.

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