News Archive

posted 01/20/06

Contact: Jill Stoddard
212-854-6465 or jstoddard@ei.columbia.edu

Infectious Diseases Thriving as Human Population Grows

Chagas' 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. View full story.