Tag: infectious diseases

What Lessons Will We Learn From Zika?

By Carl Engelking | February 5, 2016 6:09 pm
A close-up view of an Aedes aegypti mosquito. (Credit: nuwatphoto/Shutterstock)

A close-up view of an Aedes aegypti mosquito. (Credit: nuwatphoto/Shutterstock)

Zika virus caught the world off guard, but it shouldn’t have.

The rapid spread of the mosquito-borne virus, and its possible connection to birth defects and neurological disorders, compelled the World Health Organization on Monday to declare an international public health emergency. But by that time 1.5 million Brazilians had already caught the virus, and it had spread to 24 countries in the Western Hemisphere. The current tally from the Centers for Disease Control and Prevention indicates 30 countries are now reporting active transmission.

“It seems like we are always behind,” says Jorge Osorio, a professor of infectious diseases at the University of Wisconsin-Madison. Osorio returned to the United States on Friday after a research stint in Colombia, where the total of confirmed Zika cases is second only to Brazil. “We knew it was a matter of time before this would happen.”

areas_with_zika

Countries and territories with active Zika virus transmission. (Credit: CDC/NCEZID/DVBD)

There’s no doubt that a rapid global response — like what’s currently underway — is needed, but Zika’s transformation from a sleeping virus to a global crisis is all too familiar. Since the 1970s, global re-emergence of mosquito-borne infectious diseases has only accelerated. In 2001, global cases of dengue fever skyrocketed. In 2004, chikungunya re-emerged in East Africa and spread worldwide. But with every new outbreak, a recurring flaw in the approach toward infectious disease control is exposed: We’re consistently reactive.

“It’s sort of human nature. We react to the thing that’s on fire, but we aren’t so good at prevention,” says David Katz, a certified board specialist in public health and founding director of Yale University’s Yale-Griffin Prevention Research Center. “We neglect the factors that produce emerging infectious disease, and in the blink of an eye we have a global crisis on our hands.”

A Period of Apathy

By the late 1960s humanity was winning its war with malaria, yellow fever, dengue and a host of other diseases. Proactive, aggressive eradication efforts eliminated the Aedes aegypti mosquito — the primary carrier of infectious diseases — in 23 countries. But our declaration of victory was specious.

Duane Gubler, a professor of emerging infectious diseases at Duke-NUS Medical School in Singapore, noted in a 2011 review that our comfort in victory kicked off a period of “increasing apathy and complacency” toward controlling infectious diseases. A new, more reactive paradigm of surveillance and emergency response was adopted for disease control, and resources shifted to other diseases.

reforestation_aedes_aegypti

A look at how Aedes aegypti populations rebounded in tropical Americas from 1930 to 2011. (Credit: Duane Gubler, “Dengue, Urbanization and Globalization: The Unholy Trinity of the 21st Century,” Tropical Medicine and Health, Vol. 39, No. 4 Supplement, 2011, pp. 3-11)

In the four decades that followed, unprecedented population growth occurred around the world, and more people converged in crowded urban centers. Mosquitoes that once spread diseases in remote, less-populated locales had millions more human hosts to bite and infect in confined areas. On top of that, advances in global transportation made the world smaller and further enhanced the ability of viruses to expand their reach. Today, a respond-to-an-emergency approach can’t keep up with the ability of viruses to mutate and spread.

“We live in a crisis-oriented society. But this has been going on for the better part of 40 years as we’ve seen these global pandemics of infectious diseases spread,” says Gubler. “We wait for them to occur.”

dengue

The emergence of the dengue in the Americas was associated with the introduction of new variations of the virus. (Credit: DengueNet 2007 data provisional via Duane Gubler, “Dengue, Urbanization and Globalization: The Unholy Trinity of the 21st Century,” Tropical Medicine and Health, Vol. 39, No. 4 Supplement, 2011, pp. 3-11)

Writing Was on the Wall

Infectious disease researchers could see Zika’s warning signs long before the outbreak captured headlines. The virus was isolated in 1947 from rhesus monkeys in Uganda. Only sporadic human Zika infections were reported since its initial discovery, and its clinical presentation didn’t sound alarms. Oftentimes, infected people wouldn’t know Zika was in their system. For that reason, the virus didn’t garner much attention or warrant funding for research.

