1. Section 1 1 Introduction 1 Section 2 2 Drought Hazard Profile 1

13.2Disaster History

Diseases that troubled Louisiana included yellow fever, smallpox, cholera, dysentery, malaria, mange, scurvy, yaws, Hansen’s disease, and venereal diseases. The most serious epidemics developed from yellow fever, cholera, malaria and smallpox. Yellow fever, a disease with origins in Africa, was the most deadly, especially to Europeans, and killed as much as 60 percent of those who contracted the disease. In 1853, the worst epidemic year, 8000 people -- 1 out of every 15—died of yellow fever in New Orleans. The last major yellow fever epidemic in Louisiana occurred in 1905, five years after scientists discovered that mosquitoes carried the disease.

While epidemics the size and scope of the yellow fever epidemics of the eighteenth and nineteenth centuries are unlikely today, Louisiana experienced in recent decades the impact of several emergent diseases, particularly West Nile virus. According to the Centers for Disease Control and Prevention (CDC), in 2002, Louisiana had 330 cases of laboratory-positive human cases and of West Nile Virus and 24 deaths from the disease, making Louisiana the 4^th leading state in the nation for cases and for deaths. Map 10 shows the spread of the virus around the State in 2002.

13.3Rate of Occurrence and Severity

People over 50 years of age and people with compromised immune systems have the highest risk of developing a severe illness from the virus. Most people who are infected with West Nile virus have no symptoms or have an infection similar to a mild flu with fever, headache, and fatigue. Most cases of West Nile are treated in humans before the humans develop encephalitis, a serious illness of the brain. The death rate for humans who develop encephalitis ranges from 3 to 15 percent.

A global pandemic of dengue began in Southeast Asia after World War II and has intensified during the last 15 years (Figure 7 depicts the global reach of dengue). Risk factors for dengue hemorrhagic fever include age, immune status, and genetic predisposition of the patient. Currently, there is no vaccine for dengue, and the recent trend of increased epidemic activity is expected to continue. There is a small, but significant risk for dengue outbreaks in the continental United States, especially the southeast, including Louisiana. From 1977 to 1994, 481 confirmed cases of dengue were reported nationwide.

For both dengue and West Nile, mosquito control is the primary disease prevention method.

There are several other types of infectious diseases that the Louisiana Office of Public Health tracks that are transmitted by insects, similar to West Nile and dengue. Table 18, “Other Infectious Diseases,” presents the type and number of cases found in 1997, 1998, and 1999. Furthermore, Appendix I contains the complete list of the numbers of reportable disease cases for the years 1970 to 1999.