Dr Norm Evans
Dr Norm Evans grew up in rural Kentucky and in 1968 graduated from Auburn University and joined a veterinary practice. A large animal practitioner, his interest in cattle and embryo transfer eventually led him to ?exotics? and work with several hundred alpacas stationed in Lexington, Kentucky. Those of you who were part of the alpaca industry in 2000 will remember his staccato delivery and lively presentations at the British Alpaca Society conference at the Staffordshire Showground. This article is based on his latest book, the 3rd edition of the Alpaca Field Manual.
ALPACA PARASITES ARE COSTLY AS WELL AS DEADLY
The alpaca industry is on the verge of a parasite epidemic if we continue with our previous control approach. Some areas of the llama industry in the USA have thrown in the towel because of deaths due to internal parasites. A parasite is an intruder that goes along for a free ride. Parasites predispose alpacas to constant irritation and aggravation while sometimes causing hemorrhage, ulceration, paralysis and even death. Veterinarians must develop a year-round plan to keep clients ahead of parasite problems. Veterinarians and owners must be able to identify, understand the life cycle, mode of transmission, likely hosts, and effective treatment dosages for alpacas to instigate an effective parasite control program. I would like to outline some facts in a simple and straight forward form.
*Parasite contamination starts when an infected alpaca defecates on your farm. *No control program will completely eliminate parasites but we can control the numbers. *Parasite larva and coccida oocysts are desiccated by the sun in 3-4 days but can survive for months in moist areas so where are your dung piles? *Owners need to realize that parasite larva are most plentiful on lush green pasture and in barn lots where hay is fed on the ground and where there is a high density of alpacas. *Most owners do a great job of manure pick up and compost it to kill larva. But with pick up, several larva remain in the grass surrounding the dung piles. These larva can be desiccated by torching the dung pile and its edges every couple of weeks. *Key is owner management and understanding how parasites survive. *Some breeders feel that they do not have parasites, I think they are wrong. They may be doing an inferior fecal that find few or no eggs. *Horses only share one parasite with camelids and that is Strongyles. *Cattle share one major parasite Ostertagia sp. and maybe one form of Nematodirus sp. *Alpacas, Llamas, Sheep, Goats and Deer share several parasites. Do not let them forage together. *Some breeders feel that as long as their alpacas do not show diarrhea and maintain adequate flesh, they are fine. Most alpacas are affected by parasites that do damage anterior to the colon, therefore anemia, ill-thrift, hypoproteinemia and weight loss is not noticeable to the owner under the fiber. This is usually the result rather than diarrhea. *Some breeders have actually told me that they did not feel they had a parasite problem unless they saw worms in the stool. I question this statement. *If you deworm all alpacas on a regular basis, you create super resistant parasites in the ones not killed. The ones not killed become resistant to a whole class of dewormers. *We must realize that 20% of the alpacas harbour 70-80% of the parasites so it is very important to do fecals, and identify these shedders or carriers. *Best approach is to float and identify the parasites from individuals and not from groups or dung piles so you can identify the carrier. Once you identify the carrier alpacas (that 20%), they may have to be continually monitored but the other 80% if separated may not require deworming for months. *Parasites are most damaging to the young under 15 months of age and the old that have weakened immune systems.
*Are all fecals diagnostic? Absolutely not and like with most other issues in the alpaca industry there are many strong opinions and much debate. Various flotation and centrifugation techniques are described to quantify numbers of certain worms and coccidia. One university suggests the Modified Stolls Technique. Another the Modified McMaster?s Dilution Technique and yes I have tried them all. Don?t understand why they are all modified!! *Being completely old and nonacademic, I use the Modified Norm Technique and guess it is modified because it is too simple and cheap. It does not require a centrifuge but does require a pound of sugar and 12 ounces of hot tap water and a pint container. A $5.00 hydrometer from the auto parts store is suggested. Mix the pound of fine granulated sugar into the 12 ounces of very hot tap water and you have your flotation solution. Your hydrometer should measure a specific gravity of about 1.027 for best results. I think all agree on this specific gravity to float the heavy Nematodirus, Trichuris eggs and E. Mac oocysts. Make your solution fresh monthly or add a couple ml or cc?s of formalin to prevent mold in your sugar solution. *Adult alpaca beans average about 1 gram and I add 4-6 beans to about 60 ml?s of sugar solution in a zip lock bag and mash the beans thoroughly to liberate the eggs or oocysts which I think is key. I pour the liquid carefully into an upright 15cc plastic test tube holding back most of the solid. You overfill until there is a slight bubble over the top of the tube, place a cover slip on top and let set for 24 hours at which time you remove the cover slip and carefully lay it on a glass slide and count at 100x and 400x. While not 100% quantative, this method is simple and 90+ per cent accurate in the field. *See enclosed pictures to identify eggs or oocysts. Two or three small emeria sp coccidia or strongyle type eggs are not of great concern because they may create an immune type resistance. More than a couple of eggs per slide of Nematodirus, Trichuris, or E. Mac concern me greatly because of their extended incubation period. They can cause considerable damage before we know it or before the alpaca shows clinical signs. *The above method does not detect Giardia or Cryptosporidium. They are best diagnosed using the Immunocard-Stat Test by Meridian Diagnostics. (Please ask your veterinarian what the similar test would be in the UK).
