January 25, 2016
Dear Friends and Colleagues,
Today, members of the Executive Board (EB) are gathered in Geneva for their annual review of the performance and policy actions taken by the World Health Organization (WHO). It is a pivotal EB gathering, with WHO Director-General Margaret Chan and her agency facing the most severe criticism and gravest crisis of confidence since the 1988 to 1998 years, when Hiroshi Nakajima was at the helm. At least five major, highly critical assessments of the WHO’s performance in the West African Ebola epidemic—including a devastating critique leveled by the EB last year—have brought the institution’s inadequacies and structural failures into sharp focus.
The EB gathering in Switzerland comes on the heels of an unusually sober World Economic Forum (WEF) annual summit in Davos and amid a massive downturn in the global economy. The WEF traditionally prepares a global risk and threat forecast for these annual gatherings, and this year’s augury contains grim news that should grip the attention of global health leaders. It was, of course, prepared months ago, before the spectacular downturns in global stock markets. On November 6, 2015, the Dow Jones Industrial Average reached 17,918.15, prompting euphoric investors to imagine it might break the previous December 23, 2014, record of just over 18,000. But two months later, the Dow has fallen approximately 1,900 points, or nearly 10 percent. And the price of oil is down to $31/barrel (Brent Crude Futures), reflecting a 40 percent price plummet since its 2015 high.
Meanwhile, a virus that most readers did not know existed is sweeping across Latin America and the Caribbean, causing thousands of babies of infected mothers to be born with shrunken skulls and brain damage. The Zika virus crisis—like the spreading cholera epidemic in eastern Africa and the Middle East—is heavily driven by the El Niño climate event, which may be unusually bad (perhaps even record breaking) this year due to the effects of climate change.
In this update, I will examine each of these issues.
World Health Organization Faces Calls for Reform
The United States has a seat on the thirty-four member Executive Board, which oversees the WHO, convening from January 25 to 30 in Geneva. Historically, the EB meetings have been fairly secretive, with most critical budgetary and policy decisions made in closed sessions. But in the spirit of WHO reform, the EB has grown increasingly transparent and this year will stream most of its proceedings live on www.who.int. In advance of the gathering, the WHO Secretariat has released more than twenty documents and policy advisories, some of which require voted action by the EB.
China’s Margaret Chan will finish up her second term as director-general of the WHO in mid-2017, and electioneering by candidates for the position has already discreetly begun. Would-be director-generals must formally declare their candidacies in September, and campaigning for the position will commence in earnest this fall, continuing until May 2017, when the World Health Assembly—the legislative body for the WHO, which operates via a one-nation, one-vote constitutionally proscribed system—votes. Against that lame duck setting, Chan and her Secretariat team have less than eighteen months to execute sufficient reforms and policy initiatives to reverse what would otherwise be a very sour legacy for her administration. Judging by EB documents, the Secretariat is moving quickly in some reform areas, and sluggishly (if at all) in others. Not surprisingly, the most sluggish arenas are those that require action from the typically obstructive World Health Assembly.
In a careful review of the advance documents, I find the following points of special interest:
- There is repeated concern expressed about the UN-passed 2030 Sustainable Development Goals (SDGs). In particular, there is fear that the thirteen health targets under SDG 3 (health for all) will spawn a mad and divisive scramble for financial resources, exacerbating already existent disease-specific silos in the global health space. The WHO Secretariat believes that "the SDG target that underpins and is the key to the achievement of all others" in the health agenda is Universal Health Coverage (UHC). And UHC can only be attained in an environment of unity and leadership across the global health architecture. I would add that such unity assumes a credible and broad leadership role for the WHO, rather than the ever-weakening one we have witnessed since 1998.
- Undertaken by governments in response to the 2014–2015 Ebola epidemic, at least forty-one measures violated the WHO’s International Health Regulations (IHR). These regulations were ratified by the World Health Assembly in 2005. Generally, these measures stigmatized and economically damaged Liberia, Sierra Leone, and Guinea by imposing punitive trade and travel restrictions on their people and businesses. Under the IHR, all trade and travel-related measures taken by unaffected nations are supposed to reflect the best scientific advice from the WHO. During the epidemic, the Geneva leadership found no cause for denying travel or student visas, refusing to fly passengers, denying diplomatic visits, refusing to offload vital goods including oil and fuel, quarantining non-sick travelers for extended periods of time upon their arrival on foreign soil, or other such steps taken by governments ranging from Australia to Canada. I would add that nothing in the provided WHO documents offers a policy pathway toward greater WHO power to compel global compliance with these IHR provisions.
