New Zealand veterinary journal最新文献

Case history: In early summer, a wild fledgling kererū (Hemiphaga novaeseelandiae) was admitted to a wildlife hospital in Dunedin after falling from its nest and being found on the ground.

Clinical findings: The bird was underweight, weighing only 391 g (expected weight > 450 g), and determined to be in poor body condition based on palpation of pectoral muscle mass. There was bilateral periorbital swelling and ocular discharge with caseous material blocking the choana. Samples of the ocular and choanal discharge were collected and submitted for molecular testing. General anaesthesia was required for further radiographic assessment, and the bird was stabilised for 48 hours with oral electrolytes and antimicrobial and analgesic therapy with doxycycline, meloxicam, and tramadol administered orally twice daily via crop tube and voriconazole administered once daily. Chloramphenicol was applied topically to the eyes twice daily. Subsequently, due to the severity of the gross and radiographic lesions, the likelihood of the need for an extended period of treatment, the age of the chick, its weakened and underweight condition and the risk of imprinting, the bird was euthanased while under general anaesthesia.

Laboratory and pathological findings: PCR testing ruled out Chlamydia psittaci as a cause of morbidity and instead identified Mycoplasma columborale. On gross post-mortem examination, there was caseous material in the periorbital tissues, sinuses and choana. Samples of the choanal discharge grew a moderate mixed growth of Escherichia coli and Enterococcus faecalis.

Diagnosis: Severe pyogranulomatous sinusitis associated with infection with M. columborale.

Clinical relevance: This report describes the first isolation of M. columborale in any species in New Zealand and the first diagnosis of mycoplasmosis in a native kererū. The significance of this finding has not yet been determined.

Aims: To describe progress in the reduction of the consumption of antimicrobial drugs by food-producing animals in New Zealand to 2022 and to identify the animal production sectors where progress has been greatest, and those where opportunities remain.

Methods: Data were sourced from official government and industry reports to update previous estimates of consumption (as sales) of antimicrobial products applied to food-producing animals in New Zealand, European countries and the USA. Antimicrobial consumption (AMC) was estimated based on the amount of active ingredient sold, per kg of animal biomass standardised to the probable weight at time of treatment or lifetime mean weight but not slaughter weight (population correction unit; PCU). This methodology is widely used for international comparisons.

Results: The estimated gross consumption of antimicrobials in food-producing animals in New Zealand increased steadily from 2005 to 2013 (from 7.54 to 11.28 mg/PCU). From 2014 to 2018 the estimate flattened to a 5-year rolling mean of 10.40 mg/PCU. In 2019-2021 the consumption dropped. The NZ consumption in 2022 was substantially lower, estimated at 5.84 mg/PCU, 29% less than in 2005 and 45% less than the peak that occurred in 2017.

Conclusions: The use of antimicrobials in food-producing animals in New Zealand is at the lowest rate for nearly 20 years, at 5.8 mg/PCU. Key progress has been made particularly by the poultry industry. Clear future areas to be targeted include prophylactic use of intramammary products applied when drying off dairy cows and a more widespread strategic use in treatment of clinical mastitis.

Clinical relevance: Veterinarians in New Zealand should leverage the significant reduction achieved in AMC by food-producing animals by continuing to improve strategies for antimicrobial use to further reduce the risk of antimicrobial resistance.

Case history: A 9-year-old, spayed, female Golden Retriever presented with an 18-month history of small spots of opacification on the left cornea, a 3-4-month history of a raised spot on the left cornea, and a watery left eye. As a puppy, the dog had sustained an injury to the left cornea. Self-limiting, presumed papillomaviral warts were diagnosed on the face when the dog was 8 months old.

Clinical findings and initial treatment: A full ophthalmic examination revealed a well-circumscribed, pigmented, raised mass immediately adjacent to three smaller pink masses on the left cornea. The corneal tumour was resected by superficial keratectomy. The cornea was treated with topical peginterferon alfa-2a drops post-operatively.

Pathological and molecular findings: The mass was histologically diagnosed as an incompletely excised corneal pigmented squamous cell carcinoma (pSCC) displaying both exophytic growth and superficial stromal invasive characteristics and fine granular brown melanin pigment within the cytoplasm of neoplastic cells. Superficial cells showed evidence of papillomavirus-induced cell changes including enlarged cells with blue-grey cytoplasm and darkly basophilic keratohyalin granules. Canine papillomavirus type 17 (CPV17) DNA sequences were amplified from the carcinoma by PCR using consensus papillomavirus primers.

