Gammaherpesvirus infection in a free-ranging eastern grey kangaroo (Macropus giganteus)

A gammaherpesvirus was detected by polymerase chain reaction (PCR) in ocular, nasal and oropharyngeal swab samples collected from an adult free-ranging male eastern grey kangaroo (Macropus giganteus) with clinical signs of severe respiratory disease. This is the first time a gammaherpesvirus has been detected in a free-ranging macropod in Australia. The nucleotide sequence of a conserved region of the DNA polymerase gene of the detected virus showed a high degree of identity to a gammaherpesvirus recently detected in a zoological collection of eastern grey kangaroos in North America. The detection of this gammaherpesvirus in a free-ranging, native eastern grey kangaroo provides evidence that this species is a natural host.     

Reactivation of a macropodid herpesvirus from the eastern grey kangaroo (Macropus giganteus) following corticosteroid treatment.

The family Herpesviridae is a large group of viruses which contain double stranded DNA genomes. Biological characteristics, such as host signs, site of replication and site of latency have been used to describe three major subfamilies, Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae within the family Herpesviridae. Macropodid herpesviruses (MaHV) have been implicated in fatal outbreaks amongst the captive marsupial populations of Australia. These outbreaks have resulted in the isolation of nine MaHV strains which have been classified into two species called macropodid herpesvirus 1 and 2 (MaHV-1 and MaHV-2). Biological characteristics have been used to place MaHV-1 and -2 within the subfamily Alphaherpesvirinae. Molecular phylogenetic reconstructions indicate an unusual position for MaHV-1 and -2 within the alphaherpesviruses. Current isolates of MaHVs have all been obtained from marsupials exhibiting clinical disease. A common biological characteristic of herpesviruses is the establishment of latent infections in nervous tissue. We have determined that MaHV are able to latently infect eastern grey kangaroos through reactivating and isolating a herpesvirus by inducing immunosuppression. We have investigated the possible sites of latency for MaHV-1 using molecular techniques. Detection of herpesvirus DNA in the trigeminal ganglia taken from two naturally infected eastern grey kangaroos indicates dissemination via a respiratory route.     

Putative sporidesmin toxicity in an Eastern Grey kangaroo (Macropus giganteus)

A 2-year-old, captive, male Eastern Grey kangaroo (Macropus giganteus) died after progressive weight loss over a 4 week period. Biochemical analysis suggested hepatobiliary injury. At necropsy the liver was small, pale and firm. There were no abnormalities detected in other organs. Histopathological examination revealed a severe, diffuse, obliterative cholangiohepatopathy with advanced periportal fibrosis. This chronic hepatotoxicity was consistent with exposure to sporidesmin, the toxic metabolite in the spores of the fungus Pithomyces chartarum. Restricted grazing opportunities and heavy fungal pasture contamination may have precipitated sporidesmin toxicity in this animal. Sporidesmin toxicity has not previously been reported in this species.     

Identification and isolation of a novel herpesvirus in a captive mob of eastern grey kangaroos (Macropus giganteus)

A novel herpesvirus was detected in a captive mob of eastern grey kangaroos (Macropus giganteus) during diagnostic workup for individuals with ulcerative cloacitis. Virus was initially detected in tissues using a consensus herpesvirus PCR. No viral inclusions or particles had been evident in routine histologic or transmission electron microscopic sections of cloacal lesions. Virus was isolated from samples and transmission electron microscopy of the resulting isolates confirmed that the virus was morphologically consistent with a herpesvirus. Nucleotide sequencing of the PCR product from tissue samples and from the isolates revealed that the virus was in the subfamily Gammaherpesvirinae and was distinct from other known herpesviruses. The correlation between the lesions and the novel virus remains unknown. Two herpesviruses, both in the subfamily Alphaherpesvirinae, have previously been described in macropods and are known to cause systemic clinical disease. This is the first reported gammaherpesvirus within the order Marsupialia, and may provide valuable information regarding the evolution and phylogeny of this virus family. Based on current herpesvirus nomenclature convention, the authors propose the novel herpesvirus be named Macropodid herpesvirus 3 (MaHV-3).     

Detection of Toxoplasma gondii IgG antibodies in juvenile great grey kangaroos, Macropus giganteus giganteus.

