The Ecological Footprint Challenge

Last year, I took a test. You might not think this is the best way to start a blog, but stay with me. The test I took is different. My students and I, during the One Health course I was co-teaching at Washington University in St. Louis, did a group activity and took a test. It was even “fun!” This test is one that everyone, including you, should take and that allows you to calculate your ecological footprint.

An Ecological What?

First, you may ask, “What is an ecological footprint?”  One definition for an ecological footprint is that it is a measure of the ecological assets (all those living species and non-living things that share the planet with us!) a given person or population requires if she/he/they are to continue living the same way as they are right now.

Earth Overshoot Day

In 2018, the estimated ecological footprint, based on the 7.6 billion humans alive that year, was 1.7 “Earths.” This resulted in Earth Overshoot Day 2018 to be on August 1st. In other words, by August 1, 2018, we humans used up the natural resources that were available to us, without damaging the planet or overdrawing on resources, when there were still 152 days remaining in the year. We overshot our resources. We borrowed 152 days from the next year. In fact, Earth Overshoot Day shows that humans use more from nature than could ever be replaced. In 1987, the first recorded Earth Overshoot Day was calculated to be December 19th. In other words, that year we had 12 days of 1987, from December 19th – 31st, when we were in overdraw of the Earth’s resources. The Earth simply could not keep up with the resources we were extracting. Since that first year of recording the timing of Earth Overshoot Day, the date keeps moving farther from December 31st. In 1987, it was calculated on December 19th, but in 2018 it was August 1st. By 2030, projections place Earth Overshoot Day on June 28th if we continue with “business as usual.” Not only is this not sustainable, it is also crazy!

However, as you may have guessed, not all of us are equal in the size of our ecological footprint. Calculations suggest that certain populations use far more than their share of the resources. That’s right you (probably) and me (for sure) use more than our share of Earth’s resources if we want to continue to have a planet habitable for humans and other living beings.  

What’s your Ecological Footprint?

Okay, back to you. Have you ever thought about your individual ecological footprint? When my class and I did it as a group, we came up with 6.2 Earths. When I did mine solo, I came out with 4.2 Earths. If everyone lived like me, we would need 4.2 Earths. I could not believe it. I live in a single car (Prius) family, I walk to work most days, I eat very little animal-based protein, and I gave up plastic straws long ago. It takes 4.2 Earths to keep me going. I wandered how many Earths it must take for just one Kardashian?

The beauty of calculating your own Earth Overshoot Day is that it can wake you up to the planetary cost of letting you … be you. Questions factored into the calculations include, but are not limited to: 1) How often do you eat animal based products? 2) How much of the food you eat is unprocessed, unpackaged or locally grown? 3) What is the size of your house? 4) Do you have electricity in your house? 4) How far td you travel each week by motorcycle or car? 5) How many hours do you fly each year? (This last one is the one that got me!)

I dare each of you to take this test.  If you have 5 to 15 minutes right now, the energy to think about your ecological footprint, and the desire to learn how to decrease this footprint, settle in and click on the link at

This one simply tool allows each of us to consider our ecological footprint and how we might decrease our individual footprint, from the easy to do things such as carpooling, non-fossil fuel based travel like bikes and legs, to recycling.  Then maybe it will stimulate each of us to see how we might help with the more challenging, but imperative, efforts for Planetary Health. We need to come up with the next technological advances in re-useable energies and sustainable food sources and environmental restoration mechanisms.   

Did you do it? Did you take the test? How many planets would we need if everybody lived like you? When is your personal Earth Overshoot Day? Mine was March 28th! Since I took the test, I have been working on ways to move my Earth Overshoot Day away from January 1st and closer to December 31st.    

Take the test! I guarantee it will have you thinking differently and more importantly, I hope acting differently.

7 Days at Alcedo Volcano

A second blog of our July 2018 trip of a lifetime. This one written and illustrated by trip photographer, Joshua Vela Fonesca. Joshua shares his artistic vision as the Galapagos Tortoise Movement Ecology Programme team (well - not the whole team. Steve and Anne were back on Santa Cruz Island!) works for tortoise conservation.

