If your home region has a hot, wet climate and a lot of different kinds of birds and mammals living in it, there's a really good chance the region will also contain numerous kinds of pathogens that cause human diseases.
A new study examining the geography of human disease, led by Dr. Rob Dunn at North Carolina State University alongside an international team of biologists and social scientists, shows that that one can predict the number of kinds of disease-causing 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," Dunn says. "The environment and, in its broadest sense, nature determines 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."
But while the environment determines how many diseases one finds in a region, it does not determine how common they are. The researchers also examined the factors correlated to the prevalence, or commonness, of human pathogens across the globe and discovered that the most important factor is health-care spending, specifically expenditures on disease control.
"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 effort
|Contact: Mick Kulikowski|
North Carolina State University