- Final eradication of wild-type polio will require a $5.5 billion all-out campaign, focused on Afghanistan and Pakistan—the only remaining countries to report cases of the disease. However, less than half of that funding has been banked or committed. In 2015, just fifty-one polio cases were detected in the world, down from 246 in 2014. The most spectacular achievement: two of the three types of polio viruses have been eradicated from planet Earth. Only type 1 polio remains in circulation. Unstated in the documents are the obvious reasons why polio stubbornly remains a danger to the children of Afghanistan and Pakistan: the fatwas issued by conservative clerics, violence perpetrated by the Taliban and their sympathizers against vaccinators, and the anti-immunization directives to families in regions under Taliban control. Despite a decade of Taliban-led murders of vaccinators—including suicide bombings of immunization sites—the world health community has been unable to bring the governments sufficiently to the table on polio eradication to guarantee the safety of the mostly volunteer anti-polio workers.
- Some documents reveal genuine anguish within the WHO regarding the agency’s inability to reach all of the Syrians, Yemenis, and Middle Eastern refugees in "urgent need of medical attention." Logistical and violent obstacles continue to impede the free movement of WHO health experts and their colleagues from other UN agencies and humanitarian organizations. At least 85,000 refugees now in Turkey and Europe require immediate medical care, according to WHO documents. Moreover, a record-breaking sixty million people worldwide are internally displaced or refugees, most without access to healthcare, child immunization, safe drinking water, and the public goods essential for preventing injury, stillbirths and miscarriages, infections, and severe malnutrition. The crisis of refugees and internally displaced people is now at an unprecedented scale, and every responding agency and nongovernmental organization (NGO) is stretched to their limits trying to address needs and save lives. On January 14, 2016, UN Secretary-General Ban Ki-moon declared the starvation of thousands of residents of Madaya, Syria, "a war crime," and the WHO and UNICEF drew world attention to the deaths of children denied any morsels of food by the Damascus government. As Médecins Sans Frontières (MSF) has repeatedly noted, health facilities are now targeted and displays of red crosses or medical insignias fail to deter attack (as was the case in the recent U.S. bombing of an MSF clinic in Afghanistan and Saudi air strikes on MSF hospitals in Yemen). All health workers and humanitarian responders, including those with the WHO, now face a double threat: a spectacularly greater global need for their services and the relative powerlessness of the Geneva Convention and other protocols to assure their safety in providing such services.
- As the Ebola epidemic unfolded in 2014 and foreign health volunteers took ill, the lack of diagnostics, treatments, and vaccines was shameful, and disparities in access to experimental treatments drew sharp criticism. The WHO documents describe the development of a "roadmap for discovery" that would hasten research and development (R&D) during outbreaks, and create a Top Ten Pathogens list for immediate drug and vaccine discovery. This welcome effort mirrors R&D streamlining and pathogen prioritizing steps unfolding in the United States and several European countries. The WHO’s direct connections with biotechnology and pharmaceutical companies continues to be hampered by the agency’s need to straddle a great political divide; many nations and NGOs distrust Western drug and vaccine makers due to their intellectual property protections and pricing mechanisms, both of which, critics argue, prevent equitable access worldwide to vital medicines. Conversely, the industry has little appetite for developing products that have no assured markets or profit margins and will do everything possible to protect patent exclusivity on products that are profitable. A major breakthrough in this regard was announced this week at the World Economic Forum by Seth Berkley, chief executive officer (CEO) of Gavi (the Global Alliance for Vaccines and Immunization, based in Geneva). His agency will give $5,000,000 to Merck, the U.S. pharmaceutical giant, to build and maintain a stockpile of 300,000 doses of the new Ebola vaccine. This step overcomes key barriers to cooperation between global health advocates and the pharmaceutical industry by guaranteeing purchase of a product successfully developed and tested by an unusual consortium including industry, NGOs, the WHO, and government officials.
