We all know that cutting down the rainforests is bad, but now we might have even more reason to believe it. According to co-author Luis Fernando Chaves of the University of Michigan, deforestation may help spread the infectious disease American Cutaneous Leishmaniasis (ACL) in Costa Rica among marginalized populations.

In the past the theory was that less forest equaled less disease, but when researchers looked at the populations living within 5 kilometers of the forests edge, researchers found a “strong geographic overlap between disease incidence and social marginalization that was not found between disease incidence and the other ecological variables.” The reason lies with El Niño Southern Oscillation (ENSO) which influences climates and affects disease incidence. According to the researchers:

In highly deforested counties, socially marginalized human populations are more vulnerable to ENSO’s effects, and disease incidence actually is higher, the analysis suggests.

The article doesn’t go into much detail about how the forests protect humans or how ENSO affects disease incidence, just that it’s a complex connection. Never-the-less, the correlation is clear and the solution even clearer: stop cutting down forests, we need them more than we know.

The researchers are now planning control studies and focusing on other diseases.

» ScienceDaily