W. Kirk Suedmeyer, DVM, DACZM
Thermography detects differences in infrared radiation emitted by any object above absolute zero. With an increase in temperature, the amount of radiation is also increased and detected at the skin level through the use of an infrared thermography camera. Differences in emissivity are interpolated through color. In veterinary medicine, thermography is commonly utilized with marine mammals, though its use is increasing across a broader range of subjects.1-4
In many cases, visual evaluation of inflammatory or circulatory lesions belies the full extent of affected tissue. This is readily apparent with animals such as elephants. In one particular case, visual examination of a female African elephant (Loxodonta africana) demonstrated a small, superficial abrasion to the skin from intraspecific trauma, but thermography revealed much larger areas of inflammation at multiple sites. In another elephant, a small, localized abscess on the lateral aspect of the foot pad demonstrated erythema extending further proximally than could be assessed clinically. Lesions associated with abrasions in a sea lion (Zalophus californianus) revealed greater areas of erythema than what presented visually. A dromedary camel presented with a large, chronic, symmetrical swelling to the cranium. Use of comparative thermography determined the swelling was simply depots of adipose tissue. Decreased circulation, subtle differences in weight distribution, evaluation of thermoregulation and fluid administration under anesthesia, quarantine and pre-shipment exams, and detection of thermogradients in holding stalls can be determined through thermography as well.
Thermography increases the diagnostic capabilities of the zoo clinician when evaluating animals for underlying disease processes.
The author wishes to thank the staff at the Kansas City Zoo for their expertise and care of the animals
1. Fleming GJ, Isaza R. Thermography evaluation of trunk paralysis in an Asian elephant (Elaphas maximus) using digital thermography. In: Proceedings from the American Association of Zoo Veterinarians. 2000:502–503.
2. Fleming GJ, Isaza R, Spire MF. Evaluation of reptile thermoregulation and enclosure design using digital thermography. In: Proceedings from the American Association of Zoo Veterinarians. 2001:2–3.
3. Clippinger TL, Cook RA. Diagnostic thermography: applications in zoo animal medicine. In: Proceedings from the American Association of Zoo Veterinarians. 1999:191–193.
4. Weissenbock NM, Weiss CM, Schwammer HM, Kratochvil H. Thermal windows on the body surface of African elephants (Loxodonta africana) studies by infrared thermography. J Therm Biol. 2010;35(4):182–188.