Haematological reference intervals of wild southern Australian koalas (Phascolarctos cinereus)

Resident wild koalas show resilience to large-scale translocation of bushfire-rescued koalas

Wildlife translocation is increasingly utilized as a conservation management action, to mitigate the immediate negative effects of habitat loss and fragmentation (e.g. from land clearing or bushfires). Previous research has shown that stress responses can help or hinder survival in translocated wildlife and determine the efficacy of translocation as a conservation action. Yet these translocated animals are only one side of the equation, with translocation also potentially impacting the animals in the recipient population. We measured physiological markers of stress (faecal cortisol metabolite concentrations and neutrophil-lymphocyte ratios) and assessed health condition in a wild koala population one year after a major translocation of bushfire-rescued koalas on Kangaroo Island. We expected to find a high population density at the site (>0.75 koalas per hectare) and that resident koalas would show signs of chronic stress and ill health as a result of territorial conflict over food trees and reproductive opportunities. In contrast, we found that only one-fifth of the population remaining at the site were translocated koalas. The overall population density was also much lower (0.21 koalas per hectare) than anticipated. With no evidence of mass mortality at the site, we suggest that the majority of translocated koalas dispersed away from the site. Our stress marker measurements did not differ between the wild koalas and a sample of captive (non-display) koalas at the nearby Kangaroo Island Wildlife Park and were generally low compared to other studies. Veterinary examinations found that most koalas were in good body condition with very few diagnostic indicators of systemic ill health. Overall, our results suggest that, if there is adequate landscape-scale habitat connectivity and opportunity for dispersal, translocated koalas are likely to disperse from the site of release, with limited impacts on recipient koala populations at translocation release sites.

Establishment of Hematological and Plasma Biochemical Reference Values and Analysis of Risk Factors for Pet Sugar Gliders (Petaurus breviceps) in Taiwan

Hematological and plasma biochemical examination are crucial in the veterinary care of sugar gliders, which are increasingly popular in Taiwan and the United States. However, published research of the species' reference interval and related influencing factors were rare. The objectives of this study were to establish the hematological and plasma biochemical reference values for captive sugar gliders in Taiwan and to evaluate the influence of factors including age, gender, neuter status, location, season, diet, caging arrangement, and other pets in the household. A total of 42 clinically healthy pet sugar gliders were recruited. Morphometrical measurements and physiological data were collected, and hematological and plasma biochemical examinations were performed. The reference value of each index was calculated using Reference Value Advisor (RVA) software, following the American Society for Veterinary Clinical Pathology (ASVCP) guidelines. Normality of data distribution was tested, and data transformation was conducted. The parametric method and robust method were used to determine reference limits. Univariate analysis was performed, and multiple regression models were built for each hematological and plasma biochemical parameter. Red blood cell, hematocrit, and hemoglobin levels were higher in males, compared to females, while they were lower in the neutered group, compared to the intact group. Relative neutrophil counts were higher in elder sugar gliders, while relative lymphocyte counts were lower. Aspartate transaminase levels were higher in elder sugar gliders, while albumin levels were lower. Blood urea nitrogen levels were highest in spring. The blood profile and related effects presented in this study can provide useful information for veterinary care in pet sugar gliders.

Pathological Findings in Koala Retrovirus-positive Koalas (Phascolarctos cinereus) from Northern and Southern Australia

Koala retrovirus (KoRV) infection shows differences in prevalence and load between northern and southern Australian koala populations; however, the effect of this on diseases such as lymphoma and chlamydial disease is unclear. This study compared clinicopathological findings, haematology and splenic lymphoid area of KoRV-positive koalas from northern (Queensland [Qld], n = 67) and southern (South Australia [SA], n = 92) populations in order to provide further insight into KoRV pathogenesis. Blood was collected for routine haematology and for measurement of KoRV proviral load by quantitative polymerase chain reaction (qPCR). Plasma samples were assessed for KoRV viral load by reverse transcriptase qPCR and conjunctival and cloacal swabs were collected for measurement of the load of Chlamydia pecorum (qPCR). During necropsy examination, spleen was collected for lymphoid area analysis. Lymphoma was morphologically similar between the populations and occurred in koalas with the highest KoRV proviral and viral loads. Severe ocular chlamydial disease was observed in both populations, but urinary tract disease was more severe in Qld, despite similar C. pecorum loads. No associations between KoRV and chlamydial disease severity or load were observed, except in SA where viral load correlated positively with chlamydial disease severity. In both populations, proviral and viral loads correlated positively with lymphocyte and metarubricyte counts and correlated negatively with erythrocyte and neutrophil counts. Splenic lymphoid area was correlated positively with viral load. This study has shown further evidence for KoRV-induced oncogenesis and highlighted that lymphocytes and splenic lymphoid tissue may be key sites for KoRV replication. However, KoRV infection appears to be highly complex and continued investigation is required to fully understand its pathogenesis.