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Rabbits are not like small dogs or long-eared cats. And it’s not just that they eat grass.

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When something goes wrong with an animal's nervous system, it's very upsetting, and it's easy to panic. People often make generalisations, and leap to the wrong conclusion. He's falling over! He's had a stroke! He's dragging his back legs! To help animals, it's important for vets to be as objective as possible, making a careful note of precisely which part of the nervous system has gone wrong. Vets do this using a specific examination procedure, known as the “neurological examination”. There are tick sheets available to make it easier for vets: various aspects of the nervous system are examined individually, and at the end, it's then easier to be specific about the precise diagnosis. Only then can the correct treatment and prognosis be given. At last week's London Vet Show, there was a fascinating lecture, sponsored by Supreme Pet Foods, which dealt with the subject of neurological examinations in rabbits. As many rabbit owners will know, diseases of the nervous system are common. However rabbits are very different creatures to dogs and cats: they are prey animals rather than predators, and as a consequence, their nervous system doesn't always behave in the same way. Rabbits are especially sensitive to stress, and they tend to mask their fear by staying still. Anyone who has examined rabbits will know this: they tend to stay very passive until the fear is too much, and then they panic explosively, trying to jump out of your arms. This type of temperament means that rabbits react differently when their nervous system is examined. The lecturer carried out a field study, during which she made a careful comparison of a standard neurological examination in rabbits compared to other pets, and she came up with some useful tips. First, she listed the four main types of disease of the nervous system seen in rabbits: head tilt, weakness or paralysis of the back legs (or all four legs), seizures (fitting) and “miscellaneous” (muscle weakness, strange gaits, blindness and other oddities). There's a long list of possible causes of these problems, from brain diseases (including a common fungal parasite called Encephalitozoon cuniculi), to viral and bacterial infections, to spinal problems (including broken backs and slipped discs), to heat stroke, metabolic disorders and many others. In all cases, whatever the cause, the neurological examination is a key to whittling down the list of possibilities. So how are rabbits different to dogs and cats? First and most importantly, rabbits don't show a pain response in the same way. With dogs and cats, it's easy to tell if they can feel their toes by squeezing them: if sensation is normal, they pull their foot away from you. Rabbits often don't do this: they stay utterly still, however hard you squeeze their toes. It doesn't mean they aren't feeling it: they just don't react because in the wild, it makes more sense to “play dead” in the hope that the creature that's hurting you will just go away. Secondly, some of their reflexes are exaggerated. If you tap a dog's knee with a rubber hammer, there's a similar type of small “kick” reflex to a human. In rabbits, the same test elicits a sharp, exaggerated kick, perhaps reflecting the wound up stressed nervous system of the rabbit. If a dog had a reflex kick like this, you'd think there was something strange wrong with them: it's normal in a rabbit. Third, some of their reflexes are diminished or absent: for example, rabbits don't have a “menace” reflex (if you wave your hand towards a dog's eye as if you are about to hit them, they blink automatically, like humans: this is the menace reflex. Rabbits don't do this). Other reflexes in rabbits' eyes are also different: their pupils don't always narrow and widen in the same way as other creatures.  There are two sets of take home messages here. First, if you're a vet, remember to expect different results from other pets when you're assessing rabbits with neurological problems. And second, if you're a rabbit owner, remember to take your pet to a vet with an interest in rabbits: all vets are trained in the essentials of rabbit medicine, but when it comes to complex disease, the more rabbits that a vet sees, the better they will be at rabbit-specific subtleties like neurological examinations.    
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The structure of the heart: everything you didn’t know you wanted to know from Wikivet

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The heart is probably the most central structure in the body. Arguably, the brain could be said to be "more important" (death is classified technically as absence of brain activity rather than a motionless heart), but for most of us, a beating heart is synonymous with the presence of life. We all have a heart - whether we are dogs, cats, humans, or indeed frogs - and one of the fascinating things about veterinary science is the fact that the fundamental structure of many organs - including the heart - is surprisingly similar. There must be something intriguing about the structure of the heart: the Wikivet page on this subject has been the most visited page of all over the past year. The main page is a simple description of the various structures - the position of the heart in the chest, the ventricles, the atria and the other connected tissues. If you can read technical language for just five minutes, you can be briefed with a simple but accurate review of the gross anatomy of the heart. The Wikivet heart page also has links to some interesting visual media. Some of these are not publicly accessible: perhaps it's only necessary for vet students to see what heart muscle looks like under the microscope. But other links include a colour coded video that clearly shows the different structures, and the most remarkable three-dimensional video that shows how the heart sits in the middle of the chest. If you have always wondered about what MRI's look like, you can watch a video that shows you MRI sections of the chest, and if you have witnessed the plastinated human exhibitions, you can view a plastinated dog heart. Heart disease is common in pets: if your dog or cat is ever affected, it will help if you can easily visualise what's going on inside a pet's chest. This Wikivet page is a great place to learn all about it.  
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Ask a vet online – How often should my dogs get boosters?

