Veterinary Parasite

While I was seeing practice over Easter, one of the cases I had responsibility for was an alpaca with a broken leg (contained within an external fixator!).  I have (well had) zero experience with camelids, to the point where I really didn’t know what to expect going to see him for the first time.  Of course, ’twas a joyous experience!  For those of you like me, alpacas are (we decided) a cross between sheep, guinea pigs and giraffes.  The sheep gives it the coat, the giraffe the long neck, and the guinea pig it’s amazing repertoire of noises!

I could regale you with an assortment of alpaca facts now, and despite the boredom it will probably induce in you, I’m going to:

• They have not one, not two, and not even four stomachs (stomach compartments if we’re being picky) - the alpaca has three
• The glandular part of the stomach, which only makes up about 20% of the third compartment, is very prone to ulceration, secondary to non-steroidal drugs, or stress.  So, while hospitalised, they are put on Omeprazole (a proton pump blocker) to reduce stomach acidity, and are always kept with a friend to reduce stress
• They have mainly cartilage instead of a nasal bone, so halters must be very well fitted to avoid suffocating them (they are obligate nasal breathers)
• To control an alpaca, you must control its head!
•  They are very prone to vomiting under anaesthesia

OK, that’s probably enough for now!  As you may have guessed, I was charmed and intrigued by my new alpaca friends - perhaps a career as an alpaca vet beckons?  Well I doubt it, as I don’t think I’d end up with that much work to do!

Just as a bonus, here’s a pic of my alpaca mates

Throughout my undergraduate career, I’ve bought a fair few textbooks, and referred to probably hundreds more. I’ve found that while most are generally good, there are some absolute crackers, and a few that are absolute rubbish. This is the start of several posts looking at books I’ve enjoyed using, starting with anatomy and physiology books.

Anatomy & Physiology

• Veterinary Anatomy - Dyce, Sack & Wensing
  • This is my bible of veterinary anatomy - it contains all you will ever need to know on the main species. It’s reasonably well laid out, although it divides things into a general overview, then species specific sections which I find unnecessary, and a touch confusing. It also goes into massive detail, so picking out clinically relevant details can be tricky, but in conjunction with lectures it’s ideal.
  • Definitely one to buy, you will use it all the way from first to final year.
• Guide to the Dissection of the Dog - Evans & de Lahunta
  • A great book for canine anatomy, with really descriptive advice on actual dissection technique. Anatomy-wise, it covers no more than Dyce, Sack & Wensing, but it has the added bonus of the dissection guide. I found it extremely useful during dissections, but have never really referred to it since.
  • Probably one to borrow from the library, or buy as a cheaper alternative to Veterinary Anatomy. Just try not to get it covered in blood!
• Principles of Anatomy & Physiology - Tortora & Grabowski
  • A human book, but really nicely laid out, with great pictures and excellent narrative. Some sections of it do become a little redundant in the veterinary world, and some of the clinical advice doesn’t hold true, but it is worth having as a physiology text.
  • I used this a lot in first and second year, and still occasionally look back to it. It’s relatively inexpensive, and well worth having on your shelf in my opinion
• Veterinary Reproduction - Noakes, Parkinson & England
  • I’ve included this here because it does have great sections on the normal physiology of reproduction, as well as being good for the clinical side of things. It was irreplaceable during reproduction lectures and tutorials, covering all the major species in good depth.
  • I used it a lot in second year, and it’s coming into its own again now. Expensive, but if you can afford it then definitely buy it.
• Horse Anatomy - A Pictorial Approach To Equine Structure
  • I’ve got a horse anatomy book on the way, just to work through as a bit of a refresher, and see things from another point of view. I’ll update this to a full review when it arrives and I’ve read it.

Many more sections to come as soon as I find the time to write them up! Also coming soon, some equine cutaneous neoplasms - fun fun fun!

Work on my TPRMyHorse project continues (slowly - I have an equine practice rotation to fit in somewhere as well!), and I have come up with a logo. I’m posting it here for comments, criticism, and general public lambasting! Let me know what you think:

This week’s rotation. equine practice, is really good fun. Getting to do plenty of things, see lots, and spend a nice amount of time sat on my backside in the car! It’s also reasonably convinced me that this is where I’d like to work when (I’m being confident!) I qualify. As a side project, we also have to prepare a presentation on equine dermatological conditions. I’m taking on the neoplastic section, so expect a post on the evils of equine sarcoid soon.

