ANN ARBOR, Mich.---Logging roads have brought a higher incidence of diarrheal disease and new social problems among communities along the Ecuadorian coast, according to a new study by an international research team led by Joseph Eisenberg, assistant professor of epidemiology at the University of Michigan School of Public Health. The new roads connect Ecuadorian villages that previously used only rivers for transport. The study suggests the importance of considering human costs when assessing the environmental impacts of large development projects. With funding from the National Institutes of Allergy and Infectious Disease, the research team examined diarrheal infections and social networks in 21 villages being connected to a new road network built by the Ecuadorian government at the southern end of the Choc rainforest, near the Pacific Ocean and the border with Columbia.
The roads bring new people to the villages, and allow the villagers to travel more easily between villages, and also back-and-forth to larger cities. But bacteria, viruses and parasites hitch rides with the newly-mobile people, adding new strains of old bugs to the local environment and increasing infection rates, according to Eisenberg. "If you keep reintroducing strains of a given pathogen, you're increasing the endemic population of pathogens," he said.
The study looked in particular at E. coli bacteria, rotavirus and the protozoan parasite Giardia, finding different infection rates and modes of transmission for each, but the same overall trends: proximity to the road meant higher infection rates. Remote villages were found to have infection rates up to eight times lower than those close to the new road.
"The increased diversity and potency of the microbe population apparently offsets the improved health care that also comes with new roads," he said. "When you're thinking about a road, you have to also think about these impacts that will take years to unfo
Contact: Karl Leif Bates
University of Michigan