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Karen Taylor asked: How often should our dogs be re-vaccinated (boosters)? Answer: Hi Karen, thanks for your question about booster vaccinations. This is an area that’s become quite controversial in the last few years, and there’s a lot of confusion about the subject. In addition, there’s a lot of very poor-quality information out there, so I’ll try to make this quite clear and obvious! To put it as simply as possible – see your vet every year for a health check, and discuss your vaccination strategy with them. For more detail... now read on! What are vaccinations? Put simply, a vaccination is a way of teaching your dog’s immune system how to recognise and defeat the micro-organism that causes an infectious disease, without the risks (of illness, potential long term health problems or death) inherent in a “natural” infection. This is achieved in one of three ways: 1)      A weakened form of the disease-causing organism. These are called “modified live” or “attenuated” vaccines, e.g. for Distemper and Parvovirus; the organism included is unable to multiply and/or cause clinical disease, but it is active enough to stimulate a strong immune response. Most modified live vaccines give a stronger and more long-lasting immune response than an inactivated vaccine; however, they aren’t suitable for every disease (because some organisms cannot be weakened enough to make them safe). 2)      An inactivated (“killed” or “dead”) form of the organism. These cannot ever cause disease, but allow the immune system to recognise the protein coat of the organism and therefore attack it next time. They may be used for particularly dangerous or unpredictable diseases such as Rabies or Leptospirosis, but don’t always give such long-lasting protection. 3)      Subunit vaccines, introducing part of the organism to teach the immune system what it “looks like”. For these, part of the protein coat of the target organism is replicated in a lab, and included in the vaccine; this means the immune response is really tightly targeted at one particular, vital, part of the organism. These are used, for example, in the Leishmania vaccine. There are 2 groups of vaccines – core and non-core. Core vaccines are those that should be given to every dog – they protect your dog and everyone else’s against dangerous, highly contagious and potentially fatal diseases. Non-core vaccines are those that are given to protect dogs that are particularly at risk of a specific condition because of their location, lifestyle, etc. The core vaccines that every dog should have are against:
  • Distemper.
  • Parvovirus.
  • Canine Infectious Hepatitis.
The vaccine against Leptospirosis is technically non-core; however, it is generally agreed that every dog in the UK is at risk of Lepto (which is spread by rat urine), and so it is treated as a core vaccine by most vets. The non-core (optional) vaccines available are:
  • Rabies (only necessary for pets travelling abroad).
  • Parainfluenza (one of the causes of kennel cough).
  • Kennel Cough (the bacterial sort, Bordetella bronchiseptica).
  • Lyme Disease (only necessary for dogs at high risk, e.g. gundogs, in high risk areas, e.g. the South West peninsula).
  • Leishmania (only necessary for dogs travelling to southern Europe).
  • Canine Coronavirus (only usually needed in breeding kennels).
If vaccines are so good, why do they need boosting? Because nothing lasts forever! Eventually, the immune system starts to “forget” how to handle a particular disease organism. Booster vaccines effectively remind the system and refresh the immunity. However, immunity to different diseases (and different types of vaccine, for that matter) lasts a variable amount of time, and that’s the problem. Some dogs will retain immunity for longer than others – unfortunately, there’s no easy way to tell which dogs are immune to what for how long. Is there any way to tell whether my dog actually needs a booster? Not really! The trouble is that although some vaccines operate by producing protective antibodies (e.g. Rabies), others rely on inducing a Cell Mediated Immune Response (immunity that doesn’t rely on antibodies in the blood, but circulating immune cells, e.g. T-lymphocytes and Natural Killer (NK) cells) – such as the Leishmania vaccine, which may not produce any antibodies at all. And most of them probably rely to some extent on both systems. It's easy to test the dog’s blood for antibodies (and there are some commercial companies that will do this and say “yes, high levels of antibody, so the dog is protected” or “no, not enough antibody, the dog needs to be vaccinated again”. However, this is not generally considered reliable, because:
  • The serological titre (level of antibodies in the blood) can only tell you how much antibody there is in the bloodstream at the specific time the test is done - it cannot tell you whether the levels will remain high for the following 12 months.
  • The link between antibody levels and protection isn't consistent - some dogs utilise other parts of the immune system (cell mediated immunity) – for example, dogs can be protected against Leptospirosis in the presence or absence of significant circulating antibody levels.
So how long does immunity actually last? How long the vaccine lasts depends on the exact formulation of the vaccine; at the time of writing, the three Core vaccines generally need boosting 1 year after the initial course, then every 3 years. Most Rabies vaccines needs boosting only every 3 years; and the others usually require annual boosters. To get a license for a vaccine, the manufacturer has to demonstrate that the product has a protective effect, however that is defined. For Core vaccines, they have to demonstrate onset and duration of immunity such as to fulfil the license claim to:
  • “Prevent mortality and clinical signs caused by canine distemper virus infection”.
  • “Reduce clinical signs of infectious hepatitis and viral excretion due to canine adenovirus type 1 infection”.
  • “Prevent mortality, clinical signs and viral excretion following canine parvovirus infection”.
If this cannot be demonstrated to the regulator (in the UK, the Veterinary Medicines Directorate - VMD), they won’t get a license for the product. This means that manufacturer’s recommendations for duration of immunity are those that will protect the vast majority of dogs for the quoted time (3 years or 12 months, depending on the vaccine). To make life a little more complex, any vet who uses a different vaccination interval, unless they can document a good clinical justification, is technically acting illegally by using the vaccine off-license (i.e. not as licensed by the manufacturer). This sort of behaviour tends to lead to unpleasant interviews with the VMD and has led to vets being struck off (although not, to my knowledge, for vaccine infringements as yet). Can over-vaccination harm my dog? There’s no reliable evidence that it can. In cats, every subcutaneous injection (of anything, even saline!) slightly increases the risk of an Injection Site Sarcoma, but despite a lot of scientists, vets and owners trying to find a link, there’s no evidence that it causes any problems in dogs. That said, absence of evidence is not necessarily evidence of absence, so a responsible approach would be to vaccinate as infrequently as the current evidence suggests is sufficient to provide protection – in other words: 1)      Get a health check for your dog at the vets every year. 2)      Follow the manufacturer’s recommendations (unless your vet has a particular clinical reason not to):
  1. Distemper, Parvo and Infectious Hepatitis – boosters every 3 years.
  2. Lepto – annual booster.
  3. Rabies – boost every 3 years.
  4. Other Non-core vaccines – usually every year.
  I hope that helps; this is a really controversial area in some quarters, but the evidence base for the current vaccination protocols is pretty secure, and it is what I’d advise you to follow. David Harris BVSc MRCVS
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The story of Dan, a coughing Springer Spaniel

