Investigation Into Individual Health and Exposure to Infectious Agents of Platypuses (Ornithorhynchus Anatinus) in Two River Catchments in Northwest Tasmania

Abstract

Changes in the health of individuals within wildlife populations can be a cause or effect of population declines in wildlife species. Aspects of individual platypus (Ornithorhynchus anatinus) health have been reported. However, holistic studies investigating potential synergistic effects of both pathogens and environmental factors are needed to expand understanding of platypus individual health. We collected baseline data on the health of platypuses in two Tasmanian river catchments (including evidence of the potentially fatal fungal disease mucormycosis) and on individual, demographic, and geographic patterns associated with health data results. We examined 130 wild platypuses from the Inglis River Catchment and 24 platypuses from the Seabrook Creek Catchment in northwest Tasmania between 29 August 2011 and 31 August 2013. More than 90% of captured platypuses were infected with ticks, Theileria spp., and trypanosomes. Evidence of exposure to other infections, including Salmonella spp., Leptospira spp., and intestinal parasites, was low (,10%). Three platypuses had single fungal granulomas in the webbing of a forefoot, but no evidence of mucormycosis was found in any of the study animals. Possible subclinical hepatopathies or cholangiohepatopathies were found in six platypuses. Exposure to infectious agents did not cluster geographically, demographically, or in individuals, and there was minimal evidence of morbidity resulting from infection. This study has provided important baseline data for monitoring the effects of threatening processes, including mucormycosis, on the health of infected populations.

The platypus: evolutionary history, biology, and an uncertain future

“…Assessing the reproductive status of females remains reliant on inducing milk let-down using injected synthetic oxytocin (Grant et al 2004). Health assessments include external physical examination, collection of parasites, sampling excreta for reproductive hormones, corticosteroid analysis or pathogens, and sampling blood for hematology, serum biochemistry, and serology (e.g., Mucor enzyme-linked immunosorbent assay [ELISA], Leptospira serovar antibody titers—Connolly et al 1998; Macgregor 2015; Macgregor et al 2017b).…”

“…Mucormycosis may also be detectable clinically or via signs or presence of spherules in cytology or histology of lesions, but this is less accurate than culture. Corynebacterium ulcerans or non- Mucor fungal skin disease can cause similar infections and cutaneous foreign body reactions (Connolly et al 1998; Macgregor et al 2017b). Mucormycosis was accidentally introduced to toads and frogs on the Australian mainland (Northern Territory, Queensland, New South Wales) by captive frogs from Melbourne and Perth, but the infection has not been recorded in mainland platypuses.…”

“…An adenovirus-like virus causes a cytomegalic inclusion renal disease (Whittington et al 1990) and a putative papilloma virus causes webbing papules (Booth and Connolly 2008). Between 47% and 66% of platypuses in New South Wales and 10% in Tasmania had leptospirosis based on serology, while in Victoria, 25% of platypus necropsied showed suggestive nephritis histologically (McColl and Whittington 1985; Loewenstein et al 2008; Macgregor et al 2017b). The Ixodes ornithorhynchi tick is common and may cause a mild dermatitis but importantly, it can be a vector of the hemoparasites Theileria ornithorhynchi and Trypanosoma binneyi (Booth and Connolly 2008), with the former sometimes causing hemolytic anemia in immunocompromised platypuses (Kessell et al 2014).…”

Applying a modified streamlined disease risk analysis framework to a platypus conservation translocation, with special consideration for the conservation of ecto- and endoparasites

“… Endemic ( Roberts, 1970 ). Highly prevalent in platypuses across their range ( Whittington and Grant, 1983 ; Whittington and Spratt, 1989 ; Macgregor et al, 2017 ). Pathogenicity 1.…”