Clinic of Zoo Animals, Exotic Pets, and Wildlife, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
The captive population of Asian elephants (Elephas maximus) is not self-sustaining.2 Poor reproduction and high juvenile mortality are key factors in the decreasing population. Infection with endotheliotropic elephant herpes virus (EEHV) is one of the major causes of death in the captive population, and has resulted in the loss of at least 40 captive animals.1 EEHV has been responsible for the peracute death of two juvenile males at Zurich Zoo, Switzerland.
Mortality due to peracute infection with EEHV mainly is seen in juveniles. Early detection of characteristic clinical signs of EEHV and immediate initiation of therapy are of crucial importance due to its rapid progression. Based on past fatal EEHV experiences, Zurich Zoo modified its daily clinical health monitoring program to increase staff awareness of EEHV infection. Examinations have been incorporated into the daily routine and include daily evaluation of behaviour, appetite, colour of mucosal membranes and the measurement of body temperature; these examinations are performed by keepers.
In our experiences, characteristic signs of acute EEHV infection are lethargy, anorexia, mild colic, and cyanosis of the mucosal membranes. Results of temperature measurements have shown that best estimations of body temperature are done by measurement of the temperature in the centre of a fecal ball 5–9 min after defecation. Mean values of 36.5°C (± 0.2°C SD) are within published reference values, although adult elephants have shown significantly lower body temperature than juveniles. Establishment of individual reference values for each elephant is essential to detect unusual temperature peaks that may indicate possible EEHV viremia.
The present study has shown that daily health examinations increase the awareness of keepers for early signs of EEHV infection (e.g., peaks in body temperature and cyanotic mucosal membranes).
The authors thank B. Aeschbach and all elephant keepers for taking special care of our elephants. The work and organization of Ms. G. Hürlimann is gratefully appreciated.
1. Mikota, S. 2007. Endotheliotropic Herpesvirus (EEHV). http://www.elephantcare.org/herpes.htm. cited: 10.04.2008. (VIN editor: link updated on 1/12/21 https://web.archive.org/web/20060223062153/http://www.elephantcare.org/herpes.htm)
2. Wiese, R.J. 2000. Asian elephants are not self-sustaining in North America. Zoo Biol. 19:299–309.