Tissue distribution of Coxiella burnetii and antibody responses in macropods co-grazing with livestock in Queensland, Australia.

Coxiella burnetii, the causative agent of Q fever, is a zoonotic bacteria of global public health significance. The organism has a complex, diverse, and relatively poorly understood animal reservoir but there is increasing evidence that macropods play some part in the epidemiology of Q fever in Australia. The aim of this cross-sectional survey was to estimate the animal- and tissue-level prevalence of coxiellosis amongst eastern grey (Macropus giganteus) and red (Osphranter rufus) kangaroos co-grazing with domestic cattle in a Q fever endemic area in Queensland. Serum, faeces and tissue samples from a range of organs were collected from 50 kangaroos. A total of 537 tissue samples were tested by real-time PCR, of which 99 specimens from 42 kangaroos (84% of animals, 95% confidence interval [CI], 71% to 93%) were positive for the C. burnetii IS1111 gene when tested in duplicate. Twenty of these specimens from 16 kangaroos (32%, 95% CI 20% to 47%) were also positive for the com1 or htpAB genes. Serum antibodies were present in 24 (57%, 95% CI 41% to 72%) of the PCR positive animals. There was no statistically significant difference in PCR positivity between organs and no single sample type consistently identified C. burnetii positive kangaroos. The results from this study identify a high apparent prevalence of C. burnetii amongst macropods in the study area, albeit seemingly with an inconsistent distribution within tissues and in relatively small quantities, often verging on the limits of detection. We recommend Q fever surveillance in macropods should involve a combination of serosurveys and molecular testing to increase chances of detection in a population, noting that a range of tissues would likely need to be sampled to confirm the diagnosis in a suspect positive animal.

Temperature-bounded development of Dirofilaria immitis larvae restricts the geographical distribution and seasonality of its transmission: case study and decision support system for canine heartworm management in Australia.

Dirofilaria immitis is the causative agent of canine heartworm disease. We used the established heartworm development unit (HDU) principle to map the extrinsic incubation period (EIP) of D. immitis in Australia using historical weather data from 2013-2022. We found weather conditions suitable for EIP completion showed substantial seasonality and geographical variability. Whilst a considerable percentage of the Australian territory showed suitable weather conditions to always support EIP completion (17%), only 2.7% of the 2021 Australian human population lived in this region. Therefore, 97% of the population lived in an area that changed its EIP suitability within the study period. EIP completion is required prior to D. immitis transmission, meaning that infection risk of D. immitis is seasonal and location-dependent, being disrupted each year for most of the human population's dogs. We developed an online, open access tool allowing us to visualise EIP completion across Australia historically and in near real-time. We aim to support veterinarians to make risk-based recommendations for dirofilariosis prevention by using the tool, available at https://heartworm-mapping.adelaide.edu.au/shiny/.

Relative diagnostic accuracy of point-of-care tests to rule-in Dirofilaria immitis infection in clinically suspect dogs: A systematic review and meta-analysis.

Canine heartworm, Dirofilaria immitis, can cause severe disease and sometimes death of the host. Associated clinical signs, lack of preventative usage and regional endemicity are unlikely sufficient by themselves to reach a definitive diagnosis. Several point-of-care (POC) diagnostic tests are commercially available to aid in-clinic diagnosis, however, there is variable diagnostic accuracy reported and no synthesis of published evidence. This systematic review aims at meta-analysing the likelihood ratio of a positive result (LR+) to inform the selection and interpretation of POC tests in practice to rule-in heartworm infection when there is clinical suspicion. Three literature index interfaces (Web of Science, PubMed, Scopus) were searched on November 11th, 2022, for diagnostic test evaluation (DTE) articles assessing at least one currently commercialised POC test. Risk of bias was assessed adapting the QUADAS-2 protocol and articles with no evidence of high risk of bias were meta-analysed if deemed applicable to our review objective. Substantial between DTE heterogeneity was investigated including potential threshold or covariate effects. A total of 324 primary articles were sourced and 18 were retained for full text review of which only three had low risk of bias in all four QUADAS-2 domains. Of the nine heartworm POC tests evaluated, only three, IDEXX SNAP (n DTEs = 6), Zoetis WITNESS (n DTEs = 3) and Zoetis VETSCAN (n DTEs = 5) could be analysed. Both WITNESS and VETSCAN DTEs showed substantial heterogeneity due to a putative threshold effect and no summary point estimates could be reported. SNAP DTEs showed acceptable heterogeneity, and a summary LR+ was estimated at 559.0 (95%CI: 24.3-12,847.4). The quality and heterogeneity of heartworm POC test DTEs was highly variable which restricted our summary of the diagnostic accuracy to only the SNAP test. A positive result from the SNAP test provides strong evidence of the presence of an infection with adult heartworm(s) in a dog patient and this test is warranted to rule-in clinical suspicion(s) in clinics. However, our review did not appraise the literature to assess the fitness of SNAP test, or any other POC tests, to rule-out heartworm infection in dogs without clinical suspicion or following heartworm therapy.

