All ETDs from UAB

Advisory Committee Chair

Sibylle Kristensen

Advisory Committee Members

Craig Wilson

Charles Katholi

Robert Novak

Thomas Unnasch

Document Type

Dissertation

Date of Award

2010

Degree Name by School

Doctor of Public Health (DrPH) School of Public Health

Abstract

Eastern Equine Encephalitis virus (EEEV) circulates in a mosquito-avian cycle (enzootic) within well-characterized environments. However, outbreaks in birds, horses and humans can occur (epizootic/epidemic transmission). EEEV is present throughout the Americas and the Caribbean, although some geographical differences in the ecology and epidemiology of the virus exist. The North American type of EEEV is associated with severe disease in both humans and horses, and is transmitted by the enzootic vector Culiseta melanura among birds in northern North America. The South American EEEV strain in horses can present similarly to the North American type, however, in humans, infection is rare and usually presents with asymptomatic or milder form of the disease. Culex melanoconion has been implicated as the enzootic vector and small mammals and birds may serve as EEEV hosts in South America. The epidemiology of EEEV in the southeastern USA might be similar to the epidemiology of EEEV in South America. Recent advances in blood meal analysis techniques permit that we look into patterns of host preference and in consequence into the relationships between hosts and possible vectors in areas of arboviral transmission. Temporal shifts among host classes in feeding patterns of the mosquito vectors are believed to be an important factor in arbovirus ecology. The presence of temporal changes in the host preference profile of mosquito vectors involved in Eastern Equine Encephalitis Virus (EEEV) transmission at a site at the Tuskegee National Forest (TNF), Alabama, has been investigated employing a dataset containing a total of 1,583 identified blood meals from 90 different host species collected over six years. Runs test (a test of randomness) revealed that blood meals from the Great Blue Heron (GBH) and White-tailed Deer (WTD) (two of the most fed upon species) were not random across years; while meals derived from the Yellow-crowned Night Heron (another of the most frequently fed upon species) appeared to be randomly distributed. Tukey's two-way ANOVA with 1 degree-of-freedom (test for interaction) showed that normalized blood meal counts for WTD and GBH were consistent from year to year. These data suggest that the temporal profile of feeding shifts for certain species exhibited a non-random pattern that was consistent from year to year, suggesting that some species might be preferentially fed upon while other species seemed to be more opportunistically targeted.

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