This week, the World Health Organization (WHO) declared the Zika virus an international public health emergency. Though not yet confirmed, Zika is suspected of causing microcephaly — babies born with small heads and abnormal brain development — and paralysis in adults. The virus is“spreading explosively” throughout South and Central America with cases confirmed in more than 20 countries. The WHO anticipates that up to 4 million people could become infected by the end of the year and, with large numbers of travelers in and out of the region, Zika could spread to other parts of the world.
Just over a year ago, we faced a similar challenge when Ebola was spiraling out of control. At the time, two of us (Ranu and Devabhaktuni) were asked by the president of Guinea, one of the three most affected countries, to help develop a national strategy to contain the epidemic. Based on our experience fighting Ebola, we propose a four-pronged strategy for containing Zika.
Just like Ebola, there is no vaccine or cure for Zika and will likely not be one for years. Stopping this pandemic will require disrupting its “chains of transmission.” For Ebola, which is transmitted through bodily fluids (e.g., blood, stool), this meant implementing a response that identified newly infected people at the first sign of illness and then quarantined them before they infected others.
Controlling Zika, which is transmitted by mosquitoes and apparently through sex, might logically require eliminating mosquitoes in areas where the virus is present and immediately isolating infected people, especially from pregnant women. This can be done by ensuring people use mosquito repellents and sleep under insecticide-treated bed nets (similar to those that have helped achieve dramatic declines in malaria in Africa) and by eliminating conditions where mosquitoes thrive, including standing water and outdoor debris. However, because 80% of infected people show no signs of illness and others have nonspecific symptoms like fever and body aches, it is hard to know who has Zika and, therefore, pinpoint areas where these interventions need to be targeted.
Right now, affected countries are identifying local hot spots by looking for places where there are unusually high rates of babies born with microcephaly — essentially, only after severe damage has already been done. Some countries are currently trying to contain Zika by broadly recommending that all women avoid becoming pregnant and that communities take precautions against mosquitoes. But implementing these measures across entire countries will require massive changes in attitude and behavior and the mass distribution of both birth-control and mosquito-control commodities. (For example, by some estimates over half of pregnancies in the region are unintended.) These approaches will only be partially effective at large scale; pregnancies will certainly still occur and some mosquitoes will still remain.
Therefore, alongside such broad-brush efforts, a more nuanced and intensive four-pronged response is needed.
1. Pinpoint Hot Spots With Widespread Testing
In areas where Zika may be present, all patients with symptoms that could signify infection should be screened by blood testing so that hot spots can be quickly detected. This approach would benefit from the accelerated development of easy-to-use, point-of-care diagnostics for Zika.
Similar to Ebola, Zika diagnosis currently requires polymerase chain reaction (PCR), a laboratory-based test that needs special equipment and personnel and is, therefore, difficult to scale and decentralize. One of the major failures during the Ebola epidemic was the inability to quickly validate and deploy rapid diagnostic tests (RDTs) that could have been used by non-specialized health workers to diagnose Ebola within minutes with just a finger prick. This would have allowed Ebola cases to be detected earlier and transmission to be curbed more quickly. These diagnostics could have helped end the epidemic much sooner, but were never deployed because of a lack of consensus on how they should be used as well as a validation process focused on laboratory-based evaluations rather than testing in real-life conditions where the RDT ultimately performed much better.
Developing a similar test for Zika should be an immediate priority and proactively coordinated and pushed forward with dedicated financing and a fast-track validation process geared towards evaluating new tests in the field as soon as possible. In the meantime, existing labs at regional and sub-regional hospitals should be urgently equipped to carry out Zika diagnosis by PCR so surveillance of the virus’ spread can begin immediately.
2. Implement Targeted Control Measures
With information on where Zika transmission is happening, mosquito control and isolation interventions can be aggressively implemented in these areas. Bed nets and repellant should be distributed to all households, environmental conditions conducive to mosquito breeding should be addressed, and people diagnosed with Zika should be kept away from pregnant women and settings where mosquitoes can feed on them. Implementing this intensive response requires effective local health systems. In the Ebola epidemic, the affected countries in West Africa had barely functioning health systems, especially at the local level. As a result, we had to create a parallel Ebola-specific response system at great cost and time, all while the epidemic continued to expand.
Many of the countries currently affected by Zika have relatively stronger health systems. In Brazil, the most heavily affected country, for example, there is already a network of local clinics linked to community health workers who go from household to household to address health issues. These local health systems should pivot towards epidemic control and search out potential cases of Zika while providing counseling and close monitoring to pregnant women in order to minimize their risk of infection. Extra personnel, training, and resources should be deployed to fortify these existing systems to implement the interventions needed to tame Zika.
3. Prevent Widespread Transmission
At the start of the West African Ebola epidemic, the virus was clustered within a few local communities and, as in the two-dozen Ebola outbreaks before it, could have been confined and brought to a quick end. However, once Ebola eluded early response efforts and became a widespread epidemic of multiple, dispersed local outbreaks, it became a true global crisis difficult to bring back under control.
Zika has already become fairly widespread. But every effort should be made to try to pin the virus down in its current locations and stop it from reaching new geographies. Once a hot spot is identified, people traveling out of the area should be tested at diagnostic checkpoints. The point-of-care diagnostic we described above would dramatically enhance the ability to implement this approach.
4. Integrate Research with Immediate Action
With Ebola, we tried to manage the epidemic even while many critical questions about the virus remained unanswered. Despite thousands of cases and over two years of fighting the epidemic, we still did not learn as much as we should have about Ebola because of an inability to conduct effective research alongside efforts to manage the epidemic.
With Zika, we may have even more knowledge blind spots that need to be quickly understood if the pandemic is going to be contained. Does Zika actually cause microcephaly and paralysis as is suspected? If so, is everyone vulnerable or only people with certain characteristics? We should learn from mistakes we made with Ebola and deliberately consider how important research questions can be studied even while we work to immediately control the virus. Doing this will undoubtedly require bolstering the research capacity of local universities and institutions, a critical investment that we did not make during Ebola.
This four-pronged strategy should enable us to get ahead of this growing pandemic and prevent what now seems to be the inevitable spread of Zika across the globe. Amidst the chaos of the Ebola epidemic, a clear-sighted approach to disrupting the “chain of transmission” tamed runaway growth. We must heed the lessons from the Ebola crisis and employ a systematic, concrete strategy to combat the spread of Zika.
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Authors:
Ranu S. Dhillon, MD, is an advisor to the president of Guinea and the country’s National Ebola Coordination Cell. He is in the division of global health equity at Brigham and Women’s Hospital and Harvard Medical School and is a senior health advisor at Columbia University’s Earth Institute.
Robert Glatter, MD, is an assistant professor of emergency medicine in the Department of Emergency Medicine at Northwell Health’s Lenox Hill Hospital. He is editor at large at Medscape Emergency Medicine and chief editor at Medscape Consult.
Devabhaktuni Srikrishna is the founder of Patient Knowhow, which curates patient educational content on YouTube. Previously, he was founder and chief technology officer of Tropos Networks, which was acquired by ABB Group.
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