Ultrasonographic Assessment and Ultrasound-Guided Biopsy of the Retropharyngeal Lymph Nodes in Elephants
American Association of Zoo Veterinarians Conference 2006
Thomas Bernd Hildebrandt1, DVM; Robert Hermes1, DVM; Parntep Ratanakorn2, DVM, PhD; Wolfram Rietschel3, DVM; Joerns Fickel1, Dr RetNat; Roland Frey1; Catherine Reid1, DVM; Frank Goeritz1, DVM
1Institute for Zoo and Wildlife Research, Berlin, Germany; 2Faculty of Veterinary Science, Mahidol University at Salaya, Nakhon Pathom, Thailand; 3Wilhelma Zoological Botanical Garden, Stuttgart, Germany


So far there are no valid diagnostic tools available for identifying latent carriers of endotheliotropic elephant herpes virus (EEHV).4,5 For this reason, the lateral retropharyngeal lymph node complex (LARELYNOC) of elephants, identified during postmortem studies as target organ for EEHV and suitable for transcutaneous biopsy, was grossly described.3 Transcutaneous ultrasound (3.5 MHz) was applied behind the ear region to identify the LARELYNOC containing up to four single lymph nodes on each side. The lymph node tissue is situated 20–50 mm below the skin surface. An ultrasonographic assessment of the LARELYNOC and two biopsies were performed on 39 healthy Asian elephants (Elephas maximus). Samples were tested for EEHV via PCR.1,2 Whole blood samples were also collected and tested for active EEHV infection. Lymph nodes were ultrasonographically classified as active (calculated mean volume=17.4±6.9 cm3, p>0.001), inactive (calculated mean volume=3.1±0.6 cm3, p<0.001), or chronic active (calculated mean volume=10.6±1.0 cm3, p<0.05). Histology confirmed not only the presence of lymph tissue but also the ultrasonographically diagnosed reactivity status of the lymph node biopsies. Although all samples including whole blood were found to be negative for the EEHV DNA particles, the successful development of this procedure in elephants could prove beneficial for the screening of not only latent EEHV infections but might also be a less dangerous alternative method for the diagnosis of zoonotic infections such as tuberculosis.5


The authors like to acknowledge the German Research Council and the Thai government for funding this project. The authors are grateful for additional financial support by the African Lion Safari, Cambridge, Canada and the Zoo Zurich, Switzerland. The authors also thank the staff of all facilities contributing with their help and expertise.

Literature Cited

1.  Fickel, J., L.K. Richman, R.J. Montali, W. Schaftenaar, F. Goeritz, T.B. Hildebrandt, and Ch. Pitra. 2001. Detection of the elephant herpesvirus in Asian (Elephas maximus) and African (Loxodonta africana) elephants in European zoos. Vet Microbiol. 82:103–109.

2.  Fickel, J, D. Lieckfeldt, L.K. Richman, W.J. Streich, T.B. Hildbrandt, and Ch. Pitra. 2002. Comparison of glycoprotein B (gB) variants of the elephant endotheliotropic herpesvirus (EEHV) isolated from Asian elephants (Elephas maximus). Vet Microbiol. 91:11–21.

3.  Hildebrandt, T.B., R. Hermes, P. Ratanakorn, W. Rietschel, J. Fickel, R. Frey, G. Wibbelt, C. Reid, and F. Goeritz. 2005. Ultrasonographic assessment and ultrasound-guided biopsy of the retropharyngeal lymph nodes in Asian elephants (Elephas maximus). Vet Rec. 29:544–548.

4.  Montali, R.J., L.K. Richman, S. Mikota, D.L. Schmitt, R.S. Larsen, T.B. Hildebrandt, R. Isaza, and W.A. Lindsay. 2001. Management aspects of herpesvirus infections and tuberculosis in elephants. In: Schwammer, H.M., T.J. Foose, M. Fouraker, and D. Olson, eds. Scientific Progress Reports. Vienna, June 2001. Schüling Verlag, Münster, Pp. 87–95.

5.  Richman, L.K., R.J. Montali, R.L. Garber, M.A. Kennedy, J. Lehnhardt, T.B. Hildebrandt, D.L. Schmitt, D. Hardy, D.J. Alcenor, and G.J. Hayward. 1999. Novel endotheliotropic herpesviruses fatal for Asian and African elephants. Science. 283:1171–1176.


Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Thomas B. Hildebrandt, DVM
Institute for Zoo and Wildlife Research
Berlin, Germany

MAIN : All : Elephant Retropharyngeal LN US Assessment & Biopsy
Powered By VIN