Slide 1AbstractWhy worry about West Nile Virus?Louisiana: The Pelican StateMethodsWhat did we find?Slide 7Slide 8Final Thoughts and Next StepsSlide 10AbstractThe occurrence of West Nile Virus has been a concern in the United States ever since its introduction in New York in 1999. Since then, the disease has continued to spread throughout the country. However, the factors influencing the spread still are not understood to a large extent. In analyzing the growth of the disease in the state of Louisiana from 2002 to 2004, we felt that population density, major highways, wetlands areas, as well as precipitation rates and temperature will all play significant roles in determining the areas of highest West Nile Virus activity. A base map showing population density, road networks, and wetlands, as well as a graph showing average precipitation and temperature, were produced. A second map showing disease incidents was then generated, and the two were overlaid to better observe any correlations. A map showing the avian flight path through the state was also produced to analyze the potential bird species that introduced the virus to the state. Finally, a graphical representation of disease incidents versus climate data was used to analyze correlation between incidence rates and temperature and precipitation. Results showed that population density, precipitation rates, and temperature all played significant roles in establishing areas of highest disease incidence, which occurred in Central, Southwest, and South Central Louisiana. While insufficient data concerning wetlands areas limits conclusive results, population and climatic conditions seem to have the greatest effects on West Nile Virus occurrence.Why worry about West Nile?Louisiana: The Pelican StateMethodsWhat did we find?Final Thoughts &Next StepsWest Nile Virus is a potentially serious disease. It was first introduced intoNorth America in the year 1999 into New York City. Since that time, it has spread rapidlyacross the continental United States. Disease activity increase during mosquito season,particularly hot summer months. It is a disease vectored in mosquitoes. A mosquitoInfected with the disease agent then has the ability to pass it to any human or animal itmay bite. The primary host of the virus is birds, which pass it to the mosquitoes and viceversa. Humans are considered “dead-end” hosts as they cannot pass it to each otherwithout an intermittent vector. According to the US Geological Survey, less than onepercent of infected humans develop more severe illnesses from the virus, includingmeningitis and encephalitis. Because of this health risk and the diseases wide-spreadactivity in countries such as Africa, West Nile Virus has been carefully tracked since itsintroduction.There are many possible factors that affect the spread of West Nile Virus. The largest of these is mosquito travel and activity. Mosquitoes thrive and feast more onhuman blood during periods of increased temperatures. They also thrive in areas withavailable standing water. Bird activity is thought to also correlate with virus activity, asbirds are the primary hosts. Our case study focuses on West Nile Virus occurrence in the state ofLouisiana, observing change in the number of cases reported between the years 2002and 2004, in order to demonstrate the virus's progression throughout the country. Byanalyzing the geography of various physical and biological features throughout the state,we hope to determine possible factors that brought the disease to Louisiana. We predictthat the number of positive West Nile Virus cases will increase in areas with wetconditions, high population densities, and areas with higher average temperatureand precipitation.- "West Nile Virus: What You Need To Know." West Nile Virus. 12 Sept 2006. Center for Disease Control. March 2008 <http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factsheet.htm>.- "Background." West Nile Virus Maps. 19 Jan 2005. US Geological Survey. March 2008 <http://westnilemaps.usgs.gov/2004/background.html>. Results offer partial support for the original hypothesis. Population density proved to be an influential factor in the increase in the West Nile Virus incidence rate, as all three areas with the highest levels of West Nile Virus activity were home to large urban areas. There was not as strong a correlation between disease occurrence and proximity to large highways, despite the suggestion that human transportation networks also serve as a means of improved travel for mosquito vectors. While wetlands areas showed little disease activity, particularly for mosquitoes, these results may be inconclusive due to lack of testing data for 2002 in many counties, particularly those in wetland areas. Temperature and precipitation rates appeared to be the most influential factor in the occurrence of West Nile Virus in Louisiana. Those areas with the highest disease rates also had some of the highest average temperature and precipitation measures. Due to the fact that mosquitoes thrive in moist, hot conditions, and all three high virus rate areas were located near wetlands areas, this once again suggests that wetlands may prove a much greater factor than available data would imply. Lack of West Nile Virus incidence data for earlier years a major problem in conducting our analyses, as it served as a limiting factor leading to potentially misleading results. Insufficient data concerning specific bird species identified as positive West Nile Virus carriers in Louisiana also restricted the analysis of results. In subsequent analyses greater measures should be taken to fill in gaps in data. Additional factors should be taken into account, including elevation and land-cover data. Expanding the temporal and spatial scope of the data would be beneficial to reach more definite conclusions. - Level of avian West Nile Virus activity was greatest in Central, Southwest, and South Central Louisiana- Areas with the greatest increase in West Nile Virus activity typically correlated with the highest observed average precipitation and temperatures- Significant numbers of disease incidents were not reported for wetlands areas- Over 150 bird species were found to be potential carriers of the disease agent through Mississippi avian flyways Increases in West Nile Virus Activity in Louisiana: - Added a map of United States with county boundaries from UNC library - Performed an attribute query for Louisiana counties -