EPISCLERAL ONCHOCERCIASIS IN 19 DOGS

JM DREYFUS DVMRR DUBIELZIG DVM, DIPL. ACVP

COMPARATIVE OCULAR PATHOLOGY LAB OF WISCONSINUNIVERSITY OF WISCONSIN, SCHOOL OF VETERINARY MEDICINE

PURPOSE: RETROSPECTIVE STUDY OF 19 DOGS

To describe diagnostic histologicappearance

To describe regional and breed distribution

To characterize clinical signs and response to therapy

Provide a forum to share clinical experiences

METHODSDatabase search of 26,861 clinical submissions

Identification of 19 cases with definitive or likely onchocerciasis

Review of histologic slides

Review of submission records

Survey of submitting ophthalmologists: 15/19 returned either records and/or completed surveys

Contact with referring veterinarians when possible

CLINICAL PRESENTATIONChronic inflammatory lesions unresponsive to antibiotics and steroid therapy

Symptoms of 3 weeks to 1 year, average 4 months

17/19 cases: single or multiple masses in the conjunctiva, limbal or retrobulbar episclera

ALL clinical photos, courtesy of Dr. Anastasia Komnenou. School of Veterinary Medicine, Aristotle University of Thessaloniki,Greece

CLINICAL PRESENTATION

Non-specific symptoms: painful swollen eye, corneal edema, keratitis, chemosis, conjunctival swelling with mucus discharge.

+/- Parasites seen clinically:

Vermiform, stringy tissue

Parasites seen at surgery and submitted in biopsy jar.

Parasite in conjunctivalnecrosis.

HISTOLOGIC FEATURES

6 globes, 12 tissue nodules, 1 worm

Nodular tissue sections from 2 mm to 2 cm

HISTOLOGIC FEATURES

14 cases, with definitive Onchocerca spdiagnosis

Morphologic features: low, rounded, circumferential external ridges and internal striae.

Thelazia sp do not have external ridges

PRESUMPTIVE DIAGNOSES 5 CASES

Eosinophilic Granulomatousinflammation in perioculartissues Geographic location Clinician interpretation

Quiet globe beyond nodules

Greater inflammatory response to dead worms

Spendore-Hoeppli

PATENT INFECTIONS

7 of 19 contain gravid adult femalesL3 infective stage

Live microfilaria in paired uteri

SUBCLINICAL CASESEnucleation for other reasons

Parasites found incidentally

Minimal inflammation

Other subclinical cases in endemic regions?

THE LIFE OF THE DOGS

Signalment12 males and 7 femalesAverage 5 years (range, 1-11)8 OS, 5OD, 4OU, 2 unknown

Heartworm Prophylaxis?13 responses1 dog on therapy

Hobbies:Contact with other animals: ostriches, goats, horses, deer, cows, other dogsBeen to several rodeos

Herding dogs: 9/19Outdoor lifestyle?

Ivermectinavoidance?

RECENT PHENOMENON

Cases diagnosed by year18/19 after 2004

TIGHT GEOGRAPHIC DISTRIBUTION

Previous reports

Diagnosed by other labs

COPLOW cases

GREEK DIAGNOSIS AND TREATMENT

Diagnosis: acute and chronic formsClinical signs

• Microfilaria in skin • Circulating eosinophilia (40%)

Day 1:Surgical excision of cysts/nodulesOral prednisone Systemic doxycycline*

Days 9 and 10:Melarsomine, adulticideIntense pruritus and conjunctivalswelling

Day 30Ivermectin, microfilaricide

Day 1

Day 15

Day 30

RESPONSE TO THERAPY in US:

Treatment details from 12/19

Variations on Greek protocol

2 dogs with repeat excisions

No news is good news?

Don’t return to ophthalmologist

No reports of pruritus and edema

Shock-like symptoms following melarsomine treatment

SPECIATION IN US DOGS UNCLEARPARASITOLOGY MORE ADVANCED IN EUROPE

2000: Eberhart ML. Experimental infection of common domestic Onchocerca sp.