Canine olfactory detection of SARS-CoV-2-infected humans-a systematic review.

PURPOSE: To complement conventional testing methods for severe acute respiratory syndrome coronavirus type 2 infections, dogs' olfactory capability for true real-time detection has been investigated worldwide. Diseases produce specific scents in affected individuals via volatile organic compounds. This systematic review evaluates the current evidence for canine olfaction as a reliable coronavirus disease 2019 screening tool. METHODS: Two independent study quality assessment tools were used: the QUADAS-2 tool for the evaluation of laboratory tests' diagnostic accuracy, designed for systematic reviews, and a general evaluation tool for canine detection studies, adapted to medical detection. Various study design, sample, dog, and olfactory training features were considered as potential confounding factors. RESULTS: Twenty-seven studies from 15 countries were evaluated. Respectively, four and six studies had a low risk of bias and high quality: the four QUADAS-2 nonbiased studies resulted in ranges of 81%-97% sensitivity and 91%-100% specificity. The six high-quality studies, according to the general evaluation system, revealed ranges of 82%-97% sensitivity and 83%-100% specificity. The other studies contained high bias risks and applicability and/or quality concerns. CONCLUSIONS: Standardization and certification procedures as used for canine explosives detection are needed for medical detection dogs for the optimal and structured usage of their undoubtful potential.

Mitigating disease risk in an endangered pinniped: early hookworm elimination optimizes the growth and health of Australian sea lion pups.

The Australian sea lion (Neophoca cinerea) experiences high pup mortality of seasonally alternating severity, partly attributed to endemic hookworm (Uncinaria sanguinis) infection. To further explore health outcomes of early hookworm elimination, a treatment trial was conducted at Seal Bay Conservation Park, South Australia, over consecutive lower and higher mortality breeding seasons (2019, 19.2%; 2020-1; 28.9%). Pups (n = 322) were stratified into two age cohorts (median 14 d and 24 d recruitment ages) and randomly assigned to treated (topical ivermectin 500 µg/kg) or control (untreated) groups. A younger prepatent cohort <14 d old (median 10 d) was identified a posteriori. A seasonally independent growth benefit resulted from hookworm elimination across all age cohorts. The greatest relative improvements (bodyweight + 34.2%, standard length + 42.1%; p ≤ 0.001) occurred in the month post-treatment, in the youngest prepatent cohort. A significant benefit of lesser magnitude (bodyweight + 8.6-11.6%, standard length + 9.5-18.4%; p ≤ 0.033) persisted up to 3 months across all age cohorts - greatest in the youngest pups. Treatment resulted in immediate improvement in hematological measures of health - decreased anemia and inflammation severity (p ≤ 0.012). These results enhance our understanding of host-parasite-environment interactions within the context of hematological ontogenesis, confirm the seasonally independent benefits of hookworm disease intervention, and further inform conservation recommendations for this endangered species.

Blood types and antibody profiles of Straight Egyptian Arabian horses in Qatar: Preliminary results.

