The application of allostasis and allostatic load in animal species: A scoping review

Principles of allostasis and allostatic load have been widely applied in human research to assess the impacts of chronic stress on physiological dysregulation. Over the last few decades, researchers have also applied these concepts to non-human animals. However, there is a lack of uniformity in how the concept of allostasis is described and assessed in animals. The objectives of this review were to: 1) describe the extent to which the concepts of allostasis and allostatic load are applied theoretically to animals, with a focus on which taxa and species are represented; 2) identify when direct assessments of allostasis or allostatic load are made, which species and contexts are represented, what biomarkers are used, and if an allostatic load index was constructed; and 3) detect gaps in the literature and identify areas for future research. A search was conducted using CABI, PubMed, Agricola, and BIOSIS databases, in addition to a complementary hand-search of 14 peer-reviewed journals. Search results were screened, and articles that included non-human animals, as well as the terms “allostasis” or “allostatic” in the full text, were included. A total of 572 articles met the inclusion criteria (108 reviews and 464 peer-reviewed original research). Species were represented across all taxa. A subset of 63 publications made direct assessments of allostatic load. Glucocorticoids were the most commonly used biomarker, and were the only biomarker measured in 25 publications. Only six of 63 publications (9.5%) constructed an allostatic load index, which is the preferred methodology in human research. Although concepts of allostasis and allostatic load are being applied broadly across animal species, most publications use single biomarkers that are more likely indicative of short-term rather than chronic stress. Researchers are encouraged to adopt methodologies used in human research, including the construction of species-specific allostatic load indexes.

PREVALENCE, TREATMENT, AND SURVIVAL OF BURNED WILDLIFE PRESENTING TO REHABILITATION FACILITIES FROM 2015 TO 2018

In recent decades, wildfires have increased in frequency and geographic scale across the globe. The human health implications and ecological succession after wildfires are well documented and studied, but there is a lack of empirical research about the direct effects of wildfires on wildlife. Recent wildfires have demonstrated the need to better understand animal burn injuries and innovations in veterinary burn treatment. An online survey was distributed to wildlife rehabilitation facilities internationally to collect baseline information about the number and type of burned wildlife cases admitted, treatments used, and survivorship of wildlife affected by wildfires. Approximately 80% (n = 49) of all respondents (n = 61) reported admitting cases of burned wildlife from 2015 to 2018. Respondents included facilities from six different countries and roughly 43% of facilities reported having a veterinarian on staff. Electrical burns were most commonly reported with 89% of respondents stating that they had seen electrical burns while 38% of respondents reported seeing wildfire-source thermal burns in wildlife patients. Respondents were asked about their frequency of use of different treatment methods. Bandages, colloid fluids, and opioids were used at significantly higher rates at facilities with veterinarians compared with facilities that did not report having a veterinarian; however, survival of burned wildlife patients did not significantly differ based on the factor of having a veterinarian on staff. Long-term and short-term complications were commonly reported for wildlife burn patients; 88% of facilities reported scarring, 81% reported alopecia, and 61% reported sepsis. Burned animals admitted to facilities were reported to have equal odds of dying and surviving. Burn care recommendations have changed considerably in recent decades. This study provided a unique opportunity to compare contemporary recommendations in human medicine with current methods used in wildlife rehabilitation facilities to identify potential areas of further investigation and improvement for wildlife medicine.