15 month follow-upMonthly ocular and skin snip examsFull post-mortem examNo clinical signs, microfilaria or adults found

Onchocerca lupi : proposed species name in Europe

Doxycycline kills wolbachia, a rickettsial endosymbiont of Onchocerca

Doxycycline and ivermectin may act synergistically to kill adult Dirofilaria immitis

NEXT STEPS TO STUDY SPECIATION AND LIFE CYCLE

Presence of microfilaria in skin?

Bank tissues for molecular work

Skin snip procedure: 1mm circular skin snips from canthus, ears, umbilicus Float in saline, watch for microfilaria Save microfilaria, skin, and or nodules in 30-50% alcohol for up to 1 year

ACKNOWLEDGEMENTSCOPLOW Lab: Dick Dubielzig, Kate Lieber, Scott Earnest, Leandro Teixeira, Mitzi Zarfoss

Anastasia Komnenou. Clinic of Surgery, Veterinary Teaching Hospital, School of Veterinary Medicine, Aristotle University ofThessaloniki, Greece

Contributing clinicians: Jeanette da Silva Curiel, Lisa Felchle, Robert Gwin, Nicole MacLaren, Brian Marchione, Kristiane Schmidt, Bruce Silverman ,Barbara Steele, Jennifer Urbanz, Dean Vestre

Mark Eberhard, CDC

John McCall, Professor Emeritus, University of Georgia

QUESTIONS?COMMENTS?

dreyfus@wisc.edu

DOXYCYCLINE THERAPYMcCall JW, Genchi C, Kramer L, Guerrero J, Dzimianski MT, Supakorndej P, Mansour AM, McCall SD, Supakorndej N, Grandi G, Carson B. Heartworm and Wolbachia: therapeutic implications. Vet Parasitol. 2008 Dec 10;158(3):204-14.

Experimental heartworm infections treated with combinations of ivermectin, doxycycline, and melarsomine.

93% reduction of adult worm burden with all three. 78% reduction with Ivermectin and Doxycycline alone.

o Enucleation: 6

o Surgical debridement: 12

o Ivermectin, oral, injectible or both: 6

o Melarsomine (Immiticide®) IM x 2, 1 month after dx: 5

o Doxycycline: 2

o Pyrantel Pamoate (presumably w/ Ivermectin in HeartGuard+): 2

o Steroids: 4 prednisone, 1 intralesional Depo-Medrol

o Cryoablation: 2

AVAILABLE TREATMENT DETAILS IN COPLOW DOGS (12/19)

2000: Eberhard ML, Ortega Y, Dial S, Schiller CA, Sears AW, Greiner E. Ocular Onchocercainfections in two dogs in western United States. Vet Parasitology. 2000Jul 4;90(4):333-8.

Transmission of infectious stage of Onchocercavolvulus (human origin), Onchocerca linealis (cattle origin), Onchocerca cervicalis (horse origin).

