Ecology and Epidemiology of West Nile Virus in Mississippi
Varnado, Wendy Carol
Baker, Gerald T.
Guyton, John W., III
Edwards, Kristine T.
Since its introduction in 2002, West Nile virus (WNV) persists in Mississippi with dozens of cases and a few deaths each year. Little is known about the epidemiology and ecology of WNV in our state. This is the first study of the dynamics of West Nile virus in Mississippi utilizing both mosquito and human case surveillance. Herein I showed that the primary vector for WNV in MS, Culex pipiens quinquefasciatus, is associated with anthropogenic urban environments as opposed to rural wooded areas. I also found that other potential WNV vectors in MS are likely involved in enzootic transmission among natural bird reservoirs and not related to human transmission. Secondly, I showed that a simple commercial wicking assay (dip-stick test) can be beneficial to vector surveillance and mosquito control programs with limited resources when monitoring local mosquito populations in anticipation of human disease transmission. In my study, the lead time from finding infected mosquitoes to onset of human cases ranged from almost two weeks to two months, an important finding in regard to public health. Lastly, I performed a descriptive analysis on data from a survey I sent out to Mississippi WNV patients who were diagnosed between 2008 and 2013. The survey focused on self-reported personal protective behaviors and descriptions of their home and property at the time of infection. Results highlighted a few key epidemiological and behavioral aspects of WNV patients in Mississippi: 1) television and internet were the primary avenues for patient education; 2) amount of time spent outdoors appeared associated with WNV infection; and 3) use of personal protection measures did not usually change from before WNV infection to after. This study will help public health personnel achieve their goals to promote health and educate the public about personal protective behaviors for WNV and other mosquito-borne diseases, and thus, reduce risk of future infections. It will also lay groundwork for future studies such as widespread sero-surveys of populations to assess WNV infection rates and onsite environmental surveys to validate patient responses. Also, hypothesis-driven studies of specific risk factors associated with WNV infection are in order and currently planned.