Prevalence of canine heartworm infection in Queensland, Australia: comparison of diagnostic methods and investigation of factors associated with reduction in antigen detection

Background: The prevalence of Dirofilaria immitis infection in dogs is increasing globally and spreading into new areas. Prevalence of dirofilariosis in the state of Queensland, Australia, was as high as 90% before the introduction of macrocyclic lactones. Limited research on prevalence of D. immitis infection in dogs in Queensland has been reported in the last 30 years. Antigen testing is the most common method for detection of dirofilariosis but its accuracy is reduced by antigen getting trapped (blocked antigen) in immune complexes (ICs). The objectives of this research were to determine the prevalence of D. immitis infection in dogs from two geographical areas (Brisbane and Townsville) in Queensland, to determine the extent to which blocked antigen affects the validity of antigen testing, and to explore whether this was associated with microfilaraemia, location, age or sex. Methods: Blood samples from Brisbane (sub-tropical climate) and Townsville (tropical climate) shelter dogs were evaluated for the presence of D. immitis antigen before (conventional antigen testing, CAT) and after dissociation of ICs by heat treatment (antigen testing after heat treatment, ATHT), using a commercially available test. Microfilariae were detected using modified Knott’s test (MKT). Test proportions were compared with McNemar’s test and the association between antigen test-discordant results (positive for antigen after dissociation of ICs) and microfilaraemia, location, sex and age was modelled using logistic regression. Results: Dirofilaria immitis prevalence in dogs from Townsville (22% by CAT, 32.1% by ATHT and 16.7% by MKT) was significantly higher than in dogs from Brisbane (1.1% by CAT and MKT and 1.7% by ATHT) (P<0.001). Dissociation of ICs allowed detection of significantly more D. immitis infected dogs than either conventional antigen testing or microfilariae detection, or the combined antigen and microfilariae detection (P<0.001). The odds of dogs being positive for antigen after dissociation of ICs were significantly higher for microfilaraemic, 3–4-year-old female dogs from Townsville. Conclusions: The high prevalence of infection with D. immitis in dogs from Townsville poses a health risk for local susceptible host species, including humans. Dissociation of ICs increases antigen detection and should be considered in dogs suspected of D. immitis infection but negative on routine testing

Cricothyrotomy Is Faster Than Tracheostomy for Emergency Front-of-Neck Airway Access in Dogs

Objectives: In novice final year veterinary students, we sought to: (1) compare the procedure time between a novel cricothyrotomy (CTT) technique and an abbreviated tracheostomy (TT) technique in canine cadavers, (2) assess the success rate of each procedure, (3) assess the complication rate of each procedure via a damage score, (4) evaluate the technical difficulty of each procedure and (5) determine the preferred procedure of study participants for emergency front-of-neck access. Materials and Methods: A prospective, cross-over, block randomised trial was performed, where veterinary students completed CTT and TT procedures on cadaver dogs. Eight students were recruited and performed 32 procedures on 16 dogs. A generalised estimating equation approach to modelling the procedure times was used. Results: The procedure time was significantly faster for the CTT than the TT technique, on average (p < 0.001). The mean time taken to complete the CTT technique was 49.6 s (95% CI: 29.5–69.6) faster on average, with a mean CTT time of less than half that of the TT. When taking into account the attempt number, the procedure time for a CTT was 66.4 s (95% CI: 38.9–93.9) faster than TT for the first attempt, and for the second attempt, this was 32.7 s (95% CI: 15.2–50.2) faster, on average. The success rate for both procedures was 100% and there was no difference detected in the damage or difficulty scores (P = 0.13 and 0.08, respectively). Seven of eight participants preferred the CTT. Clinical Significance: CTT warrants consideration as the primary option for emergency front-of-neck airway access for dogs

Identification of microchip implantation events for dogs and cats in the VetCompass Australia database

In Australia, compulsory microchipping legislation requires that animals are microchipped before sale or prior to 3 months in the Australian Capital Territory, New South Wales, Queensland and Victoria, and by 6 months in Western Australia and Tasmania. Describing the implementation of microchipping in animals allows the data guardians to identify individual animals presenting to differing veterinary practices over their lifetimes, and to evaluate compliance with legislation. VetCompass Australia (VCA) collates electronic patient records from primary care veterinary practices into a database for epidemiological studies. VCA is the largest companion animal clinical data repository of its kind in Australia, and is therefore the ideal resource to analyse microchip data as a permanent unique identifier of an animal. The current study examined the free-text ‘examination record’ field in the electronic patient records of 1000 randomly selected dogs and cats in the VCA database. This field may allow identification of the date of microchip implantation, enabling comparison with other date fields in the database, such as date of birth. The study revealed that the median age at implantation for dogs presented as individual patients, rather than among litters, was 74.4 days, significantly lower than for cats (127.0 days, p = 0.003). Further exploration into reasons for later microchipping in cats may be useful in aligning common practice with legislative requirements

Pseudohypoadrenocorticism in a Siberian Husky with Trichuris vulpis Infection

An entire male Siberian Husky presented for diarrhoea, weakness, inappetence, and collapse following a six-day period of illness. On clinical examination the dog displayed vasoconstrictive circulatory shock, dehydration, and melena. Laboratory tests revealed a marked hyponatraemia, hyperkalaemia, and a decreased sodium/potassium ratio of ≤ 12.4. The baseline and poststimulation serum cortisol concentrations were markedly elevated following adrenocorticotropin hormone (ACTH) stimulation test, yielding 712 nmol/L and 706 nmol/L, respectively. The elevated cortisol concentration excluded hypoadrenocorticism. A concurrent Trichuris vulpis (whipworm) infection was also identified. The dog was treated with supportive care including fenbendazole and recovered uneventfully. The final diagnosis was Trichuris vulpis infection with secondary pseudohypoadrenocorticism. This case report further supports a previous observation that the Siberian Husky breed may have an increased sensitivity to infection with Trichuris vulpis and development of pseudohypoadrenocorticism

