Sea lice exposure to non-lethal levels of emamectin benzoate after treatments: a potential risk factor for drug resistance

The avermectin derivative emamectin benzoate (EMB) has been widely used by salmon industries around the world to control sea lice infestations. Resistance to this anti-parasitic drug is also commonly reported in these industries. The objective of this study was to quantify the number of sea lice potentially exposed to sub-lethal concentrations of EMB while fish clear the drug after treatments. We assessed juvenile sea lice abundance after 38 EMB treatments on six Atlantic salmon farms, in a small archipelago in British Colombia, Canada, between 2007 and 2018. We fitted a standard EMB pharmacokinetic curve to determine the time when fish treated with this product would have EMB tissue concentrations below the recommended target therapeutic level. During the study, we estimated that for each sea lice treatment there was, on average, an abundance of 0.12 juvenile sea lice per fish during the time period when the concentrations of EMB would have been lower than 60ppb, the recommended therapeutic treatment level for sea lice. The findings from this study on metaphylactic anti-parasitic treatments identify a potential driver for drug resistance in sea lice that should be further explored

Factors associated with rehoming and time until rehoming for horses listed with an equine charity

The number of unwanted horses in the UK has increased in recent years. It is therefore important to identify factors that indicate whether a horse can be rehomed and how long it takes to be rehomed. Data from 1 January 2013 until 30 March 2014 were extracted from an equine rehoming charity’s database. Exposure variables were examined using multivariable logistic and Cox regression. In total, 791 horses were included in the study and 410 (51.8%) were rehomed during the study period. Median time until rehomed was 39 days (IQR 24–75). Horses whose owner was prepared to transfer ownership were nearly three times more likely to be rehomed than those available for loan. Horses deemed suitable for beginner riders had higher odds of finding a new home, compared with those needing an advanced rider. Horses that were only suitable as unridden companions took longer to find a new home than rideable horses. A restricted rehoming radius (<50 miles) also resulted in longer time to rehoming. Findings from this study can be used to inform rehoming strategies but also to identify horses less likely to be rehomed, and thus where alternative options should be considered

Antimicrobial Susceptibilities of Aerobic Isolates from Respiratory Samples of Young New Zealand Horses

3rd Annual IEEE Energy Conversion Congress and Exposition, ECCE 2011, Phoenix, AZ, 17-22 September 2011This paper presents a method of mitigating the transient overshoots of DC-DC converters operating with large load disturbances. The method involves a small auxiliary power circuit with a complementary control scheme that provides a smooth absorption and release of excess energy from and to the main DC-DC converter in the events of large load changes. This control mechanism interactively mitigates the large transient overshoots which would otherwise appear at the converter output. Since the control scheme involves an adjustable-energy-storage feature, the proposed solution is effective for any level of step-load change within a pre-specified range.Department of Electronic and Information EngineeringRefereed conference pape

Preliminary insight into horse owners' perceptions of, and attitudes towards, exotic diseases in the United Kingdom

The potential for an exotic disease incursion is a significant concern for the United Kingdom (UK) equine industry. Horse owners’ perceptions of, and attitudes towards, exotic diseases can influence decisions to adopt disease preparedness strategies. The objectives of this study were to describe horse owners’ 1) perceptions of the term ‘exotic disease’, and 2) attitudes towards their risk of being affected by an exotic disease. In order to address these objectives, qualitative content analysis was undertaken on data collected using two open-ended survey questions

The effect of stress fracture occurring within the first 12 months of training on subsequent race performance in Thoroughbreds in Hong Kong