REFERENCES

McCall JW, Genchi C, Kramer L, Guerrero J, Dzimianski MT, Supakorndej P, Mansour AM, McCall SD, Supakorndej N, Grandi G, Carson B. Heartworm and Wolbachia: therapeutic implications. Vet Parasitol. 2008 Dec 10;158(3):204-14.Sréter T, Széll Z. Onchocercosis: a newly recognized disease in dogs. VetParasitol. 2008 Jan 25;151(1):1-13. Sréter-Lancz Z, Széll Z, Sréter T. Molecular genetic comparison of Onchocerca sp. infecting dogs in Europe with other spirurid nematodes including Onchocercalienalis. Vet Parasitol. 2007 Sep 30;148(3-4):365-70. Gionfriddo JR, Mangan B, Wilkerson G, Powell CC, Friedman D, Ehrhart EJ. A challengin case: A dog with Ocular masses. Veterinary Medicine. 2005 Aug: 570-576.Hermosilla C, Hetzel U, Bausch M, Grübl J, Bauer C. First autochthonous caseof canine ocular onchocercosis in Germany. Vet Rec. 2005 Apr 2;156(14):450-2.Zarfoss MK, Dubielzig RR, Eberhard ML, Schmidt KS. Canine ocularonchocerciasis in the United States: two new cases and a review of theliterature. Vet Ophthalmol. 2005 Jan-Feb;8(1):51-7. Komnenou A. "Canine Ocular Onchocercosis." The World Small Animal Conference , Rhodos Greece, October 2004.Komnenou A, Egyed Z, Sréter T, Eberhard ML. Canine onchocercosis in Greece:report of further 20 cases and molecular characterization of the parasite and itsWolbachia endosymbiont. Vet Parasitol. 2003 Dec 1;118(1-2):151-5. Egyed Z, Sréter T, Széll Z, Nyiro G, Márialigeti K, Varga I. Molecularphylogenetic analysis of Onchocerca lupi and its Wolbachia endosymbiont. VetParasitol. 2002 Sep 10;108(2):153-61. Sréter T, Széll Z, Egyed Z, Varga I. Ocular onchocercosis in dogs: a review.Vet Rec. 2002 Aug 10;151(6):176-80.Sréter T, Széll Z, Egyed Z, Varga I. Subconjunctival zoonotic onchocerciasisin man: aberrant infection with Onchocerca lupi? Ann Trop Med Parasitol. 2002Jul;96(5):497-502. Review. Komnenou A, Eberhard ML, Kaldrymidou E, Tsalie E, Dessiris A. Subconjunctival filariasis due to Onchocerca sp. in dogs: report of 23 cases in Greece. VetOphthalmol. 2002 Jun;5(2):119-26. Egyed Z, Sréter T, Z. Széll, G. Nyir , M. Dobos-Kovács, K. Márialigeti, I. Varga. Electron microscopic and molecular identification of Wolbachiaendosymbionts from Onchocerca lupi: implications for therapy. Veterinary Parasitology, Volume 106, Issue 1, 30 May 2002, Pages 75-82Egyed Z, Sréter T, Széll Z, Beszteri B, Oravecz O, Márialigeti K, Varga I.Morphologic and genetic characterization of Onchocerca lupi infecting dogs. VetParasitol. 2001 Dec 28;102(4):309-19. Széll Z, Sréter T, Erdélyi I, Varga I. Ocular onchocercosis in dogs: aberrantinfection in an accidental host or lupi onchocercosis? Vet Parasitol. 2001 Nov5;101(2):115-25. Széll Z, Erdélyi I, Sréter T, Albert M, Varga I. Canine ocular onchocercosis in Hungary. Vet Parasitol. 2001 Jun 12;97(3):243-9. Eberhard ML, Ortega Y, Dial S, Schiller CA, Sears AW, Greiner E. OcularOnchocerca infections in two dogs in western United States. Vet Parasitol. 2000Jul 4;90(4):333-8. Hall LR, Pearlman E. Pathogenesis of Onchocercal Keratitis (River Blindness). Clinical Microbiology Reviews, July 1999, p. 445-453.Gardiner CH, Dick EJ Jr, Meininger AC, Lozano-Alarcón F, Jackson P.Onchocerciasis in two dogs. J Am Vet Med Assoc. 1993 Sep 15;203(6):828-30. Orihel TC, Ash LR, Holshuh HJ, Santenelli S. Onchocerciasis in a California dog. Am J Trop Med Hyg. 1991 May;44(5):513-7.

TIGHT GEOGRAPHIC DISTRIBUTION

COPLOW Cases

SURVEY QUESTIONS:

Duration of symptoms before and after diagnosisAny adverse reactions to therapy?Heartworm prophylaxis?Any other clinical signs of onchocerciasis?Lifestyle: outdoor, indoor/outdoor, indoor, hunting, swimming, hiking, etc…