Edit: Here’s a revised version with new feet

Over the last few weeks, I’ve taken a lot of horse’s temperatures, lots of times. Most of these occasions were, if not enjoyable, then at least safe and uneventful! Unfortunately, a certain few horses seem to have a real problem with it, to the point of kicking out, or posturing like they were going to. This is a real problem when you’re trying to monitor a horse with an infection, as the temperature is one of they key parameters when judging if it is under control. Thanks to judicious use of twitches, and a lot of shouting, I remained unkicked, but life would have been much more pleasant had the horse not been so resentful of what is a painless, if slightly uncomfortable, procedure.

This leads me to my point, which is that if you are a horse owner, you should endeavour to take your animal’s temperature on a daily basis, from a young age. Digital thermometers are cheap and accurate, and provided you are sensible, can be used with little risk to you or the horse. A quick eBay search and they’re available including delivery for £3.48.

Regular monitoring of your horse’s temperature has some real benefits. Firstly, it means that should your horse ever have to be hospitalised, or regularly have it’s temperature taken for any other reason, he/she will be accustomed to it, and will cause no problem to the temperature taker. Believe me the vets/nurse/students will thank you for this! It also benefits the horse, as, for example, in an infected wound, the last thing we want is a horse jumping around or moving suddenly, as it might cause a wound to break down.

Secondly, regular monitoring of your horse has real preventative health benefits, even when your horse is healthy and well. If you can pick up that your horse’s temperature is increased one day, then you can ring your vet and get them to check it out - before the problem becomes any more serious. This is especially important after your horse has been in high risk situations, such as travelling, meeting new horses, etc. The stress of the situations can lead to decreased immunity, and the number of horses from different stables all in one place provides a perfect environment for the exchange of infections. This isn’t intended to put you off showing, but just to make you aware that there are some risks, but these are risks that can be minimised by careful, and easy, monitoring.

Other parameters that can be easily measured are pulse rate, and respiratory rate, and these can also be useful, although they can be a little more difficult to interpret. An increased pulse and resp rate can be associated with pain, or a variety of other conditions, but could also just be due to excitement, or recent exercise. Due to the ease with which they can be taken, I would still recommend taking them daily, and keeping records along with temperature. Here’s a quick guide on how to take them:

In the photo, the young lady’s hand is feeling for the facial artery, which runs on the medial aspect of the mandible bone. If you run your fingers over the area, then you should feel a small tube like structure. Lightly rest your fingers on the artery and you should feel the pulse. Make sure not to use your thumb, or you may inadvertently count your own pulse, not the horses! My preferred site for taking a pulse is actually the transverse facial artery, which runs across the face, below the eye, as indicated by the black line in the photo. In some horses you may be able to see the artery, but if not then run your fingers vertically down over the area, and you should feel the vessel. Both sites can be tricky to use if the horse is eating, as contractions of the muscle will confuse things, so try to take them at a time when the horse is not.

Alternatively, you could buy and inexpensive stethoscope (it doesn’t need to be a good one), and listen to your horse’s heart directly. The drum of the stethoscope should be placed on the chest wall, approximately level with the horse’s elbow, and pushed forward under the leg. The loudest point can be quite variable, so just move the stethoscope around a bit. Initially the heart beat can be tricky to hear - it is a deep sound, and your ears need to “tune in” to it. When you’re counting, a “lub-dub” counts as a single beat.

You can count pulses over a full minute, but generally counting over 15 seconds, then multiplying by 4 is adequate. Perhaps if you were concerned about a higher heart rate, then count over a longer period to make sure the increase is real.

The other parameter you can easily take is a respiration rate. This can be seen in several ways. I find the easiest method is watching the ventral (bottom) part of the abdomen - it will move slightly up and down as the horse breathes in an out. You can also watch for expansion of the rib cage, or movements of the nostrils. On a cold day, the easiest method is often to actually watch for streams of warm air coming out of the nostrils, and count those! For respiration rate, I prefer to count over at least 30 seconds. 15 seconds is not really adequate, as the respiration rate is much lower than the pulse rate.

Some normal values:

Temperature: 36.7 - 38.3 C

Pulse: 36-40

Respiration: 8-16

These are not absolute values, however. For example, if your horse’s temperature is normally in the range 36.8-37.4, which you know because you take it every day, then a temperature of 38.1 could represent a fever, even though it lies within the normal range as a whole. This is yet another advantage of doing daily TPRs on your horse - you can establish a normal range for your individual horse. Pulse rate can actually be as low as 28 in very fit horses without being abnormal.

