Exposure to Persistent Organic Pollutants in Australian Waterbirds

There is growing worldwide recognition of the threat posed by persistent organic pollutants (POPs) to wildlife populations. We aimed to measure exposure levels to POPs in a Southern Hemisphere aquatic waterbird species, the nomadic gray teal (Anas gracilis), which is found across Australia. We collected wings from 39 ducks harvested by recreational hunters at two sites (one coastal, one inland) in Victoria, southeastern Australia, in 2021. We examined three groups of POPs: nine congeners of polychlorinated biphenyls (PCBs), 13 organochlorine pesticides (OCPs), and 12 polycyclic aromatic hydrocarbons (PAHs). The PCBs, OCPs, and PAHs were detected at quantifiable levels in 13%, 72%, and 100% of birds, respectively. Of the congeners we tested for in PCBs, OCPs, and PAHs, 33%, 38%, and 100% were detected at quantifiable levels, respectively. The highest levels of exposure to POPs that we found were to the PAH benzo[b]fluoranthene, occurring at a concentration range of 1.78 to 161.05 ng/g wet weight. There were some trends detected relating to differences between geographical sites, with higher levels of several PAHs at the coastal versus inland site. There were several strong, positive associations among PAHs found. We discuss potential sources for the POPs detected, including industrial and agricultural sources, and the likely role of large-scale forest fires in PAH levels. Our results confirm that while Australian waterbirds are exposed to a variety of POPs, exposure levels are currently relatively low. Additional future investigations are required to further characterize POPs within Australian waterbird species. Environ Toxicol Chem 2024;43:736-747. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Interactions Between Heavy Metal Exposure and Blood Biochemistry in an Urban Population of the Black Swan (Cygnus atratus) in Australia

There is growing recognition of the threat posed to wildlife by pollutants. Waterbirds are robust bioindicators of ecosystem health, and metal toxicity is a threat to these species in waterways worldwide. Urban waterbirds are likely to be at the highest risk of heavy metal exposure, but this issue has not been widely explored in Australia. Our aim was to estimate contemporary heavy metal exposure in a sedentary urban waterbird population: black swans (Cygnus atratus) inhabiting an inner-city wetland in one of Australia's largest cities, Melbourne. To investigate the physiological implications of legacy heavy metal exposure in these birds, we quantified blood biochemistry profiles and examined their relationships with metal concentrations in feathers. We caught 15 swans in 2021 and took feather samples to measure the concentration of eight heavy metals (chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), and mercury (Hg)), and blood samples to measure the concentration of 13 plasma analytes. Multivariate regression analysis revealed few associations between heavy metals and biochemistry markers, and no differences between sexes or age classes. This study presents a baseline dataset of these contaminants and blood biochemical profiles of swans at this wetland that can be used for future monitoring and is an important step toward a better understanding of the threat posed by heavy metals to Australian urban waterbirds.

Toxoplasma gondii Does Not Inhibit the Assisted Colonization of Eastern Barred Bandicoots (Perameles gunnii) to Phillip Island, Victoria, Australia

Eastern barred bandicoots (Perameles gunnii) are thought to be highly susceptible to disease caused by infection with the protozoan parasite Toxoplasma gondii. This study followed a population of 67 P. gunnii introduced onto the Summerland Peninsula, Phillip Island, Australia, where the prevalence of T. gondii infection in the feral cat population was known to be very high. Prior to release, bandicoots were tested for serologic exposure to T. gondii using the modified agglutination test. A subset of bandicoots was tested on four occasions after release onto the peninsula. No seroconversion was detected at any time point. A subset of bandicoots was radiotracked after release and at two additional trapping sessions to help monitor survival. Toxoplasma gondii DNA was not detected by PCR in eight carcasses recovered for necropsy. Fourteen founder bandicoots (21% of founders) were known to be alive at 500 d post-release. A total of 29 unmarked bandicoots were trapped over the study period, confirming that the bandicoots were successfully reproducing on the island. Body weight, packed cell volume, and total plasma protein were used as measures of individual animal health; population health was inferred from these data. Body weight was significantly associated with trip number, with a general trend of increasing weight after release onto the island. This study showed that eastern barred bandicoots were able to establish a new population despite a probably high environmental load of T. gondii.

Towards a pan marsupial sero-immunological tool in the demanding field of wildlife serology: Marsupial immunoglobulin-binding capability with protein A/G, protein L and anti-kangaroo antibody

Detection of infections in wildlife species is increasingly important to reduce the risk of spreading zoonotic and economically important parasites, understand disease epidemiology and promote the conservation of wildlife species. Serological tests are key in disease diagnosis and surveillance by detecting immunoglobulins against infectious agents. However, the need for species-specific reagents has limited the application of serological tests in wildlife species. This study evaluated the serum immunoglobulin-binding capability of polyclonal anti-kangaroo antibody and two non-species-specific reagents, including protein A/G and protein L, with the largest range of Australian marsupial species so far, including 32 species representing three major marsupial orders. Immunoglobulin-binding capability was assessed using immunoblotting, enzyme-linked immunosorbent assay and Western blot techniques. Variation in immunoglobulin-binding capability was observed between the three reagents and across the species tested, both across but also within taxonomic groups. Taxonomic distance was thus not always a good predictor of immunoglobulin-binding affinity, emphasizing the need to validate these reagents for each species separately. However, all three reagents bound with the serum immunoglobulins of most marsupial species tested. The findings of this study provide a valuable reference for species differences in affinity to protein A/G, protein L and anti-kangaroo antibody, assisting in the selection of appropriate reagents and the development of sero-immunological assays in Australian marsupials.

