Genome sequence of an Australian strain of canid alphaherpesvirus 1

Objective

Characterisation of a complete genome sequence of an Australian strain of canid alphaherpesvirus 1 (CHV‐1) and its phylogenetic relationship with other varicellovirus species.

Methods

Standard pathology and PCR methods were used to initially detect herpesvirus in hepatic tissue from an infected 4‐week‐old Labrador Retriever puppy. The complete CHV‐1 genome was sequenced using next‐generation sequencing technology followed by de novo and reference assembly, and genome annotation.

Results

The CHV‐1 genome was 125 kbp in length and contained 74 predicted open reading frames encoding functional proteins, all of which have counterparts in other alphaherpesviruses. Phylogenetic analysis using the DNA polymerase gene revealed that the newly sequenced CHV‐1 clustered with canid alphaherpesvirus isolated from the UK and shared a 99% overall nucleotide sequence similarity.

Conclusion

This is the first complete genome of an Australian strain of CHV‐1, which will contribute to our understanding of the genetics and evolution of herpesvirus.     

Trichomonas gallinae in budgerigars and columbid birds in Perth, Western Australia

Objective To estimate the prevalence of infection with Trichomonas gallinae and other parasites of the alimentary tract in psittacine and columbid birds in Perth and to determine in vitro the effectiveness of drugs commonly recommended for treating trichomoniasis.
Design and procedures Samples of crop contents were collected from aviary flocks of budgerigars (Melopsittacus undulatus) and other psittacine and columbid birds in both private and commercial collections in Perth. Similar samples from wild Senegal doves (Streptopelia senegalensis) also were collected. Crop contents were examined and cultured for Trichomonas gallinae and in vitro studies were conducted on the susceptibility of isolates to several drugs used commonly. Other parasites also were detected by faecal examination and/or necropsy.
Results T gallinae was recovered from birds in 1 of 13 private collections of budgerigars (2/289 birds in total). Direct wetmount examination of crop fluid identified 36.4% of samples at four commercial bird dealers which were later determined by culture to contain T gallinae . The prevalence of T gallinae infection ranged from 0 to 11.4% in budgerigars. The prevalence of T gallinae infection in wild Senegal doves was 46% and from one flock of racing pigeons was 59%. The in vitro minimum lethal concentrations of metronidazole, dimetridazole and ronidazole ranged from 40 to 96, 30 to 80 and 40 to 92 μg/mL respectively for six isolates of T gallinae . Other alimentary parasites detected during the survey included Spironucleus sp (syn Hexamita sp), coccidia, Ascaridia platycerci and Raillietina sp.
Conclusions Thirteen budgerigar flocks belonging to members of avicultural societies in Perth had a low prevalence of trichomoniasis and other parasitic infections. The dose rate currently recommended for ronidazole may not result in complete protozoacidal activity against T gallinae infection.     

Excretion of loline alkaloids in urine and faeces of sheep dosed with meadow fescue (Festuca pratensis) seed containing high concentrations of loline alkaloids

Abstract

AIM: To determine the effect of oral dosing of sheep with loline alkaloids on their excretion in urine and faeces, and to monitor for any toxic effects.

METHODS: In Experiment 1, six 9-month-old ewe lambs were given a single oral dose of loline alkaloids (52 mg/kg bodyweight (BW); acute exposure) as a suspension of ground meadow fescue (Festuca pratensis) seed in water. In Experiment 2, on six consecutive days, six ewe lambs were given three doses of loline (68 mg/kg BW/day; chronic exposure). Blood was collected at variable intervals up to 72 h in Experiment 1, and up to 8 days in Experiment 2, for haematology and measurement of alkaline phosphatase, aspartate aminotransaminase, creatine kinase and γ-glutamyl transferase in plasma. Urine and faecal samples were collected at similar times for measurement of creatinine in urine and loline alkaloid analysis. A post mortem with histopathology was carried out on two animals at the end of each experiment.

RESULTS: The loline alkaloids, N-acetyl norloline, N-formyl loline, N-acetyl loline, N-methyl loline and loline base were detected in urine within 15 minutes after the single dosing. N-formyl loline and loline base were the predominant metabolites in urine in both experiments. The total quantity of lolines excreted in both urine and faeces was 10% and 4% of the amount dosed in Experiments 1 and 2, respectively. In both experiments, the clinical chemistry parameters in blood and urine were within normal ranges. Post-mortem and histopathological examination did not show any abnormalities.

CONCLUSIONS: This is the first report of loline alkaloid profiles in both urine and faeces of sheep. The appearance of loline alkaloids and the loline base in urine within 15 minutes suggests rapid uptake, metabolism and excretion. Loline alkaloids were non-toxic to sheep at the concentrations they are exposed to under New Zealand grazing conditions. The low recovery of loline alkaloids in urine and faeces in the absence of toxicity signs suggests lolines are extensively metabolised; probably to forms other than N-formyl loline, N-methyl loline, N-acetyl loline, N-acetyl norloline, and loline base in the digestive tract of sheep prior to absorption, and/or in the liver or other tissues following absorption.     