A pilot study evaluating the utility of a novel tube cricothyrotomy technique in providing ventilation in small animals using a live porcine model

Background: Tube cricothyrotomy has been suggested as a first-choice for emergency surgical airway access in small animals, rather than the more commonly accepted procedures of tracheotomy and needle cricothyrotomy. Methods: A small pilot study of tube cricothyrotomy in a live porcine model was conducted to evaluate this method. The technique was modified to permit the use of commonly available equipment and ease of application. Following ethics approval, a tube cricothyrotomy was performed on 9 live pigs. The endpoints were the efficacy of ventilation through the tube as measured by end-tidal carbon dioxide, successful placement of the tube and the time taken for placement. Results: Of the nine pigs, eight had a tube placed successfully, with the median procedure time being 111.5 seconds (range: 35–240 seconds). After 10 mins, the mean end-tidal carbon dioxide was 58.3 mmHg (95% CI: 55.2–61.3 mmHg), with a range of 54–64 mmHg. Tube cricothyrotomy holds promise as a means of rapidly obtaining tracheal access in small animals and temporarily sustaining ventilation in an emergency. Conclusion: Further detailed investigation is warranted to assess the use of this technique in the small animal emergency setting

Successful Treatment of Transient Central Diabetes Insipidus following Traumatic Brain Injury in a Dog

An 11-year-old female spayed Maltese presented comatose, half an hour after vehicular trauma, and was treated for traumatic brain injury and pulmonary contusions. The dog developed severe hypernatremia within six hours of presentation, which responded poorly to the administration of five percent dextrose in water. As central diabetes insipidus was suspected, desmopressin was trialled and resolution of hypernatremia was achieved six days later. Transient trauma-induced central diabetes insipidus has been described previously in two dogs; in the first, serum sodium concentrations were evaluated three days after injury and the other developed hypernatremia seven days after injury. To the authors’ knowledge, this is the first report of rapid onset, transient, and trauma-induced central diabetes insipidus in a dog that encompasses the complete clinical progression of the syndrome from shortly after injury through to resolution

Treatment of moderate grade dog bite wounds using amoxicillin–clavulanic acid with and without enrofloxacin: a randomised non‐inferiority trial

Background: Dog-to-dog bite wounds are a common veterinary emergency presentation: despite this, there is insufficient information to guide veterinarians on appropriate empirical antimicrobial management. Objectives: Investigate the effectiveness of amoxicillin–clavulanic acid with and without enrofloxacin in the treatment of moderate grade dog bite wounds (DBW). To describe common pathogens and their antimicrobial susceptibility patterns. Materials and methods: In a single-centre parallel group pragmatic trial, 50 dogs presenting with moderate grade DBW were prospectively randomised to receive amoxicillin–clavulanic acid (group A) or amoxicillin–clavulanic acid and enrofloxacin (group B). Swabs were taken for culture and susceptibility testing at admission. Stabilisation, wound care and surgical debridement were performed at the discretion of admitting clinicians. The primary outcome was complication due to infection at 10 days, with Bayesian inference used to estimate the difference in proportions between treatment groups. Results: Of the 24 dogs in treatment group A, 1 required the addition of enrofloxacin at re-examination. None of the 26 dogs in group B required alteration of antimicrobial coverage. The difference in complication rate due to infection between treatment groups was 4.2%. Twenty-one different organisms were identified: Staphylococcus pseudintermedius, Neisseria spp., Pasteurella multocida and P. canis were the most common. Over 90% of gram-negative and gram-positive isolates were susceptible to amoxicillin–clavulanic acid. Ninety-six percent of gram-negative and 86% of gram-positive isolates were susceptible to enrofloxacin. Conclusion and clinical significance: Amoxicillin–clavulanic acid is an appropriate empirical antimicrobial choice for moderate DBW in South East Queensland. Reduced empirical enrofloxacin use will promote antimicrobial stewardship and potentially antimicrobial resistance

A VetCompass Australia Study of Antimicrobial Use in Dog-to-Dog Bite Wounds (1998–2018)

Although dog-to-dog bite wounds (DBW) are a common presentation to veterinary clinics, antimicrobial prescribing habits of Australian clinics have not been reported. This study determined the frequency and results of DBW cultures; antimicrobial selection; and importance class of antimicrobials prescribed relative to wound severity, geographic location, or year. A systematic sample of 72,507 patient records was retrieved from the VetCompass Australia database. Records for 1713 dog bite events involving 1655 dogs were reviewed for presenting signs, results of culture and susceptibility testing (C&S), antimicrobial treatment, geographical location, and outcome. A crossed random effects multivariable logistic regression model was used to determine if antimicrobial importance was associated with wound severity, year, and location, and to assess the differences in antimicrobial prescription between geographical locations, clinics, and veterinarians. Antimicrobials were prescribed in 86.1% of DBW. Amoxicillin-clavulanic acid was prescribed in 70% (1202/1713) with underdosing in 15.8% (191/1202). High-importance antimicrobial use was associated with wound severity (p p = 0.007), and surgery (p = 0.03). C&S testing was recorded as having been performed in only one case. Differences in individual veterinarian prescribing habits were stronger than the clinic culture, suggesting that education utilizing clinic-wide antimicrobial guidelines may aid in improving antimicrobial stewardship