BACKGROUND Racehorses are at an increased risk of stress fracture within the first 12 months of racing and when resuming training after a break. Research in these high-risk periods and on the effect of performance post-recovery is limited. OBJECTIVES To describe the occurrence of stress fractures, diagnosed by nuclear scintigraphy (NS), in racehorses' first 12 months training in Hong Kong, and their impact on racing performance and career length. STUDY DESIGN Retrospective 1:2 matched case-control study. METHODS Clinical records of horses with NS-diagnosed stress fractures within 365 days of import between 2006 and 2018 were collated. Cases and controls were matched on import date. Univariable conditional logistic regression compared signalment, pre-fracture training and post-recovery racing performance between cases and matched controls. Shared Frailty Cox regression analysed time from import to fracture and total career length. RESULTS Eighty-seven horses sustained a NS-diagnosed fracture within their first year in Hong Kong (incidence risk 1.7% (95% confidence interval (CI) 1.4-2.1%; N=5,180)). The humerus (42.0%; 95% CI 31.8-52.6%; n=39) and tibia (28.0%; 95% CI 19.1-38.2%; n=26) were most common stress fracture sites. Cases missed a median of 63 days (Interquartile range (IQR) 49-82) of training because of fracture. Within the 12 months following diagnosis, case horses had a median of four (IQR 2-4, p<0.0001) fewer race starts and were down HK$206,188 (IQR HK$0-436,800, p=0.007) in race earnings compared to controls. Career length did not significantly differ between cases and controls (median 2 years and 3 months; IQR 15.3-39.1 months; p=0.2). MAIN LIMITATIONS Only stress fractures diagnosed by NS were included, hence, the study is not representative of all stress fractures occurring in racehorses in Hong Kong. CONCLUSIONS Racehorses sustaining a stress fracture within one year of entering Hong Kong lost significant time in training, earnings and race starts. However, overall career length was unaffected

Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013)

A key focus of the racing industry is to reduce the number of race-day events where horses die suddenly or are euthanased due to catastrophic injury. The objective of this study was therefore to determine risk factors for race-day fatalities in Thoroughbred racehorses, using a cohort of all horses participating in flat racing in Great Britain between 2000 and 2013. Horse-, race- and course-level data were collected and combined with all race-day fatalities, recorded by racecourse veterinarians in a central database. Associations between exposure variables and fatality were assessed using logistic regression analyses for (1) all starts in the dataset and (2) starts made on turf surfaces only. There were 806,764 starts in total, of which 548,571 were on turf surfaces. A total of 610 fatalities were recorded; 377 (61.8%) on turf. In both regression models, increased firmness of the going, increasing racing distance, increasing average horse performance, first year of racing and wearing eye cover for the first time all increased the odds of fatality. Generally, the odds of fatality also increased with increasing horse age whereas increasing number of previous starts reduced fatality odds. In the ‘all starts’ model, horses racing in an auction race were at 1.46 (95% confidence interval (CI) 1.06–2.01) times the odds of fatality compared with horses not racing in this race type. In the turf starts model, horses racing in Group 1 races were at 3.19 (95% CI 1.71–5.93) times the odds of fatality compared with horses not racing in this race type. Identification of novel risk factors including wearing eye cover and race type will help to inform strategies to further reduce the rate of fatality in flat racing horses, enhancing horse and jockey welfare and safety

The molecular characterisation of Cryptosporidium species in relinquished dogs in Great Britain: a novel zoonotic risk?

Surveillance was conducted to investigate the occurrence of protozoan parasites of the genus Cryptosporidium in dogs newly admitted to a dog rehoming charity in London, Great Britain. Voided faecal samples were collected from all new admissions between 2011 and 2012 during six separate 4-week sampling periods. Information on host signalment, including age, breed and reason for submission and faecal consistency, was collected. Polymerase Chain Reaction (PCR) targeting the 18S ribosomal RNA gene, confirmed by sequencing, was conducted on the faecal samples to detect Cryptosporidium genomic DNA and determine Cryptosporidium identity. In total, 677 dogs were included in the study. The prevalence of Cryptosporidium-positive faecal samples was 4.6% (31/676). There were positive samples in all of the six sampling periods. Cryptosporidium canis (n = 28), C. parvum (n = 2) and C. andersoni (n = 1) were identified. Sixty KDa glycoprotein (gp60) gene amplicon sequencing of the C. parvum samples identified genotypes IIaA17G1R1 and IIaA15G2R1 for the first time from a dog. There were no significant associations between signalment data and Cryptosporidium status. While this was a study of one rehoming shelter, the presence of the potentially zoonotic C. parvum and C. canis in dogs highlights a public health concern. Further research is needed to better understand the epidemiology and potential impacts of Cryptosporidium infection in dogs