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Dan was a nine year old Springer Spaniel who loved strenuous physical exercise. His owner, Dr Mullen, was a medical doctor who was an enthusiastic hill walker, so they made a good team. They would spend days off in the Dublin mountains together on six-hour hikes through the countryside. Dan was brought to see me because he had developed an irritating cough, and Dr Mullen was worried.

The cough did not affect Dan during exercise. He was still able to run for hours without any problem, but the following morning, immediately after getting up, he would cough repeatedly as he walked around the room. It seemed to be a productive cough: sometimes he swallowed after the cough, and other times Dr Mullen found patches of white phlegm on the floor. When Dan had been up and about for half an hour, the cough seemed to clear, and he’d be fine for the rest of the day.

I started by physically examining Dan. I listened carefully to his chest with my stethoscope. He had the perfect heartbeat of a fit dog, with slow steady sounds and no murmurs or irregularities. His lungs, however, sounded noisier than normal, with some wheezes and crackles. He definitely had some type of lung disease, and further tests were needed.

The following day, Dan was anaesthetised, X-rays were taken, an endoscope was used to directly view the lining of his airways, and finally tiny biopsies were taken of the many red sore areas that we could see. Dr Mullen called in three days later to discuss the full results of our investigations.

“I can say for certain that Dan is suffering from Chronic Bronchitis”, I began. “The initial X-rays suggested that that there was thickening of his lower airways, and using the endoscope, we could see that the thickening was because of inflammation of the lining of the small tubes of the lungs, known as ‘bronchi’. The biopsy of the red, swollen areas confirms that the disease process is simple inflammation, with nothing sinister going on. Finally, he has a mild bacterial infection in his lungs.”

Dr Mullen asked me if an antibiotic would completely cure his dog.