“In the United States, research for all science and infectious diseases has been at historic lows, so to get funding for Zika virus, which wasn’t causing many infections, was nearly impossible,” says Matthew Aliota, a research scientist at the UW-Madison School of Veterinary Medicine.

It wasn’t until 2007 that a Zika epidemic swept through Yap Island in the Federated States of Micronesia. A larger epidemic followed in French Polynesia in 2013-14. In May 2015, the Pan American Health Organization issued an alert about the transmission of Zika virus in Brazil. And in July, Gubler sounded the warning in an issue of The Lancet.

Zika-virus

A transmission electron micrograph of Zika virus. (Credit: Cynthia Goldsmith/CDC)

“We essentially predicted this months ago, and said it would follow in the footsteps of chikungunya because it has the same epidemiology,” says Gubler. “Part of our problem is that we have a mentality of looking at these viruses, including a lot of virologists, as monolithic species. These viruses change genetically, and those changes affect expression.”

Today, a virus that was largely ignored is now affecting human health in ways we didn’t anticipate. In other words, a virus that’s lying dormant doesn’t make it less of a threat to world populations. And with half the world’s population living in areas susceptible to infectious diseases, a virus that’s gone quiet doesn’t mean it won’t come roaring back.

“Yellow fever is another virus that’s sitting in the wings. It still exists in West Africa, but it’s been relegated for the past 60 years,” says Gubler. “If, or when, it starts causing trouble, it will make all of these other outbreaks pale by comparison.”

Preventing the Next Outbreak

That’s why Gubler, Osorio, Katz and others advocate for going on the offensive to strike viruses before they spiral out of control — even benign viruses. With adequate resources, vaccine development could be accelerated. Mosquito populations could be kept in check. Researchers across scientific disciplines could collaborate to build ways to predict future hotspots for outbreaks and focus energies there.

“You need to rebuild public health infrastructure in endemic countries and develop the lab capacity to support a surveillance system to give you some predictive capability,” says Gubler.That requires investment, dedication and some bit of faith on the part of policymakers that this is money well spent.”

Osorio and Aliota are working in Colombia to build more accurate laboratory diagnoses of Zika, dengue and chikungunya. The other focus of their research is to track the way Zika and viruses like it evolve and adapt in their hosts. Their research has shown that Zika split into two distinct lineages, African and Asian. The strain they’re seeing in Colombia can be traced back to the strain that existed in the 2013-14 outbreak in French Polynesia. But their work has a larger aim: predicting how viruses will mutate to get ahead of the next outbreak.

“I’m trying to be more predictive using lab studies and experimental evolution in the lab to be more proactive,” says Aliota. “It’s idealistic thinking, but we’re working to predict the evolvability and adaptability of certain viruses.”

Building a more thorough global network of early detection centers around the world is also essential for pivoting to a proactive approach to infectious disease. Expanding the reach of organizations like the Global Virus Network, which is composed of research centers around the world that focus on viral causes of human disease to prepare for novel pandemic threats, could provide enough warning stay ahead. A robust, global virus detection system could operate similarly to the global array of earthquake-detecting instruments that give advance notice of a potential disaster.

“We must continue to create those centers around the world, and ensure they are funded and equipped with people who are well trained to do this,” says Osorio. “Early indication is important, and it gives us the ability to take measures right away.”

Interdisciplinary Approach

“We need to look at culture, epidemiology, economics and ecology at a local level and develop strategies from there,” says Gubler, who helped form the Partnership for Dengue Control, which brings health experts together to do that.

Overall, infectious disease researchers are pushing toward a more interdisciplinary approach to predict outbreaks. Jonathan Patz, director of the Global Health Institute at UW-Madison, is doing research to connect the dots between climate change and global health, offering a glimpse into the ways differing scientific fields can combine to build a proactive approach to mosquito-borne disease. His research has revealed a link between dramatic climactic shifts and the occurrence of viral outbreaks.

