Lymphoid Leukemia in a Yellow Lipped Sea Krait, Laticauda colubrina: Diagnosis and Potential Etiology
IAAAM Archive
Ian D. Walker1; Brent R. Whitaker1; Anne Kincaid2
1National Aquarium in Baltimore, Baltimore, MD, USA; 2Antech Diagnostics, Farmingdale, NY, USA

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

1.  Frye F, J Carney. 1973. Acute lymphatic leukemia in a boa constrictor. Journal of the American Veterinary Association 163:653-654.

2.  Goldberg S, H Holshuh. 1991. A case of leukemia in the desert spiny lizard. Journal of Wildlife Diseases 27:521-525.

3.  Jacobsen E, M Calderwood, T French, et al. 1981. Lymphosarcoma in an eastern king snake and a rhinoceros viper. JAVMA 179:1231-1235.

4.  Jacobsen E, J. Seely, M Novilla. 1980. Lymphosarcoma associated with virus-like intranuclear inclusions in a California king snake. Journal of the National Cancer Institute 65:577-579.

5.  Langenberg J, J Teare, R Carolan, R Montali. 1983. Hematopoietic and lymphoreticular tumors in zoo animals. Laboratory Investigations 48:48A.

6.  Zschiesche W, A Konstantinov, R Ippen, Z Mladenov. 1988. Lymphoid leukemia with presence of type C virus particles in a four-lined chicken snake. Erkrankungen der Zootiere 30:275-278.

Speaker Information
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Ian D. Walker
National Aquarium in Baltimore
Baltimore, MD, USA


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