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Avian Vacuolar Myelinopathy: Model Estimating Potential Distribution. Susan B. WildeUniversity of South Carolina/SCDNRand A. Townsend PetersonUniversity of Kansas. . . Potentially toxic cyanobacterial colonies on hydrilla and other aquatic plants in AVM sites. Aquatic plants and epiphytic algae are primary food source for coots.
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2. Avian Vacuolar Myelinopathy: Model Estimating Potential Distribution Susan B. Wilde
University of South Carolina/SCDNR
and
A. Townsend Peterson
University of Kansas
3. The study proved the final link of the disease passed through the food chain. The common factor at all AVM positive sites is the aquatic plants have an epiphytic cyanobacterium growing on the leaves. Our working hypothesis is the potentially toxic cyanobacterium is growing on the leaves of vegetation in the water bodies. The coots are consuming the vegetation and the epiphytic algae as their primary food source and becoming affected by the toxin. Then the sick coots are consumed by the Bald Eagles, transferring the toxin to them. The study proved the final link of the disease passed through the food chain. The common factor at all AVM positive sites is the aquatic plants have an epiphytic cyanobacterium growing on the leaves. Our working hypothesis is the potentially toxic cyanobacterium is growing on the leaves of vegetation in the water bodies. The coots are consuming the vegetation and the epiphytic algae as their primary food source and becoming affected by the toxin. Then the sick coots are consumed by the Bald Eagles, transferring the toxin to them.
4. Supposed Structure of Transmission
5. Two Simulations
7. Eagle Data from Christmas Bird Counts; used total observed over 1990-2000 to weight inclusion of sites in the Ecological Niche Model analysis.
8. Coot Data from Christmas Bird Counts; used total observed over 1990-2000 to weight inclusion of sites in the Ecological Niche Model analysis.
9. Hydrilla Prediction based on native-range ecological characteristics, projected to North America (Peterson et al. Weed Science 2003). Blue polygons on North American map represent independent test occurrence data overlaid to show good correspondence.
10. Cyanobacterium Two distinct models developed: one based on high abundance situations (6-10 on SWs abundance scale), and the other on all detections
11. Final Predictions
12. Egeria densa
13. Myriophyllum spicatum
14. Hydrilla, Egeria, MilfoilEagles & Coots
17. Is AVM contributing significantly to the apparent decline?
18. Proposed Study Outline
19. Wrap Up
20. Successful Extraction of the Toxin Responsible for Avian Vacuolar Myelinopathy (AVM)
31. Current Research Methanol Extract Fractionation
Avian Bioassay
Cell Bioassay
Mammalian Susceptibility
Tested mice using same material from mallard assay
Suspect lesions, artifact?
Repeat experiment with new fixative