Epidemiology of Anaplasma marginale and Anaplasma centrale infections in African buffalo (Syncerus caffer) from Kruger National Park, South Africa

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A Novel Marine Mammal Coxiella burnetii-Genome Sequencing Identifies a New Genotype with Potential Virulence

The obligate intracellular bacterial pathogen Coxiella burnetii has been identified in a few species of marine mammals, some of which are showing population declines. It has been hypothesized that C. burnetii in marine mammals is a distinct genotype that varies significantly from the typical terrestrial genotypes. It appears to lack an IS1111. Isolates originating from Australian marine animals have a distinctly non-Australian profile of multiple-locus variable-number tandem-repeat analysis (MLVA). Extracted Coxiella DNA of Australian fur seal placental origin was sequenced using the Novaseq platform. Illumina 150 bp paired-end reads were filtered and trimmed with Trimgalore. The microbial community present in the sequenced genome was evaluated with Kraken and Bracken software using the NCBI database. A phylogenetic analysis was performed using 1131 core genes. Core genes were identified using Panaroo and inputted into Iqtree to determine the maximum-likelihood tree. A second phylogenetic tree was created using Rickettsiella grylii and using seven housekeeping genes. Results were compared with the C. burnetii Nine Mile RSA439 virulent genome. This new Australian marine mammal isolate of Coxiella (PG457) appears to be a novel genotype that lacks IS1111 and has a distinct MLVA signature (ms26, ms27, ms28, ms30, and ms31). The presence of genes for multiple virulence factors appears to give this genotype sufficient pathogenicity for it to be considered a possible causative agent of abortion in Australian fur seals as well as a potential zoonotic risk.

Lead exposure of mainland Australia's top avian predator

Lead (Pb) toxicity, through ingestion of lead ammunition in carcasses, is a threat to scavenging birds worldwide, but has received little attention in Australia. We analyzed lead exposure in the wedge-tailed eagle (Aquila audax), the largest raptor species found in mainland Australia and a facultative scavenger. Eagle carcasses were collected opportunistically throughout south-eastern mainland Australia between 1996 and 2022. Lead concentrations were measured in bone samples from 62 animals via portable X-ray fluorescence (XRF). Lead was detected (concentration >1 ppm) in 84% (n = 52) of the bone samples. The mean lead concentration of birds in which lead was detected was 9.10 ppm (±SE 1.66). Bone lead concentrations were elevated (10-20 ppm) in 12.9% of samples, and severe (>20 ppm) in 4.8% of samples. These proportions are moderately higher than equivalent data for the same species from the island of Tasmania, and are comparable to data from threatened eagle species from other continents. Lead exposure at these levels is likely to have negative impacts on wedge-tailed eagles at the level of the individual and perhaps at a population level. Our results suggest that studies of lead exposure in other Australian avian scavenger species are warranted.

Expanding the use of portable XRF to monitor lead exposure in an Australian duck species two decades after a ban on lead shot

There is growing worldwide recognition of the threat posed by toxic lead for wildlife and humans. Lead toxicity from ammunition has been shown to be a threat to waterbirds across the globe. Lead shot was banned for all waterfowl hunting in Victoria, Australia, in 2002. However, no assessments of lead exposure in Australian waterfowl have been published since the 1990s. Our aim was to estimate contemporary lead exposure via measuring bone lead concentrations in a harvested dabbling duck, the Pacific black duck (Anas superciliosa). We collected wings from 77 Pacific black ducks, spanning 2018 (n = 30) and 2021 (n = 47), from nine sites with long-term histories of regular waterfowl hunting. We sought to validate portable X-ray fluorescence (XRF) for this purpose by taking a piece of humerus bone from each bird, and measuring lead concentration (mg/kg), first via non-destructive XRF and then via destructive inductively coupled plasma mass spectrometry (ICP-MS) and validated the relationship via regression analysis. Portable XRF bone lead measurement demonstrated a strong correlation with ICP-MS results using root-transformed regression (R² = 0.85). Greater than 92 % of ducks had only background lead exposure (<10 mg/kg). When compared to historical studies in the same species at similar field sites from the 1990s, lead exposure levels were considerably lower, with mean lead concentrations ∼2-fold lower (3.7 c.f. 7.7 mg/kg), and the frequency of birds with severe lead exposure (>20 mg/kg) ∼3-fold lower (2.6 c.f. 7.5 %). Our results confirm that portable XRF is a useful option for measurement of bone lead in Australasian waterbird species. Our findings also demonstrate that a ban on the use of lead shot around 20 years ago has been associated with a substantial reduction in lead exposure in at least one species of waterfowl.

