Rebecca J Vaughan-Higgins

The platypus (Ornithorhynchus anatinus) is a unique monotreme endemic to eastern Australia, yet little is known about the prevalence and impact of protozoan infections in wild populations. This study investigated the occurrence of protozoan parasites and associated health parameters in wild platypuses from New South Wales (NSW), Australia, with a focus on seasonal variation and demographic risk factors. A total of 90 sampling events (79 individuals and 11 recaptures) yielded 72 blood and 81 faecal samples for parasitological screening through targeted molecular techniques. Theileria ornithorhynchi was detected in 100 % of blood samples (95 % CI: 95.01–100), confirming its widespread distribution and high prevalence in NSW platypuses. Trypanosoma spp. were identified in 40.3 % of blood samples (95 % CI: 28.88–52.50), and sequencing confirmed the presence of Trypanosoma binneyi, reported here for the first time in NSW. Toxoplasma gondii was detected in one sub-adult male (1.39 %, 95 % CI: 0.04–7.50). No blood samples tested positive for Plasmodium spp. (0 %, 95 % CI: 0–4.99). In addition, all faecal samples tested negative for Cryptosporidium spp. and Giardia sp. (0 %, 95 % CI: 0–4.45). Boosted Regression Tree (BRT) analysis identified season as the primary risk factor for Tr. binneyi infection (RI 89.5 %), with higher prevalence in summer. Males were also at increased risk (RI 10.5 %), while age class and location (river catchment) had no measurable influence. Season also significantly affected physiological parameters, including tail volume index (TVI) and packed cell volume (PCV). These findings expand the known distribution of protozoan parasites and provide new insights into the seasonal dynamics of parasitic infections in wild platypuses. This study contributes to the understanding of platypus health ecology and highlights the importance of long-term, seasonally informed monitoring programs.

Context
Links between tapir health and environmental conditions are well-established, but substantial knowledge gaps on biological and environmental causes of ill-health remain. Furthermore, anthropogenic impacts and climate change effects on disease patterns are escalating issues.

Aims
Our study aimed to build on earlier research on wild lowland tapir (Tapirus terrestris) health and investigate risk factors and potential consequences associated with infectious agents.

Methods
Between 2008 and 2018, 174 samples from 115 wild lowland tapirs across two contrasting locations in Brazil were screened for four infectious agents (bluetongue virus, porcine parvovirus, Leptospira interrogans serovar Pomona, and Trypanosoma terrestris), along with clinical and haematological findings. Generalised linear models and boosted regression trees were applied to evaluate associations with risk factors, likely disease consequences, and meteorological conditions.

Key results
Tapirs in human-modified areas presented higher risk of exposure to livestock pathogens such as bluetongue virus (relative influence (RI) 94.2%) and porcine parvovirus (RI 58.5%), whereas those in pristine habitats exhibited higher risk to Trypanosoma terrestris (RI 92.5%) and Leptospira sp. (RI 39.9%). Bluetongue cases increased from one in Year 2 to 35 in Year 10 (odds ratio 2.90, 95% CI 2.12–3.97, P < 0.001). Significant associations were found between infectious agents and pale mucous membranes (RI 85.5%), high tick burden (RI 78.4%), low red (RI 78.3%) and high white (RI 38.1%) blood cell counts, and presence of wounds (RI 59.1%). Poor body condition was weakly linked to all variables. Elevated alkaline phosphatase, glucose, and total protein levels demonstrated associations with infectious agents, whereas high creatine kinase was linked to capture-related stress. No significant associations with meteorological data were detected.

Conclusions
Our study highlighted the complex influence of biological and environmental conditions on infectious disease dynamics in tapirs. Location emerged as the main risk factor for pathogen occurrence, with biomarkers such as heavy tick burden, pale mucous membranes, presence of wounds, high white blood cell count, and low red blood cell count representing key indicators of tapir health.

Implications
Our research has provided robust scientific evidence addressing long-standing hypotheses on tapir health, supporting practical applications and informing wildlife management and disease surveillance research.

