Stanford University

Health and the Environment

The changing landscape of infectious diseases and its effects on human health

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Abstract: Concerns are mounting that changes in climate, land use, species invasions, and connectivity are changing the global landscape of infectious diseases. Ecological complexity makes these anthropogenic effects on infectious disease difficult to predict. Using data-driven mathematical models, I will show how mosquito-transmitted diseases such as malaria, dengue, and chikungunya may shift with changing climate. I will then discuss sources of uncertainty and how ecological understanding can help to mitigate future shifts in disease risk. Finally, I will introduce the new Center for Disease Ecology, Health, and Development based at Stanford University, which will work to improve human health and well-being through ecological solutions to infectious disease.

About the Speaker: Erin Mordecai has been an Assistant Professor in Biology at Stanford University since January 2015. Her research focuses on the ecology and evolution of infectious diseases in humans and natural systems, and in particular how infectious diseases respond to global change. She graduated from the University of Georgia in 2007 and received her PhD at the University of California Santa Barbara in 2012. She then completed an NSF Postdoctoral Research Fellowship in Biology at the University of North Carolina at Chapel Hill and North Carolina State University. 

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Erin Mordecai Assistant Professor in Biology Stanford University
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Stanford students craft ways to combat big tobacco

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Clifton Parker
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For Matthew Kohrman and his students, the war against tobacco needs a new communications strategy.

After all, he noted, three times as many cigarettes are currently manufactured and sold worldwide than were in the 1960s. And the global cigarette industry is the greatest cause of preventable death on the planet today.

That’s why the Stanford associate professor of anthropology decided to teach an introductory seminar this spring, Anthro 182N, titled Smoke and Mirrors in Global Health. Kohrman led his 10 students on a journey into the “strange optics” that the global tobacco industry uses – and what to do about them.

As noted in the syllabus, “entrenched challenges” to global health require society to develop “new methods” to communicate the real truth about tobacco.

Just what are those “new methods?” At the culmination of the class, the students presented some variations on that theme. Their end-of-the-quarter projects were web-based efforts profiling various features of global tobacco. They included exposés on how academicians in China assist the industry in that country, humorous parodies and critiques of Philip Morris, and flawed approaches to tobacco control in South Korea.

They tackled big-picture questions, Kohrman said. For example, they asked what exactly constitutes cigarette manufacturing and how new strategies could help slow the spread of tobacco-related diseases worldwide.

Kohrman, the director of Stanford’s Cigarette Citadels project, envisioned his class as a way for students to offer some thought-provoking and original ideas grounded in solid data. After viewing the student projects, he was astounded – and proud.

“My overall impression has been a feeling of awe,” he said. “Mostly freshmen and sophomores, the students who enrolled in this new course quickly synthesized complex intellectual concepts introduced early in the quarter, conceived their own innovative project ideas, collected relevant data, generously worked with each other, designed apt strategies for evocatively visualizing their messages, and chose and implemented strong interactive media tools – most of which were utterly new to me.”

One of those students was Minkee Sohn, a communication major, who created a video, “Fresh Recruits,” to highlight what he believes is the hypocrisy in the language of some cigarette manufacturers’ recruitment efforts.

“While cigarette manufacturers,” Sohn said, “often frame smoking as an act of free choice, that choice is just an illusion. Free choice is denied to people in all stages of cigarette manufacturing and consumption.”

For example, he explained that children in the African country of Malawi are coerced to work with their families in tobacco fields. “It’s deeply disturbing to hear companies associate freedom with high-paying jobs in cigarette manufacturing.”

For biology major Annabel Chen, the most important thing she learned was to analyze information skeptically. “Industries like big tobacco have influences in unexpected places, so you always need to do sleuthing to find out the truth,” she said.

She chose to examine the links between tobacco and academic research in China. “Seeing as China is the biggest tobacco market in the world, this was a problem we needed to address.”

Kohrman appreciates how students like Sohn and Chen were willing to try an experimental course, never taught before, and which for many was outside of their comfort zone. He said the course will be taught again in 2015-16.

“Looking back, it was the perfect-size group for all the work and one-on-one teaching we did,” he said.

The course was a classic collaboration, according to Kohrman, who also credits Claudia Engel, a lecturer in the Anthropology Department who helped with the technology and his own experiences mentoring undergraduate research, all of which proved instrumental to designing Smoke and Mirrors in Global Health.