Perspectives of vets on plastics in veterinary medicine

INTRODUCTION

The use of disposable plastics and their subsequent environmental impacts are topics of increasing concern in modern society. Medical, including veterinary, sectors are major contributors to plastic waste production. While there is an existing body of literature on the use and reduction of disposable plastics in the human medical sector, few studies, if any, have specifically investigated the use of plastics within the veterinary field. The overall aim of this pilot study was to investigate Australian veterinarians regarding their attitudes toward the ways in which they use disposable plastic in their work and personal lives.

MATERIALS AND METHODS

Seven veterinarians were interviewed, representing a range of demographics and professional backgrounds from multiple states. Thematic qualitative analysis was employed to organise the data into several major themes encompassing many smaller nodes.

RESULTS

The dataset revealed that most, if not all, veterinarians interviewed agree that disposable plastic is used in excess in veterinary medicine, but that veterinarians will never be able to avoid using plastic entirely. Participants supplied differing opinions with respect to the best strategies for reducing plastic waste production within the veterinary field, including recycling, replacing disposable items or improving education.

DISCUSSION

Despite different participants suggesting conflicting ideas, most, if not all, of the ideas presented have support in the scientific literature. This supports a hybrid approach involving refining recycling systems, reducing plastic consumption and improving education on plastic waste production. A hybrid top-down-bottom-up approach must include encouraging cooperation among stakeholders, both within and outside the veterinary sector, as this will be a major contributor to progress. In a broader context, this hybrid approach to inciting change at all levels of the veterinary sector will require engagement from many interdependent entities; as such, this study should act as a starting point for an ongoing process of cooperative change. Recommendations for future research include life cycle analyses of reusable versus disposable veterinary materials; exploring ways to expand sustainability education within and beyond the veterinary sector, and examining methods of improving technology and infrastructure.

Unravelling the Diversity of Microorganisms in Ticks from Australian Wildlife

Ticks and tick-borne pathogens pose a significant threat to the health and welfare of humans and animals. Our knowledge about pathogens carried by ticks of Australian wildlife is limited. This study aimed to characterise ticks and tick-borne microorganisms from a range of wildlife species across six sites in Victoria, Australia. Following morphological and molecular characterisation (targeting 16S rRNA and cytochrome c oxidase I), tick DNA extracts (n = 140) were subjected to microfluidic real-time PCR-based screening for the detection of microorganisms and Rickettsia-specific real-time qPCRs. Five species of ixodid ticks were identified, including Aponomma auruginans, Ixodes (I.) antechini, I. kohlsi, I. tasmani and I. trichosuri. Phylogenetic analyses of 16S rRNA sequences of I. tasmani revealed two subclades, indicating a potential cryptic species. The microfluidic real-time PCR detected seven different microorganisms as a single (in 13/45 ticks) or multiple infections (27/45). The most common microorganisms detected were Apicomplexa (84.4%, 38/45) followed by Rickettsia sp. (55.6%, 25/45), Theileria sp. (22.2% 10/45), Bartonella sp. (17.8%, 8/45), Coxiella-like sp. (6.7%, 3/45), Hepatozoon sp. (2.2%, 1/45), and Ehrlichia sp. (2.2%, 1/45). Phylogenetic analyses of four Rickettsia loci showed that the Rickettsia isolates detected herein potentially belonged to a novel species of Rickettsia. This study demonstrated that ticks of Australian wildlife carry a diverse array of microorganisms. Given the direct and indirect human-wildlife-livestock interactions, there is a need to adopt a One Health approach for continuous surveillance of tick-associated pathogens/microorganisms to minimise the associated threats to animal and human health.

Pacific Gulls (Larus pacificus) as Potential Vectors of Coxiella burnetii in an Australian Fur Seal Breeding Colony

Recently, Coxiella burnetii has been described as a novel pathogen potentially contributing to decreased pup production in Australian fur seals (AusFS, Arctocephalus pusillus doriferus). Pacific gulls (PGs, Larus pacificus) are known to scavenge AusFS placental material during the fur seal breeding season. It is hypothesized that PGs may act as vectors for this pathogen. In the present study, cloacal swabs, oral swabs and serum were collected from PGs on Kanowna Island (KI, an AusFS breeding colony) and a nearby island, Seal Island (SI), not occupied by pinnipeds. All sample sets were evaluated with qPCR for the com1, htpAB and IS1111 markers. Most oral and cloacal swabs from KI tested positive on both the com1 (94.1%; 88.2%) and htpAB targets (76.5%; 76.5%). Amplification was very low from the SI oral swabs and cloacal swabs. Only the KI serum samples had amplification (17.7% for both com1 and htpAB). There was no IS1111 amplification in either colony. The results demonstrate that PGs can potentially act as vectors for the spread of C. burnetii. In some birds, C. burnetii was detectable in the serum, indicating that gulls can experience bacteraemia. It appears that different feeding strategies in the same species within the same ecosystem can have profound effects on the prevalence of pathogens. Further studies are required to better understand the epidemiology and potential risks of this organism.