“Extreme drought conditions tend to drive the proliferation of Aedes aegypti. Epidemics of Zika, dengue and chikungunya have been preceded by drought,” says Patz. “This year, the el Nino event is looking like the strongest on record. During el Nino, northeastern brazil is generally affected with drought.”

55E7CDED-173F-48C2-8E9E-4841B65A13C0

NOAA declared 2015 as the world’s hottest year on record. In the same year northern Brazil, Colombia, parts of Venezuela, Peru and Ecuador experienced record heat.

Patz notes there are myriad other variables that shift weather patterns and the spread of disease. But, generally speaking, he is finding that drought is a contributing factor. Patz’s work reflects a larger shift toward looking beyond the infectious agent and building a broader recognition of factors that are in play. 

“It’s getting much better in terms of interdisciplinary focus,” says Aliota. “I never thought, when I first got into the hard sciences, that I would be talking to geographers, anthropologists and the other disciplines in my work.”

Of course, controlling the populations of A. aegypti, the source of the problem, is also a key area of research. Methods of population control, and wider access to mosquito nets and repellant in poor countries are essential. There’s also emerging interest in research to genetically modify mosquitoes. The research could limit their ability to breed — or wipe them out completely.

“Mosquito control has been left wanting for over 40 years, and that’s catching up with us,” says Gubler.

In It Together

If there’s any silver lining from the surge in outbreaks, it’s that it brings into sharp focus the sheer connectedness of humanity. Zika, dengue and chikungunya don’t respect political borders. Outbreaks are forcing us to break long-standing lines of division and embrace the fact that we are one species.

“Zika does not give a damn about whether you are Muslim, Jewish or Christian,” says Katz. “The world is small, and there is no ‘over there anymore.’ We’re all in the same petri dish. I think that shift in thinking is fundamental to our preparedness.”

CATEGORIZED UNDER: Health & Medicine, Top Posts

Ebola’s Possible Future as an Endemic Disease

By Kari Lydersen | January 19, 2015 11:36 am

Last fall as the Ebola epidemic continued unabated, experts started discussing something that had never before been bandied about: the idea of Ebola becoming endemic in parts of West Africa. Endemic diseases, like malaria and Lassa fever in that region of Africa, are constant presences. Instead of surfacing periodically, as it always has before now, Ebola in an endemic form would persist in the human population, at low levels of transmission, indefinitely.

The debate was stoked by a paper written by the World Health Organization (WHO) Ebola Response Team and published in October in the New England Journal of Medicine. The sentence that grabbed the world’s attention was saved till near the very end: “For the medium term, at least, we must therefore face the possibility that EVD [Ebola virus] will become endemic among the human population of West Africa, a prospect that has never previously been contemplated.”

What would it mean exactly for Ebola to become endemic, and how would it change things?

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Ebola Teams Need Better Cultural Understanding, Anthropologists Say

By Kari Lydersen | December 9, 2014 8:30 am

A defining feature of this Ebola epidemic has been the significant resistance of some of the affected communities to treatment and prevention measures by foreign aid workers and their own governments. Many local people, suspicious and fearful, have refused to go to treatment centers or turn over bodies for safe burial, and whole communities have prohibited the entry of doctors and health teams.

As the months have gone by that resistance has been less reported upon, and there are signs that it may be lessening. In the Forest Region of Guinea, where the Ebola epidemic started, foreign staff previously faced roadblocks, stone-throwing and violent attacks. But in the last few weeks, as the New York Times has reported, locals have opened up the literal and figurative barricades around their villages and sought outside help.

Still, the friction continues to shape the spread of the disease. Doctors Without Borders’ December briefing paper [pdf] calls the situation in Guinea “alarming,” with 25 percent more cases reported in November than October and many areas where there is “still a great deal of resistance towards Ebola response” and their teams are “not welcome.”

The solution, some say, is to reevaluate treatment and prevention tactics with the benefit of an anthropological perspective. That was the call delivered last week by a meeting of the American Anthropological Association in Washington D.C. If international staff had approached the epidemic from day one with more understanding of cultural, historical and political context, attendees said, local traditions and community leaders could have become assets rather than obstacles in the fight against Ebola.