With all this in mind, I plan over the next couple of weeks to add a new section to the site - TPRMyHorse. This will be a place to record daily TPR values for individual horses, as well as any daily comments. The system will then plot them as graphs, so that any trends or changes can be identified. It will also provide suggested normal ranges for your animal. This saves having hundreds of scraps of paper with numbers on (I’ve been there!), which mean nothing! I’ll keep you posted when it’s ready to be unleashed!

Disclaimer: The information in this article is for guidance only. If you have any concerns about your horse, be it because of the TPR values, or any other reason, you should not hesitate to contact your vet. While we hope that the information here will help you to look after your animal, it is in no way a substitute for proper veterinary advice from your own vet, and should not be taken as such.

No posts in over two weeks is pretty poor form in anyone’s books, so I can but offer my excuses.  I’ve been away at the Royal Veterinary College in London doing equine work, and internet access has been limited (as well as my waking hours away from their hospital!)  I should be back to a proper posting schedule now, starting with some words about my excellent two weeks away!

Other news from the last two weeks is exam results - good news all round, I passed them all, with 67% in Equine, 66% in Small Animal, and 60% in Farm.  Obviously very happy with the results, especially as it means a resit free summer!

I’m trying to think of some ways to expand my writing on this site beyond just a blog. After all, my life isn’t that exciting, there’s only so much I can rave on about unnecessarily, and I’m just not that good a writer! Anyway, here they are:

• Your Pet Problems - Anyone can email/post with a specific problem their pet has, or with any concerns they might have. It might be that getting to a vet is difficult, or maybe they just don’t think it’s a big enough problem to warrant a visit. Hopefully I’ll be able, (with the help of notes and book!) to answer the majority of these questions. This has three really good outcomes that I can see:
  • People get specific help with their problems
  • Provides a repository of answers to some probably common questions
  • Gets me to revise and research specific problems

  I’m pretty certain I’m going to go with this, but any comments would be great. Also, I’ll need a few questions to get started with, so if you have any then ask, or if you know anyone who does then direct them here! If you leave an email address with a question in the comments of this post, I promise to email you when I get an answer online.

• A Parasite A Day - Going with the title of the blog, and one of my big interests, provide a different take on a new parasite each day. I resat parasitology twice, after finding it excruciatingly boring. Only on my third go through did I realise just how amazing these things can be! (see here), and my interest really peaked. I’d hate to see others bogged down in the subject like I was, so hopefully a clinical perspective, with a not entirely serious narrative might help them out.

• So You Want To Be A Vet - I’ve literally lost count of the number of times I’ve heard “Oooh, you’re a vet student, my [son/daughter/niece/nephew/obscure relation] wants to be a vet. “  Generally followed by extensive questioning on either grades required, work experience needed, which uni is best, or what the interview was like.  Creating a section of the site which gave all the advice I had to give, neatly divided into sections such as UCAS form, interview, etc., would not only save me repeating myself, but hopefully be reasonably useful to anyone with veterinary aspirations.

OK, so there are my two ideas - comments, questions and suggestions below would be gratefully received!

Ever since I first read about it several years ago, I wanted to have a go at clicker training. For the uninitiated, it is training using a device that makes a short sharp click. This noise is associated with a positive emotional state, often by association with food, and a click then used to let the dog know they have done something right. It’s very useful, mainly because of the ability to sharply define points of reward, for example, if I wanted to teach a dog to sit, then it may offer the behaviour (sitting down), but by time I’ve given it the reward, say a biscuit, it has stood up again. This leads to the unintentional rewarding of “standing up” behaviour, the polar opposite of our aim! With the clicker, we can give a click at the exact moment the dog’s backside hits the ground. We will still give a treat/reward to the dog, but the dog associates this with the click, not the behaviour being formed when it gets the reward.



Anyway, our first week of lectures after Christmas were on animal behaviour, and clicker training was brought back to the forefront of my mind. I was also lucky to see a demonstration from Sarah Heath, a veterinary behaviourist of exceptional standing. After seeing it done, I was chomping at the bit to have a go, so I had to acquire two tools:

1) A clicker - This was relatively easy to acquire - £1.50 from eBay!
2) A dog - This is Rosie, slightly harder to acquire, as not only did she live with my parents 200 miles away, but she also wasn’t massively enthusiastic. Fortunately, once she realised food was involved, she quickly came round to the scheme!

