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Evaluation of a covered-rod silicone implant containing ivermectin for long-term prevention of heartworm infection in dogs


Cunningham, CP and Brown, JM and Jacobson, GA and Brandon, MR and Martinod, SR, Evaluation of a covered-rod silicone implant containing ivermectin for long-term prevention of heartworm infection in dogs, American Journal of Veterinary Research, 67, (9) pp. 1564-1569. ISSN 0002-9645 (2006) [Refereed Article]

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Copyright 2006 American Veterinary Medical Association

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DOI: doi:10.2460/ajvr.67.9.1564


Objective - To evaluate use of covered-rod (CR) silicone implants containing ivermectin for long-term prevention of infection with Dirofilaria, immitis in dogs. Animals - 145 adult male and female dogs. Procedures - Dogs received implants of different sizes, and ivermectin concentrations and serum ivermectin concentrations were monitored for 16, 57, and 56 weeks, respectively, in 3 preclinical dose selection studies. Ability of implants to prevent infection with D immitis was evaluated in 2 further studies; dogs were challenged with 50 infective third-stage larvae 52 weeks after implant administration and necropsied 145 days after challenge, and the total number of adult heartworms was counted. A field study was then undertaken in which client-owned dogs received an implant and plasma samples were collected at intervals until week 52 for ivermectin analysis and heartworm antigen determination. Results - Use of the implants resulted in maintenance of an ivermectin concentration ≥ 0.2 ng/mL for 12 months. In challenge studies, no treated dogs had adult heartworms, in contrast to untreated dogs, which all had adult heartworms at necropsy. In the field study, dogs treated with an implant had negative results of heartworm antigen testing for 12 months. Conclusions and Clinical Relevance - The CR silicone implant containing 7.3 mg of ivermectin was 100% effective in preventing experimental infection with D immitis larvae and resulted in negative results for heartworm antigen in a field trial. This product has the potential to alleviate poor owner compliance with monthly prevention regimens.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Veterinary sciences
Research Field:Veterinary parasitology
Objective Division:Manufacturing
Objective Group:Veterinary pharmaceutical products
Objective Field:Veterinary biological preventatives
UTAS Author:Jacobson, GA (Professor Glenn Jacobson)
ID Code:41170
Year Published:2006
Web of Science® Times Cited:5
Deposited By:Pharmacy
Deposited On:2006-08-01
Last Modified:2011-05-12
Downloads:1 View Download Statistics

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