Evidence for the vertical transmission of Sunshine virus

Sunshine virus is a paramyxovirus of pythons associated with neurorespiratory disease and mortalities. This report provides evidence for its vertical transmission. In a collection of over 200 Australian pythons, a dam and a sire, both carpet pythons (Morelia spilota), were PCR-positive for Sunshine virus at a time when the dam was likely to have been gravid. A clutch of 21 eggs was laid and three non-viable eggs were tested for the presence of Sunshine virus by PCR. One egg had been incubating for 34 days while the other two had been incubating for 49 days. The surface of all three eggs was negative for Sunshine virus but swabs of the allantois and amnion were positive in all three eggs. Embryo tissue samples were tested from the two 49 day old eggs. From one embryo, a sample of brain and a pooled sample of lung, liver, kidney and intestine were positive, while for the other embryo, a pooled sample of lung, liver, kidney, intestine and brain was positive. Fourteen of the 21 eggs hatched and all hatchlings were tested by PCR at least once between the ages of 53 and 229 days old. All hatchlings were PCR-negative for Sunshine virus

Salmonella in free-ranging quokkas (Setonix brachyurus) from Rottnest Island and the mainland of Western Australia

Salmonella is a genus of Gram-negative, motile, and facultative anaerobic bacteria with a worldwide distribution that contaminates multiple substrates (vegetation, food, soil, and water) and inhabits the gastrointestinal tract of birds, reptiles, and mammals, including humans. Rottnest Island is a popular tourist destination and is abundantly inhabited by quokkas (Setonix brachyurus), a charismatic small wallaby. Current data on the association between Salmonella and quokkas on Rottnest Island are outdated by approximately 30 years. Additionally, previous studies on quokkas on this island and mainland Western Australia did not perform physical examinations or any diagnostic tests. The aim of the project was to assess the prevalence of Salmonella spp. in quokkas from Rottnest Island and mainland Western Australia and correlate the presence of the bacterium with the health of the animal. Ninety-two quokkas from Rottnest Island (n = 71) and populations on the mainland (n = 21) were screened for Salmonella, and a prevalence of 47.9% and 4.8%, respectively, was determined. A total of 16 serovars were identified from 37 isolates; five of these serovars had previously not been described in the quokka. Salmonella appeared to have an effect on the haematology and blood chemistry of quokkas on Rottnest Island consistent with subclinical salmonellosis. The health of Rottnest Island quokkas, and their potential impact on the health of the visitors to the island, should continue to be monitored carefully

Divergent bornaviruses from Australian carpet pythons with neurological disease date the origin of extant Bornaviridae prior to the end-Cretaceous extinction

Tissue samples from Australian carpet pythons (Morelia spilota) with neurological disease were screened for viruses using next-generation sequencing. Coding complete genomes of two bornaviruses were identified with the gene order 3’-N-X-P-G-M-L, representing a transposition of the G and M genes compared to other bornaviruses and most mononegaviruses. Use of these viruses to search available vertebrate genomes enabled recognition of further endogenous bornavirus-like elements (EBLs) in diverse placental mammals, including humans. Codivergence patterns and shared integration sites revealed an ancestral laurasiatherian EBLG integration (77 million years ago [MYA]) and a previously identified afrotherian EBLG integration (83 MYA). The novel python bornaviruses clustered more closely with these EBLs than with other exogenous bornaviruses, suggesting that these viruses diverged from previously known bornaviruses prior to the end-Cretaceous (K-Pg) extinction, 66 MYA. It is possible that EBLs protected mammals from ancient bornaviral disease, providing a selective advantage in the recovery from the K-Pg extinction. A degenerate PCR primer set was developed to detect a highly conserved region of the bornaviral polymerase gene. It was used to detect 15 more genetically distinct bornaviruses from Australian pythons that represent a group that is likely to contain a number of novel species

Animal harms and food production: Informing ethical choices

Ethical food choices have become an important societal theme in post-industrial countries. Many consumers are particularly interested in the animal welfare implications of the various foods they may choose to consume. However, concepts in animal welfare are rapidly evolving towards consideration of all animals (including wildlife) in contemporary approaches such as “One Welfare”. This approach requires recognition that negative impacts (harms) may be intentional and obvious (e.g., slaughter of livestock) but also include the under-appreciated indirect or unintentional harms that often impact wildlife (e.g., land clearing). This is especially true in the Anthropocene, where impacts on non-human life are almost ubiquitous across all human activities. We applied the “harms” model of animal welfare assessment to several common food production systems and provide a framework for assessing the breadth (not intensity) of harms imposed. We considered all harms caused to wild as well as domestic animals, both direct effects and indirect effects. We described 21 forms of harm and considered how they applied to 16 forms of food production. Our analysis suggests that all food production systems harm animals to some degree and that the majority of these harms affect wildlife, not livestock. We conclude that the food production systems likely to impose the greatest overall breadth of harms to animals are intensive animal agriculture industries (e.g., dairy) that rely on a secondary food production system (e.g., cropping), while harvesting of locally available wild plants, mushrooms or seaweed is likely to impose the least harms. We present this conceptual analysis as a resource for those who want to begin considering the complex animal welfare trade-offs involved in their food choices

