A glorious country setting, a hapless body in the library, a multitude of possible villains and an unlikely sleuth brandishes her knitting. Slowly and masterfully the red herrings are sifted from those characters with means, motive and opportunity. Clues rain down, and we try our best to identify the killer. The climax is reached at the ?big reveal? when we discover identity of the perpetrator ? we find out whodunit.
Whilst I have yet to hear of a sick or deceased alpaca in a library and am a hopeless knitter, the nature of parasitology is a little Marple-esque. All too often clues are submitted to my laboratory a little too late to turn the fortunes of a stricken beast, but gathered on a regular basis, clues can provide all the evidence required to keep parasites at bay.
Of course alpacas can lose weight, become lethargic, unthrifty, lag behind the main herd, and sometimes die for many reasons other than parasite infestation. But if you suspect parasites in your herd, simple testing will allow you to identify or rule out parasites as a first step in your investigation. Testing is inexpensive and yields fast results leading to decisive, appropriate treatment.
I would urge all alpaca owners not to wait for clinical signs of disease before acquainting themselves with the potential killers on their pasture. Just as toe-nail clipping, winter vitamins and vaccinations are planned husbandry events, integrating twice yearly screening of some or all of your herd for parasites can prevent unnecessary suffering, improve alpaca welfare, improve fleece quality, reduce veterinary and medication costs.
If you are selling alpacas, think of the positive impact for your client if you can provide a clear parasitology report prior to delivery.
Our parasitic villains of the peace fall into 2 main camps. Some attack from the outside, feeding and dwelling on or in the skin, these are the ectoparasites, such as mites, fleas and ticks.
Other invisible villains which feed and reproduce within the gut or organs of the body are known as endoparasites, such as worms, coccidia and fluke.
Alpacas in the UK can be adversely affected by mites at any time of year. They are susceptible to several types of mite, the surface dwelling Psoroptes and Chorioptes species along with the deeper skin dwelling Sarcoptes and Demodex mites. In epidemiological research conducted in all counties of England, Chorioptes was the most prevalent ectoparasite identified in faecal samples and skin scrapes from alpacas. Skin wipes, scrapes and tests to detect mites can often yield negative results but the visible evidence on the skin of the alpacas, provide a clear clue to diagnosis. The skin between the digits, on the lower legs, axilla, ears, abdomen and base of tail can become crusty and inflamed. If you part the fleece you may see dry skin debris and flaking. The alpaca will show signs of itching and soreness, often losing weight as increasing hours are spent scratching rather than feeding. Nutritional status drops, the alpaca becomes stressed and the infestation can spiral. Owners often arrive at my lab with skin scrapes for testing having already injected their alpacas with ivermectin. This is ineffective in eradicating the surface dwelling Chorioptes sp. as this mite feeds too far from the skins blood supply to receive a lethal dose of the drug. The injected ivermectin fails to deal with the mites but is also a ?wormer? which may not have been required. Frequent and under dosing of wormers encourages worm resistance, removing a vital tool for future treatment.
When mites are suspected but skin scrapes fail to capture evidence of the parasite, it is useful to consider faecal testing. As the infested alpaca scratches and grooms to relieve itching, pieces of fibre along with the offending mites may be swallowed. These transit the gut along with regular feed and are often identified in a faecal test. One would almost certainly fail to identify Demodex mites with a regular skin scrape although I see this mite often in faecal testing. Demodex lives deep down in the hair follicles, causing intense itching and irritation to alpacas. It is easily identified (from its long cigar shape) in a faecal analysis.
Identification is vital as only then can the appropriate medication can be provided, linked to organism life cycle and epidemiology.
IMAGE 1 ? Chorioptes mites in a plastic sample bag!
IMAGE 2 ? Demodex mite, identified in faecal sample analysis.