- Even as the WHO documents reveal potentially revolutionary measures to improve new drug and vaccine development for control of pathogens, the world is running out of older, absolutely vital medicines. These include cancer treatments, antibiotics, older malaria drugs, and a broad range of off-patent medicines. The WHO is frustrated by an emerging pattern of drug shortages worldwide, as low-profit, off-patent medicines—especially those that must be injected—are no longer being manufactured by producers that maintain high-volume, safe, and reliable production. The gap in manufacture is either being filled by less- reliable makers, or not at all. Although this trend is not new, it has worsened considerably over the past ten years and effects all nations, rich and poor. In the United States, the Food and Drug Administration has several times called congressional attention to the emerging crisis of shortages, especially for cancer treatment. Sadly, the WHO documents reveal no actual solution to the problem, which is unsurprising given that nobody has to date offered a viable answer. How can the world maintain an affordable supply of drugs, medicines, and vaccines that offer even developing country–based generic manufacturers little or no profit?
- Many of the documents draw alarming attention to the dire shortage of skilled health-care workers and the recruitment of doctors and nurses to wealthy countries. Noting that the achievement of the SDGs and UHC "will hinge on whether supply and demand of health workers meet population needs," the mismatch between supply and demand is an exponential gap. Tens of millions of doctors, nurses, midwives, dentists, laboratory workers, and community health providers must be trained within the next ten years, but few nations have allocated funds or facilities for the necessary scale of health and medical education. A new WHO survey included in the documents shows that 68 percent of all of the world’s health labor force are nurses and midwives, many of whom burn out or cease practicing due to their low status, insufficient salaries, and high performance demands, often in the absence of essential medicines, equipment, and facilities. The best among them are easy targets for recruitment away from their home countries to wealthy nations. Three-quarters of all such recruitment sucks health workers away from poorer countries to the United States, United Kingdom, Spain, Australia, Canada, France, Germany, and Ireland, according to the WHO documents. Unless this trend can be effectively offset by both in-country initiatives to improve the status of doctors, nurses, and midwives and efforts to reduce their foreign recruitment, rich and middle-income nations will add forty-five million health workers by 2030 and poorer nations will lose eighteen million. Under human rights laws and agreements, health workers’ personal mobility cannot be restricted; if a Kenyan doctor wants to accept a job in Baltimore, Kenya has no right to stop the physician’s migration. But wealthy nations are offsetting the increasingly labor-intensive health needs of their aging populations by pilfering the cream of the medical crop from poorer countries, rather than through massive investment in the education and training of their indigenous populations. For example, current data shows 40 percent of health workers in the United States were foreign-born and most of them were foreign-trained; 70 percent of Australia’s midwives and more than half the country’s doctors and nurses were born and trained in foreign countries; and even ten years ago, a quarter of the physicians in Canada’s health system were foreign-trained. It boils down to money, of course. It is cheaper for Washington to expand special visa programs allowing American hospitals to recruit foreign doctors and nurses than it is to allocate billions of dollars to expand schools of medicine, nursing, dentistry, and pharmacology nationwide.
- The WHO has seen its budget crisis worsen every year since the world financial crisis of 2007–2008, and it was weakening prior to then thanks to the rise of competitive, disease-specific global health agencies. The multibillion-dollar decline in net funding has accompanied an ever-greater dependency on its top-twenty donors, decreasing the WHO’s independence. Every year, the World Health Assembly has refused to vote for increases in country assessments, making the agency’s core budget steadily decline when adjusted for inflation over time. The United States is the most highly assessed nation, responsible for 22 percent of the WHO’s core budget. The next-largest core contribution comes from the United Kingdom, at five percent of the total. However, the documents reveal a UN-mandated adjustment of the calculus used to determine assessments will bring that UK contribution down to 4.9 percent. When core and voluntary donations to WHO are combined, 80 percent come from just twenty nations, and the other 174 states are essentially free riders. The WHO documents understate this dependency and omit a non-state donor. The Bill & Melinda Gates Foundation is the second-largest donor, just behind the U.S. government. Combined, the foundation and the United States account for nearly 70 percent of the WHO’s financial resources.
