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Previous Issue: December 2014
Evidence for Unapparent Brucella canis Infections among Adults with Occupational Exposure to Dogs
Krueger, W. S., Lucero, N. E., Brower, A., Heil, G. L. and Gray, G. C. (2014) Zoonoses and Public Health, 61: 509–518
Brucella canis is a zoonotic infection of dogs that can cause signs of orchitis in male dogs and endometritis and abortions in females. Infection in humans has been previously thought to be rare, but there are concerns that unapparent human infections may occur. This American study used a commercial canine serological assay to investigate occupational exposure to B. canis. 306 adults with occupational exposure to dogs were compared with 101 non-matched, non-canine exposed subjects. Seroprevalence in the canine exposed subjects was 10.8% or 3.6% depending on which test was used. Kennel employees were at the highest risk of seropositivity. Two seropositive subjects reported they had experienced symptoms consistent with brucellosis. The authors conclude that Brucella canis should be considered as an occupational risk for workers with dogs.
Bottom line: Brucella canis is a zoonotic disease that may be under-reported in workers with dogs.
Aloe vera: an in vitro study of effects on corneal wound closure and collagenase activity
Curto, E. M., Labelle, A. and Chandler, H. L. (2014) Veterinary Ophthalmology, 17: 403–410
Aloe vera is a succulent plant that has been recommended for some time as a herbal remedy for various conditions. However, evidence for efficacy has generally been limited. This study aimed to evaluate the in vitro effects of an aloe vera solution on the viability and wound healing response of corneal cells, and whether the solution has an effect on collagenase and gelatinase activities. Cultures of corneal epithelial cells and fibroblasts were prepared from normal canine eyes and were treated with aloe solution at varying concentrations. None of the concentrations were found to significantly affect the viability of the cells. Higher concentrations of aloe were found to slow the rate of corneal fibroblast wound closure. Aloe solution was also found to increase the ability of collagenase to degrade type IV collagen. A slight acceleration of corneal epithelial wound healing with low concentrations did not reach significance.
Bottom line: The authors state that lower concentrations of aloe solution may speed healing of corneal wounds, but further studies are required. They also note that the increase in collagenase activity means further in vitro work should be performed before considering in vivo studies.
Incorporation of sentinel lymph node mapping in dogs with mast cell tumours: 20 consecutive procedures
Worley, D. R. (2014) Veterinary and Comparative Oncology, 12: 215–226
This study was performed to test the hypothesis that sentinel lymph node (SLN) mapping in dogs presenting for removal of a mast cell tumour would have an impact on the offered treatment. Nineteen dogs with spontaneously occurring or incompletely excised mast cell tumours were enrolled into the study. Regional lymph nodes were aspirated and SLN mapping was performed using scintigraphy. Twenty mast cell tumours were removed from the 19 dogs. The SLN in eight dogs was not the closest lymph node. Twelve dogs were found to have metastasis in the SLN. There was no correlation found between stage and c-KIT presence. In 8 cases, additional treatment was offered as a result of SLN staging that would otherwise not have been.
Bottom line: Sampling of lymph nodes in dogs with mast cell tumours based on regional anatomy is not sufficient to ensure the sentinel lymph node is sampled.
Comparison of propofol with ketofol, a propofol-ketamine admixture, for induction of anaesthesia in healthy dogs
Martinez-Taboada, F. and Leece, E. A. (2014) Veterinary Anaesthesia and Analgesia, 41: 575–582
Propofol and ketamine are common anaesthetics which have various pros and cons associated with their use. In a prospective, randomised, controlled, blinded study, 70 healthy dogs were enrolled to receive either propofol or ketofol (propofol-ketamine mixture). Anaesthesia was induced after premedication by titrating the intravenous dose until endotracheal intubation was achievable. Parameters recorded included time to first breath, pulse rate, respiratory rate and arterial blood pressure. Quality of induction and anaesthesia were scored by a blinded observer. The volume of induction anaesthetic required was lower for propofol than ketofol. Ketofol use resulted in a higher mean arterial blood pressure than propofol. Ketofol was associated with a greater drop in respiratory rate. The quality of sedation was similar between the two groups, but intubation and induction qualities were better with ketofol than propofol.
