Comparing the agreement of a commercial cortisol kit with a biologically validated assay in evaluating faecal cortisol metabolite levels in koala joeys.

Orphaned koala joeys constitute a substantial number of wildlife rescues. Mortality is highly prevalent in rehabilitating joeys, with little knowledge about the causes of mortality. The hypothalamic-pituitary-adrenal axis plays a vital role in mediating stress by producing glucocorticoids (e.g. cortisol), however, no studies have quantified glucocorticoids in koala joeys. Traditional cortisol enzyme immuno-assay (e.g. R4866) are limited in supply and are process intensive, whereas, modern enzyme immuno-assay (EIA) kits (e.g. Arbor Assay cortisol kit) are available world-wide and provide rapid results. Biological validation is unsuitable to be performed in recuperating joeys due to ethical considerations, hence, we compared the results from biologically validated R4866 assay with the commercially available Arbor Assay cortisol kit. Thirty-four faecal samples were collected, processed and analysed for faecal cortisol metabolites (FCM) using both, R4866 assay and Arbor Assay kit. The joeys presented a suite of clinical conditions which provided the natural variation in stress response for comparing the assay sensitivity and range. The results indicated that there were no significant differences between the FCM values measured by both the assays. Furthermore, the Bland-Altman plot indicated a very strong agreement between the FCM concentrations measured by the two assays. This study is only a step towards recommending the routine use of commercial kit in clinical settings with basic resources, for rapid quantification of stress in koala patients. It is crucial for future studies to perform laboratory validation procedures to confirm the efficacy of the commercial kit before practical use for FCM monitoring in koalas.

Transmission of Koala Retrovirus from Parent Koalas to a Joey in a Japanese Zoo.

Koala retrovirus (KoRV) is of an interest to virologists due to its currently active endogenization into the koala (Phascolarctos cinereus) genome. Although KoRV has frequently been isolated in wild and captive koala populations, its pathogenesis and transmission remain to be fully characterized, and most previous research has concentrated on adult koalas rather than on joeys. Here, we characterized KoRV isolates obtained from a deceased male joey and its parents (animals reared in a Japanese zoo) to investigate KoRV transmission mode and pathogenesis. We sequenced the KoRV long terminal repeat (LTR) and envelope genes isolated from the joey and its parents and found KoRV-A and KoRV-C in genomic DNA from both the parents and the joey. Notably, both parents were also positive for KoRV-B, whereas the joey was KoRV-B negative, further confirming that KoRV-B is an exogenous strain. The KoRV LTR sequence of the joey was considerably closer to that of its sire than its dam. For further characterization, total KoRV, KoRV-A, KoRV-B, and KoRV-C proviral loads were quantified in peripheral blood mononuclear cells from the parents and in blood samples from the joey. Total KoRV, KoRV-A, and KoRV-C proviral loads were also quantified for different tissues (bone, liver, kidney, lung, spleen, heart, and muscle) from the joey, revealing differences suggestive of a distinct tissue tropism (highest total KoRV proviral load in the spleen and lowest in bone). The amount of KoRV-C in the parents was less than that in the joey. Our findings contribute to an improved understanding of KoRV pathogenesis and transmission mode and highlight useful areas for future research.IMPORTANCE KoRV is unique among retroviruses in that one strain (KoRV-A) is undergoing endogenization, whereas the other main subtype (KoRV-B) and another subtype (KoRV-C) are reportedly exogenous strains. Its transmission and pathogenesis are of interest in the study of retroviruses and are crucial for any conservation strategy geared toward koala health. This study provides new evidence on the modes of KoRV transmission from parent koalas to their joey. We found vertical transmission of KoRV-A, confirming its endogenization, but with closer conservation between the joey and its sire than its dam (previous reports on joeys are rare but have postulated dam-to-joey vertical transmission). This is also the first report of a KoRV-B-negative joey from KoRV-B-positive parents, contrasting with the few previous reports of 100% transmission of KoRV-B from dams to joeys. Thus, the results in this study give some novel insights for the transmission mode of KoRV.

Macropod Pediatrics.

Macropods belong to the marsupial family Macropodidae, which includes animals such as kangaroos and wallabies. Macropod offspring are highly altricial at birth and require specialized care and environmental conditions for healthy development. The care and management of pediatric macropods poses a challenge due to the unique physiology and reproductive strategy of macropods. In order to successfully work with pediatric macropods, clinical veterinarians should have knowledge of species-specific husbandry, normal postnatal development, and common medical conditions/treatments. With limited information available on macropod pediatric medicine, further research is warranted to improve the care and management of these animals in human care.