Serial IgG antibody titers to Toxoplasma gondii from three juvenile great grey kangaroos (Macropus giganteus giganteus) with clinical signs consistent with toxoplasmosis were compared with titers from three clinically normal juveniles of similar age. The modified agglutination test was used to measure antibodies to T. gondii. Results demonstrated declining antibody titers to T. gondii in five of six animals. Antibody titers were similar in animals with and without clinical signs. This was interpreted as an indication that maternal IgG antibodies to T. gondii were transferred to juveniles, presumably in milk, rather than an indication of clinical disease. Therefore, clinicians should interpret Toxoplasma serology results in juvenile macropods cautiously.     

Collection and short-term preservation of semen from free-ranging eastern grey kangaroos (Macropus giganteus: Macropodidae)

Objectives To evaluate electro-ejaculation of free-range eastern grey kangaroos in the field and assess the efficacy of four diluents to preserve sperm motility over a 48-h period at 5°C.
Procedure and design Under gaseous anaesthesia, 25 free-range kangaroos were electro-ejaculated and characteristics of the ejaculate noted. Spermatozoa obtained from eight ejaculates were diluted in phosphate buffered saline containing various combinations of egg yolk and glucose and refrigerated at 5°C for 48 h.
Results Spermatozoa were recovered from 24 of 28 ejaculates. Mean (± SEM) semen volume (mL) and pH were 25.0 ± 1.9 and 7.1 ± 0.1 respectively. The forward motility (%), rate of movement of sperm (0 to 5) and sperm concentration (x 10⁶/mL) were 77.4 ± 1.5, 3.8 ± 0.9 and 31.2 ± 7.3 respectively. There was no significant difference between the four diluents in their ability to maintain forward motility of spermatozoa over 48 h. However, rate of movement over the same period was significantly (P < 0.01) improved when sperm were diluted in phosphate buffered saline containing 10% egg yolk.
Conclusions Electro-ejaculation is a safe and reliable method for collecting semen from free-ranging eastern grey kangaroos. Preliminary attempts at short-term preservation showed that the motility of kangaroo spermatozoa could be adequately stored for 24 h and that the addition of egg yolk to the semen diluent was beneficial for improving the rate of sperm movement.     

Electroretinography in the western gray kangaroo (Macropus fuliginosus)

Objective To perform electroretinography on normal anesthetized western gray kangaroos (Macropus fuliginosus). Animals studied Six captive western gray kangaroos. Procedures The kangaroos were anesthetized using a combination of ketamine and medetomidine via a remote drug delivery system, then were maintained on isoflurane after endotracheal intubation and reversal of the medetomidine with atipamazole. After a minimum of 20 min of dark adaptation, electroretinograms were obtained using a handheld electroretinography (ERG) machine using a single flash protocol at three light intensities: 10 mcd.s/m², 3000 mcd.s/m², 10 000 mcd.s/m². Results At 10 mcd.s/m² the mean b‐wave amplitude and implicit time was 102.0 μV (SD ± 41.3 and 95% CI 68.9–135.1) and 78.4 ms (SD ± 8.3 and 95% CI 71.8–85.0). At 3000 mcd.s/m² the mean a‐wave amplitude and implicit time was 69.9 μV (SD ± 20.5 and 95% CI 53.5–86.3) and 17.6 ms (SD ± 1.5 and 95% CI 16.4–18.8) and the mean b‐wave amplitude and implicit time was 175.4 μV (SD ± 35.9 and 95% CI 146.7–204.1) and 74.1 ms (SD ± 3.5 and 95% CI 71.2–76.9). At 10 000 mcd.s/m² the mean a‐wave amplitude and implicit time was 89.1 μV (SD ± 27.1 and 95% CI 67.5–110.8) and 16.8 ms (SD ± 1.0 and 95% CI 16.0–17.0) and the mean b‐wave amplitude and implicit time was 203.7 μV (SD ± 41.4 and 95% CI 170.6–236.8) and 75.4 ms (SD ± 3.3 and 95% CI 72.8–78.1). Conclusion Electroretinography outside of the typical clinical setting is feasible using a portable ERG system and allows for quick analysis of retinal function in exotic species.     

Fluorosis as a probable cause of chronic lameness in free ranging eastern grey kangaroos (Macropus giganteus).

