Zika and the Limits of Biomedical Fixes

—Joseph E. Davis

In February 2016, the World Health Organization declared the outbreak of the Zika virus to be a “Public Health Emergency of International Concern.” This warning comes on the heels of another such emergency, the 2014 Ebola outbreak in West Africa, and another before that and another before that. These warnings are coming with greater frequency and generate a predictable response. Critics charge the global community with being ill-prepared—for Zika or Ebola or whatever—and urge agencies to stop fighting the last battle and start fighting the new one.

Such calls to Do More often frame the problem of response as one of resolve, or institutional coordination, or biomedical remedy. But while these are certainly important steps in adapting/responding to threats, there are reasons to see the rise of Zika not as another problem in need of a biomedical fix but as a sign of the limits of biomedical fixes.

No one could have predicted the current outbreak. Virologists have known of the Zika virus, named for the Ugandan forest where it was first found, since the late 1940s. But for most of that time, it was the object of no particular concern. About 80 percent of the time people infected with Zika had no symptoms at all. Others experienced only mildly unpleasant symptoms—rash, fever, malaise, and joint pain—that cleared up in a matter of days. Moreover, the disease was rare. Zika’s natural hosts are not humans but wild primates and mosquitoes in Africa and Southeast Asia. While it was long known that “spillover” infections in humans were possible, they were very uncommon. In fact, for almost 60 years between its discovery and 2007, there were only fourteen confirmed human cases of Zika in Africa and Asia.

In 2007, Zika infected about 100 people in Micronesia. In 2013 and 2014, larger outbreaks spread through Oceania, into French Polynesia, Easter Island, and the Cook Islands. Zika’s rarity now seems due less to any property of the virus and more to acquired immunity in African and Asian populations. Once the virus reached populations with no natural immunity, it spread. In 2015 Zika reached South America, and experienced—in the words of the New England Journal of Medicine—an “explosive pandemic reemergence” that is “truly remarkable.” By May 2015, Zika was confirmed as the cause of an unexplained fever throughout Brazil, and then spread to much of the rest of Latin America.

Zika is also not the only African fever to have made the trip to the New World in recent years. Dengue fever, whose symptoms are considerably more serious than Zika’s, has now spread widely throughout the Americas and been the cause of recurrent epidemics. And there were over a million suspected cases of chikungunya, another virus in the Zika family, in the Americas during 2013-14, the first appearance of the virus in the western hemisphere. There is suspicion that the dramatic complications recently linked (if not yet proven) with some cases of Zika—Guillain-Barré syndrome, a life-threatening condition marked by temporary paralysis, and microcephaly, abnormally small heads in newborns that can portend brain damage—may be emerging from some cross reactivity with antibodies against these other viruses.

While there is no Zika vaccine, work on the related viruses for West Nile and dengue may provide valuable leads and vast resources are rapidly being repurposed in search of a medical response. Yet, the very fact of Zika—and dengue, and chikungunya, and Ebola, and all the rest—should be a sobering reminder that medicine and technology can accomplish less than we hope. Through the 1970s, leading experts argued that the era of infectious disease was over and that anything unexpected could “presumably be safely contained.” But even by then change was afoot. Marburg, Ebola, yellow fever, and then HIV/AIDS drove home a new reality.

As with these other modern epidemics, the spread of Zika has little do with the changes in the virus itself. After 60 years of inactivity, the virus is spreading because social, political, and technological developments made its spread possible, even likely. The ease and frequency of global travel, for one, enabled a string of infected travellers to carry the disease from Africa to Micronesia to French Polynesia to Brazil. By far the hardest hit areas are urban slums, where overcrowding and inadequate public services have created the stagnant pools, raw sewage, and garbage dumps that are natural breeding grounds for mosquitoes that spread the disease. Not only was Zika’s original ecological niche disrupted but other environmental factors now play a role, from deforestation to climate change. It is even possible that pesticides (indirectly) bear some of the blame: the explosion of transgenic soy crops, and their accompanying pesticides, has decreased biodiversity in large swaths of Latin America, and mosquitoes may have benefited from the disappearance of natural predators.

The natural environment is teeming with potential pathogens. Studies suggest there are over 300,000 unknown species of virus harboured by mammals alone. Our unceasing interventions and changes in ways of life are creating entirely new social and ecological relationships. We can no longer be surprised by emerging diseases, nor maintain the illusion that we can address our dynamic relationship with the microbial world with one-at-a-time biomedical fixes. For many, many vulnerable people, new vaccines will always arrive too late.

We also have to face the fact that the dominant and largely reactive biomedical approach hinders effective response. This is not only an issue of how resources are allocated. One of the great attractions of biomedicine and individual-level technological responses is that they avoid the messy and controversial work of addressing complex social problems. As the distinguished British sociologist Barbara Wootton once said: “Always it is easier to put up a clinic than to pull down a slum.” Always it is easier to turn to high-tech science then to engage with issues like quarantine, population surveillance, sanitary improvements—the primary methods of addressing the great infections of the nineteenth century—poverty, farming practices, urbanization, local public health, and more. These aspects of the human domain are inherently difficult, socially, politically, and economically; no wonder we try to sidestep them. In doing so, however, we guarantee a continued stream of Public Health Emergencies.

Without denying the real advances in treating human disease, we have to look beyond biomedicine for new strategies of prevention and response. These strategies must be more comprehensive, integrative, and holistic, bringing the biotic and social domains together, and fully recognizing, as science historian Jon Arrizabalaga has written, that “epidemics are social as much as biological events.” We can Do More, but it will have to go far beyond the lab and it will require the involvement of elites from the local to the international levels who are typically the least in danger.

Joseph E. Davis is Research Associate Professor of Sociology and Director of Research at the Institute for Advanced Studies in Culture at the University of Virginia. He is one of the editors of To Fix or To Heal: Patient Care, Public Health, and the Limits of Biomedicine (NYU Press, 2016), the Publisher of The Hedgehog Review, and is the author or editor of three other books, including Accounts of Innocence: Sexual Abuse, Trauma, and the Self.

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