- The performance of the WHO’s regional and country representatives remains a critical source of its declining credibility. All too often the representatives have been political appointees, "suggested" by local or regional governments. They have proven willing to weigh local economic and political interests against public health, coming down on the side of government interests at the expense of peoples’ medical and health needs. Even where conflicts of interest are absent, competence has been an issue. The WHO documents lay out a series of new measures that aim to eliminate both problems. For the first time, WHO representatives will have to be actual public health experts, pass examinations, and undergo training in outbreak recognition and management, the provisions of the IHR, and a host of other WHO concerns. It may come as a surprise to some readers to learn that these provisions are new. Until now, there was no requirement that an official WHO country representative have any knowledge whatsoever of the difference between a virus, bacterium, fungi, and parasite, much less to understand which diseases might be associated with which category of microbe. Moreover, many representatives knew next to nothing about the financing and economic outcomes of chronic diseases interventions, but a great deal about the economics of their local commodity extraction industries or drug manufacturers. These new provisions are welcome, if highly belated.
Some of the authors of the five critical Ebola and WHO reform assessments published this year and last are presenting their conclusions to the EB, which presumably determines which merit inclusion in the board’s final mandates to the Secretariat. The most recent of these reports was released last week by the National Academy of Medicine, at the Rockefeller Foundation in New York. (Some of you may recall the academy under its former moniker, the Institutes of Medicine.) We look forward to learning how the EB intends to select recommendations and actions from the varied reports, which have some significant differences in both analysis of the nature of problems in global responses to outbreaks and in provisions for improvement of the WHO and other responding institutions and NGOs.
World Economic Forum Offers Grim Forecast
Since 2000, the annual gathering of chief executives, famous economists, celebrities, and the super-rich in Davos has featured some successful advocacy from global health leaders. In the beginning of this century, stars of the global political and celebrity stages pleaded for support from WEF attendees to combat HIV/AIDS and malaria. The plea broadened over the years, and global health panels became regular features of the economics-dominated gathering. Last year, amid the Ebola epidemic, pandemic threats took a front seat not only at the actual gathering, but also in the WEF formal risk assessment documents.
The WEF’s Global Risks Report 2016 does not feature diseases or health among its top concerns. Based on surveys of its members—mostly CEOs—the annual risk profile gives readers a fair idea of what is keeping the executives of Goldman Sachs, Microsoft, Credit Suisse, and GlaxoSmithKline awake at night. The surveys were conducted just before the recent severe downturns in stock markets, oil prices, and the Chinese economy. The sense of where "Davos Man" sees threats to his business and national interests is mapped on the right. The cube head of each arrow-like projection indicates the direction of the threat (better or worse than 2015; widening or contracting). The x-axis indicates how likely responders feel the threat is to materialize and the y-axis displays how severe they believe the impact might be.
The WEF is far less worried about the spread of infectious diseases than it was last year during the Ebola epidemic and the downgrade reflects nothing more than these CEOs’ diminishing fearfulness: Ebola is under control, the threat is gone. Interestingly, the WEF feels that the risk of biodiversity loss and climate change has increased, in part because they believe that agreements reached at COP21, the Paris climate summit, will be implemented in time to forestall a large increase in Earth surface temperature. The WEF predicts global temperature will, by 2100, reach an increase of 2.7 degrees Celsius since the beginning of the industrial age, which would be catastrophic in terms of ice melt, sea level rise, and violent weather generation.
Topping the WEF risk assessment is concern about water resources for manufacturing, agriculture, and drinking: "According to the World Water Council, 80 percent to 90 percent of the scarce water in many of the world’s arid and semi-arid river basins is already being used, and over 70 percent of the world’s major rivers no longer reach the sea. On the other hand, inadequate sanitation exposes 2.4 billion people to many diseases, such as diarrheal disease, which is the third leading cause of death among children under five," the report states. It notes that the United States used 40 percent of its water resources for energy generation (fracking and hydropower), Brazil’s energy use of water is at 64 percent, and worldwide energy generation is expected to increase pressure on water resources by 70 percent by 2030.
The number one immediate threat—i.e., within eighteen months—cited by the WEF is large-scale involuntary migration.
Overall, the WEF forecast is grim, offering three likely scenarios for the world over the next fifteen years, each worse than the last. The WEF’s participants expressed no faith in the ability of global governance mechanisms or individual states to solve such non-state-specific crises as the shortage of water, climate change, cybersecurity, mass refugee movements, or pandemics. It imagines the balance of power shifting radically over coming years. In one scenario, the "balance of power adjusts, creating a new order of mostly regional spheres of influence," competing economically and even militarily against other regional spheres. In another scenario, the "world divides into islands of order in a sea of disorder, with people displaced by environmental change and violence."