“It was a great success today,” he said after seeing the student projects on the last day of class. Tom Glynn, a top adviser to the American Cancer Society, was on hand to see the presentations.

Kohrman added, “Students got tremendous feedback, and there was lots of enthusiasm about how this experimental course unfolded.”

Clifton Parker is a writer for the Stanford News Service.

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Income Shocks and HIV in Africa

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We examine how variation in local economic conditions has shaped the AIDS epidemic in Africa. Using data from over 200,000 individuals across 19 countries, we match biomarker data on individuals' serostatus to information on local rainfall shocks, a large source of income variation for rural households. We estimate infection rates in HIV-endemic rural areas increase by 11% for every recent drought, an effect that is statistically and economically significant. Income shocks explain up to 20% of variation in HIV prevalence across African countries, suggesting existing approaches to HIV prevention could be bolstered by helping households manage income risk better.

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Marshall Burke
Marshall Burke
Erick Gong
Kelly Jones
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Drought increases the spread of HIV in Africa

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Bad weather in sub-Saharan Africa increases the spread of HIV, according to a study published in the June 2015 issue of the Economic Journal, co-authored by Stanford professor and FSE fellow Marshall Burke.

When the rains fail, farmers in rural areas often see their incomes fall dramatically and will try to make up for it however they can, including through sex work. Analysing data on more than 200,000 individuals across 19 African countries, the research team finds that by changing sexual behaviour, a year of very low rainfall can increase local infection rates by more than 10%.

The results have important policy implications for fighting the spread of the epidemic, as co-author Erick Gong of Middlebury College notes:

‘Existing approaches to stopping the spread of HIV – such as promoting condom use and the use of anti-retrovirals – remain critically important. But our results suggest that other policy approaches could be very useful too – in particular, approaches that provide safety nets to rural households when the weather turns bad.’

Policies and investments seemingly unrelated to HIV – such as the promotion of rural insurance or household savings schemes, or the development of drought-tolerant crops – might have surprising benefits in slowing the HIV epidemic. Co-author Kelly Jones of the International Food Policy Research Institute says:

‘The HIV/AIDS epidemic remains one of the world’s greatest health challenges, with over a million new infections per year in Africa alone. Our results expand the menu of options for addressing the epidemic, and highlight some surprising options that are not at the forefront of people’s minds.’

The research sheds valuable light on why HIV continues to spread in Africa. Previous studies have documented in limited settings that poor women often alter their sexual behaviour in response to an income shortfall. But until now, there has been little evidence that this response is big enough to affect the trajectory of the HIV epidemic.

To fill this gap, the researchers combined data on the HIV status of thousands of people across sub-Saharan Africa with data on the recent rainfall history in each individual’s location.

Because years of low rainfall can lead to much lower incomes in these locations, particularly in rural areas where people depend more heavily on agriculture for their livelihoods, variation in rainfall provides a way to study how changes in local economic conditions affect infection rates. Co-author Marshall Burke comments:

‘We were surprised by how strong the relationship is between recent rainfall fluctuations and local infection rates. As expected, the relationship is much stronger in rural areas, and particularly for women who report working in agriculture. These are the people who really suffer when the rains fail, and who are forced to turn to more desperate measures to make ends meet.’

Notes for editors: ‘Income Shocks and HIV in Africa’ by Marshall Burke, Erick Gong and Kelly Jones is published in the June 2015 issue of the Economic Journal.

Marshall Burke is an assistant professor of Earth System Science at Stanford University. Erick Gong is an assistant professor of economics at Middlebury College. Kelly Jones is a research fellow at the International Food Policy Research Institute (IFPRI).

For further information: contact Marshall Burke on +1-650-736-8571 (email: mburke@stanford.edu); Erick Gong on +1-802-443-5553 (email: egong@middlebury.edu); Kelly Jones on +1-202-862-4641 (email: k.jones@cgiar.org); or Romesh Vaitilingam on +44-7768-661095 (email: romesh@vaitilingam.com; Twitter: @econromesh).