A population of eastern grey kangaroos (Macropus giganteus) inhabiting heathland and farmland surrounding an aluminum smelter at Portland, Victoria, Australia, exhibited clinical signs of lameness. An investigation was undertaken to determine the cause of this lameness. Hematology, necropsy, histopathology, fecal egg count, total worm count, reproductive status, and the population age range were examined and failed to reveal any additional underlying disease state. The specific problem of lameness was addressed with bone histopathology, radiography, quantitative ultrasonography, microradiography, and multielement analysis of bone ash samples. The significant lesions observed were: osteophytosis of the distal tibia and fibula, tarsal bones, metatarsus IV, and proximal coccygeal vertebrae; osteopenia of the femur, tibia, and metatarsus IV; incisor enamel hypoplasia; stained, uneven, and abnormal teeth wear; abnormal bone matrix mineralization and mottling; increased bone density; and elevated bone fluoride levels. Microradiography of affected kangaroos exhibited "black osteons," which are a known manifestation of fluorosis. Collectively, these lesions were consistent with a diagnosis of fluorosis.     

Metastatic Osteolytic Angioleiomyosarcoma Induced by a Foreign Body in a Kangaroo (Macropus giganteus)

An adult female Eastern Grey kangaroo (Macropus giganteus) was examined for lameness due to a mass located at the right tibiotarsal joint. Radiographs revealed a metal arrowhead‐shaped foreign body within the mass alongside a pathologic fracture. Grossly, at necropsy, there was a multilobulated and haemorrhagic mass with intralesional metal fragments, associated osteolysis of the tibiotarsus and pulmonary metastatic nodules. Histologically the neoplasm was composed of plump elongated and fusiform cells that often formed concentrically around small vessels. The pulmonary nodules were composed of similar neoplastic cells, necrosis and haemorrhage. Neoplastic cells were positive immunohistochemically for vimentin and smooth muscle actin. The histological features, immunohistochemical profiles and behaviour of this tumour support a diagnosis of a primary angioleiomyosarcoma with lung metastasis associated with a metal foreign body.     

Extended anaesthesia and nasotracheal intubation of a red kangaroo (Macropus rufus)

Anaesthesia requires maintenance of a patent airway. Nasotracheal intubation of a red kangaroo (Macropus rufus) was performed when the inability to open the animal’s mouth prevented orotracheal intubation. Nasotracheal intubation was easy to perform, secured the airway and permitted delivery of supplemental oxygen, isoflurane and intermittent positive pressure ventilation.     

Unilateral failure of development of mandibular premolars and molars in an Eastern Grey kangaroo (Macropus giganteus) and its effects on molar progression

An adult male Eastern Grey kangaroo from a wildlife reserve near Melbourne was submitted for necropsy examination and was discovered to have abnormal dentition. There was no evidence that any premolars or molars had ever been present on the right mandible, whilst the incisors were normal. The age of the kangaroo was estimated to be 1 year 9 months using the right maxillary molars and 2 years 4 months old using the contralateral side, presumably due to the asymmetry of the dental arcades. 'Lumpy jaw', a common periodontal disease of kangaroos, from which Bacteroides sp was cultured, was present on the base of the vertical ramus of the left mandible. Complete unilateral absence of premolar and molar teeth in the mandible of a kangaroo has not been described. This condition affected molar progression in both sets of maxillary molars.     

The large‐scale capture of eastern grey kangaroos (Macropus giganteus) and red kangaroos (Osphranter rufus) and its application to a population management project

Objective: A large‐scale capture method was developed to enable sterilisation of a macropod population in western Sydney from 2005 to 2018. Methods: Until March 2007, free ranging eastern grey kangaroos and red kangaroos were herded into purpose‐built 15 m diameter capture yards (CYs) for darting with a projectile syringe. From March 2007 onwards, animals were free‐range darted in large areas without herding. Kangaroos were darted with 1.33–5.10 mg/kg tiletamine/zolazepam and 0.01–0.02 mg/kg medetomidine, ± 0.03 mg/kg acepromazine. Deaths were monitored. Population counts were performed annually. Results: There were 5825 capture events involving 3963 kangaroos. Over 85% of all captures occurred from 2005 to 2008. Of all reported deaths (n = 523), 135 were attributed to ill health. Musculoskeletal injuries incurred during capture were the main project‐related cause of death (n = 116). Post capture myopathy was uncommonly diagnosed following capture (n = 19). Conclusion: The herding and capture method enabled a large number of kangaroos to be mobilised and captured with low mortality rates, and the use of CYs resulted in fewer capture‐related injuries and deaths than free‐range capture. The drug doses and combinations used for darting were safe and effective, and the capture technique was successfully applied to a population management project.