Yolk Embolization in Two Related Komodo Dragons (Varanus komodoensis)
American Association of Zoo Veterinarians Conference 2015
Dawn Zimmerman1*, DVM, MS; Ben Okimoto1, DVM; Drury R. Reavill2, DVM, DACVP, DABVP
1Honolulu Zoo, Honolulu, HI, USA; 2Zoo/Exotic Pathology Service, Sacramento, CA, USA


Two related (clutchmates) adult female Komodo dragons (Varanus komodoensis) presented with lethargy and coelomic distention during the breeding season. One died spontaneously and the other was euthanized at surgical exploration. Antemortem hematology and biochemistry profiles were within normal ISIS limits for the species.1 On gross post-mortem examination, both dragons exhibited proteinaceous hemorrhagic coelomic fluid and, bilaterally, the ovaries supported multiple necrotic-appearing and ruptured vitellogenic follicles. Multiple slugs were observed in the coelomic cavity of one dragon. Two significant histologic lesions included yolk protein material within the vasculature of many internal organs (kidney, lung, liver, spleen, intestines, adrenal glands, heart, and ovarian stroma) and severe renal mineralization of the glomerular mesangium.

Yolk coelomitis has been reported in Komodo dragons and is well described in Fiji Island banded iguanas (Brachylophus fasciatus).2,4 These two cases, while supporting some mild lesions of yolk proteins free in the coelom, had a more significant yolk embolization. Within reptilian genera, yolk embolization has been described in adult female sea turtles, all with identified evidence of trauma.3

The glomeruli appear to be one of the least common sites for renal mineralization. Vitamin D toxicity resulting in hypercalcemia is one of the better described causes; however, mineralization is generally found in additional sites such as the gastric mucosa, lungs, and major blood vessels. Further research on the pathogenesis of follicle stasis, atresia, and rupture as well as the pathophysiology of calcium metabolism in female lizards is warranted.

Literature Cited

1.  International Species Information System References Ranges for Physiological Values in Captive Wildlife CD-ROM, 2013 ed., Eagan, MN, USA.

2.  Spellman LH. Medical Management. In: Murphy JB, Ciofi C, de la Panouse C, Walsh T (eds.). Komodo Dragons: Biology and Conservation. Washington, DC: Smithsonian Press; 2002:208–210.

3.  Stacy BS, Foley A, Garner MM, Mettee N. Yolk embolism associated with trauma in vitellogenic sea turtles in Florida (USA): A review of 11 cases. J Zoo Wildl Med. 2013;44(4):1043–1048.

4.  Stacy BS, Howard L, Kinkaid J, Vidal JD, Papendick R. Yolk coelomitis in Fiji Island banded iguanas (Brachylophus fasciatus). J Zoo Wildl Med. 2008;39(2):161–169.


Speaker Information
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Dawn M. Zimmerman, DVM, MS
Honolulu Zoo
Honolulu, HI, USA

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