““A mysterious brain disease is killing birds A mysterious brain disease is killing birds in the southeastern United States and in the southeastern United States and scientists can't find the cause.” - CNN scientists can't find the cause.” - CNN
Website Website
http://www.nwhc.usgs.gov/publications/fact_sheets/pdfs/avm091002.pdf
Title
ASSESSMENT OF THE POTENTIAL FOR ASSESSMENT OF THE POTENTIAL FOR AN AVIAN VACUOLAR MYELINOPATHY AN AVIAN VACUOLAR MYELINOPATHY
OCCURRENCE IN NEW HANOVER OCCURRENCE IN NEW HANOVER COUNTY PONDSCOUNTY PONDS
Overview1. Introduction
1. Avian Vacuolar Myelinopathy
2. Avian Wildlife
3. Invasive Aquatic Weeds
4. Cyanobacteria
2. Methods
1. Pond locations
2. Pond Areas
3. Sampling Techniques
4. Avian Wildlife Surveys
3. Results
1. Pond locations
2. Pond Areas
3. Aquatic Vegetation
4. Avian Wildlife
4. Discussion
AVIAN
= BIRDS
VACUOLAR
= ACCENTUATION OF CELLULAR SWELLING
MYELINOPATHY
= DISEASE OF MYELIN (A FATTY NERVE COATING)
1. Introduction1. Avian Vacuolar Myelinopathy1.1
THOMAS, N. J., C. U. MYETEYER, AND L. SILEO. 1998. Epizootic vacuolar myelinopathy of the central nervous system of bald eagles (Haliaeetus leucocephalus) and American coots (Fulica Americana). Veterinary Pathology 35: 479-487.
First discovered at DeGray Lake, Arkansas
• 1994-1995, 29 bald eagles died
• 1996-1997, 26 bald eagles died
American coots also discovered
dead during the two winters.
Affected birds appeared intoxicated,
demonstrating a lack of coordination while
flying, swimming, and walking.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
THOMAS, N. J., C. U. MYETEYER, AND L. SILEO. 1998. Epizootic vacuolar myelinopathy of the central nervous system of bald eagles (Haliaeetus leucocephalus) and American coots (Fulica Americana). Veterinary Pathology 35: 479-487.
Examination of affected birds revealed vacuolation of the white matter of the central nervous system
Substances known to cause similar lesions in animals have not been identified in cases of AVM
1. Introduction1. Avian Vacuolar Myelinopathy1.1
http://www.aphis.usda.gov/vs/ceah/cei/taf/emergingdiseasenotice_files/avm_0101.htm
AVM has been documented in 11 lakes across 5 states since its discovery
1. Introduction1. Avian Vacuolar Myelinopathy1.1
AVM has been documented in 8 species of birds:
1. Bald Eagle, Haliaeetus leucocephalus (~ 100)
2. American coot, Fulica americana (1,000s)
3. Ring-necked duck, Aythya collaris
4. Mallard duck, Anas platyrhynchos
5. Bufflehead, Bucephala albeola
6. Canada goose, Branta canadensis
7. Great Horned Owl, Bubo virginianus (2)
8. Killdeer, Charadrius vociferous (1)
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Healthy coots and mallards were released on an AVM positive lake (Lake Surf, NC)
Results:
• the birds were diagnosed with AVM within 5 days of release
• only the birds released during November developed AVM
Significance:
• causative agent is site specific
• contraction of AVM is seasonal, causative agent may only be present at lethal levels during the winter months
• source of disease is most likely a naturally occurring chemical toxin
ROCKE, T. E., N. J. THOMAS, T. AUGSPURGER, AND K. MILLER. 2002. Epizootiologic studies of avian vacuolar myelinopathy in waterbirds. Journal of Wildlife Diseases 38: 678-684.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Tissues of American coots confirmed AVM positive fed to red-tailed hawks, Buteo jamaicensis
Results:
• all five hawks developed microscopic lesions associated with AVM despite lack of neurological dysfunction
Significance:
• AVM can be spread by ingestion of affected birds
• confirmed method of exposure to bald eagles and suggests susceptibility of other birds of prey
FISHER, J. R., L. A. LEWIS-WEIS, AND C. M. TATE. 2003. Experimental vacuolar myelinopathy in red-tailed hawks. Journal of Wildlife Diseases 39: 400-406
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Attempts to transmit AVM to mallard ducks by 4 methods of exposure
Results:
1. direct exposure to affected birds = negative
2. ingestion of water = negative
3. ingestion of aquatic plants = negative
4. ingestion of sediment = negative
Significance:
• samples either did not contain causative agent or it was not in a high enough concentration to induce AVM
• affected birds may be present for some time after the agent is no longer active
LARSON, R. S., F. B. NUTTER, T. AUGSPURGER, T. E. ROCKE, N. J. THOMAS, AND M. K. STOSKOPF. 2003. Failure to transmit avian vacuolar myelinopathy to mallard ducks. Journal of Wildlife Diseases 39: 707-711.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Attempts to transmit AVM to domestic chicken and swine by ingestion of affected birds and plant material
Results:
• swine did not develop AVM
• chicken developed AVM from both feeding trials
Significance:
• mammals may not be susceptible
• causative agent is most likely associated with the plant material collected from the AVM positive site
LEWIS-WEIS, L. A., R. W. GERHOLD, AND J. R. FISHER. 2004. Attempts to reproduce vacuolar myelinopathy in domestic swine and chickens. Journal of Wildlife Diseases 40:
476-484.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Establishing a link between aquatic plant material and AVM in Mallards
Results:
• two types of cyanobacteria discovered associated with the plant material collected during an outbreak
1. Pseudanabaena catenata
2. an unknown species of Stigonematales
• Six of Nine ducks fed the plant material developed AVM
Significance:
• established cause-effect link between AVM and aquatic vegetation
• both species of bacteria are capable of producing harmful toxins
BIRRENKOTT, A. H., S. B. WILDE, J. J. HAINS, J. R. FISHER, T. M. MURPHY, C. P. HOPE, P. G. PARNELL, AND W. W. BOWERMAN. 2004. Establishing a food –chain link between aquatic plant material and avian vacuolar myelinopathy in mallards (Anas platyrhynchos). Journal of Wildlife Diseases 40: 485-492.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Surveys of AVM positive and negative ponds for aquatic vegetation and cyanobacteria
Results:
• Three types of invasive aquatic plants dominated AVM positive ponds
1. Hydrilla (Hydrilla verticillata)
2. Brazilian elodea (Egeria densa)
3. Eurasian watermilfoil (Myriophyllum spicatum)
• Unknown species of Stigonematales rare in AVM negative ponds
• Stig. species dominated up to 95% of invasive weeds in AVM positive ponds
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
"Percentage of coverage of suspect Stigonematales species on three invasive aquatic plants in reservoirs where AVM has not been documented."
1. Introduction1. Avian Vacuolar Myelinopathy1.1
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
"Percentage of coverage of suspect Stigonematales species on three invasive aquatic plants in confirmed AVM reservoirs."
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Study: Mallard ducks released onto a small pond (1.6 ha) with a dense infestation of hydrilla and 50% to 95% coverage of the unknown Stigonematalan species
Results:
• 15 of the 20 ducks released on the pond developed AVM within 6 weeks
Significance:
• AVM had only been documented on ponds greater than 450 ha
• The unknown Stigonematales species has been documented at ALL locations that have had cases of AVM
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
1. Introduction1. Avian Vacuolar Myelinopathy1.1
Conclusions provide the basis for this study:
“We hypothesize that three elements are needed to produce AVM:
1. an abundance of preferred aquatic vegetation (e.g. hydrilla)
2. an abundance of the suspect Stigonematalan species growing on available substrate
3. and herbivores waterfowl.”
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
1. Introduction2. Avian Wildlife, Bald Eagle1.2
Populations declined from hunting, use of DDT, and loss of habitat
Endangered Species Act in 1973 helped increase nesting sites
Growth rates of North Carolina bald eagle populations as a result of the North Carolina Bald Eagle Project. From (Bald eagle fact sheet, 2005)
1. Introduction2. Avian Wildlife, Bald Eagle1.2
Susceptibility to AVM:
• Opportunistic feeders: mostly fish but also other vertebrates including waterfowl whether alive or dead. AVM outbreaks killing many coots can provide a significant source of food.
• Nests located within ½ mile from water
• Mature eagles return to site of birth to breed
Populations increase approximately 8.5% per year. However, AVM can set back populations by decades.
• An estimated 30% to 65% of population was killed during DeGray Lake outbreak
• Approximately 100 killed by AVM to date
1. Introduction2. Avian Wildlife, American coot1.2
Migratory, fresh water birds
Osprey and Eagle are main predators
Omnivorous: consume small animals and insects. Primary diet consists of submerged aquatic vegetation which they dive for in shallow water.
Demonstrate a preference for hydrilla
Thousands killed by AVM to date
1. Introduction3. Invasive Aquatic Weeds1.3
Negative Impacts:
1. Navigation
2. Water quality
3. Hydropower
4. Irrigation
5. Fisheries
6. Recreation
7. Native vegetation
8. Wildlife
9. Ability to “harbor the vector of human and animal diseases” (Kay, 1992)
1. Introduction3. Invasive Aquatic Weeds1.3
1. Introduction3. Invasive Aquatic Weeds, Hydrilla1.3
Introduced to US as an aquarium plant
Found growing wild in Florida in 1960 and spread throughout US
NC hydrilla first discovered in Raleigh in 1980
2002 North Carolina hydrilla infestations
http://www.weedscience.ncsu.edu/aquaticweeds/hydrilla2002.html
1. Introduction3. Invasive Aquatic Weeds, Hydrilla1.3
Extremely adaptive
Rooted to bottom by rhizomes in up to 30 ft of water
Leaves grow in whorls of 3-8 with serrated edge
1. Introduction3. Invasive Aquatic Weeds, Hydrilla1.3
Reproduction
• Fragmentation – broken stem fragments can survive for days before rooting to bottom
• Tubers and turions – specialized structures capable of producing new plants when released
• Seeds – contributes little due to successful vegetative means
1. Introduction3. Invasive Aquatic Weeds, Hydrilla1.3
Management
1. Physical
• drawdown
2. Mechanical
• tools, rakes
3. Biological
• Grass carp (Ctenopharyngodon idella)
4. Chemical
• herbicides
1. Introduction3. Invasive Aquatic Weeds, Brazilian elodea1.3
Introduced to US as an aquarium plant, “Anacharis” in late 1800s
Similar to Hydrilla but lacks special structures (tubers, turions)
Reproduces primarily through fragmentation
Managed primarily by grass carp
1. Introduction3. Invasive Aquatic Weeds, Eurasian watermilfoil1.3
Introduced to US as an aquarium plant, first discovered in D.C. in 1940s
Leaves thin and feather-like
Reproduces primarily through fragmentation, without turions
First discovered in NC in 1965 on Currituck Sound. Spread from 40 to 32,000 ha in 9 years.
Less desirable food source for grass carp
1. Introduction4. Cyanobacteria1.4
“Blue-green algae”
• Similar to Plants
• contain chlorophyll and release oxygen during photosynthesis
• Similar to Bacteria
• lack a nucleus and chloroplasts
• Produce wide range of toxins sometimes released during blooms
1. Introduction4. Cyanobacteria1.4
Suspect cyanobacteria responsible for causing AVM is a filamentous form found attached to submerged aquatic vegetation
New species of Stigonematales
Large colonies can be seen on the underside of leaves
WILDE, S. B., T. M. MURPHY, C. P. HOPE, S. K. HABRUN, J. KEMPTON, A. BIRRENKOTT, F. WILEY, W. W. BOWERMAN, AND A. J. LEWITUS. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environmental Toxicology 20: 348-353.
2. Methods 2
Google Earth used to locate 56 ponds based on size and accessibility
Ponds surveyed for presence of submerged aquatic vegetation
• Hydrilla
• Brazilian elodea
• Eurasian watermilfoil
Ponds surveyed for presence of susceptible avian wildlife
2. Methods2. Pond Areas2.2
ArcView GIS software used to calculate pond areas
2. Methods2. Pond Areas2.2
ArcView GIS software used to calculate pond areas
2. Methods2. Pond Areas2.2
2. Methods3. Sampling Techniques/4. Avian Wildlife Surveys
2.3/2.4
Sampling Techniques
• Visual inspection and sampling tool used from shore to retrieve submerged vegetation
• Suspect samples taken to UNCW for positive identification
Avian Wildlife Surveys
• Species of waterfowl and birds of prey identified at each site
3. Results1. Pond Locations / 2. Pond Areas / 3. Vegetation
3.1/3.2/3.3
Pond Locations
• 56 Natural ponds, Commercial and Residential Retention ponds surveyed throughout New Hanover County
Pond Areas
• 35.3 ha to 0.13 ha
Aquatic Vegetation
• NO pond contained the invasive species of interest: hydrilla, Brazilian elodea, or Eurasian watermilfoil
• One site (Airlie Lake) had infestation of coontail (Ceratophyllum)
3. Results4. Avian Wildlife3.4
17 of 56 sites contained various species of birds
1. American coot (Fulica americana)
2. Canada goose (Branta canadensis)
3. Snow goose (Chen caerulescens)
4. Mallard duck (Anas platyrhynchos)
5. Great blue heron (Ardea herodias)
6. White ibis (Eudocimus albus)
7. Great egret (Ardea alba)
8. Mute swan (Cygnus olor)
9. Redhead (Aythya valisineria)
10. Turkey vulture (Cathartes aura)
11. Assorted diving ducks, gulls, and domestic waterfowl
3. Results4. Avian Wildlife3.4
American coots on Greenfield Lake, 1/25/06
SiteDate Surveyed
Description Coordinates Area (acres)
Area (hectares)
Vegetation Avian Wildlife
111/17/200501/25/2006
Greenfield Lake 34°12'37.78"N 77°56'14.15"W 87.24 35.30 emergent, green algae
AC, CG, MD, BH, GE, RH, TV, DD, Various ducks, gulls, and domestic waterfowl
2 10/14/2005Randall Pkwy Reservoir
34°13'48.13"N 77°53'51.35"W 22.94 9.28 emergentBH, CG, DD, Various ducks
3 10/19/2005 NP 34° 7'3.09"N 77°55'17.03"W 14.03 5.68 no access none
4 10/19/2005 Silver Lake 34° 8'34.50"N 77°54'56.31"W 10.68 4.32 emergent, green algae CG
5 10/19/2005 NP? 34° 5'30.36"N 77°55'6.76"W 9.40 3.81 no access no access
6 11/3/2005 Airlie Lake 34°12'57.56"N 77°49'40.20"W 8.21 3.32 Ceratophyllum (coontail) CG, WI, MD, BH, GE, S
7 11/3/2005 NP 34°13'53.42"N 77°50'51.51"W 7.85 3.18 green algae none
8 11/3/2005 RP 34°17'25.28"N 77°49'55.81"W 7.79 3.15 none none
9 11/9/2005 NP? 34°16'48.36"N 77°45'59.53"W 7.05 2.86 none CG, WI, MD, DD
10 10/14/2005 CP 34°11'27.22"N 77°54'40.58"W 4.65 1.88 green algae DD
11 11/3/2005 RP 34°15'2.44"N 77°49'25.94"W 3.35 1.36 emergent, green algae none
12 11/17/2005 RP 34°18'11.42"N 77°52'51.56"W 3.16 1.28 none CG
13 10/19/2005 CP 34° 6'12.59"N 77°54'39.40"W 3.16 1.28 none none
14 10/19/2005 RP 34° 9'40.77"N 77°52'46.67"W 2.91 1.18 water lily (unknown species), green algae none
15 11/17/2005 RP 34°17'58.48"N 77°52'37.06"W 2.69 1.09 none none
16 11/17/2005 RP 34°18'8.18"N 77°53'2.84"W 2.68 1.09 none CG
Table 1: Results of ponds surveyed greater than 1 hectare
SiteDate Surveyed
Description Coordinates Area (acres)
Area (hectares)
Vegetation Avian Wildlife
17 11/3/2005 RP 34°17'16.78"N 77°50'18.58"W 2.45 0.99 none none
18 10/14/2005 RP 34°10'38.70"N 77°53'49.29"W 2.44 0.99 none none
19 11/9/2005 NP? 34°17'44.15"N 77°48'18.90"W 2.42 0.98 none none
20 10/19/2005 CP 34° 6'5.30"N 77°54'57.38"W 2.40 0.97 none none
21 11/3/2005 RP 34°11'36.70"N 77°52'43.06"W 2.35 0.95 none MD
22 11/3/2005 CP 34°16'14.56"N 77°49'58.65"W 2.09 0.84 none MD
23 11/17/2005 RP 34°18'9.35"N 77°52'39.90"W 2.04 0.83 none none
24 10/19/2005 CP 34° 5'46.42"N 77°54'57.91"W 1.86 0.75 none none
25 10/19/2005 RP 34° 7'15.10"N 77°53'9.81"W 1.73 0.70 green algae none
26 10/14/2005 RP 34°10'16.13"N 77°54'56.41"W 1.55 0.63 green algae none
27 10/19/2005 RP 34° 4'14.70"N 77°53'45.53"W 1.45 0.59 water lilly (unknown species) none
28 10/14/2005 RP 34°12'0.91"N 77°55'44.29"W 1.33 0.54 emergent MD
29 10/14/2005 RP 34°11'36.06"N 77°54'23.38"W 1.26 0.51 green algae none
30 10/19/2005 RP 34° 7'37.52"N 77°53'11.95"W 1.23 0.50 none CG
31 11/3/2005 RP 34°16'26.53"N 77°49'24.46"W 1.21 0.49 none none
32 10/14/2005 CP 34°11'48.71"N 77°54'26.88"W 1.19 0.48 emergent DD
33 11/3/2005 RP 34°16'34.20"N 77°49'35.26"W 1.16 0.47 none none
34 10/19/2005 RP 34° 9'5.51"N 77°52'30.93"W 1.09 0.44 emergent BH
35 11/3/2005 CP 34°16'12.09"N 77°49'33.57"W 1.01 0.41 none none
Table 2: Results of ponds surveyed between 1 and 0.4 hectares
SiteDate Surveyed
Description Coordinates Area (acres)
Area (hectares)
Vegetation Avian Wildlife
36 10/19/2005 RP 34° 9'2.83"N 77°52'34.89"W 0.95 0.39 emergent, green algae none
37 10/14/2005 RP 34° 9'38.06"N 77°53'57.51"W 0.95 0.39 green algae none
38 10/14/2005 RP 34°11'58.74"N 77°55'35.60"W 0.95 0.39 emergent none
39 10/19/2005 RP 34° 9'50.25"N 77°51'43.29"W 0.95 0.38 none none
40 10/14/2005 RP 34° 9'40.62"N 77°54'8.01"W 0.87 0.35water lily (unknown species), green algae
BH, SG
41 11/3/2005 RP 34°15'6.94"N 77°49'24.65"W 0.81 0.33 none none
42 11/3/2005 RP 34°10'39.65"N 77°52'52.82"W 0.79 0.32 green algae none
43 11/3/2005 CP 34°11'37.46"N 77°53'5.34"W 0.72 0.29 green algae none
44 11/3/2005 RP 34°11'50.44"N 77°50'23.89"W 0.68 0.28 none none
45 11/9/2005 NP? 34°17'42.67"N 77°48'10.29"W 0.67 0.27 none none
46 10/19/2005 RP 34° 5'47.89"N 77°55'15.13"W 0.65 0.26 none none
47 11/9/2005 RP 34°17'41.62"N 77°48'14.91"W 0.31 0.13 none none
48 10/14/2005 CP 34°14'59.41"N 77°52'53.94"W unavailable unavailable no access CG, DD
49 10/14/2005 CP 34°15'0.22"N 77°53'5.27"W unavailable unavailable no access none
50 10/14/2005 RP 34° 9'19.91"N 77°54'5.05"W unavailable unavailable none CG
51 10/14/2005 RP 34° 9'40.07"N 77°53'53.50"W unavailable unavailable emergent none
52 10/19/2005 RP 34° 6'32.55"N 77°54'49.19"W unavailable unavailable emergent, green algae MD, DD
53 10/19/2005 RP 34° 6'20.71"N 77°54'35.22"W unavailable unavailable none none
54 11/3/2005 CP 34°14'25.65"N 77°49'54.41"W unavailable unavailable none CG, S
55 11/3/2005 CP 34°14'40.09"N 77°50'3.77"W unavailable unavailable none none
56 11/9/2005 RP 34°18'13.47"N 77°46'30.53"W unavailable unavailable none none
Table 3: Results of ponds surveyed less than 0.4 hectares or unavailable
