PW01 Wildlife Toxicology
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW006) Investigating Avian Vacuolar Myelinopathy: A link between waterfowl and aquatic plants.
Birrenkott, A1, Hains, J2, Wilde, S3, Fischer, J4, Murphy, T5, Hope, C5, Parnell, P6, Bowerman, W1, 1 Clemson University, Pendleton, SC, USA2 US Army Corps of Engineers, Calhoun Falls, SC, USA3 University of South Carolina - Baruch Institute, Charleston, SC, USA4 University of Georgia - SCWDS, Athens, GA, USA5 South Carolina Department of Natural Resources, Green Pond, SC, USA6 Clemson University, Columbia, SC, USA
ABSTRACT- Avian Vacuolar Myelinopathy (AVM) is a neurological disease primarily affecting bald eagles (Haliaeetus leucocephalus) and American coots (Fulica americana). The disease was first characterized in bald eagles in Arkansas in 1994 and then in American coots in 1996. To date, AVM has been confirmed in 6 additional avian species. AVM has been diagnosed at 10 reservoirs in 4 southeastern United States including J. Strom Thurmond Lake (JSTL) on the border of South Carolina and Georgia. Attempts to identify the etiology of AVM have been unsuccessful. The objective of this study was to evaluate possible exposure mechanisms of AVM, including dermal and oral routes, and to establish cause-effect linkages by fulfilling Koch's Postulates as applied to toxicology. Mallard ducks were used as the avian model in all trials; quail were used in addition to mallards in the first fresh hydrilla exposure trial. Five trials were completed, including two fresh hydrilla trials, two cyanobacteria exposure trials, and a frozen hydrilla trial. The cyanobacteria exposure trials and frozen hydrilla trial involved gavaging mallard ducks with either Pseudanabaena catenata (live culture), Hapalosiphon fontinalis, or frozen hydrilla with both cyanobacteria species present. With the exception of the 2002 hydrilla exposure trial, results from all trials were negative or inconclusive. The hydrilla exposure trial in 2001 yielded inconclusive results. Results from all trial were negative for AVM. In the 2002 hydrilla exposure trial, six of nine treatment ducks were diagnosed with AVM based on histological lesions. This established a cause-effect linkage between aquatic vegetation and waterfowl for AVM and provided evidence supporting an aquatic source for the causal agent.
Key words: hydrilla, AVM, bald eagle, cyanobacteria