An assessment of ectoparasites across highland and lowland populations of Leadbeater's possum (Gymnobelideus leadbeateri): Implications for genetic rescue translocations

Leadbeater's possum (Gymnobelideus leadbeateri) is a nocturnal arboreal marsupial with a restricted range centered on the Victorian Central Highlands, south-eastern Australia. Most populations inhabit wet montane ash forest and subalpine woodland, with one notable exception - a small, outlying and genetically-distinct lowland population inhabiting swamp forest at Yellingbo, Victoria. The species has been listed as critically endangered since 2015. Translocations are the mainstay of critical genetic rescue and this study explores the ectoparasites that are ‘along for the ride’ during translocation activities. Ectoparasites (133 fleas, 15 ticks and 76 mites) were collected opportunistically from 24 Leadbeater's possum colonies during population monitoring and genetic sampling across the lowland and highland populations. The composition of the flea assemblage varied by habitat type. Significantly greater numbers of the general marsupial fleas Acanthopsylla r. rothschildii. and Choristopsylla tristis (as a proportion of total flea numbers) were detected in lowland habitats, compared to highland habitats (Fishers exact test, P < 0.0001). Two host-specific flea species, Stephanocircus domrowi and Wurunjerria warnekei were detected only on possums in highland habitats. As a proportion of total fleas this was significantly different to possums in lowland habitats (Fisher's exact test, P = 0.0042 and P < 0.0001, respectively). Wurunjerria warnekei was suspected to be extinct prior to this study. Ticks (Ixodes tasmanii, n = 15) and mites (Haemdoelaps cleptus, n = 47 and H. anticlea, n = 29) have been identified in Leadbeater's possums historically. The possible causes of the different flea assemblages may be environmental/climatic, or due to the historic geographic division between highland and lowland animals. The planned translocations of highland individuals to lowland habitats will expose lowland individuals to novel species of previously exclusively highland fleas with unknown indirect consequences, thus careful monitoring will be required to manage any potential risks.

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Ectoparasites were examined in critically endangered Leadbeater's possum populations. .

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Differences were seen between the lowland and the highland populations.

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The fleas Wurunjerria warnekei and Stephanocircus domrowi were found in the highlands.

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The fleas Choristopsylla tristis and Acanthopsylla rothschildii sp were found in the lowlands.

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Wurrenjerria warnekei, thought to be extinct prior to this study, was found.

Descriptive Comparison of ELISAs for the Detection of Toxoplasma gondii Antibodies in Animals: A Systematic Review

Toxoplasma gondii is the zoonotic parasite responsible for toxoplasmosis in warm-blooded vertebrates. This systematic review compares and evaluates the available knowledge on enzyme-linked immunosorbent assays (ELISAs), their components, and performance in detecting T. gondii antibodies in animals. Four databases were searched for published scientific studies on T. gondii and ELISA, and 57 articles were included. Overall, indirect (95%) and in-house (67%) ELISAs were the most used types of test among the studies examined, but the 'ID Screen® Toxoplasmosis Indirect Multi-species' was common among commercially available tests. Varying diagnostic performance (sensitivity and specificity) and Kappa agreements were observed depending on the type of sample (serum, meat juice, milk), antigen (native, recombinant, chimeric) and antibody-binding reagents used. Combinations of recombinant and chimeric antigens resulted in better performance than native or single recombinant antigens. Protein A/G appeared to be useful in detecting IgG antibodies in a wide range of animal species due to its non-species-specific binding. One study reported cross-reactivity, with Hammondia hammondi and Eimeria spp. This is the first systematic review to descriptively compare ELISAs for the detection of T. gondii antibodies across different animal species.

Caver Knowledge and Biosecurity Attitudes Towards White-Nose Syndrome and Implications for Global Spread

White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans, has caused catastrophic declines of bat populations in North America. Risk assessment indicates that cavers could pose a risk for the spread of the fungus, however, information on cavers' knowledge of WNS and their caving and biosecurity habits is lacking. An anonymous qualitative survey was completed by delegates (n = 134) from 23 countries at an international speleological conference in Sydney, Australia. Cavers indicated that they visit caves frequently (80.6% at least bimonthly), including outside of their own country, but 20.3% of respondents did not know about WNS prior to the conference. Some respondents were incorrect, or unsure, about whether they had visited caves in countries where P. destructans occurs (26.5%) or whether their own country was free of the fungus (7.8%). Although 65.9% of respondents were aware of current decontamination protocols, only 23.9% and 31.2% (when in Australian or overseas caves, respectively) fully adhered to them. Overall, cavers showed strong willingness to help prevent further spread of this disease, but further efforts at education and targeted biosecurity activities may be urgently needed to prevent the spread of P. destructans to Australia and to other unaffected regions of the world.