Worms, coccidia and fluke are all endoparasites that can cause illness and death of alpacas. A fully fleeced alpaca may look healthy and robust but be emaciated beneath the fluffy covering. As diarrhoea is not always a clinical sign of internal parasitism, other visible clues take on greater significance. Anaemia offers a clue to condition and a quick ?on-farm? diagnostic tool is the FAMACHA score- card. This is a simple colour card where you can match the colour of alpaca mucous membranes with the shades of red to white on a colour chart. If the mucous membranes of the eyes are white it suggests anaemia and possible presence of barbers pole worm, Haemonchus contortus, directing further testing.
As part of ongoing research projects and improving husbandry techniques, I benchmark my own and many client herds each year. Benchmarking involves taking a faecal sample from every member of the herd and running a full screening analysis to identify all endoparasites present. A small herd of 36 alpacas was benchmarked in December 2014 and the chart of worm eggs counts is shown. A similar chart is created to indicate numbers (oocysts per gram) of Eimeria, the coccidiosis causing protozoan. The chart gives us a visual, a parasite snapshot at a moment in time. The general picture shows a low level of worm infestation in alpaca adults (blue) with the expected higher level of infestation in the juvenilles (red). This picture will vary from season to season and at key times in the alpaca year such as at weaning. The snapshot allows us to see at a glance where the parasites are harboured, which adults should be observed / retested and which cria should be weighed more frequently, particularly at weaning, when stress and hence parasite vulnerability increases.
Worm eggs such as Trichuris sp and Nematodirus sp. are readily identified by morphology, looking at overall shape and external measurements. Other eggs are more difficult to identify by visual analysis alone. To get a complete species breakdown, further tests are required. Faecal samples are incubated, eggs hatch and are grown on in order to identify the proportions of different worm species in the sample. This information is vital in deciding which anthelmintic to use.
If you knew a killer was on the loose and his modus operandi was poison, there would be little point sealing all the kitchen drawers to restrict the knives. The same is true with parasites, the treatment must be consistent with offending species ? identification is key.
IMAGE 3 ? Nematodirus sp. with long, lashing tail, hatching from egg
IMAGE 4 ? Incubated egg hatched and grown on for identification
IMAGE 5 ? Herd benchmarking chart
The same is true when analysing a sample for Eimeria. Juvenile alpacas with developing immune systems are particularly vulnerable to some Eimeria sp, developing diarrhoea, lethargy and fast weight loss. Adults may also be affected particularly if stocking densities are high. Eimeria sp. are species specific and can easily be identified by faecal analysis. I commonly see 5 species of Eimeria (E. macusaniensis, E. ivitaensis, E. punuoensis, E. alpacae, E. lamae) which infest alpacas. They cause internal damage as they reproduce in several stages, each time infiltrating the intestinal tract, causing inflammation, bleeding and the potential for secondary bacterial infection. Identification is vital as some species not harmful and self limiting, encouraging adaptive immunity conferring protection in later life. Others species and groups of species can be very harmful, causing unpleasant clinical signs and spread the evidence of their disease (oocysts) across the pasture to contaminate others in the herd.
So when we look at the line-up of villains the key to correct treatment is positive identification. Alpaca parasites all leave their own calling card, the space they inhabit on the animal, the nature of inflammation and fleece loss, eggs of a particular shape, size & colour and infective worms determined by length, head shape, number of intestinal cells and tail sheath.
Recognising that a minority of your herd harbour a majority of the parasites, it makes sense to get to know your alpacas inside and out. Sampling as a facet of good husbandry goes hand in hand with pasture management, sensible stocking densities, body scoring and good nutrition. Keeping one step ahead of highly successful populations of parasites begins with the knowledge of what is actually present in your alpacas.
Lyme Alpacas Parasitology Services
The lab service offered by Lyme Alpacas is a simple, fast and effective resource for managing your herd. Regular sampling will highlight any villains to be eliminated before parasite populations? cycle up causing clinical signs and illness. We offer 4 key services.
