Evaluation of Soil as a Risk Indicator for Human Leptospirosis in Coastal, Rural Ecuador.

摘要

Leptospirosis, a zoonotic disease caused by pathogenic spirochete bacteria (family Leptospiraceae, genus Leptospira), is endemic in developing tropical regions of the world. It occurs in epidemics and is endemic in Ecuador where environmental conditions are ideal for maintenance. The role of soil as a long term reservoir has been previously been documented. Geographic Information System (GIS) and Remote Sensing (RS) technology was used in our study to further explore the role of soil as an environmental reservoir and its potential use as a static risk indicator for disease. Red, Green, Blue (RGB) spectral band data from known leptospire positive soil sites were extracted from high resolution satellite images and used to construct the first ever remotely dependent soil-based model. The soil co-variates failed to demonstrate statistical significance; however, elevation was found to be statistically significant. The soil type most associated with soil samples where leptospire DNA was detected using real-time PCR analysis was cambisol, a soil type with a common distribution in Ecuador and Africa. This exploratory analysis presented a novel idea of combining environmental microbiological sampling and GIS/RS technology to better examine static risk indicators such as soil. Further analysis is warranted based on spatial relationships noted.