Perspectives on using remotely-sensed imagery in predictive veterinary epidemiology and global early warning systems

Abstract

Abstract. Recent disease epidemics and their spread around the world have illustrated the weaknesses of disease surveillance and early warning systems (EWS), both at national and international levels. These diseases continuously threaten the livestock sector on a worldwide basis, some with major public health impact. EWS and accurate forecasting of new outbreaks of epidemic livestock diseases that may also affect wildlife, and the capacity for spread of such diseases to new areas is an essential pre-requisite to their effective containment and control. Because both the geographical and seasonal distribution of many infectious diseases are linked to climate, the possibility of using climaterelated environmental factors as predictive indicators, in association with regular disease surveillance activities, has proven to be relevant when establishing EWS for climate-related diseases. This article reviews the growing importance of using geographical information systems in predictive veterinary epidemiology and its integration into EWS, with a special focus on Rift Valley fever. It shows that, once fully validated in a country or region, this technology appears highly valuable and could play an increasing role in forecasting major epidemics, providing lead time to national veterinary services to take action to mitigate the impact of the disease in a cost-effective manner.

Epidemiological Assessment of the Rift Valley Fever Outbreak in Kenya and Tanzania in 2006 and 2007

“…), and noted unusually high morbidity and mortality in their flocks consistent with RVF. [5][6][7][8][19][20][21] These facts were common knowledge among livestock owners well in advance of the detection of RVF by veterinary service surveillance systems. They also noted human cases consistent with RVF well in advance of detection by the public health surveillance system.…”

“…3,4 In East Africa, RVF is mainly noted in arid and semi-arid areas as sudden, dramatic epidemics of the disease at intervals of approximately 10 years, associated with widespread flooding and the resultant swarms of mosquitoes. [5][6][7][8][9] In late 2006 through early 2007, following a period of heavier than usual rainfall and widespread flooding, an outbreak of RVF occurred in East Africa. 10,11 By the time the disease abated more than 1,000 people had been diagnosed with RVF and more than 300 people had been confirmed to have died of the disease.…”

Global Infectious Disease Surveillance at DoD Overseas Laboratories, 1999–2007

“…[22][23][24][25][26][27][28][29][30] A collaboration between the National Aeronautics and Space Administration, USAMRU-K, and DoD-GEIS headquarters has developed an effective, satellite-based early warning tool for rift valley fever in East Africa and is now working to expand its applicability to other climate-dependent epidemic diseases. [31][32][33][34][35][36] The network has also overseen the development and refinement of a series of systems designed to bring real-time disease surveillance to remote or low-resource settings, including Cambodia, Laos, Thailand, the Philippines, and Andean Ridge countries of South America. [37][38][39][40][41] GEIS partners at NAMRU-3 and WRAIR have additionally conducted revealing studies on the burden of diarrheal diseases among US and coalition troops in the Eurasian theater, recommending more aggressive empiric treatment.…”

Road-killed wild animals: a preservation problem useful for eco-epidemiological studies of pathogens

“…The importance of this database has direct implications in epidemiological studies since it allows data to be interactively accessed, transformed and updated, facilitating the analysis of relationships between occurrences and mapped environmental characteristics, which makes possible the identification and the delimitation of areas at risk of infection (31).…”