Diagnosis: Primary corneal pigmented squamous cell carcinoma with concurrent canine papillomavirus type 17 infection.

Outcome: Tumour recurrence was observed 2 years 9 months after surgery. Topical peginterferon alfa-2a drops were recommenced and superficial keratectomy surgery was repeated with concurrent adjunctive strontium 90 plesiotherapy. At the time of writing, the left cornea has healed well with mild fibrosis and vascularisation continuing to reduce.

Clinical relevance: This is the first report of a pSCC of the cornea in any veterinary species. Prominent papillomaviral cytopathology was visible in the corneal pSCC, and PCR confirmed the presence of CPV17.This report expands the differential diagnoses for pigmented corneal masses in dogs. It highlights the importance of obtaining a histopathological diagnosis for pigmented corneal lesions, as the clinical disease course, prognosis and treatment options vary between lesions of different aetiologies. Corneal SCC is locally invasive and can recur without complete excision. Early surgical intervention with clean margins can be curative and restore corneal clarity, vision and patient comfort.

Aims: To determine the genetic makeup of carnivore parvoviruses currently circulating in New Zealand; to investigate their evolutionary patterns; and to compare these viruses with those detected during the previous New Zealand-based survey (2009-2010).

Methods: Faecal samples from dogs (n = 40) with a clinical diagnosis of parvovirus enteritis were voluntarily submitted by veterinarians from throughout New Zealand. In addition, one sample was collected from a cat with comparable clinical presentation. The samples were used for DNA extraction and PCR amplification of viral protein 2 (VP2) of canine parvovirus type 2 (CPV-2). All samples produced amplicons of the expected sizes, which were then sequenced. The viruses were subtyped based on the presence of specific amino acids at defined locations. In addition, VP2 sequences were analysed using phylogeny and molecular network analysis.

Results: The majority (30/40; 75%) of CPV-2-infected dogs were younger than 6 months and 8/40 (20%) were aged between 9 months and 1 year. Most (39/41; 95%) parvoviruses were subtyped as CPV-2c, and one as the original CPV-2. The faecal sample from a cat was positive for feline panleukopenia virus. The majority (37/39; 95%) of New Zealand CPV-2c viruses were monophyletic. The remaining two New Zealand CPV-2c viruses clustered with Chinese and Sri Lankan CPV-2c viruses, separately from the main New Zealand clade.

Conclusions: There has been an apparent replacement of the CPV-2a viruses with CPV-2c viruses in New Zealand between 2011 and 2019. The source of the current CPV-2c viruses remains undetermined. The monophyletic nature of the majority of viruses detected most likely reflects a country-wide spread of the most successful genotype. However, an occasional introduction of CPV-2 from overseas cannot be excluded.

Clinical relevance: Current vaccines appear to be protective against disease caused by the CPV-2c viruses currently circulating in New Zealand. Vaccination and protection from environmental sources of CPV-2 until the development of vaccine-induced immunity remains the cornerstone of protection in young dogs against parvovirus enteritis. Ongoing monitoring of the genetic changes in CPV-2 is important, as it would allow early detection of variants that may be more likely to escape vaccine-induced immunity.

Aims: To determine the major causes of mortality in weka (Gallirallus australis), and to investigate associations between causes of mortality and captivity status, age, sex, decade of submission, and season.

Methods: Necropsy records were obtained from the Massey University School of Veterinary Science/Wildbase Pathology database (Palmerston North, NZ) for weka submitted between 1 January 1995 and 22 March 2022. Causes of mortality were classified into categories based on aetiology. Frequency of diagnosis was tested for association with region of submission, captivity status, age, sex, decade, and season of death.

Results: A total of 156 necropsy reports were included in this study, of which 96 (61%) were from wild weka, 57 (36.5%) were captive, and three (1.9%) were of an unspecified captivity status. Weka were submitted from 12 regions across New Zealand. There were 65 (41.7%) adults, 16 (10.3%) juveniles, and 75 (48.1%) weka of an undetermined age among the 156 submissions. Of the weka with a known sex, there was a similar distribution between sexes with 27 (17.3%) males and 29 (18.6%) females. A cause of death was determined in 132/156 (84.6%) cases, with 24/156 (15.4%) cases having an unknown diagnosis. The leading cause of mortality in weka was traumatic injury, which occurred in 65/156 (41.7%), followed by infectious and/or inflammatory diseases in 26/156 (16.7%), and degenerative and/or nutritional conditions affecting 20/156 (12.8%) cases. The distribution of the primary causes of death was found to be dependent on captivity status (p < 0.001). Traumatic and toxic causes of death were more frequent in wild than captive weka. The cause of death was also dependent on season (p < 0.001). There was a significant difference in cause of death between summer and all other seasons (spring p = 0.008; autumn p < 0.001; winter p < 0.001) and between autumn and winter (p = 0.008).