The assessment offers the following significant takeaways:
- "Social media is offering new means for all sides to conduct cy-ops and psy-ops: scare tactics, recruitment and fundraising," which fuel nation-versus-nation tensions and terrorist groups such as the self-proclaimed Islamic State.
- Although the threat of nations using cyberattacks to bring down other countries’ infrastructures has waned, the WEF cautions that "everything is networked and anything can be hacked. The 'dark net' has become a trading place fueling insecurity."
- The WEF was born at the dawn of globalization, alongside the creation of the World Trade Organization and the Doha agreement. In many ways the WEF has been a cheerleader for business globalization, but now "businesses find more obstructions as a result of anxieties around trade, technology transfer and intellectual property."
- There is virtually no faith in global governance. "Trust is waning in capacity of existing multilateral mechanisms to resolve potential flashpoints."
- Citing examples like Yemen and Libya, the report states that "vacuums created by frail or weakening states open space for armed non-state actors," such as the Islamic State.
- Meanwhile, climate change is real and devastating. "Atmospheric concentrations of three greenhouse gases (CO2, CH4 & NOx) are at their highest levels in 800,000 years, with CO2 up 13 percent since 1990." Moreover, "the world today is estimated to be about 1°C warmer, on average, than it was in the 1950s, and effects are being felt."
- The once-darling BRICS nations—Brazil, Russia, India, China, and South Africa—are on the decline and there "could be numerous corporate and sovereign defaults in emerging markets, triggering a financial crisis." (Note again that this survey was executed before the Chinese market plummeted; concerns likely reflect the near-total collapse of the Brazilian economy and political establishment.)
- Following the 2007 financial crisis and the Federal Reserve’s policy of quantitative easing, "the extent of corporate over-borrowing is up to $3 trillion and corporate debt-to-GDP ratios increased by 26 percent between 2004 and 2014."
- The refugee crisis has the potential to be explosive politically, because "the lack of integration policies [in host countries] can lead to ghettos on margins of society, vulnerable to radicalization." The WEF suggests that countries across North America and Europe, in particular, "reframe the discourse on refugees from risk to the substantial social and economic contribution they make to their host."
For global health leaders and advocates, this cynical forecast, coupled with current economic conditions, poses a significant challenge. The psychology of big private donors, with the exception of the Gates Foundation and older philanthropies, is focused on "wins" and "naming rights." Corporate and individual donors understandably prefer to target short-term achievable goals, for which they may take credit. The mounting pessimism runs counter to that mentality, projecting hopelessness and a serious lack of belief in institutional change and governance. Any pitch for resources to, for example, enhance outbreak surveillance or achieve the SDGs should first tackle this despair, offering credible hope that beneficial targets are achievable.
Zika Virus Crisis Spreads
In 2014, Brazilian health officials reported 147 cases of babies born with microcephaly, a congenital deformation of the skull that compresses the infants’ brains. By January 20, 2016, nearly 4,000 microcephaly cases were reported in the country, along with 500 other infections; about a quarter of the 4,000 were detected in the month of December. That represents a twenty-fold year-to-year increase in an extreme birth defect; the cause should be identified, preventing it from claiming more babies.
Though Koch’s Postulate has not been put to the task, the correlation between the 2015 explosion in microcephaly cases in Brazil and nineteen other countries in the Americas and the spread of the Zika virus is so strong that most public health leaders accept the hypothesis that maternal infection with the mosquito-carried virus during pregnancy causes the skull deformations. Zika virus RNA has been found in the amniotic fluids of mothers delivering microcephaly babies, and autopsies of two babies that died of the ailment in the United States discovered Zika viruses in their brains.
This X-ray picture from Colombia compares the skulls of a normal baby to "Patient 1" born to a mother who was infected with Zika Virus during pregnancy.
Though several cases of Zika have appeared this year in the United States, none of them were acquired in the country and no infected mosquitoes have been found in the fifty states—all of the mothers had traveled during their pregnancies to Zika-hit countries. But the infected insects lurk nearby, as locally acquired Zika cases have emerged in Puerto Rico and Mexico. As of January 24, the United States and Europe have identified a mounting toll of Zika-infected babies—in all cases, the mothers traveled in Zika-infected countries during their pregnancies. The United States has identified several new cases; the United Kingdom, three; Spain, two; and Portugal, four.
