A spatial risk assessment of hemorrhagic disease in cattle in Illinois from 2005 to 2011
Diseases caused by both the bluetongue (BT) and epizootic hemorrhagic disease (EHD) viruses, referred to collectively as hemorrhagic disease (HD), infect both domestic and wild ruminants in the United States. The viruses are transmitted via biting midges, and EHDV in particular causes severe disease in white-tailed deer annually in Illinois. Cattle can also be infected with these viruses; and although clinical illness is rare, the prolonged viremia in cattle after infection may play an important role in disease transmission. The recent discovery in the United States of the genotype EHDV-6 among dead white-tailed deer, an exotic pathogen responsible for cattle morbidity and mortality in Morocco and Algeria, increases the importance of improved vector control strategies in cattle operations and limiting exposure to wild deer. Utilizing a landscape epidemiology approach, we analyzed the combined effect of rainfall, temperature, forest patterns, deer density and soil on the risk of HD in cattle in Illinois from 2005-2011 at the county level. Data regarding suspected disease in white-tailed deer and areas of potential overlap between cattle and deer were also included in the analysis. Results from a pooled logistic regression for the time period suggest that suspected HD in deer and temperature were the most significant factors in determining the presence HD seroprevalence among cattle in Illinois. It was found that odds of HD seroprevalence in cattle increase by almost 4 times with the occurrence of potential HD in deer in a particular county, while a 1°C increase in temperature increased the risk of HD seroprevalence by 38%. Even though interpretation of subsequently generated risk maps is limited due to data limitations, the approach serves as a framework to enable finer scale analysis and to conduct vector serosurveys. The application of landscape genetics could further reveal the characteristics associated with the landscape that assist pathogenic evolution, or conversely act as a barrier to it.
Geographic Information System (GIS), Spatial Epidemiology, Hemorrhagic Disease, Orbiviruses, One Health, Medical Geography, Landscape Epidemiology, Health Geography, Spatial Statistics
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign