- AUGUSTA, Ga. (AP) - Scientists
are testing two bald eagles found dead along Thurmond Lake for a mysterious
neurological disease that has already killed 26 other birds on the Georgia-South
Carolina border.
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- One eagle was found on private land while the other -
too sick to fly and under attack by crows - was found at Hamilton Branch
State Park on the lake's South Carolina side, said Vic VanSant, a wildlife
biologist with the Georgia Department of Natural Resources.
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- Their carcasses were sent to the University of Georgia's
School of Veterinary Medicine for analysis. Officials believe the eagles
are the latest to succumb to Avian Vacuolar Myelinopathy, a mysterious
disease infecting eagles in the area.
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- AVM breaks down the central nervous system and causes
brain lesions. It was first diagnosed in Arkansas in 1994 and four years
later in South Carolina.
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- The disease has been confirmed every year since at Lake
Thurmond, Lake Murray, Par Pond and the Savannah River Site's L Lake.
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- The disease has been found only on inland, man-made reservoirs
low in nutrients, not along the coast.
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- Reservoirs cover 521,737 acres compared with 504,445
acres of coastal marshlands. Eagles, which once used only those coastal
sites, increasingly have spread to inland reservoirs.
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- Between 150 and 200 eagles use South Carolina reservoirs,
and 52 breeding pairs are known to nest on the largest ones, Murphy said.
Across the state, 162 pairs reproduced in South Carolina last winter.
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- Experts say AVM is caused by a naturally occurring biotoxin
produced by an alga species. The most likely suspect is a blue-green alga
that grows on hydrilla, which has been found in every reservoir where AVM
has affected birds.
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- The non-native plant, which can cover up to 4,000 acres
in one year, is expected to spread into every reservoir in the state before
long, said department aquatic nuisance species manager Steven de Kozlowski.
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- http://www.charlotte.com/mld/charlotte/news/breaking_news/4880162.htm
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- Comment
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- From Patricia Doyle, PhD
- dr_p_doyle@hotmail.com
-
- Hello Jeff: It causes leisons in brain and affects spinal
cord and central nervous system. According to the govt, it is not a prion
disease, but they don't know if proteins or prions are involved, they don't
know the causitive agent.
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- "There is NO evidence that AVM is transmissible
to humans, however, the risk to humans is unknown."
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- Is that double talk, or what?
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- Incidently, I believe that this is what caused the Brant
Geese die offs in Nov. 2000 and January 2001.
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- Patricia
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- _____
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- Emerging Disease Notice
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- January 2001
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- Summary
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- In December 2000, the US Geological Survey (USGS) issued
a Wildlife Health Alert to natural resource/conservation agencies about
significant wildlife health threats of Avian Vacuolar Myelinopathy (AVM).
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- AVM was first identified in 1994 in Bald eagles in Arkansas.
Since then sporadic cases of AVM were recognized in the Southeastern United
States in several duck species and most recently in Canada geese.
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- The host range includes only wild waterfowl and Bald
eagles.
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- No outbreaks are reported in domestic birds.
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- No data exist concerning infection of humans.
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- The disease appears to be site-specific, i.e. the lakes
where the birds are dying is the site of exposure. AVM affects the bird,s
central nervous system. The causative agent remains unknown, however, disease
appears to be caused by neurotoxins of unknown origin.
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- Many agencies are continuing field, laboratory and research
efforts to determine the cause of disease.
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- Background
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- AVM was first documented in a dozen Bald eagles and in
American coots found dead along DeGray Lake in Arkansas in the fall and
winter of 1994. Since then it was confirmed in several duck species including
Mallard, Ring-necked duck, Bufflehead, American Wigeon and in Canada geese
in the Southeastern United States. AVM is the most significant unknown
cause of eagle mortality. Disease affects birds usually between October
and March with a peak from mid-November through early December.
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- Clinical and Pathological Signs
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- AVM is an avian disease that is believed to be caused
by a neurotoxin of unknown origin. It causes open space lesions in the
white matter of the brain and in the spinal cord of affected birds. Water
birds with AVM demonstrate difficulty flying, walking and swimming. Sick
birds are usually alert and may bite when handled even if unable to escape
capture. Affected birds are usually found between October and March. Dead
birds appear to be in good body condition and have no visible external
or internal changes with the exception of microscopic neural lesions.
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- Transmission of AVM
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- It remains unknown if the disease is "spreading"
or if affected birds at other locations are being recognized because more
people are aware of the problem. All diagnostic, field and laboratory efforts
indicate the cause is most likely a chemical substance, either one naturally
occurring or manmade. It is unclear how the birds are exposed to the toxins.
One theory is waterfowl, which feed on aquatic vegetation, ingest material
associated with algae bloom. The algae is possibly producing toxic agents
fatal to Bald eagles, which feed on waterfowl. However, independent exposure
of the multiple waterfowl species cannot be ruled out. To date no confirmed
outbreak of AVM has been found in domestic waterfowl.
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- There is no evidence that AVM is transmissible to humans,
however, the risk to humans is unknown. As precautions, the USGS National
Wildlife Health Center (NWHC) recommends that people should avoid handling
wildlife having died from unknown causes. Hunters should avoid shooting
waterfowl exhibiting unusual behavior, use rubber gloves when dressing
out game, and thoroughly cook meat before eating.
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- Control and Preventive Measures
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- Many agencies including US Geological Survey, US Army
Corps of Engineers, US Fish and Wildlife Service and State agencies are
continuing field, laboratory and research efforts to determine the cause
of disease. This include water analysis from affected lakes, toxicology
analysis of affected avian tissues, and multi-state epidemiological investigation
by the Southeastern Cooperative Wildlife Disease Study Center.
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- For more information on this subject please go to the
official AVM web site, Pro-MED web site, or the USGS - NWHC web site:
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- http://www.mvk.usace.army.mil/offices/od/odm/avm
- http://www.fas.org/promed/index.html
- http://www.umesc.usgs.gov/nwhchome.html
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- If you wish to comment on this notice, please contact
Milo Muller at (970) 490-7844 or miloslav.muller@aphis.usda.gov.
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- Patricia A. Doyle, PhD
- Please visit my "Emerging Diseases" message
board at:
- http://www.clickitnews.com/emergingdiseases/index.shtml
- Zhan le Devlesa tai sastimasa
- Go with God and in Good Health
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