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Wednesday, September 17, 2014

Ebola, population and evolution whip up a wicked recipe for disaster

The 1918 influenza pandemic infected one-fifth of the world's population. On an increasingly hot, overcrowded planet, could Ebola be our next global scourge? 
By Paul R. Ehrlich The Daily Climate

Editor's Note: "Climate at Your Doorstep" is an effort by The Daily Climate to highlight stories about climate change impacts happening now. Find more stories like this here.
Ebola gloves-768
Gloves and hospital garb worn by workers treating Ebola patients are set to dry. Some 4,200 people across West Africa have become infected since the first Ebola case was confirmed in Guinea earlier this year. Photo courtesy Jean-Luis Mosser/European Commission.
We have a problem with "emergent" diseases, ones that are becoming potentially serious to a larger and more vulnerable human population. Ebola and Marburg viruses, because of their high death rates, could become this generation's version of the flu pandemic that swept the globe at the end of World War I.

If it does, we have only to blame ourselves: Our degraded environment, our unchecked population growth, our nonchalance at global poverty, hunger and disease and our jet-setting ways.

The filoviruses are native to Africa and commonly infect non-human primates (don't eat chimpanzee meat) and some bats, which may be the main natural reservoir. The favorable conditions for transfer are directly related to human population size. The more people who come into contact with animal reservoirs and the more people who need "bushmeat," the higher the odds of a virus transferring into people. 


A global problem

Ebola beddingThose odds also are increased with the number of immune-compromised people. Today that number may be in the billions globally because of hunger, micronutrient deficiency and the prevalence of HIV/AIDS. 

Furthermore, the human population size necessary for a self-extinguishing disease to persist is another determinant of the potential for generating a pandemic. Needless to say, the existence of rapid global transport systems (especially airlines) certainly makes any infectious disease a global problem, regardless of where it first appeared among people. 

The Ebola epidemic has already involved 10 times as many people as any previous one; it has invaded Nigeria and is moving into urban areas, spreading fast. The more people infected, the higher the chance that its mode of transmission may evolve. If the virus evolves – and viruses have a nasty habit of doing so – to move in droplets, Homo sapiens could be in deep trouble. 

Other threats are the possibility that Ebola will evolve to live in new reservoirs, or that the reservoirs will evolve in response to climate disruption. Furthermore, virulence itself may evolve, especially in response to evolution in transmission. If Ebola evolves the ability to be carried by, say, mosquitoes, it might become even more virulent because immobile patients can easily be a source of virus spread. 

Need for preparedness

Ebola deathIn the current emergency, the world should mobilize rapidly to send medical aid to isolate and treat victims in Africa. 

Beyond that effort, the world community should put much more effort into preparedness; doing the biomedical research and building the infrastructure in vulnerable developing countries (stocks of drugs and protective gear, more isolation facilities, etc.) needed to guard against pandemics in general.

All nations should promote educational programs for medical doctors and the general public that give much more attention to the relatively neglected topics of demography and evolution and their connections to emergent diseases. People need to understand that the human system and the environmental system are totally intertwined and coevolving. 

Ever-changing interactions

Ebola meatThese ever-changing interactions are important not just from the viewpoint of pandemics. Population growth, for instance accelerates climate disruption, since the more people there are, the more greenhouse gases. 

That disruption can clobber agriculture; as billions more mouths to feed arrive. Climate-damaged food production presents a great threat to the nutritional security of our grandchildren as well as the ability of their immune systems to fight off infections such as Ebola.

Ignorance of basic evolutionary theory is a major source of humanity's insane and self-defeating patterns of antibiotic and pesticide use, which facilitate the evolution of resistance in pathogens and pests. 

The longer I watch the Ebola crisis unfold in Africa, the more I'm convinced H.G. Wells had it right when he said, "Human history becomes more and more a race between education and catastrophe."

Paul Ehrlich is president of the Center for Conservation Biology and the Bing Professor of Population Studies at Stanford University. 

The Daily Climate and its sister site, Environmental Health News, are independent, nonprofit news sites covering energy, the environment and climate change. Views expressed by the author are his own and not the opinion of The Daily Climate. Contact editor Douglas Fischer at dfischer [at] DailyClimate.org

A version of this story was published by the Millennium Alliance for Humanity and the Biosphere.

Photos of Ebola outbreak courtesy of the European Commission