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Actinide Chemistry and the Battlefields of the Cold War

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Abstract: The Cold War rivalry between the United States and the Soviet Union lasted for much of the second half of the 20th Century. While the superpowers never engaged directly in full-scale armed combat, a nuclear arms race became the centerpiece of a doctrine of mutually assured destruction, and prompted a mass production of plutonium, and the designing, building, and testing of large numbers of nuclear weapons. In more than 50 years of operation, the Cold War battlefields created over 100 metric tons of plutonium, produced tens of thousands of nuclear warheads, oversaw more than 1000 detonations, and left behind a legacy of contaminated facilities, soils, and ground water.  

The extent of long-term adverse health effects will depend on the mobility of plutonium and other actinides in the environment and on our ability to develop cost-effective scientific methods of removing or isolating actinides from the environment. Studying the complex chemistry of plutonium and the actinides in the environment is one of the most important technological challenges, and one of the greatest scientific challenges in actinide science today.

I will summarize our current understanding of actinide chemistry in the environment, and how that understanding was used in the decontamination and decommissioning of the Rocky Flats Site, where plutonium triggers for U.S. nuclear weapons were manufactured. At Rocky Flats, synchrotron radiation measurements made at the Stanford Synchrotron Radiation Laboratory were developed into a science-­based decision-­making tool that saved billions of dollars by focusing Site-­directed efforts in the correct  areas, and aided the most extensive cleanup in the history of Superfund legislation to finish one year ahead of schedule, ultimately resulting in billions of dollars in taxpayer savings.

 

About the Speaker: David L. Clark received a B.S. in chemistry in 1982 from the University of Washington, and a Ph.D. in inorganic chemistry in 1986 from Indiana University. His thesis work received the American Chemical Society’s Nobel Laureate Signature Award for the best chemistry Ph.D. thesis in the United States. Clark was a postdoctoral fellow at the University of Oxford before joining Los Alamos National Laboratory as a J. Robert Oppenheimer Fellow in 1988. He became a Technical Staff Member in the Isotope and Nuclear Chemistry Division in 1989. Since then he has held various leadership positions at the Laboratory, including program management for nuclear weapons and Office of Science programs, and Director of the Glenn T. Seaborg Institute for Transactinium Science between 1997-2009. He has served the DOE as a technical advisor for environmental stewardship including the Rocky Flats cleanup and closure (1995-2005), closure of High Level Waste tanks at the Savannah River Site (2011), and as a technical advisor to the DOE High Level Waste Corporate Board (2009-2011). He is currently the Program Director for the National Security Education Center at Los Alamos, a Fellow of the American Association for the Advancement of Science, a Laboratory Fellow, and Leader of the Plutonium Science and Research Strategy for Los Alamos. His research interests are in the molecular and electronic structure of actinide materials, applications of synchrotron radiation to actinide science, behavior of actinide and fission products in the environment, and in the aging effects of nuclear weapons materials. He is an international authority on the chemistry and physics of plutonium, and has published over 150 peer-reviewed publications, encyclopedia and book chapters. 

Actinide Chemistry and The Battlefields of the Cold War
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David L. Clark Laboratory Fellow and Program Director, National Security Education Center, Speaker Los Alamos National Laboratory
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The Tropical Oil Crop Revolution: Food, Feed, Fuel, and Forests

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Over the last two decades global production of soybean and palm oil seeds have increased enormously. Because these tropically rainfed crops are used for food, cooking, animal feed, and biofuels, they have entered the agriculture, food, and energy chains of most nations despite their actual growth being increasingly concentrated in Southeast Asia and South America. The planting of these crops is controversial because they are sown on formerly forested lands, rely on large farmers and agribusiness rather than smallholders for their development, and supply export markets. The contrasts with the famed Green Revolution in rice and wheat of the 1960s through the 1980s are stark, as those irrigated crops were primarily grown by smallholders, depended upon public subsidies for cultivation, and served largely domestic sectors.  

The overall aim of the book is to provide a broad synthesis of the major supply and demand drivers of the rapid expansion of oil crops in the tropics; its economic, social, and environmental impacts; and the future outlook to 2050. After introducing the dramatic surge in oil crops, chapters provide a comparative perspective from different producing regions for two of the world's most important crops, oil palm and soybeans in the tropics. The following chapters examine the drivers of demand of vegetable oils for food, animal feed, and biodiesel and introduce the reader to price formation in vegetable oil markets and the role of trade in linking consumers across the world to distant producers in a handful of exporting countries. The remaining chapters review evidence on the economic, social, and environmental impacts of the oil crop revolution in the tropics. While both economic benefits and social and environmental costs have been huge, the outlook is for reduced trade-offs and more sustainable outcomes as the oil crop revolution slows and the global, national, and local communities converge on ways to better managed land use changes and land rights. 

