A Flexible Spatial Framework for Modeling Spread of Pathogens in Animals with Biosurveillance and Disease Control Applications

Montiago Labute,Mac Brown,Benjamin Mcmahon,Jeanne Fair,Carrie Manore

doi:10.3390/ijgi3020638

Abstract

Biosurveillance activities focus on acquiring and analyzing epidemiological and biological data to interpret unfolding events and predict outcomes in infectious disease outbreaks. We describe a mathematical modeling framework based on geographically aligned data sources and with appropriate flexibility that partitions the modeling of disease spread into two distinct but coupled levels. A top-level stochastic simulation is defined on a network with nodes representing user-configurable geospatial “patches”. Intra-patch disease spread is treated with differential equations that assume uniform mixing within the patch. We use U.S. county-level aggregated data on animal populations and parameters from the literature to simulate epidemic spread of two strikingly different animal diseases agents: foot-and-mouth disease and highly pathogenic avian influenza. Results demonstrate the capability of this framework to leverage low-fidelity data while producing meaningful output to inform biosurveillance and disease control measures. For example, we show that the possible magnitude of an outbreak is sensitive to the starting location of the outbreak, highlighting the strong geographic dependence of livestock and poultry infectious disease epidemics and the usefulness of effective biosurveillance policy. The ability to compare different diseases and host populations across the geographic landscape is important for decision support applications and for assessing the impact of surveillance, detection, and mitigation protocols.

Highlights

Emerging infectious diseases are of critical concern from the perspectives of global economics, security, and public health
The two largest drivers for the overall economic cost of livestock epidemics are the magnitude and duration of the epidemic, and we compare the day of the epidemic peak and total animals for highly pathogenic avian influenza (HPAI)
For HPAI, epidemics initiated in California remain small and peak rapidly, while epidemics initiated in Arkansas peak rapidly, but are, in general, the largest epidemics of the three sites

Summary

Introduction

Emerging infectious diseases are of critical concern from the perspectives of global economics, security, and public health. Most new infectious diseases important to public health have emerged from animal reservoirs and are considered zoonotic [1]. Other animal epidemics such as the 2001 outbreak of foot-and-mouth disease (FMD) in the UK resulted in the culling of approximately four million animals and a cost of $3.7–6.3 billion [2]. The current epizootic spread of highly pathogenic avian influenza (HPAI) A subtype H5N1 among wild avian and domestic poultry species has resulted in 200 million birds destroyed with an impact of $10 billion dollars [3] and continues to pose a significant zoonotic threat [4]. The emergence of the 2009 pandemic influenza A (H1N1) strain as a triple re-assortment of swine influenza viruses underscores the need for intensive monitoring in livestock populations for future infectious diseases with great zoonotic potential [6]

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Results

Discussion

Conclusion