Conclusion: Trauma was identified as the most significant cause of mortality in the free-living weka necropsied. The inherent and uncertain submissions biases, and low case numbers over a long period of time, means that temporal patterns and the effect of captivity status on causes of mortality should be interpreted with caution.

The aim of this scoping review was to investigate the range of methods used to guide veterinarians in their approach to the death of their animal patients with the guiding question: how is this topic addressed in the training of veterinarians? We included studies written in Portuguese or English, with a theme aligned with the objective of the review and which answered the guiding question. Studies not fulfilling these criteria were excluded. A total of 22 complete studies were identified by searching the Scopus, Web of Science, PsycINFO and Pubmed databases/libraries, with no restrictions on the date of publication. Studies from 1989 to 2023 were identified, mostly by North American authors. The results were organised into three major themes: topics in the veterinary curriculum about patient death and its impacts on students and future professionals; teaching methods used to cover this topic; and the extracurricular training available to support veterinarians with their direct experience of this topic. Analysis of these papers indicated that the theme of death appeared in three distinct contexts operating at different stages of veterinarians' training: the hidden curriculum, compulsory training initiatives, and extracurricular training. The review included reflections on the challenges inherent in this theme and inferences from the timeline of publications in this area. Our review clearly indicates that there is increasing recognition of the importance of this subject, as well as a feeling within the profession of being unprepared to manage this aspect of veterinary experience and a perception that teaching in this area needs to be improved.

Aims: To compare the responses of liver Cu concentrations in dairy cows between three forms of injectable Cu supplementation and a negative control group.

Methods: Across two dairy farms in North Canterbury, New Zealand, 80 mid-lactation dairy cows (n = 28 and 52 per farm) were randomly allocated to four treatment groups: (a) 100-mg or (b) 200-mg dose of Cu administered as Ca Cu EDTA; (c) 75-mg dose of Cu as disodium Cu EDTA combined with Se, Zn, and Mn; or (d) no treatment (negative control). Each treatment group contained 20 cows. Groups were balanced for age, plasma Cu and pre-treatment liver Cu concentration. Blood samples and liver biopsies were collected prior to treatment. Six liver biopsies were performed on the same cow over a period of 70 days and the concentration of liver Cu was measured over time and compared to pre-treatment baseline. A mixed, multivariable, linear regression model was constructed to determine the effect of treatment on the change in liver Cu concentration compared to pre-treatment concentrations, accounting for repeated measurements taken from each cow.

Results: There was a difference in the distribution of pre-treatment liver Cu concentration between farms (p = 0.008), with medians of 1,400 (IQR 1,200-1,625) and 1,050 (IQR 805-1,425) µmol/kg on Farms 1 and 2, respectively. There was an interaction between treatment group, study day, and farm, with a treatment effect confirmed only on Farm 2. In the final model, the predicted change in liver Cu concentration (compared to pre-treatment concentrations) among cows on Farm 2 that were treated with 200 mg of Ca Cu EDTA was significantly higher than that of control cows on Days 3, 14, 28 and 42, peaking on Day 14 with a difference of 325.35 (95% CI = 97.00-554.03) µmol/kg. The study found no associations between changes in liver Cu concentration and age or prior plasma Cu concentration. The intraclass correlation coefficient was 0.57 (95% CI = 0.45-0.66), indicating the proportion of variability in changes in liver Cu concentration attributable to inter-cow variation.

Conclusions and clinical relevance: This study shows there are differences in response to injectable Cu supplementation at the farm level and wide variation in liver Cu among cows from the same farm. On one farm, a 200-mg dosage of Ca Cu EDTA significantly increased liver Cu concentration for at least 42 days.

Aims: To develop a colourimetric loop-mediated isothermal amplification (LAMP) assay for the detection of Pasteurella multocida in clinical poultry samples and compare the performance of this assay with PCR. A secondary aim was to evaluate a simple DNA extraction method that could enable LAMP-based testing in the field without the need for specialised laboratory equipment.

