Biologist sheds light on geography of human diseases

If your home region has a hot, wet climate and lots of different kinds of birds and mammals, there’s a good chance it also contains numerous kinds of disease-causing pathogens.

A recent study examining the geography of human disease, led by N.C. State University’s Dr. Rob Dunn alongside an international team of biologists and social scientists, shows that one can predict the number of kinds of pathogens in a region just by knowing its climate or the number of birds and mammals found there.

Multiple things, Dunn says, might influence the diversity of pathogens in a region: human population size and density, the amount of time people have lived there or expenditures on disease control. Each of these undoubtedly has some influence, but the environment is dominant.

“We imagine that we have nature under control, but nobody seems to have told nature,” says Dunn, of the Department of Biology. “The environment and, in its broadest sense, nature determine the number of kinds of diseases in different regions of the world in much the way that it has influenced the number of kinds of birds, mammals, ants or bees.

“On the one hand, we are not very effective at altering the numbers of kinds of pathogens present, as those numbers are strongly correlated with environmental conditions. The vagaries of climate and life over which we have little control determine which diseases you are at risk of contracting in any given place,” Dunn says.

“But on the other hand, we can control the prevalence of pathogens by spending money on disease-control efforts. It is that prevalence that influences human health and well-being.”

– N.C. State University News Services