Bottom line: Ketofol induction led to a higher mean arterial blood pressure than propofol, but a lower respiratory rate. Quality of induction and intubation were more consistently good with ketofol than propofol.
Effects of rapid intravenous 100% L-isomer lactated Ringer's administration on plasma lactate concentrations in healthy dogs
Boysen, S. R. and Dorval, P. (2014) Journal of Veterinary Emergency and Critical Care, 24: 571–577
Lactated Ringer’s solution is commonly used as fluid therapy in sick animals. However, lactate is becoming increasingly measured to provide prognostic and other information in critically ill patients. This prospective cross over study aimed to determine whether lactated Ringer’s solution affects the plasma lactate concentrations in healthy dogs. Six healthy adult beagles were enrolled into the study, and blood samples were taken at baseline and every 10 minutes after starting an infusion of 180ml/kg/hour of lactated Ringer’s solution for 60 minutes. After a four week washout period, the procedure was repeated with 0.9% sodium chloride instead of lactated Ringer’s solution. An increase in plasma lactate concentration was found within ten minutes of administration of lactated Ringer’s solution, but this returned to baseline within 60 minutes of cessation of infusion.
Bottom line: Plasma lactate concentrations should be interpreted cautiously where large volumes of lactated Ringer’s solution are being infused.
A 6-month observational study of changes in objectively measured physical activity during weight loss in dogs
Morrison, R., Reilly, J. J., Penpraze, V., Pendlebury, E. and Yam, P. S. (2014) Journal of Small Animal Practice, 55: 566–570
Weight loss of obese animals can improve health and quality of life in various ways. This 6 month observational study aimed to evaluate the long term changes in physical activity and sedentary behaviour in dogs undergoing weight loss. 16 overweight and obese dogs that were enrolled in a 6 month calorie controlled weight loss programme were fitted with accelerometers for three consecutive days every month. Valid data was obtained for 14 of the dogs. The mean weight loss was 15% of starting body weight. No increase in physical activity or reduction in sedentary behaviour was found.
Bottom line: No spontaneous increase in physical activity was noted in this study despite significant weight loss. However, the authors recommend dogs are still encouraged to exercise because of the wide range of other benefits to the animals of physical activity.
MAGNETIC RESONANCE IMAGING CHARACTERISTICS IN FOUR DOGS WITH CENTRAL NERVOUS SYSTEM NEOSPOROSIS
Parzefall, B., Driver, C. J., Benigni, L. and Davies, E. (2014) Veterinary Radiology & Ultrasound, 55: 539–546
Neosporosis is a protozoal infection that can affect the central nervous system (CNS). A previous report has described the MRI changes in a group of dogs with CNS neosporosis, which largely consisted of cerebellar lesions. This study aimed to describe and compare the MRI findings of four dogs with CNS neosporosis to the earlier study. Mild bilateral and symmetrical cerebellar atrophy was noted in three out of four of the dogs included in the study. Intramedullary spinal cord changes were seen in two, and multifocal lesions in two dogs, including lesions in the the thalamus, brainstem and cortical grey matter of the cerebrum. The authors conclude that neosporosis can cause lesions throughout the CNS and not just in the cerebellum.
Bottom line: Neosporosis can appear as multifocal lesions on magnetic resonance imaging.