? Analysis of skin swabs & scrapes for identification of mites
? Faecal analysis for worms, coccidia and fluke
? Herd benchmarking, test a minimum of 10% of your herd
? Parasitology courses ? An introduction to parasitology and analysis, enabling you to test your alpaca faecals on your own farm. Introductory course length ? 1 day.
IMAGE 6 ? Eimeria alpacae
IMAGE 7 ? Eimeria macusaniensis
Which tests are used?
All faecal samples supplied to Lyme Alpacas Parasitology Services are analysed using the sensitive Modified Stolls procedure, to identify and quantify the species of worm and Eimeria present in the sample.
If you suspect coccidiosis on your farm, tests will highlight, identify and quantify the species present.
Liver fluke, another internal parasite of alpacas, is identified by an alternative sedimentation test, although sometimes fluke can be floated. Be cautious with fluke test results as the adults shed eggs intermittently, so a negative result doesn?t always mean that your alpaca is free from fluke. If in doubt, repeat the test after a few days.
How to use the service.
1. Prior to sending, please email me (firstname.lastname@example.org) to confirm I am in the lab and not at University or on a field visit to another farm. I analyse all tests personally.
2. Collect a faecal sample from a named alpaca (tag no.). For full fluke, worm and coccidia analysis about 20g (20 adult size pellets) of faecal material is required.
a. Please collect fresh pellets ? not from the poo pile!
3. If the alpaca has diarrhoea, collect in a plastic jar or sealed bag ? around 4 teaspooons full.
4. Seal the plastic bag and double wrap in a secondary plastic bag to avoid leaks.
5. Cover in kitchen roll (in case of leaks) and securely pack all samples in a box or Jiffy bag for 1st Class postage.
6. Go to my website http://www.lymealpacas.co.uk/parasite-screening/ to download the parasite screen packing form. Complete this form and include it with your samples.
How to post
1st class to Sue Thomas, Lyme Alpacas, Ware Barn, Ware Lane, Lyme Regis, Devon DT7 3RH
To get the best information from testing
Don?t put samples from different animals together, you must be sure which alpaca gave which sample.
It is recommended that you benchmark at least 10% of your herd. If you have less than 10 alpacas, then test them all.
If you are concerned about particular alpaca because they have lost weight, are generally unthrifty or lagging behind the herd, then test that alpaca first.
Young alpacas are more likely to have higher counts that older animals so choose weaned cria and alpaca up to two years of age to test as a priority.
If you want to test a number of alpacas, try to collect their samples on the same day and post them as soon as possible. Whilst you can refrigerate a sample for a day or two, fresher samples yield more reliable results.
If you are in any doubt, email for more information.
Perform your own ?on-farm? testing.
If you are interested in the incredible life cycles of the numerous alpaca parasites and want to know more, why not join me on a parasitology course. I will guide you through the science of basic parasites, making flotation solutions, microscope best practice, preparing the tests and identification of endoparasites so that you can test your own alpaca faecals, on your own farm. Fast results can open up immediate dialogue with your vet without having to rely and wait for others. Drop me an email at email@example.com for more information or contact me through the Lyme Alpacas website at www.lymealpacas.co.uk
Sue Thomas is a Biology and Ecology graduate, Biology teacher and for the past ten years, an alpaca farmer. Her passion for optimizing alpaca welfare through research into camelid parasites led her to an MSc in Veterinary Parasitology from the University of Bristol. Sue later carried out further PhD research at the Royal Veterinary College where conducting a UK wide epidemiological study of alpaca parasite distribution and interactions.
Full information regarding parasite screening for alpacas may be found at the website www.lymealpacas.co.uk/parasite-screening
Images provided, files attached, see below for reference
Image 1 Chorioptes mite Image 2 Demodex mite
Hatching Nematodirus battus worm, with lashing tail, about to emerge from egg capsule
Worms hatched and grown to infective stage for identification
Image 6 ? Eimeria alpacae Image 7 ? Eimeria macusaniensis