Use of infrared thermography in early diagnosis of pathologies in Asian elephants (elephas maximus)

Thermography is an imaging technique using a specialized heat sensitive infrared camera, mapping body surface temperature changes which may indicate inflammatory, vascular or neurological disorders. Thermal images were collected over three months from four Asian elephants at the Tisch Family Zoological Gardens in Jerusalem in which 935 body regions were identified with possible inflammatory pathologies. Suspected thermal areas were divided into three groups according to the appearance of inflammatory processes in a clinical examination: negative, positive and a pre-inflammatory group, which showed a thermal change while imaging, with clinical signs appearing only later on. An analysis of the documented regions it was found that in areas with a clinical signs delta temperatures were significantly higher compared to areas with no clinical signs. It was also found that pre-clinical areas showed a significantly higher temperature compared with that of the clinical and non-clinical areas. Receiver operating characteristic (ROC) test results showed an area under curve (AUC) of 0.91 with sensitivity values of 89.2% and a specificity of 83.4%. In addition, positive predictive value and negative predictive value received were: NPPV = 99.4%, PPV = 19.3%. It was concluded that thermography can be an effective diagnostic tool for early diagnosis of inflammatory processes and useful for regular and continuous monitoring of zoo elephants in general. Early detection of inflammatory processes using this technique makes it possible to prevent unnecessary stress that often accompanies veterinary examinations and to accelerate recovery.