Environmental change and infectious disease: how new roads affect the transmission of diarrheal pathogens in rural Ecuador - PubMed (original) (raw)

Comparative Study

. 2006 Dec 19;103(51):19460-5.

doi: 10.1073/pnas.0609431104. Epub 2006 Dec 7.

William Cevallos, Karina Ponce, Karen Levy, Sarah J Bates, James C Scott, Alan Hubbard, Nadia Vieira, Pablo Endara, Mauricio Espinel, Gabriel Trueba, Lee W Riley, James Trostle

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Comparative Study

Environmental change and infectious disease: how new roads affect the transmission of diarrheal pathogens in rural Ecuador

Joseph N S Eisenberg et al. Proc Natl Acad Sci U S A. 2006.

Abstract

Environmental change plays a large role in the emergence of infectious disease. The construction of a new road in a previously roadless area of northern coastal Ecuador provides a valuable natural experiment to examine how changes in the social and natural environment, mediated by road construction, affect the epidemiology of diarrheal diseases. Twenty-one villages were randomly selected to capture the full distribution of village population size and distance from a main road (remoteness), and these were compared with the major population center of the region, Borbón, that lies on the road. Estimates of enteric pathogen infection rates were obtained from case-control studies at the village level. Higher rates of infection were found in nonremote vs. remote villages [pathogenic Escherichia coli: odds ratio (OR) = 8.4, confidence interval (CI) 1.6, 43.5; rotavirus: OR = 4.0, CI 1.3, 12.1; and Giardia: OR = 1.9, CI 1.3, 2.7]. Higher rates of all-cause diarrhea were found in Borbón compared with the 21 villages (RR = 2.0, CI 1.5, 2.8), as well as when comparing nonremote and remote villages (OR = 2.7, CI 1.5, 4.8). Social network data collected in parallel offered a causal link between remoteness and disease. The significant and consistent trends across viral, bacterial, and protozoan pathogens suggest the importance of considering a broad range of pathogens with differing epidemiological patterns when assessing the environmental impact of new roads. This study provides insight into the initial health impacts that roads have on communities and into the social and environmental processes that create these impacts.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.

Fig. 1.

Map of study region. The 21 villages are categorized by river basin (Santiago, Cayapas, Onzole, Bajo Borbón, and road) and by remoteness (close, medium, and far).

Fig. 2.

Fig. 2.

Causal diagram linking proximity of the road to increases in infection and diarrheal disease

Fig. 3.

Fig. 3.

Relationship between social factors and remoteness. (A) Movement outside of community, measured by the percentage leaving the village during the past week (linear fit _R_2 = 0.25, P ≤ 0.05). (B) The social connectedness within a community, as measured by the number of villagers a given individual spent time with during the past week (linear fit _R_2 = 0.50, P ≤ 0.05).

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