Monday, December 11, 2006

Risk assessment of EEE virus infection in an endemic focus in Central Alabama

Xin Yue, yuexin1@auburn.edu1, Bertram Zinner, zinnebe@auburn.edu2, Eddie W. Cupp, ecupp@acesag.auburn.edu1, Micky D. Eubanks, eubanmd@auburn.edu1, and Thomas R. Unnasch, tunnasch@uab.edu3. (1) Auburn University, Dept. of Entomology and Plant Pathology, 301 Funchess Hall, Auburn, AL, (2) Auburn University, Dept. of Mathematics and Statistics, 221 Parker Hall, Auburn, AL, (3) University of Alabama - Birmingham, Dept. of Medicine/Division of Geographic Medicine, Bevill Biomedical Research Building (BBRB), #538, 845 19th Street South, Birmingham, AL

Mosquitoes were collected in an enzootic Eastern Equine Encephalomyelitis (EEE) virus focus in central Alabama (Tuskegee National Forest) from 2001 to 2003 and analyzed for virus as well as host selection. Host risk of EEE infection was estimated by an assessment measure that combines abundance, infection prevalence, vector competence, and biting behavior of vectors according to host group, mosquito species, and collection year. The point estimates of relative risk suggest that Cs. melanura and Cx. erraticus were mainly responsible for EEE infection of birds compared to Ae. vexans, Cq. perturbans, and Cx. peccator. Ur. sapphirina, Cs. melanura, and Cx. peccator(except 2003) were more responsible for EEE infection of reptiles and amphibians compared to Cx. erraticus. Cx. erraticus was completely responsible for EEE infection of mammals compared to other five species in 2003 and was mainly responsible for mammal EEE infection in 2001 and 2002 compared to Ae. vexans at the study site from 2001 to 2003. The interval estimates however do not permit making any statistical significant assertions.

Species 1: Diptera Culicidae Culiseta melanura
Species 2: Diptera Culicidae Aedes vexans
Species 3: Diptera Culicidae Culex erraticus