The U.S. CDC will shortly announce that suspected Zika infections are "mandatory reportable" diseases, thereby compelling all of the nation's health agencies to monitor and compile information. Until that goes into effect, the best reckoning, according to CDC officials, is that "close to two dozen" cases of travel-related Zika have appeared in the United States, including babies with microcephaly. There is little immediate concern that the virus will spread across the United States because mosquitoes are dormant during winter, and this year's winter weather has been harsh even in the southernmost parts of the continental United States. However, as temperatures rise and spring rains create potential breeding sites, there is genuine cause for concern. This CDC map demonstrates why the agency is fretting about Zika (and Chikungunya and dengue)—both Aedes mosquito species are in the country, especially across southern states.
Other than the spread from mother to fetus in utero, there is no evidence of person-to-person transmission of the Zika virus; to be infected, a person must have been bitten by a feeding mosquito, or hypothetically, receive a contaminated blood transfusion. Once infected, the individual’s immune system determines whether the illness is so mild as to go unnoticed, or more severe.
There is no vaccine or treatment for Zika and the skull malformations in infected babies cannot be reversed. Nevertheless, most Zika fever cases are mild enough to be confused with the flu or a bad cold and rarely merit hospitalization. In countries such as Brazil, where the other rapidly spreading mosquito-carried viruses—dengue and chikungunya—are found, the flu-like symptoms are so similar that blood tests are needed to distinguish the causes. All of these pathogens cause headaches, fevers, joint aches, malaise, weakness, and nausea in milder cases. In very rare cases, Zika can cause the neurological disorder known as Guillain-Barré syndrome, which can be permanently debilitating. (This is, however, so rare that of the 8,200 Zika cases in the 2013 French Polynesia outbreak, just fourty-two developed the neurological syndrome, or 0.51 percent.) In addition to rising microcephaly rates in Brazil, Colombia, and at least a dozen other countries in the hemisphere, there are new reports of rising numbers of Guillain-Barré syndrome cases. Both Zika and chikungunya can cause the syndrome. French Polynesia is still struggling with Zika after nearly three years, and recently reported an increase in brain defects in newborn babies.
In 1947, disease hunters from the Rockefeller Foundation were in Uganda, studying yellow fever using rhesus macaque monkeys. The animals were placed in cages that were perched in trees in the Zika Forest (meaning "overgrown" in the Luganda language). On April 18, 1947, one of the Asian Rhesus monkeys took ill with a previously unknown virus, which the researchers dubbed Zika. In a lab in Entebbe, the Rockefeller scientists injected the new virus into mice, which then developed the feverish illness, thereby proving the virus they had discovered was the cause of the disease. The first human case of Zika fever was identified in Nigeria in 1954.
In Africa, the virus is carried by the Aedes africanus mosquito, which is classically found along the continent’s equatorial belt stretching from Cape Verde to Kenya. Few human beings ever acquired Zika because the africanus mosquitoes mostly fed on wild monkeys and chimpanzees. David Morens and Anthony Fauci (who heads the U.S. National Institutes of Allergy and Infectious Diseases) argue that changes in lifestyle in Africa in the later twentieth century afforded the virus the opportunity to infect another, more globally common mosquito, Aedes aegypti. As villagers built rainwater-catching devices and uncovered containers full of water became common across Africa, the aegypti mosquitoes placed their larvae in the fresh, clean still water. The aegypti populations swelled all over the continent, expanding into Aedes africanus territory and likely feeding on primates that had been infected with Zika by africanus.
In 1978, a handful of Zika cases were identified in Indonesia, but the disease seemed to disappear without any public health intervention. The first serious outbreak of Zika outside of Africa occurred in April 2007 on Yap Island, part of Micronesia, eventually spreading to neighboring islands of the nation. Frustrated scientists from the U.S. Centers for Disease Control (CDC) discovered dengue blood tests falsely tested positive for Zika. It remains difficult to discriminate between them with rapid commercial tests, and clear diagnosis requires use of genetic RNA tests (polymerase chain reaction).
Since the Yap outbreak, Zika has emerged eastward across the Pacific in the Cook Islands, Tahiti, and, last year, the Easter Islands off Chile. Until 2015, Zika had never been seen in the American hemisphere.
For unknown biological reasons, Zika appears to follow the emergence of chikungunya, which in turn follows new spread of dengue.