Mechanical nociceptive threshold testing in Bos indicus bull calves

The aim of this prospective, controlled, randomised trial was to develop a technique for mechanical nociceptive threshold testing (NTT) to assess pain in Bos indicus bull calves undergoing surgical castration. Analgesia was provided by 0.5 mg/kg subcutaneous (SC) meloxicam (M) and/or 2 mg/kg of intra-testicular and SC (at the surgery sites) lidocaine (L). Forty-eight Brahman bull calves at 6–8 months of age were divided into six study groups, each with eight animals: no surgery control; surgical castration (C) without analgesia; C and Mpre-op; C and Mpost-op; C, L and Mpost-op; C and L. Mechanical NTT was performed the day before surgery (Day –1) and on Days 1, 2, 6, 10 and 13 after surgery. A handheld manual pneumatic device with a 1-mm (diameter) blunt pin was used to deliver a mechanical stimulus to a maximum of 27 Newtons either side of the most dorsal aspect of the sacrum. The most frequent responses to the mechanical stimulus were lifting or kicking of the leg on the same side as the stimulus (31%) and stepping away from the stimulus (24.9%). Data were analysed with a mixed effect linear model with the nociceptive threshold (NT) as the response variable and day and analgesic treatment as predictors (P < 0.05 was considered significant). For all groups, there was a trend towards decreasing NT over the study period but there were no significant differences between groups. Step down model selection with day, batch and treatment terms revealed a significant effect of day (P < 0.001) and batch (P = 0.007). Mechanical NTT for assessment of pain in Bos indicus bull calves requires further refinement to determine if this is a useful method of pain assessment

Animal welfare and the use of procedural documents: Limitations and refinement

Increased scrutiny of animal welfare in wildlife management has seen a recent proliferation in the use of procedural documents (standard operating procedures, codes of practice etc.). Some procedural documents are presumed to represent 'best practice' methods, whereby adherence to prescribed inputs is explicitly purported to generate humane outcomes. However, the relationship between what is done to animals (inputs) and what they experience (outputs), as assessed by animal-based measures, has received little attention. Procedural documents are commonly developed in the absence of empirical animal-based measures, creating uncertainty in animal welfare outcomes. Prescribed procedures are valuable as guidelines for standardising methodology, but the development of 'welfare standards' that focus on desired thresholds for animal-based measures offers many advantages for improving animal welfare. Refinement of the use of procedural documents in wildlife management is required to ensure they generate desirable outcomes for animals, and do not preclude the development of improved methods

Qualitative Behavioural Assessment of Bos indicus cattle after surgical castration

There are various methods to perform castration of cattle, but surgical castration is the most common. Although it is well documented that surgical procedures inflict pain, analgesic use is usually omitted for surgical castration of production animals in Australia. This study compares the behavioural responses of castrated cattle (C) with non-castrated (NC) controls, and C with those castrated and given lignocaine and meloxicam (CLM) for analgesia. Brahman bull calves (n = 8 for each treatment) were filmed in the morning pre- (day -1) and post- (day +1) castration in the paddock and feed yard (‘context’ of observation). Over four sessions, volunteer observers viewed the video footage for Qualitative Behaviour Analysis (QBA) using the Free Choice Profiling methodology comparing C and NC cattle, and C and CLM cattle under both contexts. The QBA consensus profiles explained 37.4% (C vs. NC) and 40.6% (C vs. CLM) of variation among observers for paddock sessions and 34.7% (C vs. NC) and 38.7% (C vs. CLM) for feed yard sessions. Significant treatment x day interaction effects were recorded in the paddock (P = 0.007 and P < 0.001) and yard (P =  0.004 and P =  0.025) contexts for comparisons between NC vs C, and C vs CLM respectively. Compared to NC, post-castration C cattle were described as more ‘bored’/’lethargic’ and ‘alone’ (paddock) and were more ‘calm’/’relaxed’ and ‘relaxed’/’lonely’ (yard). Similarly, compared to CLM, post-castration C cattle were described as more ‘docile’/’chilled’ and ‘curious’/’aware’ (paddock) and were less ‘hungry’/’alert’ (yard). There was only one correlation between qualitative and quantitative behaviour scoring; ruminating showed significant correlation with one dimension in each context, that reflected a positive emotion (‘calm, relaxed’). The comparison between C vs. NC suggest that C were less active and less engaged with their environment compared to the NC group following castration. The C vs. CLM comparison suggests a more subtle response whereby analgesia was associated with more positive valence (higher scores on ‘calm/comfortable’, and ‘hungry/alert’ dimensions) following castration. The interpretation of findings requires careful consideration of the emotional responses given these calves were unhabituated and reactive to their surroundings. These results suggest the body language of Bos indicus cattle may reveal indicators of pain, and that the administration of analgesia may be beneficial at the time of castration. The study highlights the complexities and challenges of identifying pain responses in Brahman cattle