Methods: Primer sets for both LAMP and PCR were designed to amplify the KMT1 gene of P. multocida. DNA was extracted from 12 P. multocida isolates using a commercial extraction kit, and subjected to analysis using both LAMP and PCR. The analytical specificity of the LAMP assay was evaluated by testing it against a panel of 12 unrelated bacterial species, and the analytical sensitivity (limit of detection) was determined through testing of serial dilutions of the target DNA and compared to that of PCR. Subsequently, cloacal swabs (n = 40) from a commercial turkey flock were subjected to analysis using both LAMP and PCR assays, using a rapid DNA extraction method and a commercial extraction kit. Clinical sensitivity and specificity of the LAMP assay were calculated in comparison to PCR.

Results: A single DNA fragment of the expected size (∼ 200 base pairs), was amplified by PCR from 12 P. multocida isolates, which were also all positive by the LAMP assay. The identity of all PCR amplicons was confirmed by sequencing. Both PCR and LAMP showed similar analytical sensitivity, with a LOD of 20 pg of target DNA. As neither PCR nor LAMP assays produced positive results with 12 non-related bacterial species, the analytical specificity was assessed as 100%. However, LAMP demonstrated lower clinical specificity (94.74%) compared to PCR (100%) when 40 clinical samples were tested. None of the DNA samples extracted using the simplified DNA extraction method were amplified by either LAMP or PCR.

Conclusion: The LAMP assay developed in this study exhibits comparable performance to PCR in detecting P. multocida.

Clinical relevance: The use of a rapid and portable DNA extraction method, in conjunction with LAMP assays, could create opportunities for point-of-care testing for fowl cholera in field settings.

Aims: To investigate the effect of injection of trace mineral supplement (TMS) 14-28 days before calving on white blood cell count (WBCC) and function, serum antioxidant capacity (SAC) and reactive oxygen species (ROS) in pasture-fed cattle after calving.

Methods: On each of two South Island, seasonally calving, pastoral dairy farms,1 month before dry-off, a random sample of 150 multiparous cows predicted to calve within 7 days of the herd's planned start of calving (PSC) were stratified on individual somatic cell count, age, breed and expected calving date. On each farm, 14-24 days before PSC, 60 selected cows were randomly assigned for TMS (Zn, Mn, Se, Cu) injection, and 60 were controls. All 240 cows were contemporaneously injected with hydroxocobalamin, and controls with Se. Blood samples were collected pre-injection and 3, 12 and 40 days after calving. Phagocytic activity, count and proportion of neutrophils, lymphocytes and monocytes, WBCC, ROS, SAC were measured. Plasma concentrations of Se, Cu and glutathione peroxidase (GPx) were monitored from a random subset of animals. Differences attributable to TMS were estimated using mixed-multivariable Bayesian analysis, expressed as mean and highest density interval (HDI).

Results: Three and 40 days after calving, TMS-treated cows had 0.36 (90% HDI = 0.00-0.77) x 10⁹ and 0.25 (90% HDI = 0.00-0.55) x 10⁹ fewer neutrophils/L. Neutrophils comprised 6 (90% HDI = 0-11)% and 4 (90% HDI = 0-8)% less of the WBCC, and the neutrophil count was 14 (90% HDI = 0-27)% and 9 (90% HDI = 0-18)% less than controls. However, 3 days after calving, there were 7 (95% HDI = 2-12)% more cells phagocytosing and 2,900 (95% HDI = 2,600-3,200) more bacteria ingested/cell. Twelve and 40 days after calving, TMS-treated cows had 0.65 (95% HDI = 0.17-1.17) x 10⁹ and 0.28 (95% HDI = 0.00-0.59) x 10⁹ more lymphocytes/L. Lymphocytes comprised 10 (95% HDI = 3-18)% and 5 (95% HDI = 0-9)% more of the WBCC, and the lymphocyte count was 30 (95% HDI = 11-51)% and 9 (95% HDI = 0-9)% more than controls. There were no meaningful differences in ROS, SAC, ROS/SAC, other white blood cells, or WBCC. Plasma Cu, Se and GPx concentrations were above recommended thresholds.

Conclusions: Pre-calving TMS injection was associated with differences in white blood cell population and function that may reduce the risk of disease.

Abbreviations: BHOB: Beta-hydroxybutyrate; GPx: Glutathione peroxidase; HDI: Highest density interval; MESF: Molecules of equivalent soluble fluorophore; OSi: Oxidative stress index; PSC: Planned start of calving; ROPE: Region of probable equivalence; ROS: Reactive oxygen species; SAC: Serum antioxidant capacity; THI: Temperature humidity index; TMS: Trace mineral supplement; WAIC: Widely applicable information criterion; WBCC: White blood cell count.