Comparison of the modified agglutination test and real-time PCR for detection of Toxoplasma gondii exposure in feral cats from Phillip Island, Australia, and risk factors associated with infection

Toxoplasma gondii is considered a disease risk for many native Australian species. Feral cats are the key definitive host of T. gondii in Australia and therefore, investigating the epidemiology of T. gondii in cat populations is essential to understanding the risk posed to wildlife. Test sensitivity and specificity are poorly defined for diagnostic tests targeting T. gondii in cats and there is a need for validated techniques. This study focused on the feral cat population on Phillip Island, Victoria, Australia. We compared a novel real-time PCR (qPCR) protocol to the modified agglutination test (MAT) and used a Bayesian latent class modelling approach to assess the diagnostic parameters of each assay and estimate the true prevalence of T. gondii in feral cats. In addition, we performed multivariable logistic regression to determine risk factors associated with T. gondii infection in cats. Overall T. gondii prevalence by qPCR and MAT was 79.5% (95% confidence interval 72.6-85.0) and 91.8% (84.6-95.8), respectively. Bayesian modelling estimated the sensitivity and specificity of the MAT as 96.2% (95% credible interval 91.8-98.8) and 82.1% (64.9-93.6), and qPCR as 90.1% (83.6-95.5) and 96.0% (82.1-99.8), respectively. True prevalence of T. gondii infection in feral cats on Phillip Island was estimated as 90.3% (83.2-95.1). Multivariable logistic regression analysis indicated that T. gondii infection was positively associated with weight and this effect was modified by season. Cats trapped in winter had a high probability of infection, regardless of weight. The present study suggests qPCR applied to tissue is a highly sensitive, specific and logistically feasible tool for T. gondii testing in feral cat populations. Additionally, T. gondii infection is highly prevalent in feral cats on Phillip Island, which may have significant impacts on endemic and introduced marsupial populations.

When less is more: a comparison of models to predict fluoride accumulation in free-ranging kangaroos

Vegetation contaminated by industrial fluoride emissions can cause disease in herbivorous mammals. Spatially explicit exposure models offer a quantitative approach for evaluating and managing the potentially toxic effects of chronic fluoride consumption on wildlife. We monitored eastern grey kangaroos (Macropus giganteus) inhabiting a high-fluoride environment in the buffer zone of an aluminium smelter in southeastern Australia between 2010 and 2013. We measured fluoride levels at 19 pasture sites and determined the foraging range of 37 individual kangaroos. A series of generalised linear models were developed to estimate bone fluoride accumulation as a function of pasture exposure. Model outputs were compared to identify the most appropriate predictive tool for kangaroo bone fluoride accumulation relative to exposure. Accounting for age there was a negative association between bone fluoride concentration and distance of the central emission point from both the mean centre of foraging range and the point of death. The mean foraging range centre was the best predictor, with point of death just as suitable (and simpler), whereas more complex parameters such as monthly and cumulative fluoride exposure were poor predictors of bone fluoride concentration. The more complex dietary fluoride exposure estimates did not improve predictive capability compared with the simple, spatial models. We conclude that in actively managed wildlife populations, simple, locally validated models can provide estimates of bone fluoride accumulation sufficient to support decision-making.

Does the fungus causing white-nose syndrome pose a significant risk to Australian bats?

Abstract ContextPseudogymnoascus destructans is the fungus responsible for white-nose syndrome (WNS), which has killed millions of hibernating bats in North America, but also occurs in bats in Europe and China without causing large-scale population effects. This is likely to be due to differences in species susceptibility and behaviour, and environmental factors, such as temperature and humidity. Pseudogymnoascus destructans is currently believed to be absent from Australia. AimsTo ascertain the level of risk that white-nose syndrome poses for Australian bats. Methods This risk analysis examines the likelihood that P. destructans enters Australia, the likelihood of the fungus coming in contact with native bats on successful entry, and the potential consequences should this occur. Key results This risk assessment concluded that it is very likely to almost certain that P. destructans will enter Australia, and it is likely that bats will be exposed to the fungus over the next 10 years. Eight cave-dwelling bat species from southern Australia are the ones most likely to be affected. ConclusionsThe risk was assessed as medium for the critically endangered southern bent-winged bat (Miniopterus orianae bassanii), because any increase in mortality could affect its long-term survival. The risk to other species was deemed to range from low to very low, owing to their wider distribution, which extends beyond the P. destructans risk zone. Implications Although Australia’s milder climate may preclude the large mortality events seen in North America, the fungus could still significantly affect Australian bat populations, particularly bent-winged bats. Active surveillance is required to confirm Australia’s continuing WNS-free status, and to detect the presence of P. destructans should it enter the country. Although White-nose Syndrome Response Guidelines have been developed by Wildlife Health Australia to assist response agencies in the event of an incursion of WNS into bats in Australia, these guidelines would be strengthened by further research to characterise Australian cave temperatures and hibernating bat biology, such as length of torpor bouts and movement over winter. Risk-mitigation strategies should focus on education programs that target cavers, show-cave managers and tourists, particularly those who have visited regions where WNS is known to occur.

Ectoparasites are unlikely to be a primary cause of population declines of bent-winged bats in south-eastern Australia

While bats carry a diverse range of ectoparasites, little research has been conducted on the effects these organisms may have on bat populations. The southern bent-winged bat (Miniopterus orianae bassanii) is a critically endangered subspecies endemic to south-eastern Australia, whose numbers have declined over the past 50 years for unknown reasons. As part of a larger study to investigate the potential role of disease in these declines, southern bent-winged bats from four locations were captured and examined for the presence of bat flies, mites, ticks and the nematode Riouxgolvania beveridgei (previously associated with skin nodules in bent-winged bats). Results were compared with those obtained from the more common eastern bent-winged bat (Miniopterus orianae oceanensis), sampling animals from three different locations. All four types of parasite were found on both subspecies. There was no correlation between the presence of ectoparasites, body weight or any signs of disease. However, prevalence of tick and R. beveridgei infections were greater in Victorian southern bent-winged bats than South Australian southern bent-winged bats and eastern bent-winged bats, possibly indicative of some type of chronic stress impacting the immune system of this subspecies.