The characterization of the blood groups, antibody profiles, and its distribution pattern among different horse breeds and geographic locations, can be very useful in life-threatening situations where a blood transfusion is needed, and compatibility tests are not readily available. This study estimated the distribution of blood types and antibody profiles in Straight Egyptian Arabian horses from Qatar. A total of 20 Straight Egyptian Arabian horses, from multiple origins and genetic background were included. Venous blood from each horse was typed and screened for anti-red blood cell (RBC) hemolytic and agglutinating antibodies. Descriptive statistical analysis and Fisher Exact test were applied, considering 95% confidence interval (95% CI). All included horses (100%) had Aa and Ca blood types (95% CI: 83.2%-100.0%). Other blood types found less frequently included Ua (50%), Qc (45%), Pa (40%), Qb (25%) and Qa (5%). Only horses with travel history developed anti-RBC antibodies (6 out of 9), however, no horse carried more than one type of anti-RBC antibodies, supporting the premise that environmental factors may influence the development of alloantibodies. Although pre-transfusion testing regardless the circumstances should be prioritized, even considering a small population of horses, our findings suggest that Straight Egyptian Arabian horses in Qatar could be safely used as blood donors, due to the apparent omnivalence of Aa and Ca blood types and lower incidence of alloantibodies, important in emergency situations where pre-transfusion testing is unavailable.

Clinical findings and assessment of factors associated with survival in dogs presenting with hyperbilirubinaemia: 115 cases in Victoria, Australia (2015-2020).

Introduction: Hyperbilirubinaemia is an important clinicopathological finding in canine medicine. The objectives of this study were to describe the clinical presentation and outcome of dogs with hyperbilirubinaemia; also to identify factors associated with survival. Materials and methods: Retrospective study of dogs with hyperbilirubinaemia from two referral centres in South Australia (2015-2020). Signalment, clinical signs, clinicopathological data, diagnosis and outcome were obtained from searching clinical records. Univariable analysis and logistic regression modelling were used to compare outcomes and overall survival. Results: A total of 115 cases were included. The most common clinical signs were vomiting (63.5%), anorexia (62.6%), lethargy (55.7%) and pyrexia (18.3%). Pre-hepatic icterus was diagnosed in 18 cases (15.7%), hepatic icterus in 51 cases (44.3%) and post-hepatic icterus in 42 cases (36.5%). The median survival time across all cases was 40 days (95% confidence interval [CI]: 9-126 days). There was an increased risk of death in dogs with serum bilirubin greater than 60 µmol/L at diagnosis (odds ratio [OR] = 3.55; 95% CI: 1.53-8.22; p-value = 0.003) and in dogs with pre-hepatic icterus compared to hepatic (OR = 4.35; 95% CI: 1.18-16.0; p-value = 0.027) and post-hepatic icterus (OR = 6.52; 95% CI: 1.67-25.5; p-value = 0.007). Conclusions: Pre-hepatic icterus was associated with a significantly higher risk of death than hepatic and post-hepatic icterus. Serum bilirubin >60 µmol/L at diagnosis was associated with a significantly shorter median survival time. This cut-off may be useful in discussions with owners regarding pursuing further diagnostic investigation and treatment. Further prospective studies are needed to prove the validity of this cut-off.

Investigation of Weather Triggers Preceding Outbreaks of Acute Bovine Liver Disease in Australia.

Acute bovine liver disease (ABLD) is a hepatic disease affecting cattle sporadically in southern Australia, characterised histologically by striking periportal hepatocellular necrosis. The cause of ABLD is unknown; however, the seasonality and acute presentation of outbreaks suggest mycotoxin involvement. We described the geographical and seasonal occurrence of ABLD reports from 2010 to 2020 in Victoria, Australia, and explored potential weather triggers preceding 26 outbreaks occurring across 23 properties using a case-crossover design. Outbreaks occurred most frequently in autumn/early winter and in herds located along the southern coastal plain of Victoria, and occasionally within the low-lying regions of the Great Dividing Range. Lactating adult dairy cattle represented the most reported cases. We observed a significant association between an increase in average daily dewpoint in the 15 days preceding an ABLD outbreak, suggesting that dew formation may be a key determinant for this disease. Our findings support the etiology of a potent hepatotoxic agent that requires moisture for proliferation and/or toxin production.

Evaluation of canine detection of COVID-19 infected individuals under controlled settings.

