mrgnty mrtes.CHORIOptIC SkIN DIsease IBy Dr. Ed McCaslin, DvM

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.'';~Ski1J/disease i11;dlpacastalz be'due to '." .·it vari~t)! ojdif!ei:ent:qauses: ba~teria, ,lu,11:g{;.·q}~fg'eN}1J;~lt1ii.tiQ~f!U!!qb,lel!lS;~:.;;c;..and. various parasites.Oize of these .

'. parasites is the;Choriopticmange mite.Choiioptic mange can be a real··· ..··.. .

headac~e ·to th~"alpflciiQl~tl:~r.DijJip1:t?tto diagn()se and even more difficult •to treat, .this exasperating parasite canmasqueradeils ltsc6usiri~ Sm:copti~mange,.o~hideoutimder~econdarJ' .jlt1igaiitizdjor bacierialinj~ctions.Symptoms can be<quite v(iriablefromoneanl111a!totbeilext,.fu.,ther .confusing th~ situation ... '"..... '. .

The econornic impact'o!Chori()pticmange' due to loss of usablefiber, loss .'of animal sale~~mid cost of treatment ..is hardt()esti11lCtte,'but itceriain/yis'substalztial This does1zol lake into .accatintthe discoinfOJt to the animalsa;zd the general u~thriftine$s it creates..Alpacasare susceptible toat leas:

fattr dijforenttypis ofhi'ange mites,Unf01tU1zatelJ~the threemostr;ommonkinds -::Sarcoptes, ,Chorioptes, and .' i

'.Psoroptes. :"'l(jo~'lJeryJmudf alike underthel1ii~l:dscop(}.Mmiy times, a vetwill give a quick glimce: see mites,andassumetheydre'Sarcoptes; .long ,thougbUo beth~mp~tcomnwltkind

.in alpacas. Basetl olz. tIle cases! amnowsee1ng,'"hOllJeVel;'ib~lieveChorioptes .has become the lmost common fJPe,atleast in. Ohfoand surl'oltndingstates: .

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© 2009Alpacas A{agiL!ineaEa, .Dr. Ed McC~lin, DVM., All 'rights reser..'ed.Reprinted by·'pemUssjortofthe autli<?randAlpacas Magazine. . - .

tHe JOURNeyMy story started in 2007, withan alpaca that had been treatedunsuccessfully for Sarcopricmange over a two-year period.Repeated skin scrapings werealways negative for mites, andyet the symptoms were there.The herd-mates all seemed prettynormal, though eventually acouple of them showed a bitof a scaly area between the toes.A skin scraping from the toearea revealed a single mite. AsI studied the mite under themicroscope, it did not lookexactly like a Sarcoptes mite.I consulted textbooks and cameto the conclusion that it mustbe Chorioptes. I sent the slideout to a parasitologist, whoconfirmed my suspicion that itwas indeed Chorioptes bovis.Chorioptic mange can affecthorses, cows, and (rarely) sheepand goats, as well as alpacas.Unlike Sacrcoptic mange, itdoes not affect humans .

Well, now I had a diagnosis.I just needed an effective treat-ment. I consulted with variouscamelid experts, parasitologists,and a veterinary dermatologist.The consensus was "This stuffis really hard to treat." Nothingseemed to work very well.Injectable iverrhectin sometimesreduced the number of mites,but never completely eliminatedthem. The various "Witch'sBrew" mixtures were often usefulin the short term, especiallywhen there were secondaryinfections present, but the lesionsalmost always came back eventu-ally. Pour on treatments suchas Eprinex" and Frontline Plus"

alpacashad also been tried withoutmuch success. One clinicianmentioned lime sulfur dip.I had used lime sulfur dip' yearsago on kittens. It was smelly andmessy and a lot of work. Theidea of using it on a whole herdof alpacas was not appealing, soI kept it in the back of my headas a last resort and kept looking.

A veterinarian from MerialTechnical Services found somearticles that had been publishedin the UK concerning the Useof fipronil on Chorioptic mangein horses and camelids. I decidedto try it and it worked very well.As time went on, I saw otheranimals at other farms withsimilar symptoms. Diligent skinscrapings turned up Choriopticmites in these animals also. Onceagain, we found it was mucheasier to recover the mites fromthe healthy herd mates thanfrom the obviously symptomaticanimal. This was consistent withthe findings described in theBritish literature. Fipronil workedwell on these animals also.