Skin disease affecting the conservation of the western swamp tortoise (Pseudemydura umbrina)

Objective To review the present position of the western swamp tortoise ( Pseudemydura umbrina ) as an endangered species and significant health issues affecting efforts to save it from extinction.
Procedure A retrospective analysis of the husbandry, hospital and pathology records of the western swamp tortoise captive breeding program at Perth Zoo.
Results In 1987 a captive breeding project was developed to prevent the extinction of the western swamp tortoise but an outbreak of a necrotising dermatitis in 1989 threatened the survival of the captive bred hatchlings. Less severe outbreaks occurred in 1990 and 1993, with isolated cases in between. Of 283 tortoises that were born in captivity or came into captivity from the wild, 37 (13.1%) were affected, comprising 37% of all males, 26% of all females and 13% of animals of unknown gender. Of the affected animals, 70% were less than 2 years of age and 29% were older. Males were 1.6 times more likely to be infected than females but this difference was not statistically significant (P = 0.27). Culture of the lesions consistently yielded unidentified Pseudomonas sp.
Conclusion Improved husbandry, such as strict maintenance of water quality and temperature conditions similar to that of the animal's natural habitat, and monitoring the health of individual tortoises have successfully controlled skin disease in the captive breeding of the western swamp tortoise.     

A survey on bloat in southern Australian beef production systems

Frothy bloat, associated predominantly with grazing legume-based pastures, is considered the second most costly disease in beef cattle in southern Australia, costing $84.4 M annually. It frequently results in the sudden death of cattle. In response to concerns from cattle producers, an online survey was conducted in southern Australia in late 2020 to determine the impact of bloat, identify risk factors and determine the efficacy of current preventive measures. For 217 responses, over two-thirds (70%) of producers reported bloat occurring in the previous 12 months, with estimated morbidity and mortality rates of 3.7% and 5.0% respectively. Bloat was associated with clover or clover-dominant paddocks (79%) and was not associated with grass or grass-dominant pastures or low clover pastures (92%) nor grazing crops (27%). For bloat that occurred in the past 12 months, cattle were very commonly grazing on clover or clover-dominant paddocks (90%) and occasionally lucerne-dominated paddocks (7%). Two-thirds of producers reported having preventive measures in place when losses occurred. Bayesian Network analysis confirmed that grazing clover-based pastures for more than 7 days, yearling cattle and the months of July–September were the main risk factors for bloat occurrence, with pasture type (clover) being the most important. Conversely, no clear relationship between weather conditions and bloat occurrence was evident. This survey highlights the known risk of clover-based pastures for causing bloat in cattle, and that losses occur in many cases despite preventive measures being used. This suggests that current methods for preventing bloat in cattle are suboptimal.     

miRNA and piRNA expression profiles of breeder cock testes detected by next‐generation sequencing

miRNAs are small non‐coding regulatory RNAs that play key roles in diverse biological processes. In this study, we used the Solexa sequencing technique to profile miRNAs in breeder cock testes to illustrate their functions. A total of 663 co‐expressed miRNAs and 3,180 co‐expressed piRNAs were detected in three libraries. Based on Mir‐X^? miRNA qRT‐PCR, three miRNAs representing low, medium and high expression levels according to the sequencing results were selected randomly to validate the miRNAs' expression profiles. Results suggested that the miRNA expression profiles data could represent actual miRNA expression levels. Moreover, target genes prediction of the co‐expressed miRNAs and further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed, which revealed that some candidate miRNAs were involved in the regulation of the spermatogenesis process, spermatozoa function and testicular metabolism. In conclusion, we provided a useful resource for further elucidation of the miRNAs' regulatory role in spermatogenesis, contributing to a preliminary database for functional and molecular mechanistic studies in testicular metabolism, spermatogenesis and other testes functions.     

Clams As recorders of ocean ridge volcanism and hydrothermal vent field activity

The clam Calyptogena magnifica lives at abyssal depths in association with hydrothermal venting on midocean ridges. Analysis of strontium/calcium ratios in C. magnifica shells provides a temperature proxy with submonthly time resolution. A 21-year strontium/calcium record of two clams from 9 degrees50'N on the East Pacific Rise captures the known 1991 and 1992 eruptive events, documents several additional events between 1992 and 1996, and demonstrates the absence of major hydrothermal episodes during the period 1974 to 1991. These clam archives can increase our understanding of the thermal and chemical history of midocean ridge hydrothermal and volcanic activity on decadal time scales.