In the unfortunate case of the Americas in 2015–2016, a perfect storm of biological events has unfolded—any one of which by itself would have been relatively harmless. Introduction of Asian and African mosquitoes, spread of yellow fever, then dengue, followed by chikungunya and then Zika; the El Niño climate event; and a Brazilian crisis in both economics and politics. Combined, these have fueled explosive spread of the disease to twenty nations, twenty of which have severe enough outbreaks to warrant public health emergencies and travel advisories from the U.S. CDC.
Morens and Fauci warn that another, highly aggressive mosquito, Aedes albopictus, a.k.a. "Tiger Mosquito," is found all over the Americas today. Were it to take up the Zika virus, as aegypti did, the spread of the disease could reach far greater proportions.
Because there is no human-to-human transmission of the virus outside of the womb, the smart place to focus public health attention is on those Aedes mosquitoes, none of which originated in the Americas. As these insect species have appeared in the hemisphere, public health entomologists have warned of their tremendous potential to spread life-threatening disease. The warning, which typically included calls for resources to kill off the mosquitoes, have largely gone unheeded by politicians that control purse strings across the region. In the United States, politicians have faced another non-fiscal threat: the NIMBYs who fought all efforts to use chemicals to kill insect larvae and spray adult mosquitoes.
The aegypti mosquito was first brought to the Americas in 1648, a hitchhiker aboard slave ships from Africa. Across the hemisphere, the mosquito spread during the eighteenth century, spawning huge yellow fever epidemics. In 1793, one out of every ten inhabitants of Philadelphia—then the capital of the United States—died of yellow fever. In the late 1890s, Cuba’s William Gorgas spotted the association between yellow fever and the aegypti mosquitoes, executing the first campaign to drain swamps and kill off the insects. His effort proved so successful that it was mimicked by the U.S. Army in 1904 in Panama during the construction of the canal.
In 1789, American physician Benjamin Rush described another seemingly new disease, dubbed break bone fever. Like yellow fever, break bone was chiefly seen during summer months, could kill nearly a third of those that took ill, and could not be cured. Today, break bone is called dengue, which is caused by four different subtypes of viruses. In its most severe form, typically resulting from coinfection with more than one subtype or sequential infections with different forms of dengue, the virus causes an Ebola-like hemorrhagic disease that is most often fatal. In 1997, the CDC’s Duane Gubler showed that dengue became a global killer during World War II, when soldiers hunkered across the Pacific theater were exposed to multiple subtypes, carrying the viruses in their bodies from one battle site to the next where they were absorbed by biting mosquitoes.
Widespread aegypti eradication campaigns in Asia and Latin America after World War II dramatically reduced dengue and yellow fever, as did rising use of window screens and elimination of open water storage. But in 1997, the world experienced the largest El Niño event in history (until the current one), bringing record rainfalls across Southeast Asia, Singapore, and Malaysia. With the rain came more breeding grounds for aegypti in the form of puddles and pools, and a major regional dengue epidemic ensued. Complicating the control efforts was albopictus, the tiger mosquito, which had become another vector for dengue.
Tiger mosquitoes are larger, tougher insects that travel greater distances in their feeding compared to aegypti and can bite more people in a given day, thereby taking up more viruses. As a result, viruses evolve faster in albopictus, mutate, and become more virulent, as happened with dengue.
That year, another African virus appeared in the Americas for the first time, West Nile virus, also spread by the Aedes aegypti mosquitoes. First seen in New York City during the summer of 1997, West Nile virus is now endemic across the continental United States and parts of Canada. Fortunately, the disease is rarely a severe ailment in human beings, but its nearly two decades of endemicity in the United States illustrates the gaps in the country’s mosquito abatement programs, and vulnerability to dengue, chikungunya, and now Zika.
Chikungunya exploded in 2006 across southern India and nations along the Indian Ocean from Madagascar to Sri Lanka. It was carried by both albopictus and aegypti, causing tens of thousands of cases of the self-limiting, flu-like ailment. Fortunately, chikungunya is rarely, if ever, fatal. But India suffered nearly 1.5 million cases of the disease in 2006, with an attack rate of 45 percent, affecting the economy due to medical costs and lost worker productivity. Like Zika, chikungunya is frequently misdiagnosed in areas that also have dengue. From 2007 to 2009, the virus spread across Asia and the Indian Ocean, reaching Singapore in 2008 and then Malaysia and Thailand. By 2010, the virus was endemic across southern Asia, carried primarily by the tiger mosquito.