The American Anthropological Association is asking for anthropologists to become more involved in the global Ebola response. They have started the Ebola Emergency Response Initiative to connect anthropologists who are already working in or experienced with West Africa, and to build structures and programs that help more anthropologists spend time directly involved in the Ebola response on the ground.

“We’ve worked in these places and we’re watching our friends die,” said University of Florida professor Sharon Abramowitz, one of the founders of the initiative.

Abramowitz points out that the anthropologists involved in the initiative have a total of 300 years of ethnographic experience in the affected West African nations – experience which could help medical scientists both understand and respond to the epidemic.

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CATEGORIZED UNDER: Health & Medicine, Top Posts

To Halt Ebola’s Spread, Researchers Race for Data

By Kari Lydersen | November 28, 2014 10:32 am
At a burial in Freetown, Sierra Leone, on Nov. 19, a member of the burial team struggles to regain his footing. Photo by Nikki Kahn/The Washington Post

An Ebola victim’s burial in Freetown, Sierra Leone, on Nov. 19. Nikki Kahn/The Washington Post/Getty Images

The Ebola virus has consistently stayed several steps ahead of doctors, public officials and others trying to fight the epidemic. Throughout the first half of 2014, it spread quickly as international and even local leaders failed to recognize the severity of the situation. In recent weeks, with international response in high gear, the virus has thrown more curve balls.

The spread has significantly slowed in Liberia and beds for Ebola patients are empty even as the U.S. is building multiple treatment centers there. Meanwhile the epidemic has escalated greatly in Sierra Leone, which has a serious dearth of treatment centers. And in Mali, where an incursion was successfully contained in October, a rash of new cases has spread from an infected imam.

Predicting the trajectory of Ebola rather than playing catching-up could do much to help prevent and contain the disease. Some experts have called for prioritizing mobile treatment units that can be quickly relocated to the spots most needed. Figuring out where Ebola is likely to strike next or finding emerging hot spots early on would be key to the placement of these treatment centers.

But such modeling requires data, and lots of it.  And for stressed healthcare workers on the ground and government and non-profit agencies scrambling to combat a raging epidemic, collecting and disseminating data is often not a high priority.

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Should Patients Be Given Experimental Ebola Drugs?

By David Warmflash | August 8, 2014 3:07 pm
An Ebola victim is buried by the Guinea Red Cross in May 2014. ©EC/ECHO/Jean-Louis Mosser

An Ebola victim is buried by the Guinea Red Cross in May 2014. ©EC/ECHO/Jean-Louis Mosser

Official response to the Ebola outbreak reached new heights today, as the World Health Organization declared the Ebola outbreak a Public Health Emergency of International Concern – a status that allows them to issue recommendations for travel restrictions. “We’re going to see death tolls in numbers that we can’t imagine now,” Ken Isaacs, a vice president at the NGO Samaritan’s Purse, told a congressional hearing yesterday.

The attention on Ebola, and the urgent need for solutions, has focused attention on experimental treatments waiting in the wings – and ignited an ethical debate about whether giving untested drugs to patients is the best course of action.

Tracking the Outbreak

Based on the most recent official reports, 1,712 people have been infected in the current outbreak. Nearly all of these cases have been in Sierra Leone, Liberia, and Guinea, but another West African country, Nigeria, reports 9 infected people, one of whom died after flying from Liberia. Also, Saudi Arabia reported a likely case after a Saudi man died following a trip to Sierra Leone. And now, the two infected Americans, both stricken with the virus while helping victims in affected areas, have been flown to Atlanta to receive treatment. This will be achieved under special quarantine conditions at Emory University Hospital, where their body fluids will be handled using biohazard level 4 laboratory precautions in which scientists wear outfits resembling spacesuits.