Joshua’s photography and words capture this magical week!


Find this month’s blog at

Science and Conservation at the Edge of a Volcano in Galapagos


In July 2017. I spent a week working and living on the edge of Alcedo Volcano on Isabela Island in the Galapagos. I could not have asked for a better team than my travel companions of Freddy Cabrera, Ainoa Nieto Claudin, Surya Castillo, Joshua Vela and José Haro. This trip was part of the larger Galapagos Tortoise Movement Ecology Programme as well as part of Dr. Ainoa Nieto Claudin’s PhD work.

Ainoa wrote a really nice blog that has been shared on the Charles Darwin Foundation and the Galapagos Conservation Trust websites. Ainoa did such a nice job on capturing the trip that I share her blog here as well.

Please find this month’s blog at

An Inconvenient Truth – Zoonotic Pathogens

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Animal to Human Pathogen Transmission

Most likely in the last year you have heard of at least one disease event caused by a  pathogen “spillover” from animals to humans. I would even venture if you have not heard of any zoonotic disease, you probably live in a bunker in Indiana. Coverage of these disease events has increased greatly in recent years as the frequency and types of human and animal intersections continue to escalate. Zoonotic diseases—those infectious diseases shared between human and non-human animals—are often significant and costly, in both the loss of human lives and impacts to the global economy. There are so many zoonoses that I could spend the rest of this blog playing “name that zoonotic disease” as I write out the 1,600 or so diseases that humans share with animals: many of which are emerging within human populations.

I might start the list with diseases like avian influenza and swine flu. Then I could mention the zoonotic viruses Ebola and monkeypox. These two viruses are extremely important, but for some reason feel exotic to people in the United States, even though people have tested positive to both while on US soil. One person even died of Ebola in a hospital in Texas in 2014. I might then list the oldest known zoonotic disease—rabies—and consider the fear it instills with the recent reminder following the tragic rabies related death of a child in Florida. Other zoonoses on the list may include West Nile virus, Sudden Acute Respiratory Syndrome (SARS), Middle Eastern Respiratory Syndrome (MERS), Zika virus, Q fever, and toxoplasmosis. The list would go on and on. In our globally connected world, any one of these diseases could show up anywhere on the planet, from Alabama to Zimbabwe. The often-cited statistics that 75% of human emerging infectious diseases (EIDs) are zoonotic and that 70% of these have a wildlife reservoir should be of interest to anyone that cares about human health. But, what about the other side of the equation? Do animals get infected with pathogens transmitted from people?

Human to Animal Pathogen Transmission

The simple answer is yes. Humans can and do transmit pathogens to non-human animals. Some call these diseases anthropozoonoses to reflect the human (anthro) to animal (zoonosis) direction of the transmission. However, I am much more comfortable to call these diseases zoonoses. The term zoonotic should include the diseases from non-human animals to humans AND from humans to non-human animals. Zoonoses may be bi-directional. However, even with all the current news on human EIDs and their zoonotic link, we rarely hear about pathogens that humans transmit to non-human animals.  

In a recent study ( ), we looked at the other side of the zoonoses equation and sought to determine if humans transmit pathogens to our great ape relatives. In the paper entitled “Pathogen Transmission From Humans to Great Apes is a Growing Threat to Primate Conservation” we provide data from a meta-analysis (a review!) of the scientific literature on great ape infectious diseases acquired from humans. We looked at great apes living in captivity, semi-free living conditions (such as great apes habituated for ecotourism) and free-living. We found 33 individual occurrences of probable or confirmed pathogen transmission from humans to great apes during the period 1964-2012. Occurrences were found in great apes in captive (n = 7), semi-free-living (n = 25), and free-living (n = 3) conditions, with two occurrences affecting populations in both semi-free-living and free living conditions. The majority of occurrences involved chimpanzees (Pan troglodytes) (n = 23) and mountain gorillas (Gorilla beringei beringei) (n = 8). This may reflect a larger amount of research with these species or possibly higher human to chimp and human to mountain gorilla contact.