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Ectoparasites not associated with ill health in bent-winged bats.

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Greater prevalence of ticks and R. beveridgei infections on Victorian southern bent-winged bats.

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Bat flies and mites more common in summer. Ticks more common in spring. R. beveridgei more common in winter and spring.

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Mites more common on juvenile bats.

Chronic excess fluoride uptake contributes to degenerative joint disease (DJD): Evidence from six marsupial species

One of the manifestations of chronic fluoride toxicosis in mammals is skeletal fluorosis, which can include lesions of degenerative joint disease (DJD). Although DJD lesions have been less commonly studied than bone or dental lesions in relation to the pathology and epidemiology of fluoride toxicosis, there have been multiple independent studies in various species that have concluded that there appears to be an effect. The mechanisms by which fluoride affects the joints are not clear, but our data provide evidence that chronic excess dietary fluoride intake contributes to DJD. Our study is the first to specifically address the association between fluoride exposure and DJD in multiple species of free-ranging mammals. We describe levels of DJD in six marsupial species (Macropus giganteus, Notamacropus rufogriseus, Wallabia bicolor, Phascolarctos cinereus, Trichosurus vulpecula and Pseudocheirus peregrinus) inhabiting high and low fluoride environments. Lesions occurred to varying extents in all species, and lesion distribution varied with biomechanical differences in gait. In addition, we show an association (independent of age) between increasing bone fluoride concentration (as a measure of fluoride exposure) and increasing prevalence of moderate and severe DJD in five species of marsupial, which we propose does not persist at the highest levels of fluoride exposure due to selective survival bias.

Two subspecies of bent-winged bats (Miniopterus orianae bassanii and oceanensis) in southern Australia have diverse fungal skin flora but not Pseudogymnoascus destructans

Fungi are increasingly being documented as causing disease in a wide range of faunal species, including Pseudogymnoascus destructans, the fungus responsible for white nose syndrome which is having a devastating impact on bats in North America. The population size of the Australian southern bent-winged bat (Miniopterus orianae bassanii), a critically endangered subspecies, has declined over the past 50 years. As part of a larger study to determine whether disease could be a contributing factor to this decline, southern bent-winged bats were tested for the presence of a range of potentially pathogenic fungi: P. destructans, dermatophytes and Histoplasma capsulatum (a potential human pathogen commonly associated with caves inhabited by bats). Results were compared with those obtained for the more common eastern bent-winged bat (M. orianae oceanensis). All bats and their environment were negative for P. destructans. A large number of fungi were found on the skin and fur of bats, most of which were environmental or plant associated, and none of which were likely to be of significant pathogenicity for bats. A 0–19% prevalence of H. capsulatum was detected in the bat populations sampled, but not in the environment, indicative of a low zoonotic risk. Based on the results of this study, fungi are unlikely to be contributing significantly to the population decline of the southern bent-winged bat.

Skeletal fluorosis in marsupials: A comparison of bone lesions in six species from an Australian industrial site

In this study we explored the prevalence, type, location and severity of skeletal lesions in six species of Australian marsupial (Macropus giganteus, Notamacropus rufogriseus, Wallabia bicolor, Phascolarctos cinereus, Trichosurus vulpecula and Pseudocheirus peregrinus) from high and low-fluoride environments. Lesions occurred to varying extents in all species, and lesion distribution varied with biomechanical differences in gait and mastication. Bone fluoride levels increased with severity of periosteal hyperostosis. The mean bone fluoride concentration of individuals lacking hyperostosis (across all species, from both high and low-fluoride environments) was 1100±260μgF^-/g dry bone, compared to 4300±1200μgF^-/g and 6300±1200μgF^-/g in those with mild and severe grade hyperostosis, respectively. Multivariable modelling showed that the probability of observing a lesion varied across species, anatomical location, age and bone fluoride concentration (in a non-linear manner). The pathological changes reported in the marsupials are consistent with the range of fluoride-related lesions described in other mammals, and biomechanical differences among the studied marsupial species offer some explanation for the degree of interspecific variability in prevalence, type, anatomical location, and severity of the lesions.

