Abstract: Globally, infectious diseases are emerging at an increasing rate. Vector-borne diseases in particular present one of the biggest threats to public health globally. Many of these diseases are zoonotic, meaning they cycle in animal populations but can spillover to infect humans. As a result, risk to humans of acquiring a zoonotic or vector-borne disease largely depends on the distribution and abundance of the reservoir hosts—the species of animals that pathogens naturally infect—as well as of the vector species. The ecology of many reservoir hosts and vectors is rapidly changing due to global change, which will fundamentally alter human disease risk in as yet unforeseen ways. In this talk, I will present and discuss three lines of research aimed at identifying drivers of disease emergence and risk at multiple spatial scales including 1) the ecological and environmental drivers of Lyme disease in California, 2) the roles of human behavior and land use in driving human Lyme disease in the northeastern US, and 3) effects of deforestation, land use policy and socio-ecological feedbacks in driving malaria in the Brazilian Amazon.
About the Speaker: Andrew MacDonald is a disease ecologist and a National Science Foundation Postdoctoral Fellow in Biology at Stanford University. He received his PhD from the Department of Ecology, Evolution and Marine Biology at the University of California, Santa Barbara in September 2016. His dissertation focused on the effect of land use and environmental change on tick-borne disease risk in California and the northeastern US. His current work focuses on coupled natural-human system feedbacks and land use change as drivers of mosquito-borne disease, with a focus on malaria in the Amazon basin.
The health gap between rich and poor children in developing countires is staggeringly high, but Assistant Professor of Medicine Eran Bendavid found that it is shrinking. In his pilot project, "Empirical Evidence on Wealth Inequality and Health in Developing Countries," Bendavid discovered that since the mid-2000s, life expectancies for children under five are starting to converge. How can we continue to close the gap? Watch to find out.
Consider the lowly worm. For some, it’s just a garden pest. But for more than a billion people in the developing world, parasitic worms can be a pernicious threat, causing disease, disability and sometimes death.
In a newly published perspective in the medical journal The Lancet, Stanford researchers, including Stanford Health Policy's Eran Bendavid and a host of distinguished colleagues, urge the World Health Organization to develop sweeping new guidelines to help end parasitic worm diseases, one of the world’s most prevalent health problems. They call for greatly expanded treatment of these diseases, which could save years of human suffering and an estimated $3 billion in lost productivity — similar to the impact of the Ebola and Zika epidemics of recent years, they say.
“Now everyone is coming together to say, ‘Now is the time, after more than a decade of new experience and data, to update the way we do things,’ said Nathan Lo, a Stanford MD/PhD candidate who is the first author of the commentary. “There is so much opportunity, whether it’s expanding treatment from children to the entire community or bringing in other strategies, such as sanitation, to strengthen the way we approach these diseases.”
The perspective is published today in Lancet Infectious Diseases and coincides with a WHO meeting in Geneva where officials, including many of the authors, are gathering to consider new treatment guidelines.
The U.S. Preventive Services Task Force now recommends adults ages 40 to 75 with no history of heart disease — but who nevertheless have at least one risk factor and an elevated risk of cardiovascular disease — take a low- to moderate-dose statin.
The independent panel of experts in prevention and evidence-based medicine issued the recommendation in the Nov. 15 issue of JAMA.
An estimated 505,000 adults died of coronary heart and cerebrovascular disease in 2011. The prevalence of heart disease increases with, ranging from about 7 percent in adults ages 45-64 to 20 percent in those 65 and older. It is somewhat higher in men than in women.
We ask Owens some questions about the new guideline:
Q: What prompted this new recommendation by the task force?
Owens: Cardiovascular disease is the leading cause of death in the United States, accounting for 1 in 3 deaths among adults due to heart attack and stroke. And statins can provide an important benefit to people at elevated risk of cardiovascular disease. But in order to know whether statins are going to be beneficial, it’s important to know something about the patient’s cardiovascular risk.
We reviewed the literature comprehensively — including 19 randomized clinical trials involving more than 73,340 patients, as well as additional observational studies — to understand both the benefits and the harms of statins. We concluded that the benefits outweigh the harms in appropriate patients at increased risk of cardiovascular disease. The primary benefit of statins is a reduction in your chance of having a heart attack or stroke.