Consequences of a screening programme on the prevalence of congenital hereditary sensorineural deafness in the Australian Cattle Dog
Sommerlad, S. F., Morton, J. M., Johnstone, I., O'Leary, C. A. and Seddon, J. M. (2014) Animal Genetics, 45: 855–862
Screening programmes for hereditary diseases are being used for various diseases in various breeds of dog and cat with the aim of reducing the prevalence of these diseases. A brainstem auditory evoked response (BAER) based scheme was introduced in 1998 to screen for canine congenital hereditary sensorineural deafness (CHSD) in litters of Australian Cattle Dogs. After 10 years of testing, 608 pups from 122 litters, drawn from 10 breeding kennels, were enrolled into a study to assess the impact of the screening scheme on prevalence of the condition. No substantial reduction in prevalence of the condition was noted over this time period. Even parents that were both tested clear for CHSD had no substantial reduction in prevalence of CHSD in their litters. However, there was a reduction noted where all four grandparents tested negative. The authors conclude that screening based on phenotype may not be successful in reducing the prevalence of a disease in the medium term, although in this case breeding exclusively from litters in which both parents and all four grandparents were tested clear should give the biggest reduction in the prevalence of CHSD.
Bottom line: Congenital hereditary sensineuronal deafness in Australian Cattle Dogs has not decreased substantially in prevalence since the onset of a screening scheme to help eradicate it.
Detection of bacteraemia and host response in healthy neonatal foals
ES Hackett, DP Lunn, RA Ferris, DW Horohov, MR Lappin and PM McCue Equine Veterinary Journal
This prospective observational study aimed to determine if a transient bacteraemia occurs in normal healthy foals within the first seventy-two hours of life. Blood was collected from seven healthy foals at birth (normal, unassisted foaling) and then hourly for the first four hours, followed by further samples at 8, 12 ,24 ,48 and 72 hours of age. Blood samples were collected aseptically and submitted for culture, in addition to analysis for interferon gamma, various interleukins and detection of monocyte chemotactic protein 1 by RT-PCR, all of which are increased in human neonatal sepsis. Seventy blood samples were collected in total, of which a positive blood culture was obtained in nine. All positive blood cultures were from samples collected within the first 12hours of life, two of which were from samples obtained at birth. Cultured bacteria were predominantly Bacillus spp (6/9 positive blood cultures), the route of infection was not determined in this study. A rise in cytokine gene expression was noted within the first twenty-four hours after birth, with an increase in IL-10 being associated with positive blood cultures. All foals remained healthy during the study period and thereafter.
Bottom line: Healthy foals may undergo a transient bacteraemia in the early post-natal period which may not be associated with disease. This study will assist in the interpretation of blood culture results from foals.
The effect of passively acquired antibodies on Lawsonia intracellularis infection and immunity in the horse
AE Page, HF Stills Jr and DW Horohov Equine Veterinary Journal
It is well understood that equine proliferative enteropathy caused by Lawsonia intracellularis affects weanling horses. The reasons for this have not been documented and a decline in passively acquired antibodies has been hypothesised. This study investigated the effect of the decline in maternal antibodies on the development of clinical or subclinical equine proliferative enteropathy. 453 mare and foal pairs from a small area around central Kentucky were enrolled in the study; serum samples were taken within 48 hours of parturition and at monthly intervals thereafter until the foals were yearlings. Antibody status was measured using an enzyme-linked immunosorbent assay (ELISA); disease status was either subclinical (if there were no clinical signs but hypoalbuminaemia was detected) or clinical, if clinical signs were apparent. 44.2% of mares and 38% of foals were seropositive at the initial post partum sample, although a marked variation in farm-specific seroprevalence was noted. 5.3% and 6.3% of seropositive horses developed clinical or subclinical disease respectively during the study period. There was no effect of maternal antibody status on the development of subclinical or clinical disease. Colts were found to be significantly more likely than fillies to develop clinical disease and foals weaned later were at lower risk of developing clinical disease.
Bottom line: This study shows that passively acquired antibodies to Lawsonia intracellularis to do not have an effect on the development of clinical or subclinical equine proliferative enteropathy, therefore additional factors associated with the weaning period, such as stress, may be the underlying reason for weanling predisposition to the disease.