The folks at Merial TechnicalServices have been very helpfulto us. Because the British litera-ture provided a dosage, but nota treatment protocol, they pro-vided me with enough Frontline"Spray to work out the optimumfrequency and duration of treat-ment in our own herd. Doingskin scrapings on every animalin the herd every month was"character building," bur I wasable to determine that treatingevery three weeks for a totalof four treatments was themost effective plan.

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symptomsThis condition ofren presents asa somewhat "itchy" animal withspotty hair loss, usually aroundthe feet and lower leg region, butit can occur on other areas of thebody, as well. The foot lesionsmay be partially hidden by thefleece and may not be terriblyobvious from a distance (fig. 1),but are quickly apparent whenyou lift the foot and separate thetoes (jig. 2). In longstanding cases,the tissues can thicken, causing thetoes to splay. (jig. 5) The most com-mon sites, other than the feet, arethe axillary (armpit) and inguinal(groin) regions, the perineal(genital) region, and the ventraltail area, but all parts of the bodycan on occasion be involved.

Most of the animals showrather mild symptoms and ownersmay be unaware that there is any-thing wrong. A small percentageof animals (only one or two perfarm) are more severely affectedwith easily visible lesions and hairloss. This is why many people willthink "It can't be mites becauseonly one animal on the farm isaffected." This was also consistentwith the British literature. TheBritish authors posit that this isa hypersensitivity, and I concur.

Some of these more severely-affected animals will developsecondary bacterial and/or fungalinfections. These secondaryinfections are more commonunder humid conditions and lesscommon during dry times.

This disease does not appear torun in family lines. Overcrowdingas can occur through the wintermay contribute to this being spreadmore rapidly through a herd.

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LIfe cycLeUnlike Sarcoptic and Psoropticmange mites, which burrowdeep into the epidermis (see

fig. 1), the chorioptic mitenormally lives its entire three-week life cycle on the surface ofthe skin. The favored locationfor Chorioptic mange mites isthe dorsal skin of the areabetween the toes. Choriopticmites feed on dead skin cells anddander. The female can lay up to90 eggs during its life. Because itis a superficial mite, Chorioptescan be easily dislodged into theenvironment, where it has beenreported that the adult mite cansurvive up to 70 days off thehost in the environment. (Onehardy specimen from our studyeven survived for 11 days com-pletely immersed in mineral oiland under a glass cover slip')

Unlike the sarcoptic mangemites, the chorioptic mites arenot contagious to humans butwill spread easily to other alpacasand even other livestock likecattle, horses, sheep, and goats.Fomites - physical objects liketoe nail trimmers, groomingtools, halters, bedding, shearingequipment, and the ground itself- can harbor live mites that thenspread to the next animal.

We tried to find a product thatwould eliminate the mites fromthe environment. We found that ~99% alcohol will kill the mites on ishearing equipment and other ~fomites. Fipronil will do the same. ~However, we could not findanything that was safe, effective,and economically feasible forbarn floors and paddocks, ere.

As I studied the life cycle of

Figure 1 Affectedfoot, standing.

Figure 3 Same foot,one month post-treatment, hairstarting to regrow.

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Figure 4 Same foot.9 months posttreatment.

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Figure 5Chronic casewith thickenedtissues andsplayed toes.

Figure 6 lesionsOil upper legsand body.

the Chorioptic mites, it becameapparem why some of the previ-ous treatments had not worked.Injectable ivermectin worksextremely well against Sarcoptesand Psoroptes, which it canreach through the blood vesselsin the epidermis, but is muchless effective against Choriopteswhich scays on the surface, wherethe injectable drug does notpenetrate well.

Eprinex" and Frontline Plus"are applied along the top of theback and depend on transloca-tion via the lipid layer on thesurface of the skin to spread overthe body surface. Since thealpaca has almost no lipid layer,it is not surprising that theseproducts failed to spread fromthe top of the back all the waydown to the feet, where themajority of the Choriopticmites are found.

Figure 7 Cross Section of Mammalian Skin.

