disease now infects 16 to 18 million
people, and there are 1 to 3 million new cases a year. Image
Credit: Rockefeller University
Humans have provoked a lot of wobbling in the
global food web, and one result is the explosion of infectious
diseases.
“All of our infectious diseases are other
species making a living off of us,” says Joel
Cohen, a populations expert at both Columbia and Rockefeller
Universities. “Think of the thousands of bacteria in our
gut, the fungi on our skin, the insects that suck our blood, and
the diseases those insects inject.”
As a result, new microbes and viruses that prey
on humans, such as Ebola and HIV, are burgeoning around the world,
and old ones continue to thrive.
“Over the last 10,000 years, the number
of humans has increased about 1,000 fold, creating a lot more demand
on other species, and providing more available material,” says Cohen.
Of particular interest to Cohen is Chagas’ disease, caused
by an insect-borne parasite similar to the one responsible for
African sleeping sickness. Cohen’s mathematical model of
how the disease spreads has had public health implications for
millions of poor Latin Americans.
“The network of infectious disease is incredibly dynamic,” Cohen
says.
Because most species rely on other species for
their energy, or are consumed by other species in search of energy,
the species are all interconnected, forming a network known as
the food web.
Cohen himself has kept logs of the species of
food he eats, and over time it comes to about 150 different species
of plants and animals. Humans collectively consume tens
of thousands of other species. “That represents a lot of
energy, and a lot of diversity, coming in,” he says.
Cohen’s life work is to figure out the dynamics
and interactions between the 100 million or so interconnected species
on this planet.
The broad reach of his research has earned Cohen
not only entrance into expected societies, such as the U.S. National
Academy of Sciences, the American Academy of Arts and Sciences,
and the American Philosophical Society, but also onto the worldwide
Board of Governors of The Nature Conservancy.
Cohen is Abby
Rockefeller Mauzé Professor at Rockefeller University and
Professor of Populations at the Earth Institute at Columbia University.
In 2002, New York Mayor Michael R. Bloomberg
gave Cohen his Award for Excellence in Science and Technology.
This is an edited version of a Rockefeller
University article written by Renee Twombly.