Reverse transcription polymerase chain reaction (RT-PCR) is currently the standard diagnostic method to detect symptomatic and asymptomatic individuals infected with Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, RT-PCR results are not immediate and may falsely be negative before an infected individual sheds viral particles in the upper airways where swabs are collected. Infected individuals emit volatile organic compounds in their breath and sweat that are detectable by trained dogs. Here, we evaluate the diagnostic accuracy of dog detection against SARS-CoV-2 infection. Fifteen dogs previously trained at two centres in Australia were presented to axillary sweat specimens collected from known SARS-CoV-2 human cases (n = 100) and non-cases (n = 414). The true infection status of the cases and non-cases were confirmed based on RT-PCR results as well as clinical presentation. Across dogs, the overall diagnostic sensitivity (DSe) was 95.3% (95%CI: 93.1-97.6%) and diagnostic specificity (DSp) was 97.1% (95%CI: 90.7-100.0%). The DSp decreased significantly when non-case specimens were collected over 1 min rather than 20 min (p value = .004). The location of evaluation did not impact the detection performances. The accuracy of detection varied across dogs and experienced dogs revealed a marginally better DSp (p value = .016). The potential and limitations of this alternative detection tool are discussed.

Topical ivermectin is a highly effective seal 'spot-on': A randomised trial of hookworm and lice treatment in the endangered Australian sea lion (Neophoca cinerea).

The Australian sea lion (Neophoca cinerea) is an endangered and declining otariid species, with a high rate of pup mortality associated with endemic hookworm (Uncinaria sanguinis) infection a suspected contributor to this decline. Injected ivermectin is an effective treatment for Uncinaria sp. in otariids, with optimal outcomes achieved by the early treatment of pups prior to disease development. This randomised controlled trial evaluated the effectiveness of the novel use of a topical ivermectin formulation against hookworm infection and lice (Antarctophthirus microchir) infestation, in comparison with injected ivermectin. During the 2017 breeding season at Dangerous Reef, South Australia, pups ≤ 70 cm in standard length (≤ 2 weeks of age; n = 85) were randomised to single dose topical (500 µg/kg spot-on; n = 27) or injected (200 µg/kg subcutaneous; n = 29) ivermectin treatment groups, or to an untreated control group (n = 29). Topical ivermectin was highly effective for U. sanguinis elimination, and not significantly different to the injected formulation (estimated effectiveness 96.4% and 96.8%, respectively; P > 0.05). Its application resulted in an 81.6% reduction and 62.7% additional clearance for A. microchir infestation by 15-24 days post-treatment, compared with untreated control pups (also not significantly different to injected ivermectin; 83.1% and 59.4%, respectively; P > 0.05). Treatment with either ivermectin formulation significantly ameliorated increases in inflammatory markers detected in the blood of untreated control pups - peripheral blood eosinophil counts (persisting to 36-41 days post-recruitment P < 0.05) and increased plasma protein concentrations (15-24 days post-recruitment; P < 0.05). Further, an initial short-term decrease in body condition in the control group was not observed in either of the treatment groups. This study demonstrates that topical ivermectin is an effective antiparasitic treatment in N. cinerea. It offers an alternative administration method for ivermectin delivery to a young pup cohort in this species, and an alternative, minimally invasive management tool for species conservation.

INFECTION PRESSURE IS NECESSARY, BUT NOT SUFFICIENT BY ITSELF, TO EXPLAIN TOXOPLASMA GONDII SEROPREVALENCE IN INTERMEDIATE HOST SPECIES.

Parasite infection pressure is suggested to be a strong driver of transmission within ecosystems. We tested if infection pressure drives seroprevalence in intermediate host species for Toxoplasma gondii. We defined Toxoplasma infection pressure to intermediate host species as the combined influence of cat abundance, environmental conditions, and its prevalence in the cat population. We sampled and tested 2 species of rodent and collated information on Toxoplasma seroprevalence in koalas, wallabies, kangaroos, and sheep. All species were sampled using equivalent methods, within a 2-yr period, and from adjacent regions of low and high Toxoplasma infection pressure. The seroprevalence of Toxoplasma in kangaroos scaled with infection pressure, but we observed no statistical difference in seroprevalence for any other species between these 2 regions. Within the region of low infection pressure, Toxoplasma seroprevalence did not differ between species. However, within the region of high Toxoplasma infection pressure, we observed large variation in seroprevalence between species. Our results demonstrate that infection pressure is not sufficient by itself, but merely necessary, to drive Toxoplasma seroprevalence in intermediate host species. Where Toxoplasma seroprevalence in an intermediate host species is already low, further reducing infection pressure will not necessarily further decrease seroprevalence in those species. This has important ramifications for the mitigation of parasite infections and suggests that reductions in Toxoplasma infection pressure, intended to reduce infections, may be most effective and applicable to species that are known to experience high rates of infection.

