A random forest approach for predicting the presence of Echinococcus multilocularis intermediate host Ochotona spp. presence in relation to landscape characteristics in western China

Marston, CG; Danson, FM; Armitage, RP; Giradoux, P; Pleydell, DRJ; Wang, Q; Qui, J; Craig, PS

Abstract

Understanding distribution patterns of hosts implicated in the transmission of zoonotic disease remains
a key goal of parasitology. Here, random forests are employed to model spatial patterns of the presence of
the plateau pika (Ochotona spp.) small mammal intermediate host for the parasitic tapeworm Echinococcus
multilocularis which is responsible for a significant burden of human zoonoses in western China.
Landsat ETM þ satellite imagery and digital elevation model data were utilized to generate quantified
measures of environmental characteristics across a study area in Sichuan Province, China. Land cover
maps were generated identifying the distribution of specific land cover types, with landscape metrics
employed to describe the spatial organisation of land cover patches. Random forests were used to model
spatial patterns of Ochotona spp. presence, enabling the relative importance of the environmental
characteristics in relation to Ochotona spp. presence to be ranked. An index of habitat aggregation was
identified as the most important variable in influencing Ochotona spp. presence, with area of degraded
grassland the most important land cover class variable. 71% of the variance in Ochotona spp. presence
was explained, with a 90.98% accuracy rate as determined by ‘out-of-bag’ error assessment. Identification
of the environmental characteristics influencing Ochotona spp. presence enables us to better understand
distribution patterns of hosts implicated in the transmission of Em. The predictive mapping of this Em
host enables the identification of human populations at increased risk of infection, enabling preventative
strategies to be adopted.

Citation

Marston, C., Danson, F., Armitage, R., Giradoux, P., Pleydell, D., Wang, Q., …Craig, P. (2014). A random forest approach for predicting the presence of Echinococcus multilocularis intermediate host Ochotona spp. presence in relation to landscape characteristics in western China. Applied Geography, 55, 176-183. https://doi.org/10.1016/j.apgeog.2014.09.001

• Journal Article Type: Article
• Online Publication Date: Sep 30, 2014
• Publication Date: Sep 30, 2014
• Deposit Date: Oct 3, 2014
• Journal: Applied Geography
• Print ISSN: 0143-6228
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 55
• Pages: 176-183
• DOI: https://doi.org/10.1016/j.apgeog.2014.09.001
• Publisher URL: http://dx.doi.org/10.1016/j.apgeog.2014.09.001
• Related Public URLs: http://www.journals.elsevier.com/applied-geography/
• Additional Information: Funders : National Science Foundation (NSF);US National Institutes of Health; Grant Number: EID TW001565-01 & 05