Anyway, to the training! I decided on a pretty simple target behaviour - sitting on a mat placed somewhere in the room. The first thing to do was associate click with good - so a click followed by a biscuit, until her ears pricked at the sound of the click, clearly expecting the reward! With this association in place, I moved on to getting her to sit. OK, this was pretty simple, given she’s been trained to sit already, and even without any prompting on my behalf, she quickly picked up that I wanted that backside on the floor. Now we wanted to transfer that sitting behaviour from anywhere to a specific place. She was pretty taken with the whole sitting thing at this point, so I got her to move around with moving myself, tempting her with treats, and things like that. Whenever she had paws on the mat, she got a click. Now, using a bit of body lingual suggestion, I got her to offer a sit on the mat, with a click when she hit the deck. It took a while, but I’m now the proud owner of a dog that will sit on a mat, and expect food for it! The next step is to associate sitting on the mat with the word “Mat”, and then we might have something half useful!

I wasn’t sure how long all this should be taking, but assuming it’s variable between dogs, and knowing my dog ain’t the sharpest knife in the drawer, getting this far in 2×20mins/day for 5 days isn’t bad! Even better, now I know I can get the dog to do whatever I like, it’s time to ingrain some parent annoying behaviours in her!

Ah, the question, the bane of every vet student’s life. The killer interview question that will “make or break your application!” The justification of your hopes, dreams and aspirations. To be summed up in an answer of approximately 1 minute, maximum. Without sounding like a hopeless romantic who wants to “save all the cuddly little animals.”

It’s a question I found myself asking myself a few times during the dark, pre-clinical days of the course, and here’s what I came up with.  I’d like to see some comments as well - why do you want to be a vet? Or if you don’t, why did you choose your career path?  Anyway, here goes…

For as long as I can remember animals have been a part of my life - cats, dogs, guinea pigs, rabbits and mice as family pets. Horses at the stables when we went riding. Cattle on my uncle’s farm. It’s unsurprising then that I began to develop an interest in animals, even at a very early age. As I then entered my teens, I found myself standing out in certain areas at school - Sciences and Maths to be exact, but it was always Biology that really caught my interest, well as long as you leave the plants out of it! It was a natural progression from there to start thinking about combining my natural abilities with my interest in animals, and it’s no shock that veterinary science came up somewhere along the line. This next part almost makes me vomit when I say it, but I have to admit I was influenced by TV programmes - Animal Hospital and Vet School were both in their prime right around the age I started to think about the future, and the image of the vet as a lifesaver, a real hero made an impact. Soon, it came round to work experience time, and I was lucky enough to get a place with a local vets. That was the real turning point, and I haven’t looked back since. Explaining how I got to this point is relatively easy, but why do I want to be a vet now? Well, it isn’t just the hero status! I’m an outdoorsy man, and the thought of having a life driving round the countryside is incredibly appealing. I considered being a rural postman, but there was too much bloody competition! The final, somewhat shallow reason lies with my massively competitive nature - I like to be the best, and to be the best means putting the biggest challenges in your way. Veterinary science was the biggest challenge I knew of, and remains the biggest I know of today.

Of course, this is a bit long winded, so I also have a single stock answer to this question - “Well, it’s the only way you can kill animals legally!” It’s a shame this blatantly isn’t true - there are plenty of other ways to kill animals legally!

Well, as this is a vet student’s blog, and also a self-proclaimed parasite’s blog, I thought it was about time to write something about veterinary parasites! I have a “special affinity” with parasites, after a year resitti…I mean studying them in more depth, and to my shame and horror found myself enjoying the subject. Anyway, here are my four favourites!
First on our list is Dictyocaulus viviparus, the bovine lungworm, which has a quite fantastic means of getting about. To set the scene, the momma worm is living in the cow’s lungs, lays some eggs, which the cow kindly coughs up, swallows, and the craps out. So the poor little parasite is now embedded in a big pile of cow turd on the ground, where it has the pleasure of hatching from its egg. Now this baby parasite would quite like to get to another cow, so it can have babies of its own, but what self-respecting cow is going to eat its own crap. Perhaps it would be best off getting off this steaming pile that it calls home, and finding some grass, but how? This is the fantastic part, as it turns out that a species of fungus (Pilobolus spp) grows on the cow dung, and when it’s ready to send out its spores, it does so in an explosive fashion. So our little baby worm climbs onto the fungus, waits until it sporulates, then rides the explosion out onto the grass! Truly fantastic I’m sure you’ll agree.