The impact of PIT tags on the growth and survival of pythons is insignificant in randomised controlled trial.

Individual identification is fundamental to the study of captive and wild animals but can have adverse impacts if the method of identification is inappropriate for the species or question of interest. We conducted a randomised controlled trial to test whether passive integrated transponder (PIT) tags reduced the growth or survival of pythons. We randomly allocated 200 captive-bred Burmese python (Python bivittatus) hatchlings into two groups, tagged versus untagged. Hatchlings were individually identified using a combination of PIT tags and unique colour patterns, and their mass, snout-vent length (SVL) and body condition measured at 9, 73, 134, 220, 292 and 385 days of age. We recorded the date of all mortalities. Python morphometrics and their rate of change increased or fluctuated non-linearly with age. The impact of PIT tagging on python body mass and body mass growth over the 376 day study period was insignificant. PIT tagging additionally had an insignificant impact on python survival. However, we found minor differences in SVL growth between tagged and untagged pythons. These differences peaked at approximately 0.5 mm/day and appeared to drive similar, but more pronounced, differences between tagged and untagged pythons in their rate of change in body condition; peaking at approximately 3-4 g/day. While we cannot be certain that these small differences are, or are not, biologically meaningful, they nonetheless appear to be short-term and readily resolved. Unsurprisingly, the strongest driver of python growth was their age, with growth rapidly increasing or highest amongst younger snakes for all measures of size. Python sex was associated with their body mass and survival, with higher mass but lower survival amongst females. Python size at hatching did not impact on their growth or survival. Our results confirm that PIT tags are a valuable and effective tool for the identification and tracking of captive pythons, and snakes generally, and meet high safety and animal welfare standards.

Bat E-Commerce: Insights Into the Extent and Potential Implications of This Dark Trade.

Little is known about the global bat souvenir trade despite previous research efforts into bat harvest for bushmeat. We screened eBay listings of bats in Australia, Canada, Italy, Switzerland, United Kingdom and USA to assess the nature and extent of the online offers. A total of 237 listings were retrieved in between the 11th and 25th of May 2020 with a median price per item of US$38.50 (range: US$8.50-2,500.00). Items on offer were mostly taxidermy (61.2%) or skull (21.1%) specimens. Overall, 32 different species of bat were advertised, most of which (n = 28) are listed as "Least Concern" on the International Union for Conservation of Nature (IUCN) Red List. One species (Nycteris javanica) is classified as "Vulnerable" and one (Eidolon helvum) as "Near Threatened." Pteropus spp. specimens were the most expensive specimens on offer and the conservations status of these species may range from "Critically Endangered" to "Data Deficient" by IUCN and the entire genus is listed in the Appendix II by the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, the exact species concerned, and their respective conservation status, could not be confirmed based on the listings' photos. The sourcing of bat was restricted to mostly South-East Asian countries (a third of items sourced from Indonesia) and to two African countries. Our survey revealed that the online offer of bat products is diverse, abundant, and facilitated by worldwide sellers although most offered bats species are from South-East Asia. With a few exceptions, the species on offer were of little present conservation concern, however, many unknowns remain on the potential animal welfare, biosecurity, legal implications, and most importantly public health risks associated with this dark trade.

Serological evidence of exposure to a coronavirus antigenically related to severe acute respiratory syndrome virus (SARS-CoV-1) in the Grey-headed flying fox (Pteropus poliocephalus).

Many infectious pathogens can be transmitted by highly mobile species, like bats that can act as reservoir hosts for viruses such as henipaviruses, lyssaviruses and coronaviruses. In this study, we investigated the seroepidemiology of protein antigens to Severe acute respiratory syndrome virus (SARS-CoV-1) and Middle eastern respiratory syndrome virus (MERS-CoV) in Grey-headed flying foxes (Pteropus poliocephalus) in Adelaide, Australia sampled between September 2015 and February 2018. A total of 301 serum samples were collected and evaluated using a multiplex Luminex binding assay, and median fluorescence intensity thresholds were determined using finite-mixture modelling. We found evidence of antibodies reactive to SARS-CoV-1 or a related antigen with 42.5% (CI: 34.3%-51.2%) seroprevalence but insufficient evidence of reactivity to MERS-CoV antigen. This study provides evidence that the Grey-headed flying foxes sampled in Adelaide have been exposed to a SARS-like coronavirus.

