Abstract
Cardiovascular disease is a significant cause of morbidity and mortality in captive orangutans.5 Knowledge of heart disease in orangutans lags behind other ape species. Peer-reviewed publications on orangutan cardiac disease are limited to case reports, mostly focusing on congenital conditions and postmortem diagnoses.1,2,6,7,9,11 Orangutans have evolutionary differences and specialized physiologic adaptations that may make comparison of cardiac parameters between orangutans, other apes, and humans potentially problematic.3,4,8,10
In a 2012 health survey of captive U.S. orangutans, 15% of zoos housing orangutans reported diagnosing cardiac disease pre-mortem (Orangutan Species Survival Plan, unpublished data). A systematic review of medical records from participating institutions has shown that of the eight orangutans diagnosed with cardiac disease pre-mortem, five were asymptomatic when diagnosed during routine examination. Seven out of the eight cases were diagnosed via echocardiogram. Echocardiograms are integral in the diagnosis of this disease process and should be included in all routine exams. Collaboration with human cardiologists to obtain precise images and the Great Ape Heart Project (GAHP) in the accurate interpretation of these images is crucial.
The science of treating orangutans with cardiac drugs is still in its infancy. In conjunction with the GAHP, a treatment using ACE inhibitors and beta blockers has been used to manage cardiovascular disease in orangutans, but more information is needed to ensure a beneficial impact on management and survival. It is vital for institutions housing orangutans to collaborate with the GAHP to help assemble this information and develop a database of normal parameters for orangutans.
Acknowledgments
The authors thank the Orangutan Species Survival Plan (https://orangutanssp.org) and the Great Ape Heart Project (https://greatapeheartproject.org), as well as cooperating zoological institutions, for the support provided in the successful completion of this project.
Literature Cited
1. Greenburg MJ, Janssen DL, Jamieson SW, Rothman A, Frankville DD, Cooper SD, Kriett JM, et al. Surgical repair of an atrial septal defect in a juvenile Sumatran orangutan (Pongo pygmaeus sumatraensis). J Zoo Wildl Med. 1999;30(2):256–261.
2. Kenny DE, Knightly F, Haas B, Hergott L, Kutinsky I, Eller JL. Negative-pressure pulmonary edema complicated by acute respiratory distress syndrome in an orangutan. J Zoo Wildl Med. 2003;34(4):394–399.
3. Knott CD. Reproductive, Physiological, and Behavioral Responses of Orangutans in Borneo to Fluctuations in Food Availability [PhD Dissertation]. Cambridge, MA: Harvard University; 1999. https://cherylknott.files.wordpress.com/2011/06/knott-1999-thesis.pdf
4. Locke DP, Hillier LW, Warren WC, Worley KC, Nazareth LV, Muzny DM, Yang S, et al. Comparative and demographic analysis of orangutan genomes. Nature. 2011;469(7331):529–533.
5. Lowensteine LJ, McManamon R, Bonar CJ, Perkins L. Preliminary results of a survey of U.S. and Canada orangutan mortalities in the North American SSP population from 1980 to March 2008. In: Proceeding from the American Association of Zoo Veterinarians; 2008. Abstract 40.
6. Miyagi J, Tsuhako K, Kinjo T, Iwamasa T, Kamada Y, Kinju T, Koyanagi Y. Coxsackievirus B4 myocarditis in an orangutan. Vet Pathol. 1999;36(5):452–456.
7. Robbins PK, Pye GW, Sutherland-Smith M, Papendick R, Greenberg M, Levy D, Mandani M. Successful transabdominal subxiphoid pericardiostomy to relieve chronic pericardial effusion in a Sumatran orangutan (Pongo abelli). J Zoo Wildl Med. 2009;40(3):564–567.
8. Pontzera H, Raichlenb DA, Shumakerc RW, Ocobocka C, Wiche SA. Metabolic adaptation for low energy throughput in orangutans. In: Proceedings from the National Academy of Sciences of the United States of America; August 10, 2010; 107(32):14048–14052. Available from: https://www.pnas.org/content/107/32/14048.
9. Slaffer SN, Allchurch AF. Diagnosis and treatment of dilated (congestive) cardiomyopathy in a Sumatran orangutan. Dodo. 1995;31:147–152.
10. Tomokazu K, Sato F. Detailed comparative anatomy of the extrinsic cardiac nerve plexus and postnatal reorganization of the cardiac position and innervation in the great apes: orangutans, gorillas, and chimpanzees. Anat Rec (Hoboken). 2012;295:438–453.
11. Weisenberg E, Snook S. Sudden death in an obese orangutan with hypertensive heart disease and a history of stroke. In: Proceedings from the American Association of Zoo Veterinarians; 1991. Abstract 172.