Q: What are statins and why do they offer such benefit?
Owens: A statin is a drug that reduces the production of cholesterol by the liver. High cholesterol is a significant risk factor for cardiovascular disease and stroke, and statins help prevent the formation of the so-called bad cholesterol. Statin drugs also help lower triglycerides, or blood fats, and raise the so-called good cholesterol, HDL.
While there are some reported side effects from the use of statins, such as muscle and joint aches, most people tolerate statins fairly well. There is mixed evidence about whether statins may result in a modest increase in the chance of diabetes, but the task force assessed the benefits to clearly outweigh harms in patients at increased risk of cardiovascular disease.
Q: Who should be taking low- to moderate-dose statins?
Owens: The task force recommends that clinicians offer statins to adults who are 40 to 75 years old and have at least one existing cardiovascular disease risk, such as diabetes, hypertension, high cholesterol or smoking. They also must have a calculated risk of 10 percent or more that they will experience a heart attack or stroke in the next decade.
The task force recommends clinicians use the American College of Cardiology/American Heart Association risk calculator to estimate cardiovascular risk because it provides gender- and race-specific estimates of heart disease and stroke.
For people with a risk of 7.5 to 10 percent of heart attack or stroke over the next decade, the task force recommends individual decision-making, as the benefits of statins are less in this age group because these people have a lower baseline risk of having a cardiovascular event.
The task force also looked at the initiation of statins in people 75 or older and found there wasn’t enough evidence to determine whether people in this age group who have not previously been on a statin would benefit from starting a statin. So the task force suggests people in this age group consult their physicians about whether a statin may be beneficial.
Q: Do these new statin guidelines override the task force recommendation in 2008 that adults be screened for lipid disorders due to high cholesterol?
Owens: Yes, this recommendation replaces the 2008 recommendation on screening for lipid disorders in adults.
The accumulating evidence on the role of statins in preventing heart disease has now led the task force to reframe its main clinical question from “Who should be screened for dyslipidemia?” to “Which population should be prescribed statin therapy?”
We recommend that physicians go beyond screening for elevated lipid levels and assess the overall cardiovascular risk to identify adults ages 40 to 75 years who will benefit most from statin use.
Q: What does the task force hope to accomplish with the new recommendation?
Owens: We hope this guideline will help both clinicians and patients decide what their cardiovascular risk is and what steps they can take to reduce those risks, which include a healthy lifestyle, a healthy diet and exercise, and for appropriate patients at elevated risk for cardiovascular disease, potentially a statin.
We also hope to highlight areas that would benefit from additional research. Further research on the long-term harms of statin therapy, and on the balance of benefits and harms of statin use in adults 76 years and older, would be helpful in informing clinicians and patients.
As he explained during the recent Rosenkranz Prize Symposium, Stefano M. Bertozzi used this slogan to promote health reform in the Mexico City prison system. By encouraging inmates to step up and get themselves tested for HIV and other chronic illnesses, Bertozzi, dean and professor of health policy and management at the UC Berkeley School of Public Health, was able to decrease the spread of illnesses in Mexican prisons and the surrounding communities.
The Rosenkranz Prize Symposium celebrated research projects that—like Bertozzi’s—address the health care needs of the world’s most vulnerable populations. With support from the Rosenkranz Prize for Health Care Research in Developing Countries, Stanford scholars have stepped up to tackle health issues in regions in need.
Since 2010, the award has funded six young Stanford researchers who aim to improve health in developing countries. The symposium celebrated their achievements.
The award honors the work of Dr. George Rosenkranz who spent his career reducing health disparities around the globe. Rosenkranz, who was the first to synthesize cortisone and the active ingredient in the first oral contraceptive, also celebrated his 100th birthday at the symposium.
Producing research that will increase care for vulnerable populations globally is the ultimate goal of the Rosenkranz Prize.
Andrés Moreno-Estrada, the 2012 winner, has used the award to study genetics in Latin American and Caribbean populations, aiming to increase knowledge of potential genetic illnesses. He said, “The Rosenkranz Prize is a clear, important step forward to demonstrate that we can do cutting edge science in developing countries that is of international relevance.”