4. Discussion4
NONE of the 56 ponds surveyed will currently produce an AVM occurrence based on Dr. Wilde’s hypothesis
The Suspect bacteria has been documented on several native species:
1. Coontail (Ceratophyllum demersum)
2. Illinois pondweed
3. Bladderwort
4. Lemon bacopa (Bacopa caroliniana)
5. Fragrant water lily (Nymphaea odorata)
6. Watershield (Bransenia shreberi)
4. Discussion4
Therefore the potential exists for a future occurrence of AVM at several sites:
1. Airlie Lake
• 3.32 ha
• Significant population of water birds
• Infestation of coontail
4. Discussion4
2. Sites 14, 27, and 40
• Contained various species of water lilies
• All less than 1.18 ha
• Lack susceptible
birds
4. Discussion4
3. Greenfield Lake
• 35.3
• Highest number of susceptible birds including American coot
• Significant infestation of preferred vegetation could harbor the suspect Stigonematalan species in large enough numbers to produce AVM
4. Sites 2, 4, and 9
• 9.28 ha to 2.86 ha
• several species of susceptible birds including mallard ducks and Canada geese
• An infestation of vegetation could support the bacteria and produce an AVM occurrence
4. Discussion4
Birds at Greenfield Lake
4. Discussion4
Green algae at Greenfield Lake
4. Discussion4
The 56 ponds surveyed represent an estimated 1/5 of the total ponds in New Hanover County.
Many ponds too small for consideration or not accessible due to location.
A more thorough survey should include ALL ponds greater than perhaps 1 ha.
4. Discussion4
Current research:
1. Suspect bacteria has been cultured and fed directly to American coots
• Did not produce AVM lesions
• May require environmental triggers to produce toxicity
2. Grass carp fed hydrilla material with associated Stig. Bacteria
• Developed lesions similar to those seen in birds
• Carp then fed to mallard ducks
• Ducks developed AVM lesions
3. Methods are being developed for extracting the toxins produced by the bacteria
4. Discussion4
Future research:
1. Continue to focus on suspect Stig. species and isolation of it’s toxic metabolites
2. Determine the environmental factors responsible for controlling it’s production
3. Accurate database of sites infested with aquatic vegetation capable of supporting bacteria
4. Continue to focus on how AVM is spread
5. Increase public awareness to reduce number of undiagnosed cases of AVM.
4. Discussion4
Contacts:
AVM
1. USGS National Wildlife Health Center at (608) 270-2400, http://www.nwhc.usgs.gov/disease_information/avian_vacuolar_myelinopathy/index.jsp
2. Southeastern Cooperative Wildlife Disease Study at (706) 542-1741, http://www.uga.edu/scwds/index.htm
3. U.S. Fish and Wildlife Service at (919) 856-4520, http://nc-es.fws.gov/ecotox/avm.html
4. South Carolina Algal Ecology Lab, http://links.baruch.sc.edu/scael/research/avm/avm.html
5. NC Wildlife Resources Commission at (919) 707-0050, http://www.ncwildlife.org/
Invasive Weeds
1. NC Aquatic Weed Control Program at (919) 733-4064, http://www.ncwater.org/Education_and_Technical_Assistance/Aquatic_Weed_Control/
2. New Hanover County Cooperative Extension at (910) 452-6393, http://newhanover.ces.ncsu.edu/
Questions?Questions?