Our second fantastic parasite is called Onchocerca, and our more knowledgeable readers may question this designation, as it causes River Blindness in Africa, a far from fantastic disease. However, what is fantastic is how this worm avoids being killed by the immune system. To grasp the beauty of its evasiveness, we must first learn a small amount about how the human body kills invaders. Parasites such as Onchocerca are attacked using a type of cell known as an eosinophil, whereas bacteria are generally destroyed by another type, called neutrophils. These two types of cell are pretty specific in their killing, so neutrophils are useless at killing parasites. Now brace yourself for the fantasticness! Onchocerca worms allow bacteria to live beneath their cuticle (skin), so the body finds these bacteria, and despatches neutrophils to kill them. It also notices the worm, and sends out eosinophils to kill them. However, the response to the bacteria surrounds the worm with neutrophils, which block the eosinophils from reaching their target, protecting the worm from the immune attack. Further, the worm’s cuticle protects the bacteria from being killed, so the worm can sit happily in a protective cocoon of neutrophils, kindly provided by the human’s own immune system.

Next up we have the first of our mind-controlling parasites, Toxoplasma gondii, a protozoon parasite, that can cause disease in immuno-compromised humans, such as those with AIDS, but is in fact generally transmitted between cats and mice. Now for this parasite to complete its life cycle, it requires the infected mouse to be caught by a cat, which represents a small problem, as mice are usually repelled by the smell of cat urine, keeping them away from cat hunting grounds. This is but a small problem for Toxoplasma though, as it “simply“ alters the mouse’s behaviour, making it attracted to cat urine. Thus, mouse is more likely to be caught by a cat, completing the parasite’s life cycle.

Our second mind-controlling parasite is a liver fluke of cattle, which goes by the name of Dicrocoelium dendriticum. Its life cycle is complex, but involves first a snail (Galba truncatula), and then an ant (Formica spp.), with the ant being eaten by a cow to complete the cycle. Another small parasitic problem…ants tend to live either underground, or on the surface of the ground, but cows tend to eat tall grass. How then can we get the cow to eat the ant. Well we could do this by getting the ant to stop being repelled by light (negatively phototrophic), and instead be attracted to it. So the stage of the fluke found in the ant (the cercariae), send some emissaries to the ant brain, where they encyst to become metacercariae. This causes a lesion in the ant brain, changing its behaviour, so it’s attracted to light, and climbs tall grass blades to get as close to the sun as possible. A perfect target for a cow to eat.

One of the seven deadly sins if you believe in all that, and I came damn close to it today!  Not once, but twice!  EMS, or extra-mural studies is the work placement component of the vet course, and there are 26 weeks of it to do, all in “holiday time.”  Now to be fair, it’s generally good fun, and there’s a lot to be learnt, so I’ve no problem with actually doing it.  What I hate, however, is the organising part…and to be specific, organising the farm practice part.  As it turns out, there don’t appear to be many farm vets within an hour’s drive of either my rented house, or my parents house.  Those that there are, are already full of students far more organised than me!  Anyway, after getting through at least 10 practices that claimed to do farm work in the Yellow Pages, but had packed it in, or were full, my patience was wearing a little thin.  Visions of having all my placements organised for me flashed before my eyes - Lo! For I was a Bristol student!  Fortunately, it was but a fleeting vision, before I quickly realised I’d rather graduate with a degree that meant something… (for those of you who aren’t aware, Bristol were recently given 2 years to improve standards, or their right to produce veterinary graduates would be suspended!)

Fortunately, a few more phone calls did the trick, and the summer’s fun was sorted.  The next task for today was the dreaded dentist.  Fortunately, all was fine, and a quick 5 minutes of running a probe over my teeth seemed to quell the man’s desire to cause pain.  Unfortunately, the receptionist was not so easily pleased - for this 5 minute visit, the princely sum of £15.90 was demanded!  Forgive me if I’m being naive, but I thought this was an NHS dentist?  Anyway, that sin came back to me all to quickly when I realised this equated to an hourly rate of £190.80.  Compare this with a certain Australian equine clinician, with more letters after his name than I’ve had hot dinners (OK, I was a packed lunch kid, but it’s still a fair few) , who declares an hour of his time to be worth in the region of £100.  Was I really jealous of a mouth-obsessed torturer?  Well I came close, I’m man enough to admit that, but after experiencing the joys of drilling teeth in dead dog’s heads, there’s no way I could do that to a live human!  No, for that I’d need at least 200 quid an hour!