Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida

Trenton R. Schoeb, Terrell G. Heaton-Jones, Roger M. Clemmons, Dwayne A. Carbonneau, Allan R. Woodward, Diane Shelton, Robert H Poppenga

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semi-circularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.

Original languageEnglish (US)
Pages (from-to)320-337
Number of pages18
JournalJournal of Wildlife Diseases
Volume38
Issue number2
StatePublished - Apr 2002
Externally publishedYes

Fingerprint

Alligators and Crocodiles
alligators
Lakes
necropsy
mortality
lakes
Mortality
lake
abnormality
hematology
peripheral nerves
electron microscopy
Peripheral Nerves
tilt
refuge
brain
microscopy
serum
muscle
Anisocoria

Keywords

  • Alligator mississippiensis
  • American alligator
  • Electromyography
  • Encephalopathy
  • Florida
  • Neuropathy

ASJC Scopus subject areas

  • veterinary(all)

Cite this

Schoeb, T. R., Heaton-Jones, T. G., Clemmons, R. M., Carbonneau, D. A., Woodward, A. R., Shelton, D., & Poppenga, R. H. (2002). Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida. Journal of Wildlife Diseases, 38(2), 320-337.

Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida. / Schoeb, Trenton R.; Heaton-Jones, Terrell G.; Clemmons, Roger M.; Carbonneau, Dwayne A.; Woodward, Allan R.; Shelton, Diane; Poppenga, Robert H.

In: Journal of Wildlife Diseases, Vol. 38, No. 2, 04.2002, p. 320-337.

Research output: Contribution to journalArticle

Schoeb, TR, Heaton-Jones, TG, Clemmons, RM, Carbonneau, DA, Woodward, AR, Shelton, D & Poppenga, RH 2002, 'Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida', Journal of Wildlife Diseases, vol. 38, no. 2, pp. 320-337.
Schoeb TR, Heaton-Jones TG, Clemmons RM, Carbonneau DA, Woodward AR, Shelton D et al. Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida. Journal of Wildlife Diseases. 2002 Apr;38(2):320-337.
Schoeb, Trenton R. ; Heaton-Jones, Terrell G. ; Clemmons, Roger M. ; Carbonneau, Dwayne A. ; Woodward, Allan R. ; Shelton, Diane ; Poppenga, Robert H. / Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida. In: Journal of Wildlife Diseases. 2002 ; Vol. 38, No. 2. pp. 320-337.
@article{0acae726527b468483817cb0caff2a83,
title = "Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida",
abstract = "From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semi-circularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.",
keywords = "Alligator mississippiensis, American alligator, Electromyography, Encephalopathy, Florida, Neuropathy",
author = "Schoeb, {Trenton R.} and Heaton-Jones, {Terrell G.} and Clemmons, {Roger M.} and Carbonneau, {Dwayne A.} and Woodward, {Allan R.} and Diane Shelton and Poppenga, {Robert H}",
year = "2002",
month = "4",
language = "English (US)",
volume = "38",
pages = "320--337",
journal = "Journal of Wildlife Diseases",
issn = "0090-3558",
publisher = "Wildlife Disease Association, Inc.",
number = "2",

}

TY - JOUR

T1 - Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida

AU - Schoeb, Trenton R.

AU - Heaton-Jones, Terrell G.

AU - Clemmons, Roger M.

AU - Carbonneau, Dwayne A.

AU - Woodward, Allan R.

AU - Shelton, Diane

AU - Poppenga, Robert H

PY - 2002/4

Y1 - 2002/4

N2 - From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semi-circularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.

AB - From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semi-circularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.

KW - Alligator mississippiensis

KW - American alligator

KW - Electromyography

KW - Encephalopathy

KW - Florida

KW - Neuropathy

UR - http://www.scopus.com/inward/record.url?scp=0036547594&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036547594&partnerID=8YFLogxK

M3 - Article

C2 - 12038132

AN - SCOPUS:0036547594

VL - 38

SP - 320

EP - 337

JO - Journal of Wildlife Diseases

JF - Journal of Wildlife Diseases

SN - 0090-3558

IS - 2

ER -