Clinical usefulness of infrared thermography to detect sick animals: frequent and current cases

Abstract

Infrared thermography (IRT) is a tool that has been studied extensively in the experimental medical field as a method for assessing surface thermal responses under various conditions. These may involve local inflammatory processes resulting from surgical procedures, wounds, neoplasms, pathologies, painful events, or stressful states in animals. IRT measures changes in blood flow in surface blood capillaries and the resulting heat radiation. In the clinical field, thermography has been used as a support method for detecting painful conditions. However, some guidelines indicate that it could be applied for assessing and monitoring animals in rehabilitation to quantify objectively possible improvements in their quality of life. Similarly, it has been observed that IRT makes it possible to assess the degree of circulation in dermal tissue, suggesting that it could be used to determine the degree of damage in traumatized tissue in cases of thromboembolic diseases and burns. This would be useful to distinguish between damaged and healthy tissue and thus determine the optimal therapy for burn patients. This review aims to analyze scientific evidence on the clinical applications of IRT for detecting diseases and assessing painful conditions. A literature search on different databases was performed to recover articles related to the application of IRT as a complementary diagnostic tool, as well as its potential for assisting in rehabilitation, monitoring wounds, and evaluating body temperature in domestic animals.

Is the Weight of the Newborn Puppy Related to Its Thermal Balance?

“…According to the results reported in this study, the most notable thermoregulatory changes in newborn puppies were low temperatures in the distal regions, that is, in the thermal windows of TLM and FPL, and high temperatures in thermal windows A, T, and ULP. This could be because the most important structures related to metabolism and vital functions are found in the thoracic, abdominal, and cranial regions [ 47 , 48 ]. The appendicular windows presented the lowest temperatures, which can be explained, in the case of newborn puppies, because they still do not present locomotion, as they are an altricial species, and their degree of neurological development, responsible for the mechanism of thermal modulation, is immature.…”

Thermoregulation mechanisms and perspectives for validating thermal windows in pigs with hypothermia and hyperthermia: An overview

“…Research into the use of IRT with swine seeks to confirm its applicability in new areas of study due to its information on physiological states and animal health. One possibility could be to implement IRT continuously to evaluate the temperature in real time on production units in both individual animals and entire herds and so determine the presence of lesions or infectious diseases ( 161 , 162 ). Although these future applications would be the areas to be developed, it is necessary to establish the reliability of IRT at different body regions.…”

“…Likewise, IRT monitoring may help reduce economic losses for producers while simultaneously procuring animal welfare by allowing early detection of diseased individuals ( 162 ) or recognizing injured animals during transport and the association that this might have on meat quality due to acute stress or dehydration ( 8 , 162 ). Applying IRT prior to slaughter, for example, makes it possible to estimate levels of well-being ( 118 ).…”

Thermal Imaging to Assess the Health Status in Wildlife Animals under Human Care: Limitations and Perspectives

“…IRT is helpful in the case of pregnancy because increased blood irrigation causes an increase in the surface temperature at the level of the flank in pregnant females. Additionally, it can help determine the association of certain emotional states with temperature changes and indirectly evaluate the habitat or housing of those animals [ 11 , 17 ].…”

“…The authors of those reports affirm that IRT has a high sensitivity for evaluating facial ( faciei regions ) and appendicular regions ( membri thoracici and membri pelvini regions ), but low diagnostic sensitivity in regions such as the trunk ( regio pectoris ) and abdomen ( regio abdominis ), due to the presence of thick fur that interferes with thermographic readings [ 56 ]. Other windows suggested for these species are at the facial level (eye, mouth, tongue) [ 11 ]. They could help assess thermoregulation in wild felines [ 13 ].…”