Mitigation of electroencephalographic and cardiovascular responses to castration in Bos indicus bulls following the administration of either lidocaine or meloxicam

Objective To investigate the mitigating effects of administration of local or systemic meloxicam on the electroencephalographic (EEG) and cardiovascular responses during surgical castration of Bos indicus bull calves. Study design Prospective, randomized, experimental study. Animals Thirty-six 6–8 month-old Bos indicus bull calves, with a mean ± standard deviation weight of 237 ± 19 kg. Methods Animals were randomly allocated to three groups of 12 (group L, 260 mg of 2% lidocaine subcutaneously and intratesticularly 5 minutes prior to castration; group M, 0.5 mg kg−1 of meloxicam subcutaneously 30 minutes prior to castration; group C, no pre-operative analgesia administered). Anaesthesia was induced and maintained with halothane (0.9–1.1%) in oxygen. Electroencephalogram, heart rate (HR) and mean blood pressure (MAP) were recorded for 300 seconds prior to (baseline, B) and from the start of surgery (first testicle incision, T1). HR and MAP were compared at 10 second intervals for 90 seconds from the start of T1. Median frequency (F50), spectral edge frequency (F95) and total power of the EEG (Ptot) were analysed using area under the curve comparing T1 to B. Results All EEG variables were significantly different between B and T1 (p ≤ 0.0001). No differences in F50 were found between groups during T1 (p = 0.6491). F95 and Ptot were significantly different between group L and groups C and M during T1 (p = 0.0005 and 0.0163, respectively). There were transient significant changes in HR and MAP in groups L and M compared to group C during the 20–50 second periods. Conclusions The EEG changes indicate nociceptive responses in all three groups during surgical castration, greater in group L compared to groups C and M. Both analgesics attenuated the peracute cardiovascular response. Lidocaine and meloxicam administered prior to castration attenuated these responses in Bos indicus bull calves. Clinical relevance These findings provide support for the pre-operative administration of lidocaine and potentially meloxicam for castration in Bos indicus bull calves

The pharmacokinetics of medetomidine administered subcutaneously during Isoflurane anaesthesia in Sprague-Dawley rats

Anaesthetic protocols involving the combined use of a sedative agent, medetomidine, and an anaesthetic agent, isoflurane, are increasingly being used in functional magnetic resonance imaging (fMRI) studies of the rodent brain. Despite the popularity of this combination, a standardised protocol for the combined use of medetomidine and isoflurane has not been established, resulting in inconsistencies in the reported use of these drugs. This study investigated the pharmacokinetic detail required to standardise the use of medetomidine and isoflurane in rat brain fMRI studies. Using mass spectrometry, serum concentrations of medetomidine were determined in Sprague-Dawley rats during medetomidine and isoflurane anaesthesia. The serum concentration of medetomidine for administration with 0.5% (vapouriser setting) isoflurane was found to be 14.4 ng/mL (±3.0 ng/mL). The data suggests that a steady state serum concentration of medetomidine when administered with 0.5% (vapouriser setting) isoflurane can be achieved with an initial subcutaneous (SC) dose of 0.12 mg/kg of medetomidine followed by a 0.08 mg/kg/h SC infusion of medetomidine. Consideration of these results for future studies will facilitate standardisation of medetomidine and isoflurane anaesthetic protocols during fMRI data acquisition

Meta-transcriptomic discovery of a divergent circovirus and a chaphamaparvovirus in captive reptiles with proliferative respiratory syndrome

Viral pathogens are being increasingly described in association with mass morbidity and mortality events in reptiles. However, our knowledge of reptile viruses remains limited. Herein, we describe the meta-transcriptomic investigation of a mass morbidity and mortality event in a colony of central bearded dragons (Pogona vitticeps) in 2014. Severe, extensive proliferation of the respiratory epithelium was consistently found in affected dragons. Similar proliferative lung lesions were identified in bearded dragons from the same colony in 2020 in association with increased intermittent mortality. Total RNA sequencing identified two divergent DNA viruses: a reptile-infecting circovirus, denoted bearded dragon circovirus (BDCV), and the first exogeneous reptilian chaphamaparvovirus—bearded dragon chaphamaparvovirus (BDchPV). Phylogenetic analysis revealed that BDCV was most closely related to bat-associated circoviruses, exhibiting 70% amino acid sequence identity in the Replicase (Rep) protein. In contrast, in the nonstructural (NS) protein, the newly discovered BDchPV showed approximately 31%–35% identity to parvoviruses obtained from tilapia fish and crocodiles in China. Subsequent specific PCR assays revealed BDCV and BDchPV in both diseased and apparently normal captive reptiles, although only BDCV was found in those animals with proliferative pulmonary lesions and respiratory disease. This study expands our understanding of viral diversity in captive reptiles