Other winners include Eran Bendavid, Sanjay Basu, Marcella Alsan, Jason Andrews and Ami Bhatt. Their projects range from the effect of AIDS relief efforts on health care delivery to the treatment of diabetes in India to low-cost diagnostic tools for regions lacking infrastructure.
“I can’t think of a better way to celebrate (my father’s) birthday than listening to the bright future of science,” said Ricardo T. Rosenkranz, son of Dr. George Rosenkranz and a prize donor. “We can’t wait to hear what the next Rosenkranz Prize winners tell us.”
Dr. George Rosenkranz celebrated his 100th birthday at the symposium. The first to synthesize cortisone as well as the active ingredient in the first oral contraceptive, Rosenkranz spent his life reducing health disparities around the globe.
Studying the microorganisms that live in our gut is a relatively new field, one that has only really taken off in the last decade. In fact, it is estimated that half of the microbes that live in and around our GI track have yet to be discovered.
“This means there is a huge amount of this dark matter within us,” said Ami S. Bhatt, an assistant professor of medicine and genetics who runs the Bhatt Lab at the Stanford School of Medicine. The lab is devoted to exploiting disease vulnerabilities by cataloguing the human microbiome, the trillions of microbes living in and on our bodies.
“I think if we fast-forward to the impact of some these findings in 10 years, we’re going to learn that modifying the microbiota is a potent way to modulate health,” Bhatt said. “Humans are not only made up of human cells, but are a complex mixture of human cells and the microbes that live within us and among us — and these microorganisms are as critical to our well-being as we are to theirs.”
Bhatt, along with key collaborators at the University of Witwatersrand in Johannesburg, and the INDEPTH research consortium, now intends to take this research to Africa.
The $100,000 prize is targeted at Stanford’s emerging researchers who are dedicated to improving health care in poorer parts of the world, but may lack the financial resources.
Bhatt, MD, PhD, intends to take the prize money to execute the first multi-country microbiome research project focused on non-communicable disease risk in Africa. The project intends to explore the relationship between the gut microbiome composition and body mass index (BMI) in patients who are either severely malnourished or obese.
“As a rapidly developing continent with extremes of resource access, Africa is simultaneously faced with challenges relating to the extremes of metabolic status,” Bhatt wrote in her Rosenkranz project proposal. The Bay Area native, who is also the director of global oncology at Stanford, came to the School of Medicine in 2014 to focus on how changes in the microbiome are associated with cancer.
In this new project, Bhatt and members of her lab will team up with colleagues in Africa, first in South Africa, and then in Ghana, Burkina Faso, and Kenya. They will leverage the infrastructure already in place at the INDEPTH Network of researchers, using an existing cohort of 12,000 patients at within those four countries. The patients have already consented to be involved in DNA testing and have given blood and urine specimens.
Identifying alterations of the microbiome that are associated with severe malnutrition or obesity could pave the way for interventions that may mitigate the severity or prevalence of these disorders, Bhatt said.
“These organisms are critical to our health in that they are in a delicate balance with one another and their human hosts,” she said. “Alterations in the microbiome are associated with various diseases — but have mostly been studied in Western populations. Unfortunately, little is known about the generalizability of these findings to low- and middle-income countries – where most of the world’s population lives.”
Bhatt said that as Africa rapidly continues to develop, the continent is simultaneous faced with challenges relating to extreme weight gain and loss. While the wealthy are facing obesity and its associated disease such as stroke, heart failure and diabetes, many people are still faced with issues related to food insecurity, hunger and malnutrition.
The research, she hopes, could lead to aggressive behavioral, dietary and lifestyle modifications targeted at maintaining healthy BMI in at-risk individuals.
Grant Miller, an associate professor of medicine and core faculty member at Stanford Health Policy who chaired the Rosenkranz Prize committee this year, believes Bhatt’s research could eventually break new ground.
“The entire Rosenkranz Prize selection committee was highly impressed with Ami and the innovation of her project,” Miller said. “Ami’s work on the human microbiome in the extremes of nutritional status in developing countries — including its potential link to obesity, an emerging challenge in low income countries — is potentially path-breaking.”
The award’s namesake, George Rosenkranz, first synthesized cortisone in 1951, and later progestin, the active ingredient in oral birth control pills. He went on to establish the Mexican National Institute for Genomic Medicine, and his family created the Rosenkranz Prize in 2009.