One thing is for sure, these 33 events are just the tip of the iceberg since we know many disease events in great apes go undocumented and never reach the scientific literature. For example, I am personally aware of two zoonotic disease outbreaks: chickenpox from a keeper to gorillas in a zoo in the U.K. and polio in chimps at a zoo in the Republic of Congo. You will not find either of these events reported in the literature, but there is no doubt that both were caused by human to non-human great ape pathogen transmission. How many more stories like this are out there?


Six great ape species are endangered or critically endangered as determined by the International Union for the Conservation of Nature (IUCN). All six are experiencing decreasing population trends. (In fact, Homo sapiens [yes - us!] is the only species of the seven within the Hominidae family that is having population increases and is not endangered.) Our review shows that zoonotic pathogens transmitted from humans to our non-human Hominidae relatives may be a significant, but unappreciated, issue. We must work to better understand these zoonoses if we are to prevent human caused disease events from further threatening our closest living relatives.  

Work Cited

Dunay, E, Apakupakul, K, Leard, S, Palmer, JL, Deem, SL. 2018. Pathogen Transmission From Humans to Great Apes is a Growing Threat to Primate Conservation. EcoHealth. 1-15.

One Nation Under … Siege

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We are a nation under siege. Siege as “a prolonged period of misfortune” sums up the state of our Union today. We are indeed in a prolonged period of mass misfortune, which has only become worse since January 20, 2017, as the government chips away at health care access and women’s rights while sitting quietly on gun control. Refusing to begin a discussion on gun control is unfortunate on so many levels. 

Guns and Guitars

A shocking combination. (Image from )

A shocking combination. (Image from

You may think me naïve, but when the Guns and Guitars store front flashed onto my screen Monday following the Las Vegas massacre, I thought how odd that a store would sell guns and guitars. My confusion was mixed with the dread, horror and all but complete sense of hopelessness I felt in the face of the uncontrolled gun insanity that has crossed our land. Waking on October 2, 2017 to the news of the latest and greatest mass shooting in modern USA history did not feel unexpected. This news hit me in the same way as the news following the Columbine High School gun violence in 1999, Sandy Hook Elementary School killings in 2012, and the Pulse Nightclub slayings in 2016. Thoughts of sadness and rage and empathy all mixing together this week, just as they had following each of the countless other gun related murders in the US. The national heartache over the past week feels like déjà vu. Similar heartache to that which I felt after the shooting in 2007 at my Alma mater, Virginia Tech, even if the Va Tech violence felt a little more “personal”. All these gun tragedies were in one sense the same, while in so many other ways different; different for each of the victims and their families and friends. Similar in that they all may have been prevented if we could bring about common sense gun control.   

Living in the USA

I feel amazingly lucky to have been born in the USA and that I hold a United States of America passport. The places it has allowed me to travel and rights it has afforded me are a privilege. However, I am frankly shell shocked that so many of my fellow citizens cannot grasp the fact that we need change. This week I have been reading and re-reading the Amendments. They are mostly good, helpful and powerful for the people: this is especially true if considered in the context of what our country was like when the Bill of Rights came about.   

Of all the Amendments, the one that seems to have us stuck in a time warp is Amendment 2 - The Right to Bear Arms. Ratified in December 1791 this Amendment provides U.S. citizens the right to bear arms. The Amendment states, “A well-regulated Militia, being necessary to the security of a free state, the right of the people to keep and bear Arms, shall not be infringed.” Arms in 1791 might have looked something like this gun.  

Here is a Ketland Pistol. (Image from )

Here is a Ketland Pistol. (Image from

I am all for citizens of the US having rights and freedom. However, I question what we mean by freedom and rights. Do I have freedom from fear of being shot if I go into a school, stop next to someone at a traffic light, or enjoy myself at an outdoor concert? When does someone else's right impinge on my freedom? 

Bullets and Burgers  

For those seeking "The Ultimate Outdoor Machine Gun Experience" (Image from )

For those seeking "The Ultimate Outdoor Machine Gun Experience" (Image from

This week seeing Guns and Guitars reminded me of another commercial stop along the American road – Bullets and Burgers.  Famous for the incident in 2014 when a 9 year old girl accidentally killed her “instructor” at this restaurant/shooting range. This one gun mistake by a 9 year old ruined the instructor’s life and his family, as well as the girl’s life. 

