Spontaneous Lesions of Endangered Geriatric Julia Creek Dunnarts (Sminthopsis douglasi, Archer 1979) with Emphasis in Reproductive Pathology

TL;DR

This study examines age-related health issues in endangered Julia Creek dunnarts, revealing common reproductive and skin conditions that may impact conservation efforts.

Contribution

The first documentation of spontaneous geriatric diseases in Julia Creek dunnarts, offering insights into reproductive and oncogenic conditions in this endangered species.

Findings

Cystic glandular hyperplasia was the most common issue in female dunnarts.

Males showed testicular degeneration and possible lymphoid neoplasia.

Cutaneous lesions suggest a possible oncogenic viral etiology in both sexes.

Abstract

This study focuses on the spontaneous lesions observed in a captive colony of geriatric Julia Creek dunnarts, an endangered carnivorous marsupial. Despite their conservation status, no prior research has focused on the conditions affecting captive individuals attaining senescence. We examined one wild and thirty-five captive-born, mostly elderly dunnarts that failed to reproduce over several breeding periods. From these, ten dunnarts had normal findings. Among females, the most common issue was cystic glandular hyperplasia (eight cases); cutaneous lesions were infrequent (two cases). Males showed testicular degeneration, aspermatogenesis, or atrophy (three cases). Cutaneous lesions compatible with epitheliotropic T cell lymphomas were observed in both sexes (five cases) and thus, an underlying oncogenic viral etiology is suspected. This is the first study that documents spontaneous diseases in aging Julia Creek dunnarts, shedding light on geriatric conditions within a conservation context.

Julia Creek dunnarts are an endangered species of carnivorous marsupials and the focus of multiple conservation strategies involving significant resources such as captive breeding programs. Despite the relevance for conservation, no study to date has focused on evaluating geriatric diseases in dunnarts. This study describes the pathology findings in a group of one wild and thirty-five captive-born, mostly geriatric Julia Creek dunnarts that failed to produce offspring over multiple breeding periods. A total of 20 females and 16 males were submitted for a postmortem examination, with ages ranging from 9 to 42 and 12 to 42 months for females and males, respectively. Of these, 10 had unremarkable findings. The most common condition in females was cystic glandular hyperplasia (n = 8), typical of hormonal dysregulation profiles in senescence, particularly hyperestrogenism. Rarely, cutaneous disease represented by unidentified dermal round cell infiltrates was observed in females (n = 2). Primary reproductive hormonal dysregulation was also suspected in males diagnosed with testicular degeneration, aspermatogenesis and/or atrophy (n = 3). Cutaneous round cell infiltrates, possibly compatible with epitheliotropic lymphomas, were seen in males (n = 3), and 2/3 affected males also had concurrent testicular degeneration or atrophy, indicating male sex could be a predictor for lymphoid neoplasia in aged dunnarts, especially in individuals with concurrent testosterone-luteinizing hormone dysregulation as it occurs in gonadectomized animals. The role of an underlying viral etiology is also explored. This study is the first to describe major spontaneous diseases in endangered aged Julia Creek dunnarts, providing an important understanding of senescence and geriatric diseases within a conservation context.

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