International Research Journal of Public and Environmental Health
Vol.5 (6),pp. 83-89, September 2018
Available online at https://www.journalissues.org/IRJPEH/
Author(s) retain the copyright of this article. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Modelling local and regional spatial distribution patterns of Toxocara canis eggs using spectral indexes
Leticia Ramirez Rubio1*, Ma. de los Ángeles Campos Osorio1, Jesús Antonio Jiménez Angulo1, Margarito Quintero Núñez2, O.Rafael García Cueto1, Socorro Romero Hernández1 and Jaime Reyes López1
1Autonomous University of Baja California, Mexico.
2Secretary of Environmental Protection of Baja California, Mexico
*Corresponding Author: Email: leticia.ramirez.rubio(at)uabc.edu.mx
Soil contaminated by Toxocara spp. eggs is considered as one of the main infection sources of Toxocariasis worldwide. In this study, we developed with a maximum entropy model (MaxEnt) a local and regional simulation for predicting the spatial patterns of Toxocara spp. eggs in soil in urban parks of Mexicali, Baja California Mexico, based on a remotely sensed Normalized Difference Vegetation Index (NDVI), an indicator of vegetation greenness, Normalized Difference Water Index (NDWI) and Earth Surface Temperature (EST). 56 public parks were sampled during a year (2016-2017). Flotation technique was used for the determination of Toxocara eggs contamination in soil samples. 54% of the parks were positive to helminths eggs. The regional model includes all urban areas, the local model represents one single park. Our findings indicate that NDVI is the variable with more contribution for the survival of the parasite. The probability of favorable conditions for the existence of Toxocara spp. is 89% in green spaces. It is documented that Toxocara eggs survive up to two years in humid, clayey and grassy conditions, being sensitive to direct sunlight. Due to the climate of the city of Mexicali, it is thought that there is a minimum presence of this organism. However, Toxocara spp. has been reported in July, where temperatures exceed 35 °C. This validates that vegetation, regardless of temperature contributes in a greater measure to its presence.
Key words: Soil contamination, spectral indexes, Toxocara spp., maximum entropy, parks.