Thanks to globalized trade, the tiger mosquito spread across the Pacific and reached Brazil via recycled tires in 1986. Worn-down tires from Malaysia, Thailand, and Singapore were loaded into ships, often during heavy rains. Water pooled inside the tires, where tiger mosquitoes laid their eggs. The larvae emerged as flying insects on arrival in Rio de Janeiro, Brazil, where the tires were off-loaded for rubber reprocessing. The albopictus thrived and spread, soon dominating mosquito niches from southern Argentina all the way to Central America and the Caribbean. During the 1997 El Niño climate event, the tiger mosquito took hold in Cuba, spawning an epidemic that sickened three thousand people, causing hemorrhagic fever in two hundred of them and killing twelve.
In late 2015, the record-breaking El Niño was wreaking havoc across South America, forcing evacuation of more than 150,000 people in Paraguay due to torrential downpours and flooding and causing a drought in northern Brazil. Much of Brazil has been hit by heavy rains, however, causing significant agricultural losses and prompting President Dilma Rousseff to declare emergencies after Christmas in the country’s southernmost states. The rains left more puddles, pools, and ponds for mosquito breeding, allowing both Aedes species to surge across the region. And all three diseases—dengue, chikungunya and Zika—are now prevalent. In the first quarter of 2015, Brazil suffered 460,000 cases of dengue,120,000 more than in the same period of 2014.
A new climate model predicts the aggressive tiger mosquito will greatly benefit from changes in rainfall and heat patterns: "From the climate projections for 2050, and adopting a habitat suitability index larger than 70 percent, we estimate that approximately 2.4 billion individuals in a land area of nearly 20 million square kilometers will potentially be exposed to Aedes albopictus." Moreover, albopictus will be more likely to spread disease and have a distinct competitive advantage over other mosquito species as it exploits new habitats.
Albopictus has taken hold on Hawaii’s Big Island, where it spawned a 2015 dengue outbreak that continues at this time, with more than 220 cases reported as of January 21. The tiger mosquito also emerged in Southern California during the 2015 summer, brought from Asia in U.S. Navy ships to San Diego, and has subsequently spread over much of the state.
In the absence of vaccines or treatments for the three diseases, public health officials are taking drastic steps to slow the epidemics. The CDC this week issued a warning to American women of child-bearing age, suggesting they not travel to countries that have Zika. The Brazilian government has warned women to avoid getting pregnant until the outbreak is controlled.
Perhaps the most extreme government action comes from El Salvador, which strongly advises women to delay pregnancy until 2018 due to Zika risks. Since 1988, it has been illegal to obtain an abortion in El Salvador, even in cases of rape, incest and danger to the mother’s life, prompting women’s health advocates to insist the law be revoked in cases of Zika infection. Under El Salvador’s laws, women are imprisoned for two to eight years if they undergo an abortion, all pregnancies that terminate before the fortieth week are investigated for possible murder prosecution, and health professionals that perform abortions face eight to twelve years of imprisonment.
For Brazil, the Zika crisis comes as the country is spiraling into economic and political disorder, the president faces threatened impeachment, and the nation hopes to impress the world as host of the 2016 Olympics in Rio. Desperate times call for desperate measures: the government is now considering release of genetically modified aegypti mosquitoes that die before reaching adult stage.
It is summertime in Brazil, with Carnivale season not far off. Perhaps the country’s greatest hope is that the chill of winter in June will drive the mosquitoes into dormancy during the July Olympics. The Brazilian government is concerned that the billions of dollars’ worth of tourism expected for the Rio2016 Olympics will be erased by global Zika panic. Some three million travel agencies worldwide have received letters from Rio, promising that there would be no Zika threat during the Games, thanks to aggressive mosquito control efforts. And the Ministry of Sports issued a memo that noted the Olympics commence on August 5, in the middle of Brazil’s winter when the mosquitoes are rarely seen, and "only a minor incidence of cases of dengue" are found nationwide.
The final word goes to Morens and Fauci:
"In our human-dominated world, urban crowding, constant international travel, and other human behaviors combined with human-caused microperturbations in ecologic balance can cause innumerable slumbering infectious agents to emerge unexpectedly. In response, we clearly need to up our game with broad and integrated research that expands understanding of the complex ecosystems in which agents of future pandemics are aggressively evolving."
As always, I will strive to keep you informed of major issues in global health.
Senior Fellow for Global Health
Council on Foreign Relations