Using spatial tools for high impact zoonotic agents’ surveillance design in backyard production systems from central Chile

Raul Alegria-Moran, Andres Lazo, Santiago Urcelay, Christopher Hamilton-West


Veterinaria México OA
ISSN: 2448-6760

Cite this as:

  • Alegria Moran R, Lazo A, Urcelay S, Hamilton West C. Using spatial tools for high impact zoonotic agents’ surveillance design in backyard production systems from central Chile. Veterinaria México OA. 2017;4(1). doi: 10.21753/vmoa.4.1.435

Specific locations of backyard production systems (BPSs) in Chile remain unclear, creating dificulties for designing surveillance activities for promptly detecting zoonotic agents with high impacts on health, such as avian influenza and Salmonella spp. This study aims to prove the use of spatial tools for improving the surveillance of BPSs in central Chile. A stratified and proportional random sampling was performed in 15 provinces of the Valparaiso, Libertador General Bernardo O’Higgins and Metropolitana regions. In this sampling, 329 BPSs were detected. In the first stage, 329 random sample points were allocated within the study area that searched for BPSs with poultry or swine breeding. Then, these random points were validated with remote sensing and in the field by searching for the presence of rural or semi-rural areas, nearby crops and houses or small towns within a 5 km radius around each point, while points allocated over hills or water sources (lakes or rivers) were discarded. Over 70 % of the sampling points were correctly allocated. In Los Andes, Cordillera and Chacabuco, less than 50 % of the points were allocated within feasible sampling areas.
From the total BPSs sampled, 89 % met the 5 km radius criteria, and in the provinces of Valparaiso, Cordillera and Cachapoal, over 20 % of the sampling points were outside the radius criteria. This study is the first in Chile to explore the locations and sanitary statuses of BPSs. Given the lack of knowledge about the specific locations of BPSs, their identification during field activities represents a high cost for the surveillance of pathogens. We argue that using spatial tools in BPS surveillance design is an important support for healthcare management.

Figure 1. Random sampling points by province assigned using ArcGIS® 10 and compatible zone detection by using free spatial tools. A. Study region with random sampling points. Study area and provinces: (1) Petorca; (2) Valparaiso, (3) Quillota; (4) San Felipe; (5) Los Andes; (6) San Antonio; (7) Melipilla; (8) Chacabuco; (9) Santiago; (10) Cordillera; (11) Talagante; (12) Maipo; (13) Cardenal Caro; (14) Cachapoal; (15) Colchagua. B. Random point (red pushpin) located in the Andes Mountains and 5 km searching area (yellow circle). C. Random point (red pushpin) and sampling candidate backyard farms (Yellow paddle) within less than 5 km.


Spatial tools; high impact zoonotic agents; backyard production system; public health; surveillance design.

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