I am happy for and appreciate my “inalienable rights” as a US citizen.  However, I have to believe that even the government officials who ratified the second Amendment in 1791 would see the world through different glasses—definitely through a different scope on their gun—today, and they too would realize it is time for change. 

This “gun thing” leaves me thinking of something Charles Darwin said a long time ago, “It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is most adaptable to change.”  America - it is time for change. 

Gun control = public health = One Health.

An Amazing Park and an Accident

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Three months ago today, I had an accident.  I would have rather of had a dream, but I had an accident.  Happily traveling along on my bike heading to work in Forest Park, St Louis, Missouri, I came to a standstill.  20 to 0 mph in a nanosecond.  The bike tumbled over 180 degrees, with my face the first body part to meet pavement.  The next 7 hours I spent drugged up in an ER getting ER type care.  Surgery days later to “fix” the shattered and lacerated nose and mouth.  In the intervening months, I have had lots of time to think about health across many scales: from the individual (me in this case!) to countries full of individuals; from humans to octopuses; and even from Earth to the Universe.   It also gave me plenty of time to contemplate why Forest Park and all urban parks matter. 

During these months, my thinking of health and parks was done out in the world, working on health projects in parks. First, I was at the Forest Park field site working with box turtles and snapping turtles and then in the Galapagos, studying giant tortoises (see for links to both these projects).   My doctor said, “You can heal in Missouri or you can heal in the Galapagos Islands.  Your choice.” (Yes, he is a very smart surgeon!)  Therefore, off to the Galapagos I went.  The past three months of contemplation of urban parks began within minutes of hitting the ground.  My first thought was ‘what the heck?’  The next thought was ‘where am I?’ It was this second thought to lead me on the path of pondering urban parks.         

No different to most accidents, I was within a mile of my house.  I was in a little known treasure in America, Forest Park in St. Louis, Missouri.  Forest Park is one of the largest, and dare I say best, urban parks in the USA at 1,293 acres with forests, fields, a Zoo (Best free attraction in America!), museums, golf courses, an outdoor theater or two, lakes, creeks and wildlife.  The wildlife in Forest Park alone is amazing.  There are birds, both resident and migratory, including the great horned owls of Mark the Owl Man fame (, amphibians, reptiles (all kinds of turtles), and mammals from the small to the not so small, with an occasional coyote or deer finding their way into the park.   Trust me when I say the best urban park in American claim is not something I take lightly as I grew up next to Rock Creek Park in DC and spent 5 years living near Central Park in NYC.  Forest Park is an urban gem surrounded by city. 

The park receives an estimated 13 million human visitors annually, which is not bad in a city of 316,000.  The Zoo alone gets roughly 3 million visitors a year.  At the Zoo, visitors may enjoy the natural world and learn to care for creatures with whom they share planet Earth, while improving their own health.  For example, zoo visits have been shown to improve human health both physiologically (lots of footsteps and lower blood pressure) and psychologically (increasing happiness and energy levels while decreasing tension).   If not a visit to the zoo, you may instead go to a museum for art, history or science, take a paddle boat out on the lake, walk the dog, take a stroll, smell a flower, or go bird watching.  The opportunities are endless, allowing one to reconnect to life and to, maybe just maybe, get a little healthier.  

That freaky accident on that beautiful May morning gave me the chance to spend time thinking about the value of urban parks, and the importance of these places for human, animal, and planetary health.  Urban parks help to minimize cities as heat sinks and areas of carbon dioxide build up.  A good thing for planetary health.  For animals, wildlife species increasingly rely on urban areas for survival, and parks may serve as safe havens for many species or stopover sites for migrating birds and other migrating animals.  As for humans, with more than 50% of us living in urban areas these oases of nature, in an increasingly urbanized world, may be what we need to remain sane and healthy in a world that often feels less than sane or healthy.  Parks might be just what the doctor ordered.  So get out into a park.  Remember though, if you are visiting on a bike, wear a helmet. 