Fractional seroprevalence rates in common prey species can cause more than half of feral cats to be exposed to Toxoplasma gondii annually.

Rodents comprise a major component of cat (Felis catus) diets in many ecosystems, and life cycle diagrams of Toxoplasma gondii typically depict small rodents as quintessential intermediate hosts. Counter-intuitively, small rodents often experience a lower T. gondii seroprevalence than do larger sympatric mammals. This observation has repeatedly caused confusion about the relative importance of small rodents to the ecology of T. gondii. To address this confusion, we modified the Reed-Frost epidemic model to develop a simple binomial equation to model T. gondii transmission from prey to feline predators. This equation takes into account variations in prey seroprevalence and the frequency with which they are consumed by felids. Even when T. gondii seroprevalence in prey is < 1%, computation reveals that the risk of feline exposure to T. gondii can easily exceed 50 % annually. For example, if cats eat an average of 1 mouse per day, a seroprevalence of 0.2 % (1/500) in mice will cause 51.9 % of cats to be exposed to T. gondii annually. Our simple equation demonstrates that both prey seroprevalence and the rate at which prey are consumed are of approximately equal importance to the ecology of T. gondii. When inferring the importance of various prey species to the ecology of T. gondii, researchers must consider the predation and dietary habits of felids from within their study system. Our simple binomial equation could also be used to predict T. gondii exposure rates of humans or other carnivorous animals from various dietary sources or be applied to other predator-prey parasite life cycles.

Investigation of risk factors associated with sub-optimal holding survival in southern rock lobster (Jasus edwardsii) in Australia.

Southern rock lobster (SRL1, Jasus edwardsii) are caught from the wild waters of southern Australia and form an important commodity economically for the fisheries industry in Australia. Between landing and export, SRL are held in specialised tanks within holding facilities for varying time periods before being exported to China. During the 2015-16 fishing season a lower stock survival rate was reported by some holding facilities when compared to previous fishing seasons. An investigation was undertaken to identify possible causes and favouring factors using a retrospective, single cohort, observational study. A custom questionnaire was built and trialled to collect qualitative and quantitative information on facilities infrastructure and capacity (10 questions), water systems (16 questions), SRL stock and health management (12 questions). Onsite visits and interviews of consenting holding facilities, with active holding operations, were conducted. Facilities were categorised into different capacity and management profiles based on a multivariate factor analysis. The association between facility profiles and perceived sub-optimal survival was then explored using simple logistic regression models. Out of the 83 license holders on record, 63 were in operation at the time of survey and 52 (83%) consented to participate. Perceived sub-optimal survival was reported in 22 (42%) facilities. The capacity, bio-filtration and water management practices across the surveyed facilities was highly variable but did not appear to be associated with survival. However, 'Intensive holding' facilities compared to the 'Extensive holding' facilities were significantly associated with an increased risk of sub-optimal survival (OR = 7.0, 95% CI: 2.1-26.13, P = 0.002). 'Intensive holding' facilities were more likely to hold higher annual tonnage sourced from distant, diverse and higher number of sources, to multiple handle and stock SRL in crates (as opposed to free swimming in tanks), and hold them for longer time periods. Holding practices are highly diverse across the SRL industry with little evidence of impact on survival, however, intensive and large scale holding practices appeared to be at higher risk of sub-optimal survival. A longitudinal and finer scale study is warranted to identify which one(s) of the stock management practices directly impact SRL survival during holding.

Comparison of three serological tests for the detection of Coxiella burnetii specific antibodies in European wild rabbits.

BACKGROUND: Coxiella burnetii causes Q fever, a zoonotic bacterial disease with a multi-host cycle and reservoirs in wild and domestic animal species. Q fever has a significant impact on the Australian public health and economy but its ecology and contributing reservoir species remain poorly understood. In Europe, rabbits (Oryctolagus cuniculus) were identified as a major reservoir of C. burnetii and it is possible that they play a similar role in Australia. In absence of commercial kit available for rabbit, the Thermo Fisher - PrioCHECK™ Ruminant Q fever Ab Plate Kit was adapted to successfully screen rabbits population in Europe. However, this assay is not accessible in Australia and we assessed the equivalency of two commercially available kits in Australia - IDEXX - CHEKIT Q Fever Antibody ELISA kit and IDVet - ID Screen® Q Fever Indirect Multi-species with the Thermo Fisher kit (reference kit). RESULTS: A total of 94 rabbit sera were screened by all three ELISA kits using the same confirmed positive and negative controls. While the IDEXX kit failed to agree the other two assays (concordance correlation coefficient, rb < 0.77), IDVet kit showed satisfactory equivalency with Thermo Fisher (rb = 0.927). CONCLUSION: IDvet kit provides the best alternative for Thermo Fisher in the detection of C. burnetii specific antibodies in rabbits in Australia. Further trials are required to confirm these preliminary results due to the low seroprevalence of Coxiella burnetii observed in the study sera.