Through evaluation of serum and plasma buterylcholinesterase (BChE) and brain acetylcholinesterase (AChE) activity, we investigated the possibility of the involvement of an acute organophosphate toxicosis in the pathogenesis of ongoing annual outbreaks of paresis and paralysis that in some cases progress to death, in endangered Western Australian Carnaby's cockatoos (Zanda latirostris). The condition, named Carnaby's hindlimb paralysis syndrome (CHiPS), was first described in 2012. Following initial investigations involving clinical, epidemiologic, toxicologic, gross necropsy, and histologic evaluation, a toxic etiology, specifically an organophosphate toxicosis, was considered most likely. The study aimed to validate the BChE assay for use in serum and plasma in Carnaby's cockatoos. This study found no evidence of changes in serum or plasma BChE or brain AChE that indicate an acute organophosphate toxicosis as the cause of CHiPS. Although these results render an acute organophosphate toxicosis unlikely, an organophosphate-induced delayed neuropathy has not been ruled out. Based on the results from the BChE validation study, the authors can recommend this assay for the evaluation of BChE measurement in plasma and serum from Carnaby's cockatoos with results showing excellent accuracy and precision.

The impact of diseases on tapir mortality and potential implications for preventive medicine and conservation remain unclear. A systematic literature review was conducted using seven databases and grey literature to address these gaps. The PRISMA statement was adopted to report results, and boosted regression tree models were employed for data analysis. After screening 5323 records and removing duplicates, the title and abstract of 2484 records were assessed. Out of 502 eligible studies, only 206 met all inclusion criteria. These were published between 1924 and 2023 in ten languages, comprising mainly case reports (45.1 %) and cross-sectional studies (41.3 %). Infectious diseases were found in 72.9 % of the reports, and 27.2 % presented clinical signs. The most affected systems were gastroenteric (22.7 %), integumentary (22.1 %), and respiratory (17.5 %). Respiratory diseases were associated with increased mortality. Factors affecting tapir mortality included species (relative influence 41.5 %), followed by geographic location (23.5 %) and captivity (16.8 %). Clinical signs were the least important variable (4 %). While infectious diseases were associated with higher mortality risk, tapirs were more likely to become ill from non-infectious than infectious diseases. Captive individuals were also more likely to present with illness than their wild counterparts. When considering external causes, vehicle collisions represented the most significant cause of death (52.2 %), followed by hunting (38.2 %). Diseases (8.7 %) were the third most important, with bacterial infections the leading cause of death. This review represents the most comprehensive overview on tapir health to date and provides novel ways to collate epidemiological data from disparate study designs.

Malaria and other haemosporidian parasites are common in reptiles. During baseline health surveys of sea turtles in Western Australia (WA), haemosporidian parasites were detected in flatback (Natator depressus) and green (Chelonia mydas) turtle erythrocytes during routine blood film examination. 130 blood samples were screened via polymerase chain reaction (PCR), including 105 N. depressus, 20 C. mydas, and 5 olive ridley turtles (Lepidochelys olivacea). A novel Haemocystidium sp. was identified, detected exclusively in foraging turtles and not in nesting turtles. The combined prevalence by microscopic and molecular methods was 16.9% (22/130), primarily affecting immature C. mydas (77.3%; 17/22). Mature N. depressus were also affected (22.7%; 5/22). DNA sequencing of a partial fragment of the mitochondrial cytochrome b (cytb) gene together with phylogenetic analysis identified two different Haemocystidium sp. genotypes, A and B, with genotype A being most prevalent. The phylogenetic analysis showed close genetic relationships to Haemocystidium sp. in freshwater and terrestrial turtles, suggesting a shared evolutionary lineage despite ecological differences. Preliminary analysis indicates that this parasite is incidental, as no association between health and parasite presence or grade was detected. This study provides the first formal detection of haemosporidian parasites in sea turtles, contributing essential baseline data while highlighting their evolutionary significance and host–parasite ecological relationships.

A wild male Carnaby's cockatoo (Zanda latirostris) was presented to a veterinary hospital after falling from a tree. The bird showed few clinical signs during the first days of hospitalization. On Day 4, the cockatoo showed excessive hemorrhage at a venipuncture site, epistaxis, and significant anemia (packed cell volume, 15%). The cockatoo was euthanized due to ongoing blood loss, weakness, and inappetence. Liver concentrations of brodifacoum (0.439 mg/kg wet weight) and difenacoum (0.033 mg/kg wet weight) had a total anticoagulant rodenticide concentration of 0.472 mg/kg wet weight and were above the threshold for toxicity for many avian species. To the authors' knowledge, this is the first time that anticoagulant rodenticide intoxication has been identified in a wild Australian psittacine species.