Dlaf;NOSISAlpacas are susceptible to at leastfour different types of mange mites.Unfortunately, the three mostcommon types - Chorioptic,Sarcoptic, and Psoroptic - willat first glance under a microscopelook remarkably similar, but thetreatments are very different. Evenmany veterinarians will confusethe three if they are not familiarwith the subtle differences. It iscritical for your veterinarian tobe able to identity the subtleStructural differences in the mitesto make the correct diagnosis andtreatment recommendations.

Skin scrapings are done using a.#10 scalpel blade (held betweenthumb and finger - .nor on a han-dle) and mineral oil. It is importantto scrape firmly and gently untilyou begin to see capillary bleeding.This insures that you have gonedeep enough not to miss anySarcoptic mites that are burrowed

Figure 8 Dr. Edobtaining a skin scraping.

152 • Alpacas Magazine

into the epidermis. Multiple scrap-ings are generally needed.

I can usually get good skinscrapings from the body surfacesor the feet without sedation. Forsevere cases where the animal is inpain or to collect samples from theface and ears (figs. 9 and 10), somesedation may be prudent. I preferto take my time and get a goodsample than to rush and miss adiagnosis. Be sure to have yourveterinarian get samples fromsome of the healthy-lookinganimals housed with the obviouslyaffected animal. The mites aremuch more numerous and easierto find on them.

Once the sample is on themicroscope slide and the mites are"trapped" under a cover slip, startat 40x magnification and look formovement. The mites are quiteactive at room temperature.

You must move up to the lOOxmagnification to identify the mite.The only visible differences are inthe pedicel, the slender stalk thatconnects the small "suction cup"to the end of the leg (fig. 14). Thepedicel of the chorioptic mite isshort and unsegmented, the pedi-cel of the sarcoptic mite is longand unsegmented. The pedicelof the psoroptic mite is long andsegmented. As you can imagine,it is not easy to focus on this tinystructure at the end of a tiny,rapidly-moving leg. At this point,it may be helpful to refrigerate theslide for a little while to slow downthe activity of the mites. Be sureto identify multiple mites fromeach sample before making a finaldiagnosis. It is possible for a singleanimal to be carrying more thanone kind of mite.

Herd Sire 2009 • 153

stUDY DeSlf;NThe "Alpaca Grapevine" ismarvelously efficient and whenword gOt out that we had foundan effective treatment, we beganto get referrals from veterinariansand other alpaca farms fromseveral surrounding states. Manyfolks were encouraging us towrite about it, so we decided todo an informal study at our ownexpense. We asked each partici-pating farm to bring the animalthey perceived to have a problemand to also bring an animal theyperceived to be healthy from thesame pen or paddock. We tookan oral history (asked questionsabout onset and duration ofsymptoms and other questionsabout husbandry, etc.) We care-fully examined the skin on eachanimal from ear tip to toenailand from nose to tail. We didskin scrapings on both animalsusing a # 10 scalpel blade andmineral oil. We scraped the areabetween the toes on the rightfront and right rear foot of eachanimal and, in addition, didscrapings from anyother area thatshowed hair loss,scaling, thickening,or other changes.In a few of themore severelyaffected animals,we elected to dobiopsies and culturesfor bacteria andfungus.

Figure 8 lesions on nose and face.

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Figure 9 lesions on ear.

ResultsI have been able to find choriopticmange mites in almost all of the200+ animals that I have exam-ined. Ihave found live mites oncrias as young as two months ofage and as old as 16 years. Theseanimals came from more than 50different farms in fiveMidwestern states. There wereover 2,000 alpacas representedon these farms. Each of thefarms that came to us did sobecause they had an animal withan obvious problem. Very fewfarms had more than one animalthey were concerned about.Symptoms ranged from itchingto a severe generalized hair losswith secondary infection (pyo-derma) over large portions of thebody.

Most of the "problem" animalshad been under treatment fortheir skin problems using avariety of different productsfor weeks or months beforewe saw them. Several hadbeen misdiagnosed as having

~ "iverrnectin-resistant Sarcoptic~ mange." No Sarcoptic mites were§ found on any of them. Others~ had been diagnosed as fungal,~ allergic, and zinc deficient.~ The interesting thing is thatco al "al'" alg most every norm arum@ that we saw had some symptoms

" '. ,. " Ij of Chorioptic mange - muchmilder symptoms than the"problem" animal, but veryevident to the trained eye, oftenwithout even bending over. Themost frequent symptoms in these"normal" animals were scaly andthickened skin between the toes.The most severely affectedanimals consistently yielded thefewest mites on skin scrapings,

Figure 11 Adult male Chorioptic mite, 400x..