Food, Feed, Fuel, and Forests
by Derek Byerlee, Walter P. Falcon, and Rosamond L. Naylor
will be published by Oxford University Press on November 10, 2016
$74.00 | 304 Pages | 9780190222987
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Can we feed the world in the 21st century?

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In a recent speech, Stanford professor Rosamond Naylor examined the wide range of challenges contributing to global food insecurity, which Naylor defined as a lack of plentiful, nutritious and affordable food. Naylor's lecture, titled "Feeding the World in the 21st Century," was part of the quarterly Earth Matters series sponsored by Stanford Continuing Studies and the Stanford School of Earth Sciences. Naylor, a professor of Environmental Earth System Science and director of the Center on Food Security and the Environment at Stanford, is also a professor (by courtesy) of Economics, and the William Wrigley Senior Fellow at the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.

"One billion people go to bed day in and day out with chronic hunger," said Naylor. The problem of food insecurity, she explained, goes far beyond food supply. "We produce enough calories, just with cereal crops alone, to feed everyone on the planet," she said. Rather, food insecurity arises from a complex and interactive set of factors including poverty, malnutrition, disease, conflict, poor governance and volatile prices. Food supply depends on limited natural resources including water and energy, and food accessibility depends on government policies about land rights, biofuels, and food subsidies. Often, said Naylor, food policies in one country can impact food security in other parts of the world. Solutions to global hunger must account for this complexity, and for the "evolving" nature of food security.

As an example of this evolution, Naylor pointed to the success of China and India in reducing hunger rates from 70 percent to 15 percent within a single generation. Economic growth was key, as was the "Green Revolution," a series of advances in plant breeding, irrigation and agricultural technology that led to a doubling of global cereal crop production between 1970 and 2010. But Naylor warned that the success of the Green Revolution can lead to complacency about present-day food security challenges. China, for example, sharply reduced hunger as it underwent rapid economic growth, but now faces what Naylor described as a "second food security challenge" of micronutrient deficiency. Anemia, which is caused by a lack of dietary iron and which Naylor said is common in many rural areas of China, can permanently damage children's cognitive development and school performance, and eventually impede a country’s economic growth.

Hunger knows no boundaries

Although hunger is more prevalent in the developing world, food insecurity knows no geographic boundaries, said Naylor. Every country, including wealthy economies like the United States, struggles with problems of food availability, access, and nutrition. "Rather than think of this as 'their problem' that we don't need to deal with, really it's our problem too," Naylor said.

She pointed out that one in five children in the United States is chronically hungry, and 50 million Americans receive government food assistance. Many more millions go to soup kitchens every night, she added. "We are in a precarious position with our own food security, with big implications for public health and educational attainment," Naylor said. A major paradox of the United States' food security challenge is that hunger increasingly coexists with obesity. For the poorest Americans, cheap food offers abundant calories but low nutritional value. To improve the health and food security of millions of Americans, "linking policy in a way that can enhance the incomes of the poorest is really important, and it's the hard part,” she said.” It's not easy to fix the inequality issue."

Success stories

When asked whether there were any "easy" decisions that the global community can agree to, Naylor responded, "What we need to do for a lot of these issues is pretty clear, but how we get after it is not always agreed upon." She added, "But I think we've seen quite a few success stories," including the growing research on climate resilient crops, new scientific tools such as plant genetics, improved modeling techniques for water and irrigation systems, and better knowledge about how to use fertilizer more efficiently. She also said that the growing body of agriculture-focused climate research was encouraging, and that Stanford is a leader on this front.

Naylor is the editor and co-author of The Evolving Sphere of Food Security, a new book from Oxford University Press. The book features a team of 19 faculty authors from 5 Stanford schools including Earth science, economics, law, engineering, medicine, political science, international relations, and biology. The all-Stanford lineup was intentional, Naylor said, because the university is committed to interdisciplinary research that addresses complex global issues like food security, and because "agriculture is incredibly dominated by policy, and Stanford has a long history of dealing with some of these policy elements. This is the glue that enables us to answer really challenging questions." 

 

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