Detecting pathogens in endangered animal populations is vital for understanding and mitigating threats to their survival. The critically endangered western ground parrot ( Pezoporus flaviventris , WGP), with a population as low as 150 individuals in Australia, faces an imminent risk of extinction. Despite this urgency, research on viral pathogens in this species remains limited. This study aimed to identify and characterise viruses present in faecal samples from seven individual WGP using a viral metagenomic approach. Analysis of the sequenced datasets revealed the presence of a novel virus belonging to the Parvoviridae family, named psittaciform chaphamaparvovirus 7 (PsChPV‐7). The genome of PsChPV‐7 contains typical structural and functional gene sequences found in Parvoviridae but is highly divergent, indicating its classification as a distinct species. Phylogenetic analysis placed PsChPV‐7 within a unique sub‐clade of the Chaphamaparvovirus genus, suggesting its evolutionary significance as an ancient lineage within this group. These findings may contribute to the development of strategic management and biosecurity plans aimed at conserving this endangered WGP.

Forficuloecus pezopori Martin, Keatley & Ash n. sp. from the western ground parrot Pezoporus flaviventris North, 1911 (Psittaculidae) is proposed based on combined evidence from morphology and COI mitochondrial DNA. Phylogenetically, the new species is closest to its two known congeners from Western Australia: F. josephi Price, Johnson & Palma, 2008 from Bourke's parrot Neopsephotus bourkii (Gould, 1841) and the scarlet-chested parrot Neophema splendida (Gould, 1841), and F. palmai Guimarães, 1985 from the Australian ringneck parrot Barnardius zonarius (Shaw, 1805). Morphologically it is distinguishable by abdominal chaetotaxy and characters of the male genitalia, and is most similar to F. josephi and F. greeni Guimarães, 1985; the latter has no representative sequence data. Forficuloecus pezopori is the eleventh species of its genus and the only metazoan parasite known from P. flaviventris, which is among Australia's most endangered vertebrates. The new louse is apparently restricted to P. flaviventris and is therefore co-endangered, facing at least the same likelihood of extinction as its host. We recommend ongoing translocation and field monitoring efforts for P. flaviventris include monitoring but not treatment for lice infestations in otherwise healthy individuals, and that the care management plan for captive P. flaviventris considers that F. pezopori is similarly imperilled.
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•The first metazoan parasite known from the western ground parrot.•The new louse is likely restricted to its host and thus also critically endangered.•Conservation interventions for the parrot ought to consider the louse.•Host interventions are opportunities to discover and conserve parasites.

The aim of this study was to describe the gross and histopathological features of a neurological syndrome in endangered Western Australian Carnaby's black cockatoos (Zanda laitirostris) that was first observed in 2012. The syndrome, named hindlimb paralysis syndrome in Carnaby's cockatoos (CHiPS), is characterized by annual outbreaks of hindlimb paralysis with occasional loss of deep pain and cloacal tone, typically occurring between January and March. Previous limited investigations suggested a possible toxic aetiology. Full gross necropsy and histopathology examinations were performed on 17 CHiPS cases and on 11 control birds for reference. Histopathological examination was carried out on all major organs including brain, spinal cord, brachial plexus, sciatic nerve and wing and hindlimb muscles. Gross and histopathological examinations did not elucidate a definitive cause of the clinical signs seen in CHiPS cases. There were no substantial gross or histopathological changes within the brain, spinal cord, sciatic nerve or brachial plexus that could explain the hindlimb paralysis. The most noteworthy changes were seen in the hindlimb and wing muscles, with a monophasic to polyphasic myopathy present in the hindlimb muscles of 15 of the 17 CHiPS cases and in the wing muscles in 11 of those cases. The cause and significance of the myopathy is unclear and requires further investigation. Based on the above findings, the most likely differential diagnoses include neurotoxicoses (eg, organophosphate, organochlorine and carbamate) and, less likely, myotoxicosis (eg, ionophore toxicosis), nutritional myopathy (eg, vitamin E/selenium deficiency) or botulism.

Platypuses are the world's most evolutionarily distinct mammal and have several host-specific ecto- and endoparasites. With platypus populations declining, consideration should also be given to preserving these high conservation priority parasites alongside their charismatic host. A disease risk analysis (DRA) was performed for a platypus conservation translocation, using a modified streamlined methodology that incorporated a parasite conservation framework. DRA frameworks rarely consider parasite conservation. Rather, parasites are typically considered myopically in terms of the potential harm they may cause their host. To address this, a previously proposed parasite conservation framework was incorporated into an existing streamlined DRA methodology. Incorporation of the two frameworks was achieved readily, although there is opportunity for further refinement of this process. This DRA is significant as it is the first performed for any monotreme species, and implements the emerging approach of balancing the health and disease risk of the host with parasite conservation.
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