The award embodies Dr. Rosenkranz’s belief that young scientists hold the curiosity and drive necessary to find alternative solutions to longstanding health-care dilemmas.
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Ami S. Bhatt with Ricky Rosenkranz (Stanford '85, son of George Rosenkranz) celebrate her winning the 2016 Rosenkranz Prize for emerging research in the developing world. The prize will help Bhatt launch a microbiome research project in Africa.
Could out of pocket drug costs be responsible for pandemics? In this Public Health Perspectives article, Marcella Alsan discusses how copayments for antibiotics can cause people in poor areas to turn to unregulated markets.
On May 26, 2016, researchers at the Walter Reed National Military Medical Center reported the first case of what they called a “truly pan-drug resistant bacteria.” By now, the story has been well-covered in the media: a month earlier, a 49 year old woman walked into a clinic in Pennsylvania with what seemed to be a urinary tract infection. But tests revealed something far scarier—both for her and public health officials. The strain of E. Coli that infiltrated her body has a gene that makes it bulletproof to colistin, the so-called last resort antibiotic.
Most have pinned the blame for the impending doom of a “post-antibiotic world” on the overuse of antibiotics and a lack of new ones in the development pipeline. But there’s another superbug incubator that hasn’t gotten the attention it deserves: poverty.
Last month at the IMF meeting in Washington, D.C., UK Chancellor George Osborne warned about the potentially devastating human and economic cost of antimicrobial resistance. He called for “the world’s governments and industry leaders to work together in radical new ways.” But Gerry Bloom, a physician and economist at the Institute for Development Studies, argued that any measures to stop overuse and concoct new drugs must be “complemented by investments in measures to ensure universal access to effective antibiotic treatment of common infections.”
“In many countries, poor people obtain these drugs in unregulated markets,” Bloom said. “They often take a partial course and the products may be sub-standard. This increases the risk of resistance.”
For at least fifteen years, we’ve known about these socioeconomic origins of antimicrobial resistance. Other studies have revealed problems with mislabeled or expired or counterfeit drugs. But the clearest link between poverty and the rise of antimicrobial resistance is that poor people may not see a qualified health care provider or complete a course of quality antibiotics. Instead, they might turn to unregulated markets for substandard drugs.
But why do people resort to unregulated markets or take drugs that aren’t that great if they are available? Marcella Alsan, an assistant professor of medicine at the Stanford School of Medicine who studies the relationship between socioeconomic disparities and infectious diseases, led a study that answered this question. In last October’s Lancet Infectious Diseases, Alsan and her colleagues showed that it might have a lot to do with requiring copayments in the public sector. To show this, they analyzed the WHO’s 2014 Antibacterial Resistance Global Surveillance report with an eye toward the usual suspects, such as antibiotic consumption and antibiotic-flooded livestock.
Stanford University's Asian Liver Center (ALC) and the Global Business Group on Health jointly hosted the inaugural JoinJade for China Summit and Awards Ceremony at SCPKU on April 22, 2016. 29 major employers committed to a hepatitis B discrimination-free work environment were recognized at the event. Lenovo, General Electric and IBM also participated in an employer panel to discuss key strategies for a discrimination-free work environment and next steps.
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JoinJade for China is a joint initiative involving global organizations including the ALC in the U.S. and China, Global Business Group on Health, IBM, General Electric, Intel, Hewlett Packard Enterprise, and HP Inc. The initiative focuses on building fully inclusive workplaces free from hepatitis B discrimination.
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The ALC at Stanford University is the first non-profit organization in the U.S. that addresses the disproportionately high rates of chronic hepatitis B infection and liver cancer in Asians and Asian Americans. Founded in 1996, the center addresses the gap in the fight against hepatitis B through a four-pronged approach of collaboration, advocacy, research, and education and outreach (CARE). The ultimate goal of the ALC is to eliminate the transmission and stigma of hepatitis B and reduce deaths from liver cancer and liver disease caused by chronic hepatitis B.
Photos courtesy of Stanford University's Asian Liver Center
The threat of a pandemic claiming millions of lives and devastating economies around the world is as serious as the potential perils of global climate change, renowned economist Larry Summers told a Stanford audience during a recent visit to campus.