Louv, R.  2011. The Nature Principle: Reconnecting with Nature in the Virtual Age.  Algonquin Books of Chapel Hill.  320 Pp.

Sakagami T., and Ohta M.  2010. The effect of visiting zoos on human health and quality of life. Animal Science Journal. 81: 129–134.

Sahrmann, J., Niedbalski, A., Bradshaw, L., Johnson, R.A., and Deem, S.L.  2016. Changes in Human Health Parameters Associated with a Touch Tank Experience at a Zoological Institution.  Zoo Biology. 35: 4-13.

Williams, F.  The Nature Fix: Why Nature Makes Us Happier, Healthier, and More Creative.  W.W. Norton & Company.  288 Pp.


Preventive Medicine for a Changing World

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Ecologists, veterinarians, and human medical professionals are recognizing infectious disease as an increasing threat to domestic animal, wildlife, human, and ecosystem health.  Although infectious diseases have always been a concern for human survival—data on human and animal disease pandemics date back centuries—it is only within the latter part of the twentieth century that the term Emerging Infectious Disease (EID) jumped into the daily discussions of ecological and health professionals.

An EID is any infectious disease that has newly appeared in a population or that is rapidly increasing in incidence or geographic range.  Examples of EIDs with impacts on species survival and/or human health include avian influenza, the coronaviruses - Sudden Acute Respiratory Syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS), and filoviruses in humans; fibropapillomatosis, chytridiomycosis, and canine distemper virus in wildlife; parvoviruses and feline immunodeficiency virus in domestic animals; and chestnut blight and sudden oak death in plants.  

Studies are now shedding light on these EIDs and the role that anthropogenic changes, from the 7.6 billion humans alive today, play in the emergence of so many diseases.  Humans are changing the Earth with landscape modifications, the over consumption of natural resources, pollution, and global trade and travel.  We are affecting planetary health.   Welcome to the Anthropocene!

There is hope

While the incidence of documented EIDs is increasing, so is the interest in the ecology of infectious diseases.  These studies are often driven by ecologists as they strive to include pathogens in the ecological equation.  Additionally, collaborative partnerships have emerged among ecologists, epidemiologists, veterinarians, medical doctors, and others.  These nascent relationships, impeded too often by traditional disciplinary thinking, must be nurtured and grown.  Only then will we be able to create the One Health Work Force needed to combat challenges of today.   

Although many view the medical community—veterinarians and human doctors—in the traditional “fire engine role” of “putting out the fire” (disease), this view of medicine is very limited, and so yesteryear.  It is true that animal, plant, and human medicine, including the field of EIDs, is rooted in this fire engine approach, which will remain an important weapon in combating disease.  However, the preventive medicine fields—public health, herd health and agricultural systems health— have been in place for centuries and provide critical data and comprehensive thinking, both of which will be vital as we work to become proactive in studying and managing disease on an ecological scale. 

Preventive medicine is the key.  For example, few (if any!) of us would be here today, to read this blog and contemplate disease ecology, had we not received proper nutrition, hygiene, and infectious and parasitic agent chemoprophylaxis, all important tools of preventive medicine.  Prevention may be at the individual or population level and is the ingredient necessary to perform holistic medicine for a changing world.

 Why the need for preventive medicine

Parasites and pathogens are an integral part of ecosystems.  The definition of ecology, the study of the relationship of organisms to their environment, includes all organisms - micro and macro.  However, the increased awareness of infectious disease in animals, humans, and plants, associated with these pathogens, provides us with an impetus for using ecological approaches to better anticipate and respond to emerging pathogens.

If preventive medicine is applied within these ecological studies, the outcome can only be an improvement in ecosystem health.  We accept agriculture health, human public health, and domestic animal health as proper areas of medical study and the benefits have been tremendous.  Ironically, preventive medicine success in these fields helped create our vast impact on ecosystems, which now demand a similar holistic and preventive approach. A managed care approach at the intersection of animals, humans and the planet will be necessary to ensure further survival of all species.  The planet is now the patient.