It’s got lots of the trappings of similar science fiction plotlines, such as TNT’s The Last Ship, the topic of my previous post. On that series a viral pandemic, whose symptom profile looks eerily similar to that of Ebola, has killed off 80 percent of humanity. The fictional virus has managed this because it’s 100 percent contagious, nearly 100 fatal, and because the fictional scientists and physicians on the series have insufficient knowledge of the virus and no way to treat or even slow the disease. Such extreme situations facilitate nail-biting drama.

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CATEGORIZED UNDER: Health & Medicine, Top Posts

How We’d Really Deal With the Pandemic in ‘The Last Ship’

By David Warmflash | July 17, 2014 11:36 am

THE-LAST-SHIP

A United States Navy Destroyer is sent to the Arctic and ordered to radio silence for four months. During that time, a mysterious virus – 100 percent fatal and 100 percent contagious – spreads from isolated pockets in Africa and Asia into a pandemic. When radio silence ends and the captain and his 217 crew finally learn what’s going on, 80 percent of the human population is either dead or dying, and all government control has collapsed.

Unrealistic? Perhaps. But this is the setting of the TNT hit series The Last Ship. While that fictional virus may indeed be too lethal and spread too rapidly to be realistic, one thing this nail-biting, apocalyptic story should scare us into doing is to respond faster to viral outbreaks than we’ve been able to do in the past. The real-life models for this are two coronaviruses: Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV).

First identified in humans in 2012, MERS-CoV has since caused 572 laboratory-confirmed infections, 173 of which have been fatal, and yet clinicians have no drug that targets the virus specifically. The same is true of SARS. Despite some initial, anecdotal reports suggesting that the drug ribavirin might work against this virus, and some modest success with interferon (which has a general inhibitory effect against many viruses), there is no specific anti-SARS agent.

So whether we’re talking about a virus in real life that’s killed hundreds, or the unnamed, fictional virus from The Last Ship that’s killed billions, global and national health organizations can respond via several strategies.

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CATEGORIZED UNDER: Health & Medicine, Top Posts

Information Wants to Be Free. What About Killer Information?

By Malcolm MacIver | December 27, 2011 1:52 pm

Malcolm MacIver is a bioengineer at Northwestern University who studies the neural and biomechanical basis of animal intelligence. He also consults for sci-fi films (e.g., Tron Legacy), and was the science advisor for the TV show Caprica

A few years ago, the world was aflame with fears about the virulent H5N1 avian flu, which infected several hundred people around the world and killed about 300 of them. The virus never acquired the ability to move between people, so it never became the pandemic we feared it might be. But recently virologists have discovered a way to mutate the bird flu virus that makes it more easily transmitted. The results were about to be published in Science and Nature when the U.S. government requested that the scientists and the journal withhold details of the method to make the virus. The journals have agreed to this request. Because the information being withheld is useful to many other scientists, access to the redacted paragraphs will be provided to researchers who pass a vetting process currently being established.

As a scientist, the idea of having any scientific work withheld is one that does not sit well. But then, I work mostly on “basic science,” which is science-speak for “unlikely to matter to anyone in the foreseeable future.” But in one area of work, my lab is developing new propulsion techniques for high-agility underwater robots and sensors that use weak electric fields to “see” in complete darkness or muddy water. This work, like a lot of engineering research, has the potential to be used in machines that harm people. I reassure myself of the morality of my efforts by the length of the chain of causation from my lab to such a device, which doesn’t seem much shorter than the chain for colleagues making better steels or more powerful engines. But having ruminated about my possible involvement with an Empire of Dark Knowledge, here’s my two cents about how to balance the right of free speech and academic freedom with dangerous consequences.

Consider the following thought experiment: suppose there really is a Big Red Button to launch the nukes, one in the U.S., and one in Russia, each currently restricted to their respective heads of government. Launching the nukes will surely result in the devastation of humanity. I’m running for president, and as part of my techno-libertarian ideology, I believe that “technology wants to be free” and I decide to put my money where my slogan is by providing every household in the U.S. with their very own Big Red Button (any resemblance to a real presidential candidate is purely accidental).

If you think this is a good idea, the rest of this post is unlikely to be of interest. But, if you agree that this is an extraordinarily bad idea, then let’s continue.

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