Interspecific variation in the diets of herbivores in an industrial environment: implications for exposure to fluoride emissions

Atmospheric fluorides (gaseous and particulate) are deposited on, and absorbed by, vegetation. Ingested fluoride accumulates in calcified tissues of vertebrates, and if it is excessive, it may lead to dental and skeletal fluorosis. The prevalence, form and severity of the effects vary greatly between species. Foraging strategy can be an important determinant of fluoride exposure in herbivores, because foliar fluoride concentrations vary between plant species, for example, according to vertical and lateral position in the vegetation. We combined microhistological analysis of diet and analysis of foliar fluoride levels to examine interspecific variation in dietary fluoride exposure of macropodid marsupials (swamp wallaby Wallabia bicolor, red-necked wallaby Notamacropus rufogriseus and eastern grey kangaroo Macropus giganteus), in the buffer zone of an aluminium smelter in Victoria, Australia. Dietary niche differentiation between species was evident. The swamp wallaby and the red-necked wallaby were browsers or mixed feeders, depending on the classification system used. The eastern grey kangaroo was a grazer, consuming almost entirely grasses. However, foliar fluoride did not vary significantly between the main plant groups consumed. Our results indicate that interspecific variation in diet at this site is unlikely to explain variation in fluoride exposure.

Reconstructing temporal variation of fluoride uptake in eastern grey kangaroos (Macropus giganteus) from a high-fluoride area by analysis of fluoride distribution in dentine

Trace element profiling in the incrementally formed dentine of mammalian teeth can be applied to reconstruct temporal variation of incorporation of these elements into the tissue. Using an electron microprobe, this study analysed fluoride distribution in dentine of first and third mandibular molars of free-ranging eastern grey kangaroos inhabiting a high-fluoride area, to assess temporal variation in fluoride uptake of the animals. Fluoride content in the early-formed dentine of first molars was significantly lower than in the late-formed dentine of these teeth, and was also lower than in both, the early and the late-formed dentine of third molars. As early dentine formation in M1 takes place prior to weaning, this finding indicates a lower dentinal fluoride uptake during the pre-weaning compared to the post-weaning period. This is hypothetically attributed to the action of a partial barrier to fluoride transfer from blood to milk in lactating females and a low bioavailability of fluoride ingested together with milk. Another factor contributing to lower plasma fluoride levels in juveniles compared to adults is the rapid clearance of fluoride from blood plasma in the former due to their intense skeletal growth. The combined action of these mechanisms is considered to explain why in kangaroos from high-fluoride areas, the (early-formed) first molars are not affected by dental fluorosis while the (later-formed) third and fourth molars regularly exhibit marked to severe fluorotic lesions.

Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus) Exposed to High Environmental Levels of Fluoride

Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface) enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species.

Dental fluorosis and skeletal fluoride content as biomarkers of excess fluoride exposure in marsupials

Particulate and gaseous fluoride emissions contaminate vegetation near fluoride-emitting industries, potentially impacting herbivorous wildlife in neighboring areas. Dental fluorosis has been associated with consumption of fluoride-contaminated foliage by juvenile livestock and wildlife in Europe and North America. For the first time, we explored the epidemiology and comparative pathology of dental fluorosis in Australian marsupials residing near an aluminium smelter. Six species (Macropus giganteus, Macropus rufogriseus, Wallabia bicolor, Phascolarctos cinereus, Trichosurus vulpecula, Pseudocheirus peregrinus) demonstrated significantly higher bone fluoride levels in the high (n=161 individuals), compared to the low (n=67 individuals), fluoride areas (p<0.001). Necropsy examinations of all six species from the high-fluoride area near the smelter revealed dental lesions considered characteristic of dental fluorosis in eutherian mammals. Within the high-fluoride area, 67% of individuals across the six species showed dental enamel lesions, compared to 3% in the low-fluoride areas. Molars that erupted before weaning were significantly less likely to display pathological lesions than those developing later, and molars in the posterior portion of the dental arcade were more severely fluorotic than anterior molars in all six species. The severity of dental lesions was positively associated with increasing bone fluoride levels in all species, revealing a potential biomarker of excess fluoride exposure.

Haematology and serum biochemistry of adult free-ranging mountain brushtail possums (Trichosurus cunninghami), including correlations with season, sex, age, habitat type and disease status

For many wildlife species only limited data are available on haematology and blood biochemistry for free-ranging populations because these are often difficult to obtain. We collected blood samples from wild adult mountain brushtail possums (Trichosurus cunninghami) in the Strathbogie Ranges, Victoria (Australia), over two years, to provide reference values for haematological and some serum biochemical parameters (serum protein, sodium, chloride, potassium, urea, creatinine, creatine kinase and cortisol) for free-ranging animals. We also investigated patterns associated with sex, season, age, habitat type and disease status, including a form of skin disease (rumpwear – one of the major diseases of brushtail possums) and parasite loads. Values for several blood parameters correlated with sex, and most also changed significantly with season. Eosinophil counts increased significantly with the number of strongyle eggs in faeces, and packed cell volume decreased significantly with increasing numbers of ticks. Surprisingly, there was a significant negative relationship between mean population serum cortisol concentrations and the prevalence of rumpwear. Serum sodium and chloride concentrations were significantly lower in possums with moderate to severe rumpwear; however, the biological significance of this is unclear. While there is a growing body of data on the blood parameters of marsupials, these are mainly derived from captive animals, or single sample sets from wild populations, thus are unlikely to accurately reflect the changing status of wild animals/populations across seasons and under varying environmental conditions and parasite loads. More comprehensive, longer-term data from free-ranging marsupial populations, such as those presented here, provide extremely important reference data to aid in determining the health status of wild populations and interpreting data collected from individuals.