*Use the proper dewormer at the proper dosage for the proper weight and insure individual intake. *What about Natural, Holistic, New Wave Parasite Control?? Dr David Pugh and Dr Murray Fowler say, ?They don?t work? ?They have no value in controlling internal parasites.? ?Diatomaceous Earth may scarify the outside coat of the worm but it does not hurt the mucus membrane of the worm?s mouth. Try it where there is a real problem.? Well, I have no knowledge or field experience with these products but will refer you to page 203 in my 3rd edition Alpaca Field Manual where Dr Ed Schaffer who has many years of experience with Holistic Medicine describes his suggestions. At this point, I will use any tool that I can get that shows promise in alpaca parasite control.
*Deworm tactfully and never deworm every animal unless a very serious problem exists. Don?t go through the motions. If an animal spits it on the wall, give it again. *Before oral dewormers, fast for 12-18 hours and give only limited hay and plenty of water. Dewormers are most effective on an empty stomach. **While few if any of my experienced fellow practitioners agree with me, I feel without a doubt that deworming newly pregnant females (especially days 15 through 35 after breeding) can cause birth defects in a small percentage of crias. Because of stress and the unknown, I recommend to my clients that no shots or parasite control be given in the first 45-60 days or the last 45 days of pregnancy. *Alpacas metabolize drugs faster because of a slower moving digestive tract and that may be the reason they require higher dosages for a longer period of time. You will dose many oral products at 2 to 5 times the dose for other species and often give for 3 to 5 consecutive days.
A very important point that I have learned the hard way is that if you have a heavily parasitized alpaca do not give 2x or 3x the dose but give the recommended dose for other species and give it for 5 to 7 days and repeat again in 10-14 days. Heavy immediate breakdown has caused apparent toxic affects with indigestion, elevated heartbeat, abdominal tucking, colic and even death on the second to third day after deworming. *It is wise to isolate dewormed alpacas for 3-4 days before allowing them back on a clean pasture while shedding worms or larva. Then move them to new ground and avoid wet pasture areas when possible.
Emeria macusanesis (E. Mac) Facts: *Most common fatal coccidosis *Mostly seen in adults but also in crias. *Present in 50% of Evans fecals in US. *About 1 in 8 alpacas show diarrhea with E. Mac.*Alpacas can die 2 weeks prior to a positive fecal for E. Mac. *Clinical Signs: weight loss and lethargy. *Parasite dewormers do not control any coccidia or E.Mac. *Prepatent period for E. Mac is 35 to 43 days so if a fecal is done on farm admission it may take 6 weeks to find oocysts. Consider fecals every 10 days in quarantine for at least 6 weeks. *For stressed or poor doing alpacas, monitor body condition score and weight loss. Suspects need blood work & if you see a severe hypoproteinemia and slight anemia (Low total protein and low Hct. or PCV), consider treatment for E. Mac.
E.Mac Treatment: (Who; How; and with What)? I think the key is to dose each alpaca individually. Corid (Amprolium) or Albon (Sulfadimethoxine) (ask your veterinarian for the UK equivalent) in the water has been very questionable for me. Should you use Albon or Corid? I don?t care. Corid works best for me. I use Corid at 2x the cattle dose for 5 days on, 5 days off, and 5 days back on again. I have also had good success with Marquis (ponazuril) 20 mg/kg daily for 3 days. To my knowledge, all of the products are safe in pregnant females. Observation: There are several different techniques for detecting parasite eggs and coccidia oocysts. Some feel that centrifugation fecal exams are much more sensitive and reliable. Many veterinary clinics float fecals for about 10 to 15 minutes as in other species, and it just does not work for alpacas. Likewise there are many different opinions and dosages used successfully for parasite control. The key is awareness of parasite damage, resistance to the drugs currently used, and a protocol satisfactory to you and your veterinarian for your alpacas. In my hands Ivermectin and Doramectin have become non effective and are parasite resistant due to their continued use for many years. Both however seem effective for meningeal parasite control. I have herds of well managed alpacas that have not been dewormed for 2 years. The bottom line is, do not deworm as a preventive. Do fecals. Quarantine new arrivals and do at least two fecals 14 to 17 days apart. Take the sample directly from the animal in question. Samples from the dung pile can show false negatives.