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"Figure 12 Adult female Chorioptic mite, 400x.Shows location of the pedicel.

Figure 13Chorioptic miteshowing very short,non-segmentedpedicels.

whereas "normal" animalshoused with these "problem"ones consistently yielded muchlarger numbers of mites.

We tried doing Scotch tapepreps on some of these animals.The Scotch tape is applied to theskin between the toes and thenapplied to a microscope slide.We had hoped to find a lessinvasive way to detect the miresand one rhar alpaca ownerscould collect without veterinaryassistance and mail off easily fora diagnosis. It did work in somecases, but gave too many falsenegatives, plus it was very diffi-cult with the Scotch tape prepsto visualize the pedicels wellenough to identity the mitesreliably.

We were able to follow up atleast in the short term with mostof the participating farms andthe results were overwhelminglypositive. We have only been ableto follow up in the long termwith a few of the participatingfarms, but those who followedthe protocol have cleared all theirmites and remain mite-free. Thenumbers we have right now aretoO small to draw sweepingconclusions, and it is likely thatthe farms participating in thefollow-up were among the mostcompliant farms. Because wedealt only with farms that knewthey had a problem of some sort,we cannot generalize these num-bers to the overall population.It would be interesting to studyanimals from farms where allof the animals have healthy skinand see if those animals harborany mites.

154 • Alpacas Magazine

tneatmextI have had good success treatingand controlling this conditionwith fipronil (Frontline" Spray)by Merial. Fipronil works byaltering the function of thenervous system of invertebrates.It will kill the mites it contactswithin two hours and willcontinue to work for up toone momh. I have found thatrepeat treatment of affected andcompanion animals every threeweeks, for a total of four treat-ments, gives the best results.(I initially tried treating once amomh and found it inadequate.)

Frontline" Spray doesn't trans-locate (spread out to areas of thebody that have not been sprayed),although a small amount maytransfer to the axillary (armpit)and inguinal (groin) areas whenthe animal is cushed. It doesn'temer the body of mammals. Ittravels along the hair follicles andenters the sebaceous glands. It isstored in the sebaceous glands andgradually "wicks our" over thenext 21-30 days.

Fipronil is safe to use on late-term pregnant animals andeven nursing mothers, althoughI avoid applying it direcrly to theudder while a cria is still nursing.Fipronil is not harmful tohumans or any other mammal,but does carry a warning forhoney bees and fish.

The most effective way to usethe fipronil is to apply it to allfour feet from the fetlock jointdown to the toenails covering thefront, back, and sides of the feet.You should also treat all othervisibly affected areas of the body.Especially look at the armpit,groin area, and perineal region

Herd Sire 2009. 1 55

extending up to the undersideof the tail. Application of thefipronil to the face, head, orother sensitive areas should bedone carefully with a gauze padsoaked in the spray. I can gener-ally treat 10 to 12 adult alpacaswith each 500 ml bottle of theFrontline" Spray.

Concurrent use of antibioticslike Naxcel (Upjohn) may beneeded if there is secondaryinfection. Your veterinarian canadvise you as to whether othermedications including topicalantibiotics and/or amifungalswould be helpful.

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Chorioptic - short. unsegmented pedicel

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Sarcoptic - long. unsegmented pedicel

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Psoroptic - long segmented pedicel

Figure 14 Differences between the pedicels of the various mites.

aecomrnennatroxsIf you suspect that you are dealing with Chorioptic mange in your herd, have yourveterinarian do skin scrapings on as many of your animals as possible. Be sure toinclude some apparently healthy animals that are housed with the visibly affectedanimal(s). Also be sure you veterinarian is aware of the differences in the pedicel(see Diagnosis).

To rid a farm of Chorioptic mange mites:

1. Treat all animals on the farm that are one month old or older with Frontline"Spray as directed every three weeks for at least four treatments.

2. Remove all organic material from the barn floor to the extent possible.

3. Randomly recheck 10% ofherd by skin scrapings 1-2 months after the lasttreatment to be sure you have eliminated the problem.

4. Be very cautious about buying Frontline" Spray over the Internet. There area number of companies out there selling counterfeit products.

