Abstract
An adult yellow lipped sea krait (Laticauda colubrina) was found dead in its tank on 20 September 1998 and was presented to the
Animal Health Department at the National Aquarium in Baltimore. Prior to its death, the animal had been housed on display for seven months with four conspecifics
and five erabu sea kraits (Laticauda semifasciata). It had shown no signs of illness, and all environmental parameters were within normal limits. All nine
snakes had been maintained on a diet of live American eels (Anguilla rostrata). The remaining snakes continue to appear healthy, although diagnostic
tests have not been performed.
The dead L. colubrina was originally part of a consignment of eleven wild-caught animals from Fiji. After their initial quarantine
period, these animals were housed for four weeks with nine yellow bellied sea kraits (Pelamis platurus). The two groups were separated due to health
problems that ultimately resulted in the death of all but one P. platurus. None of the L. colubrina appeared to be affected, and this population
remained healthy for a further year.
Following the animal's death late in the day, it was stored overnight in a refrigerator at 4°. A necropsy examination showed an enlarged
and grossly abnormal liver. Aerobic cultures of the liver grew three bacteria: Morganella morganii, Edwardsiella tarda, and a Staphylococcus sp.
Following necropsy, the carcass was placed in 10% buffered formalin for histopathological examination.
Histopathology revealed atypical circulating blood cells and infiltrates in multiple organs. The morphology of these cells was characterized
by round to oval open nuclei, one nucleolus, fine chromatin stippling, and scant eosinophilic cytoplasm, implying a lymphoid origin. These cells within the kidney
had a mitotic index of 0-5 per high power field. In addition, marked myeloid hyperplasia with normal cellular maturation was observed in the bone marrow of the
vertebrae. This would further suggest that the atypical circulating cells were of lymphoid rather than myeloid origin.
A pathological diagnosis of hematopoietic neoplasia with a leukemic phase, lymphosarcoma and secondary sepsis was made. Dr. John Harshbarger,
Director of the Registry of Tumors in Lower Animals at the Smithsonian Institution, confirmed this diagnosis.
A review of the literature revealed that lymphoid leukemia1,2 and lymphosarcoma3,4 have never been documented in sea
snakes. Several cases have been reported in terrestrial snakes, all of which presented similarly and had a history of sudden death with no overt clinical signs. A
viral etiology was suspected in some of these cases.4,5,6 The tissues from this sea snake will be examined further using electron microscopy and
antibody staining studies to determine if a virus is the etiological agent.
Acknowledgements
The authors wish to thank John C. Harshbarger Ph.D (Director, Registry of Tumors in Lower Animals, Smithsonian Institution) for his
expertise and invaluable assistance. We also wish to thank Laura Chadwick (veterinary student, NC State Veterinary School) for helping with the literature review.
References
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