Neurological disease in wild loggerhead sea turtles Caretta caretta.
Beginning in October 2000, subadult loggerhead sea turtles Caretta caretta showing clinical signs of a neurological disorder were found in waters off south Florida, USA. Histopathology indicated generalized and neurologic spirorchiidiasis. In loggerhead sea turtles (LST) with neurospirorchiidiasis, adult trematodes were found in the meninges of the brain and spinal cord of 7 and 3 affected turtles respectively, and multiple encephalic intravascular or perivascular eggs were associated with granulomatous or mixed leukocytic inflammation, vasculitis, edema, axonal degeneration and occasional necrosis. Adult spirorchiids were dissected from meningeal vessels of 2 of 11 LST brains and 1 of 10 spinal cords and were identified as Neospirorchis sp. Affected LST were evaluated for brevetoxins, ciguatoxins, saxitoxins, domoic acid and palytoxin. While tissues from 7 of 20 LST tested positive for brevetoxins, the levels were not considered to be in a range causing acute toxicosis. No known natural (algal blooms) or anthropogenic (pollutant spills) stressors co-occurred with the turtle mortality. While heavy metal toxicosis and organophosphate toxicosis were also investigated as possible causes, there was no evidence for their involvement. We speculate that the clinical signs and pathologic changes seen in the affected LST resulted from combined heavy spirorchiid parasitism and possible chronic exposure to a novel toxin present in the diet of LST.
Jacobson
Elliott R
ER
College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA. jacobsone@mail.vetmed.ufl.edu
Homer
Bruce L
BL
Stacy
Brian A
BA
Greiner
Ellis C
EC
Szabo
Nancy J
NJ
Chrisman
Cheryl L
CL
Origgi
Francesco
F
Coberley
Sadie
S
Foley
Allen M
AM
Landsberg
Jan H
JH
Flewelling
Leanne
L
Ewing
Ruth Y
RY
Moretti
Richie
R
Schaf
Susan
S
Rose
Corinne
C
Mader
Douglas R
DR
Harman
Glenn R
GR
Manire
Charles A
CA
Mettee
Nancy S
NS
Mizisin
Andrew P
AP
Shelton
G Diane
GD
D000818:Animals; D001921:Brain / Q000469:parasitology; D002802:Cholinesterases / Q000032:analysis; D005260:Female; D005431:Florida; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D008297:Male; D008387:Marine Toxins / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis; D018482:Muscle, Skeletal / Q000737:chemistry / Q000473:pathology; D009422:Nervous System Diseases / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D035964:Oxocins / Q000032:analysis; D012584:Sciatic Nerve / Q000473:pathology; D014200:Trematoda / Q000302:isolation & purification* / Q000472:pathogenicity; D014201:Trematode Infections / Q000473:pathology / Q000662:veterinary*; D014426:Turtles / Q000469:parasitology*; D000095702:Polyether Toxins
D002802:Cholinesterases; D008387:Marine Toxins; D019216:Metals, Heavy; D035964:Oxocins; C053342:brevetoxin; D000095702:Polyether Toxins