 How to apply preventive medicine

 As we endeavor to apply preventive medicine to the ecology of infectious diseases, four areas will require attention and activity: interdisciplinary collaboration, a combination of study designs, attitude shifts, and political activity. 

Interdisciplinary collaboration—among ecologists, epidemiologists, veterinarians, medical doctors, sociologists, and politicians—will be vital to ensuring a holistic, preventive medicine approach. Ecologists bring an understanding of whole systems—how the interactions among animals, humans and plants impact ecosystems.  Epidemiologists, in knowing the nature of EIDs and how they spread, can use data provided by ecologists to identify possible disease matrices—perhaps preventing trouble spots before they evolve.  Sociologists provide insight into how humans will respond to preventive measures and how societies have and will continue to impact the emergence of pathogens.  Of course, veterinary and human medical practitioners have diagnostic and preventive skills, both of which must be incorporated in order to mitigate EID impacts. 

As this integrative and holistic approach remains relatively new and in some ways uncharted, these different disciplines must create a common language—we must all mean the same thing when we use terms such as “pathogens”, “ecosystem”, and “disease”.  A slightly different shade in meaning creates confusion.  We can all learn from each other, generating a greater and more useful pool of knowledge. 

The design of future studies must be both retrospective and prospective.  We must gather more baseline data—ecological and epidemiological—in order to determine the nature of “normal’ pathogens in ecosystems.  Knowing how pathogens behave “normally” will help us better identify aberrations, perhaps linking them directly to anthropogenic change or even other, more nefarious motivations.  Collecting these baseline data has implications for future disease surveillance and international security. 

Prospective studies should be designed with preventive medicine in mind—helping us predict and prevent the next epidemic in plants, animals, and/or humans.  These studies cannot simply address the human medical implications of an EID; or the effect on a particular species of plant.  Our studies must be interdisciplinary, and need to look at EIDs from an ecological and preventive approach. 

Perhaps the most difficult areas of change will be a shift in human behavior and values.  Humans react to crises.  Most people must have a heart attack before admitting that their drinking, smoking or eating habits were truly detrimental.  Need an example? Human immunodeficiency virus became a worldwide killer before people undertook basic preventive measure.  In fact, some may argue that the recent interest in the ecology of infectious diseases is reactionary—that the world is in a current EID crisis.  If we are to be truly preventive, we must convince the public (and ourselves!) that reacting to an infectious disease pandemic, instead of preventing one, is bad medicine.   

Finally, change almost always requires political action.  In order to affect this political action, we must educate politicians on the potential impact of EIDs on their constituents and the regions over which they have jurisdiction.  The practitioners of infectious disease ecology must provide to politicians the data that demonstrate how EIDs impact ecosystems, and how preventive study is the best approach for the prediction, control and mitigation of these EIDs.  Practitioners of infectious disease ecology must become preventive medicine specialists.  We must understand the role and nature of pathogens in the whole ecosystem and use this understanding to apply preventive measures that may decrease the impact of these pathogens, without causing more harm than good. 

Similar to preventive measures used in animal, human, and plant medicine, these measures may include proper hygiene (e.g., decrease environmental pollutants), appropriate space (e.g., reducing high population densities), proper nutrition (e.g., protecting prey by controlling industrial fishing), and proper pathogen and parasite control (e.g., controlling the introduction of invasive species into naïve populations).

Final thoughts

It is an exciting time for the field of infectious disease ecology.  There is much to be discovered in this developing field and as such all of us should be motivated by new interdisciplinary team work.  Now is the time to apply preventive measures to mitigate the impacts of EIDs.  In the 1960s, Lovelock, Margulis, and others noted the planet was self regulating—in itself, “alive”.  Their theory, accepted by many and shunned by others, is widely known as Gaia, named after the Greek Goddess of the Earth.  They suggested that life on Earth was the creator and regulator of the atmosphere and charged that damage to the Earth, once done, was very difficult to undo.  This tenant is the perfect backbone of preventive medicine for a changing world: prevention is always easier than the cure.  Let’s be preventive medicine specialist as we strive to understand the ecology of infectious diseases while maintaining the health of Earth’s plants, animals, and people.