The world is taking dramatic and costly steps to prevent the calamitous impact of climate change on the economies and national security of most countries. Yet preparations for a worldwide pandemic on the scale of the 1918 flu are vastly underfunded and ill-formed.
“My biggest fear is that the world is way short of focus on all the issues associated with pandemic,” said Summers, former treasury secretary in the Clinton administration and Harvard president emeritus, who in recent years has focused on the economics of global health care.
“We are talking about something that could kill surely tens of millions and perhaps 100 million people, and the Stanford football program is substantially more expensive than the WHO budget for pandemic flu,” he said. “It’s just crazy that we are so underinvested and underprepared.”
Summers, the Charles W. Eliot University Professor at Harvard, also served as director of the White House National Economic Council in the Obama administration. He was in conversation with Stanford Health Policy’sPaul Wise for the March 8 event co-sponsored by the Stanford Institute of Economic Policy Research for faculty and students.
The World Health Organization budget for outbreaks and crisis response has been reduced by nearly 50 percent from 2012 to 2015. Some global health experts blame these cuts in part for its slow response to the Ebola outbreak in West Africa and the ongoing Zika crisis in Brazil.
In Brazil, Zika has been linked to a spike in cases of microcephaly, a birth defect marked by small head size and underdeveloped brains. Brazil has confirmed more than 640 cases of microcephaly and is investigating an additional 4,200 suspected cases. Puerto Rico is now preparing for an expected outbreak there.
Summers said the mortality rate from the great flu pandemic was far greater than the recent Ebola outbreak in West Africa, which killed some 11,300 people mostly in Sierra Leone, Liberia and Guinea. Some 50 million people died worldwide during the 1918-1919 flu pandemic.
‘I don’t want to minimize in any way the significance of Ebola, but there are things to worry about that are vastly larger,” said Summers, who gave the keynote address for the January unveiling of the National Academy of Medicine’s report on global health risks.
That report by the Commission on a Global Health Risks Framework for the Future found that, compared with other major threats to global security, the world has “grossly underinvested” in efforts to prevent and prepare for the spread of infectious diseases. The commissioners — some 250 independent experts in health, governance and research and development — estimate $60 billion in annualized expected losses from pandemics.
“Pandemics cause devastation to human lives and livelihoods much as do wars, financial crises and climate change,” the report said. “Pandemic prevention and response, therefore, should be treated as an essential tenet of both national and global security — not just a matter of health.”
Summers estimates that pandemic flu risk is in the same range of global climate change in terms of expected costs over the next century. Yet a potential pandemic is getting only 2 percent of the attention and resources that global climate change has today.
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Summers also chaired the Lancet Commission on Investing in Health, an independent group of 25 leading economists and global health experts from around the world. Their landmark report, Global Health 2035, provides a specific roadmap for this achieving “a grand convergence” in health within our lifetimes. Ahead of the U.N. General Assembly last fall, Summers led a joint declaration together with economists from 44 countries calling on world leaders to prioritize investments in health.
Wise, in the Department of Pediatrics at Stanford and senior fellow at the Freeman Spogli Institute for International Studies, asked Summers how one plans for pandemics when faced with so many failed governments and conflicts around the world.
“One of the central challenges that I worry about a lot in the deliberations of pandemic control is that many of the (regions) of greatest concern are characterized by chronic political instability, conflict and very weak governance,” said Wise, who for more than 30 years has been traveling to rural Guatemala to provide medical care to children there for his Children in Crisis project.
Summers said the world has been fortunate that there are so many brave and devoted medical workers who are trained to go into these conflict regions to try and contain outbreaks.
“But I think it would be disingenuous of me to say that you can solve these problems without in some way containing the failed state,” he said.
Wise then asked Summers what sort of advice he would give to the Stanford students who were trying to decide between a career in which one might use economics to make a fortune on Wall Street, or use economics for the greater good.
“I have always believed that you can count — and you can care,” Summers said. “There is nothing about counting and using numbers and analyzing the math that means you don’t care in a moral way.”
When a physician works with a patient and saves her life, he said, that has a profound and direct impact on both the patient and physician. But working on a vaccination program that has the potential of saving thousands of lives one day comes with delayed gratification.
“But the impact of making the world a better place and enabling people to survive and avoid grieving the loss of of a family member is as great — or greater,” he said.