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To keep a farm tree of Chor~opticmange mit~:

1. Do skinscrapings on allnew animalsbrought to your farm.

2. Whether positive or negative, spray all feet on animals entering the farm or return-ing (0 the farm, including those returning from shows.

3. Don't share halters, leads, nail trimmers, or grooming or shearing equipmentbetween animals without cleaning, disinfecting, or spraying withIipronil first.

4. Be careful aboutconract withorherlivestock silchas 'cattle; sheep, goats; and horses.

5. Randomly recheck 10% of the herd by skin scrapings every six months.

WRap upI do believe we can concludeChorioptic mange is much moreprevalent than was previouslybelieved. It also appears thatfipronil can be a useful tool incontrolling it. Some new workis also being done using topicallime-sulfur treatment. It, too,looks promising, but the wholeChorioptic mange mite syn-drome needs a lot more studybefore we can say we have itcompletely understood or canoffer a sure-fire "cure."

The work behind this studyand this article is a task I could

never have accomplished alone.Patricia Nash has provided muchtechnical support and enthusiasmand most of the photographs.Her daughter, Alexandra Felice,provided the detailed drawingsof the pedicels. Mary Jane Foxpatiently held many animals formultiple skin scrapings and alsohelped Patricia test disinfectantsfor the shearing equipment.Finally, without the help ofmy wife, Dr. Ruthanne, andthe countless hours she has con-tributed to this project, it wouldnever have been completed.

Dr. Ed McCaslin, affectionately knownas "Dr. Ed," grew up on a chicken farmin rural Maine. He graduated fromveterinary school at Michigan StateUniversity, where he met and married"Dr. Ruthanne." Together, they own theLakeshore Animal Hospital in Mentor,Ohio. They also own Promised LandFarm in Chardon, Ohio where they havebeen raising alpacas (and Dr. Ed's petchickens) since 1995. Dr. Ed has alwayshad a special interest in dermatologyand parasitology. He can be reachedat www.blackalpaca.com orblackalpaca@hotmail.com.

BIBLIOf;RC!PHY1. Managing Parasites: Parasitic Skin Disease in South American Camelids, Alpaca World, Aiden P. Foster PhD, Dip ACVD, MRCVS, VeterinaryInvestigation Officer VLA, Shrewsbury, UK

2. Concurrent Sarcoptic and Chorioptic Acariosis in a British Llama, Veterinary Record 2001, 149, 208-209, C.F.Curtis, S. J. Chappell, R. Last

3. Efficacy ofTopical Epinomectin in the Treatment of Chorioptes sp. Infestation in Alpacas and Llamas, 10-10-06, Jon D. Plant,oMichelle A. Kutzler,and Christopher ~·gebra

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6. L1amaberma.toldQy,yet Clin North Am Food Animalfract., 1989 Mar: 5{1}: 203-15 Rosychuk, ,BA

7. Equine Chorioptic Mange: An Epidemiologic StudyandControlled Clinical Trial, BritishVeterinary Dermatology Study Grqup,Bristbl UK,October 1999, Llttewood, J.D. . .' . . . .

8. Control of Ectoparasites in Horses, In Practice, Sept 1999, Janet Littlewood, UK

9. Fipronil: NPTN, Oreqon State Univ, EPA,Corvallis, Oregon, 1996

10. Epidemiological Investigations of Bovine Chorioptes Mange in Germany, Berl Munch Tierarztl Wochenschr, Mar-Apr 2005, 118 f3-4} 128-33,Beck w., Pfister K'JWeiland G.

11. Comparative StudY of Doramectin and Fipronil in the Treatment of Chorioptic Mange,' The Veterinary Record {British Veterinary Association,161:335-338 {200?}, D.I. Rendle BVSc, MRCVS, H.J. Cottle BVSc, MRCVS, S. Love, BVMS, PhD, MRCVS, K.J. Hughes BVSc, MRCVS

12. Alpaca Field Manual, 3rd edition, 285-322, C. Norman Evans, D.V.M.

13. Medicine and Surgery of South American Camelids{205-210, 250-259}, Murray E. Fowler, OVM

14. Parasitology for Veterinarians {54-61} Jay R. Georgi D:V.M., PhD.

15. Helminths, Artt{ropoas, and Protozoa of Domesticated Animals, 6th Edition {512-513} E.J.L. Soulsby

156 • Alpacas Magazine