“Although antibiotics will help him, for a complete cure, he needs to go onto long term medication using other drugs. The chronic bronchitis probably started out with a simple infection, but there is now also an irritant and allergic aspect to the disease. The tiny particles of dust, smoke and pollens that are always in the air are perpetuating the bronchitis. We’ll use two drugs to help him. Firstly, a ‘broncho-dilator’, which will widen his airways and lessen the tight narrowing of the bronchi that is making them irritated. Secondly, a low dose of steroids will directly lessen the irritation. We’ll modify his dose of each drug so that he should be able to live a normal, symptom free life without side effects from medication.” There are other options for treatment, including an inhaler mask, but this treatment was my standard first stage.

Dan was sent home with three containers of tablets, and twice-daily medication ritual became part of his routine. I saw him again two weeks later, and the cough had almost completely stopped. He was suffering some side effects from the steroids, with increased thirst and appetite, but we were then able to reduce the dosage, so that he was given tablets only on every second day. When he came back a full month later, Dr Mullen was delighted.

“His cough has vanished completely”, he told me. “And he is enjoying his walks more than ever. The only problem is that he’s wearing me out! Do you know any tonic pills for a fifty-five year old human?”

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Oils and fats in pets’ diets: everything you need to know (and more besides) from Wikivet

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There's one aspect of nutrition that many people – including vets – can find particularly daunting: fats and oils. There have been mixed messages over the years about good fats/ bad fats, essential oils/ unnecessary oils, long chain/short chain, saturated/unsaturated. This is one area where Wikivet can help – for veterinary professionals as well as members of the public. The Wikivet section about fatty acids provides a clear, comprehensive summary.

Technical stuff about fatty acids that vets need to know (optional for pet owners)

The most important facts are worth summarising in ten key points:

1) The terms “fats” and “oils” tend to be replaced by “fatty acids” by nutritionists, as it is the fatty acids in fats and oils that give them their most significant properties.

2) Fatty acids (FA) are carboxylic acids with long hydrocarbon chains, which can be saturated or unsaturated.

3) Saturated fatty acids have single bonds, and tend to have a high melting point making them more likely to be solid at room temperature (e.g. butter or fat on meat)

4) Unsaturated fatty acids have at least one double bond, and tend to have a low melting point so tend to be liquid at room temperature (e.g. olive oil)

5) Mammals are able to synthesize certain saturated fatty acids from other dietary components (such as glucose and proteins) so they do not need to have these in the diet.

6) Dogs and cats, like other mammals, have an essential dietary requirement for certain unsaturated fatty acids since they cannot be manufactured in their bodies: omega-3 and omega-6: these are known as "essential fatty acids".

7) (A technical point, but an important one for biochemistry nerds): Omega-3 FAs are a family of unsaturated fatty acids that have a double bond in the third carbon-carbon bond: the most important are Alpha-linolenic acid (ALA), Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)

8) Omega-6 FAs are a family of unsaturated fatty acids that have a double bond in the sixth carbon-carbon bond: e.g. linoleic acid (LA) is an essential ingredient in animal diets. Others in the group include  Gamma linolenic acid (GLA), Dihomo-gamma-linolenic acid (DGLA) and Arachidonic acid (AA) (which is essential for cats, but not for dogs).

9) Omega-3 and omega-6 fatty acids are in competition for the same metabolic enzymes in the body and the ratio of omega-6 to omega-3 fatty acids, as well as the total amount of each type, is important.

10) (The key take home point!) These essential unsaturated fatty acids are important for growth (including the development of the brain and eyes), for skin and coat function (including influencing allergic skin disease)

What does this all mean in practice for pet owners?

First, choose a good quality diet that is adequately supplemented with the right proportions of omega-3 and omega-6 unsaturated fatty acids.

The optimal ratio of omega-6 to omega-3 fatty acids is thought to be between 10:1 to 5:1. Most pet foods contain far more omega-6 fatty acids than omega-3. Omega-3 fatty acids are sometimes added to commercial pet foods to lower the ratio of omega-6 to omega-3 fatty acids.

Second, if your pet suffers from skin disease, in particular, or poor skin/coat quality, talk to your vet about dietary supplements to enhance their omega-3 and omega-6 intake, aiming to get both the absolute quantity and the ratio correct.

Third, remember that it takes around six weeks for a dietary supplement of fatty acids to make a visible difference to the quality of a pet's coat.

Fourth and finally, if you have a good head for understanding chemistry and nutrition, go ahead and read the Wikivet article, and better again, look up the references at the end. This is pure nutritional science, as good as you can get, and it's what pet food companies use to formulate the products on the shop shelves. It may be hard to follow sometimes, but the best way to optimal nutrition is to fully understand the science behind what you feed your pet.

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