Bone fluoride concentrations of eastern grey kangaroos (Macropus giganteus) resident near an aluminium smelter in south-eastern Australia

Lesions of skeletal and dental fluorosis have been described recently in eastern grey kangaroos (Macropus giganteus). The present study further examined the epidemiology of skeletal fluorosis in this species. Bone fluoride concentrations were obtained from a range of skeletal sites of animals from a high (Portland Aluminium) and a low (Cape Bridgewater) fluoride environment in Victoria, Australia. Age, but not sex, affected the mean bone fluoride concentration of kangaroos. For a given age, bone fluoride concentrations were significantly higher in kangaroos from Portland than Cape Bridgewater. Concentrations varied between skeletal sites examined, with samples containing cancellous bone having higher fluoride concentrations than those containing only cortical bone.

Helminth parasite communities in four species of sympatric macropodids in western Victoria

Helminth parasites of Macropus fuliginosus, M. giganteus, M. rufogriseus and Wallabia bicolor were examined in a region of western Victoria, Australia, where all four species of hosts are sympatric. M. fuliginosus and M. giganteus shared most of their parasites while the helminth communities of M. rufogriseus and W. bicolor were distinctive. The sympatric distribution of the host species studied provides evidence in support of the hypothesis that the differences between the parasite communities of M. fuliginosus–M. giganteus compared with those of M. rufogriseus and W. bicolor are due to parasite specificity rather than to host ecological differences. However, lack of detailed data on the ecological differences of these hosts in areas of sympatry prevents more precise conclusions being drawn on the reasons for the distinctiveness of the parasite communities.

The role of host and environmental factors in the epidemiology of rumpwear in brushtail possums

Rumpwear is a common, but poorly defined and understood disease of brushtail possums (Trichosurus spp.) in Australia and New Zealand, resulting in varying degrees of fur loss. Populations of Trichosurus cunninghami (mountain brushtail possum) and T. vulpecula (common brushtail possum) were studied over two years at Boho South (Victoria), to describe the disease, investigate its prevalence and explore its epidemiology. The main type of lesion observed was coat damage in the lumbo-sacral region, and increased severity of rumpwear was related to decreased coat length and increased hair breakage. Significant skin lesions were rare and hair breakage patterns suggested mechanical damage. Rumpwear was very prevalent in both T. cunninghami and T. vulpecula, but very severe rumpwear was rare. There was no true seasonal pattern to the prevalence of rumpwear in T. cunninghami and sex and habitat did not affect prevalence or severity. Prevalence and severity of rumpwear did, however, increase with age. There were no significant relationships between the number of previous captures or body condition index with rumpwear.

Ectoparasitic dermatitis in free-ranging swamp wallabies (Wallabia bicolor) in New South Wales

We report extensive dermatological lesions in three, free-ranging, adult, male swamp wallabies (Wallabia bicolor), presented to Taronga Western Plains Zoo wildlife hospital. All three animals were moderately infested with the louse species Heterodoxus ualabati, and two were concurrently infested with a previously undescribed sarcoptiform mite of the genus Diabolicoptes. Histological changes included moderate to marked compact hyperkeratosis, focal deep pyoderma and superficial dermatophytosis. Mild to moderate hyperplastic perivascular and periadnexal dermatitis with marked superficial and follicular hyperkeratosis was evident in the skin of the inguinal region and lateral thigh of the two wallabies infested with the Diabolicoptes species. This is the first report of ectoparasitic dermatitis in free-ranging swamp wallabies and the first report of mites of the genus Diabolicoptes from a macropodid.

Eimeria trichosuri: phylogenetic position of a marsupial coccidium, based on 18S rDNA sequences

Phylogenetic analysis of the genus Eimeria suggests that parasite and host have coevolved over broad evolutionary timescales. Here we extend this analysis by determining the 18S rDNA gene sequence of the marsupial coccidium, Eimeria trichosuri, and assessing its phylogenetic position relative to Eimeria from birds, reptiles and placental mammals. This analysis placed E. trichosuri clones in a clade that diverged before the major clade comprising species from placental mammals. The position of E.trichosuri is consistent with host phylogeny where marsupials represent an ancient evolutionary line that predates the placental mammal line.

Identification of zoonotic Giardia genotypes in marsupials in Australia

A total of 421 fecal samples from a variety of captive and wild marsupial hosts in Western Australia, Victoria and South Australia were screened for the presence of Giardia species/genotypes using PCR and sequence analysis of a fragment of the 18S rRNA gene. Giardia spp. were identified in 13.4% (28/209) of samples from captive marsupials and 13.7% (29/212) of samples from wild marsupials. Sequence analysis at the 18S locus identified the zoonotic Giardia duodenalis Genotypes A and B in both captive and wild marsupials. Eight isolates were typed as genotype B3 and B4 at the gdh locus, although 7/8 were typed as genotype A at the 18S rRNA locus. The possible reasons for this discordance are discussed. This is the first report of genotype B and only the second report of genotype A in marsupials. As some of the genotype B isolates were identical to human-derived Giardia gdh sequences, these results suggest that marsupials in catchments may pose a public health risk and therefore warrant further investigation.