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their heart disease. Therefore it is not advisable to wait for signs to develop before considering the introduction of therapy. Dogs with more advanced MVD may be more likely to have higher heart rates and a regular heart rhythm (i.e. have lost the natural variation in heart rate associated with respiration) on auscultation.
Dogs suspected of having more advanced preclinical MVD should undergo diagnostic imaging to determine whether or not its heart is enlarged. Dogs entering the EPIC study underwent both echocardiography and radiography. Of those two techniques echocardiography is the better test for demonstrating evidence of subtle cardiac enlargement. Ideally therefore dogs suspected of having DMVD should undergo echocardiography
to determine their heart size. This is not to imply that radiography is of no value in determination of heart size. It is very likely that a dog with a clearly enlarged cardiac silhouette on a thoracic radiograph will probably have echocardiographic evidence of enlargement. However breed differences in heart size (and VHS) mean that where fine distinctions need to be made between normal and enlarged hearts echocardiography is superior.
M. Burrows1
1Animal Dermatology Clinic, Murdoch University Division of Vet- erinary and Biomedical ScienceMurdoch, Western Australia
A new group of parasiticides has recently been introduced to veterinary medicine. Afoxolaner, fluralaner, sarolaner and lotilaner are new insecticide-acaricide molecules from the isoxazoline family that act on the insect aminobutyric acid receptor (GABA) and glutamate receptors, inhibiting GABA and glutamate-regulated uptake of chloride ions resulting in excess neuronal stimulation and death of the arthropod.
Afoxolaner (NexGard®)
Afoxolaner [1-Naphthalenecarboxamide, 4-[5-[3-chloro-5- (trifluoromethyl)phenyl]- 4,5-dihydro-5-(trifluoromethyl)-3- isoxazolyl]-N-[2-oxo-2-[(2,2,2-trifluoroethyl)amino]ethyl}] is one of the members of the isoxazoline family. Afoxolaner has been demonstrated to be a highly effective and safe form of flea and tick control.
Afoxolaner has been shown to be highly effective for treatment of demodicosis in case reports (Chavez 2016, Mueller 2017) and one controlled study. (Beugnet 2016). The controlled published report evaluated eight dogs diagnosed with generalised demodicosis and compared the efficacy with a topical combination of imidacloprid/ moxidectin. Afoxolaner was administered at the recommended dose (at least 2.5 mg/kg) on Days 0, 14, 28 and 56 and the topical combination of imidacloprid/ moxidectin was given at the same intervals at the recommended concentration. Clinical examinations and deep skin scrapings were performed every month to evaluate the effect on mite numbers and the resolution of clinical signs. The percentage reductions of mite counts were 99.2%, 99.9% and 100% on Days 28, 56 and 84, respectively, in the afoxolaner-treated group, compared to 89.8%, 85.2% and 86.6% on Days 28,
56 and 84 in the imidacloprid/moxidectin-group. Mite reductions were significantly higher on Days 28, 56 and 84 in the afoxolaner-treated group compared to the imidacloprid/moxidectin treated group. (Beugnet 2016).
In a large series of clinical case evaluations at a
referral dermatology practice, 102 cases of generalized demodicosis were treated with excellent results. Of the 102 cases, 68 were dogs with adult onset demodicosis. The product was administered at 2.5 mg/kg PO, initially used every two weeks in the first ten dogs. With the high degree of efficacy seen in those dogs, the dosage
Your Singapore, the Tropical Garden City
  The echocardiographic criteria used to recruit dogs
to the study were relatively simple and therefore a competent echocardiographer should be able to determine whether a dog has evidence of left-sided cardiac enlargement on the basis of two-dimensional and M-mode echocardiographic images obtained from the right parasternal viewing locations.
It is natural to ask whether in order to initiate pimobendan therapy in a dog with preclinical MVD
the dog must first undergo echocardiography. Where
a dog has considerable cardiomegaly evident on radiography it is probably safe to assume there will also be cardiomegaly evident on echocardiography. The cut-off of 10.5 for vertebral heart score used in the EPIC study is too lenient to use as a sole criterion for initiating therapy because a number of normal dogs of certain breeds will exceed this value. A group of cardiologists in the US – the “Cardiac education group” – have prepared a useful algorithm.[1] They recommend that where access to echocardiography is limited a VHS of 11.5 or a rapid rate of increase of VHS may be used as a way to identify dogs that may benefit from therapy. It is however worthy of note that more than half the dogs enrolled in the EPIC study had a VHS lower than 11.5; meaning that applying this criterion alone would result in many dogs that may benefit from therapy not receiving it.
Whether there are other methods by which dogs that will benefit from therapy can be reliably identified is currently not known and therefore initiating treatment in the absence of diagnostic imaging is not recommended.
[1] uploads/2016/12/CEG_Recommendations_EPIC_121316. pdf

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