# A Retrospective Review of Wild and Zoo-Housed Platypus Medical Records (1991–2024)

## TL;DR

This study reviews 34 years of platypus medical records to better understand their health and diseases, revealing new insights for conservation and zoo care.

## Contribution

The study reports novel diseases in platypuses, including cancers and rat lungworm infection, using a multi-institutional retrospective review.

## Key findings

- Juvenile platypuses in northern regions were more frequently presented to veterinarians, especially around weaning time.
- Skin conditions were common in zoo-housed platypuses, suggesting a need for further research.
- Novel diagnoses such as cancers and rat lungworm infection were identified in platypuses for the first time.

## Abstract

Platypuses are unique and iconic Australian mammals. Because they are frequently nocturnal and spend significant time either in burrows or in water, it can be challenging to understand platypus health and diseases. We accessed and reviewed the veterinary records of 278 individual wild platypuses and 40 zoo-housed platypuses from 21 organisations and individuals, spanning 34 years. From these records, we looked at information including: age and sex; location and date of presentations; why the platypuses were presented to a veterinarian; whether they died or survived; and health and disease findings. Wild juvenile platypuses were more likely to be presented to veterinarians in the north of their range than in the south, with many juvenile presentations around the time of weaning. Skin conditions were common in zoo-housed platypuses. The records included diagnoses not previously reported in platypuses, including cancers and rat lungworm infection. This study increases our understanding of platypus health and disease, and we believe its insights will both support the species’ conservation and improve the welfare of zoo-housed platypuses.

Understanding platypus health and disease is made challenging by the cryptic nature of this unique and iconic species. The retrospective medical record review methodology offers a valuable tool to better understand platypus health. A multi-institution review was performed, with 21 organisations and individuals contributing veterinary and pathology records spanning 34 years and 5 Australian states and territories. In total, records were reviewed from 278 wild platypuses and 40 zoo-housed platypuses, with a combined total of 383 presentations. Data from these were extracted and analysed, providing information on demography (age, sex), geographic location, season, reason for presentation, outcome of presentation, and clinical and pathological findings. For wild platypuses, key findings included that the juvenile age class was disproportionately represented in Queensland and New South Wales, and that the peak in juvenile presentations corresponded with weaning. For both wild and zoo-housed platypuses, novel reports of neoplasia were identified, and in wild platypuses, the first reports of neural angiostrongyliasis. For zoo-housed platypuses, an area identified for future research is the high prevalence of presentations for skin lesions. This study contributes to our understanding of platypus health and disease and should be used to guide further work to improve both conservation and welfare outcomes for one of the world’s most unique mammals.