Seroprevalence of three paramyxoviruses; Hendra virus, Tioman virus, Cedar virus and a rhabdovirus, Australian bat lyssavirus, in a range expanding fruit bat, the Grey-headed flying fox (Pteropus poliocephalus).

Habitat-mediated global change is driving shifts in species' distributions which can alter the spatial risks associated with emerging zoonotic pathogens. Many emerging infectious pathogens are transmitted by highly mobile species, including bats, which can act as spill-over hosts for pathogenic viruses. Over three years, we investigated the seroepidemiology of paramyxoviruses and Australian bat lyssavirus in a range-expanding fruit bat, the Grey-headed flying fox (Pteropus poliocephalus), in a new camp in Adelaide, South Australia. Over six, biannual, sampling sessions, we quantified median florescent intensity (MFI) antibody levels for four viruses for a total of 297 individual bats using a multiplex Luminex binding assay. Where appropriate, florescence thresholds were determined using finite mixture modelling to classify bats' serological status. Overall, apparent seroprevalence of antibodies directed at Hendra, Cedar and Tioman virus antigens was 43.2%, 26.6% and 95.7%, respectively. We used hurdle models to explore correlates of seropositivity and antibody levels when seropositive. Increased body condition was significantly associated with Hendra seropositivity (Odds ratio = 3.67; p = 0.002) and Hendra virus levels were significantly higher in pregnant females (p = 0.002). While most bats were seropositive for Tioman virus, antibody levels for this virus were significantly higher in adults (p < 0.001). Unexpectedly, all sera were negative for Australian bat lyssavirus. Temporal variation in antibody levels suggests that antibodies to Hendra virus and Tioman virus may wax and wane on a seasonal basis. These findings suggest a common exposure to Hendra virus and other paramyxoviruses in this flying fox camp in South Australia.

Field immobilization using alfaxalone and alfaxalone-medetomidine in free-ranging koalas (Phascolarctos cinereus): a randomized comparative study.

OBJECTIVE: To characterize and compare two intramuscular drug protocols using alfaxalone and alfaxalone-medetomidine combination for the field immobilization of free-ranging koalas. STUDY DESIGN: Blinded, randomized, comparative field study. ANIMALS: A total of 66 free-ranging koalas from the Mount Lofty Ranges, South Australia. METHODS: Koalas were randomly allocated into two groups. Group A animals were given alfaxalone alone at 3.5 mg kg-1. Group AM animals were given alfaxalone 2 mg kg-1 and medetomidine 40 µg kg-1, reversed with atipamezole at 0.16 mg kg-1. Blinded operators recorded heart rate (HR), respiratory rate (fR), cloacal temperature, depth of sedation and times to: first effect, sedation suitable for clinical interventions, first arousal and full recovery. Data were analysed using independent t test, Mann-Whitney U test, chi-square analysis and log-rank test at 5% level of significance. RESULTS: Suitable immobilization for clinical examination and sample collection was achieved in all animals. In groups A and AM, median time to working depth was 6.5 minutes (range: 3.4-15) and 8.1 minutes (range: 4.3-24) and time to complete recovery was 66 minutes (range: 12-138) and 34 minutes (range: 4-84), respectively, following reversal. Time to first effect was significantly shorter in group A (p = 0.013), whereas time to full arousal was significantly shorter in group AM (p = 0.007) probably due to the administration of atipamezole. Maximum HR was 117 ± 28 beats minute-1 in group A, which was a significant increase from baseline values (p < 0.0001), whereas group AM showed a significant tachypnoea of 67 ± 25 (normal fR 10-15; p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Both the protocols produced immobilization, enabling clinical examination and sample collection; however, protocol AM was more suitable for field work due to shorter recovery times.