Efficacy of ivermectin in paste and injectable formulations against microfilariae of Onchocerca cervicalis and resolution of associated dermatitis in horses.
Abstract: The efficacy of a single dose of ivermectin (0.2 mg/kg), in injectable or paste formulations, against microfilariae of Onchocerca cervicalis and associated skin lesions was evaluated in 20 naturally infected horses during midsummer months in Louisiana. All horses had clinical signs of dermatitis of the ventral midline and/or limbs, shoulders, thorax, and withers. Efficacy was monitored at 21, 42, and 63 days after treatment. Procedures done at these intervals included microfilarial counts of 6-mm skin biopsy specimens of affected ventral midline, grading of gross lesions, and photography and histologic assessment of ventral midline biopsy specimens. Microfilarial numbers were reduced to 0 by 21 days after treatment in all but one horse. Active lesions improved or were resolved completely by 63 days after treatment. Total inflammation, as judged by histologic methods, was reduced in all horses by 63 days after treatment, but there was a residual population of inflammatory cells in all horses. Adverse reactions after treatment were not observed in any of the horses.
Publication Date: 1988-09-01 PubMed ID: 3223664
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article evaluates the efficiency of ivermectin, administered through injectable or paste formulations, in the treatment of microfilariae of Onchocerca cervicalis and related skin ailments in horses.
Study Methodology
- 20 naturally infected horses were selected for the study.
- These horses showed clinical signs of atypical dermatitis on different parts of their bodies such as the ventral midline, limbs, shoulders, thorax, and withers.
- The horses were treated with a single dose of ivermectin (0.2 mg/kg), either as an injection or as a paste, during the midsummer months in Louisiana.
- The efficiency of the treatment was monitored at intervals of 21, 42, and 63 days after the administering.
- Assessment procedures included microfilarial counts of 6-mm skin biopsy specimens from the affected ventral midline, grading of visible skin lesions, and histologic assessment of ventral midline biopsy specimens.
Research Findings
- By the 21 day check-in, the number of microfilariae significantly reduced to 0 in all but one of the horses.
- All horses showed improvements in or total resolution of active lesions 63 days post treatment.
- Total inflammation as assessed through histologic methods was reduced in all horses by the 63-day mark, but a residual population of inflammatory cells persisted.
- No adverse reactions to the treatment were observed in any of the horses in the cohort.
Conclusion
- The study illustrates that a single dose of ivermectin (in either injectable or paste form) is a very effective treatment against microfilariae of Onchocerca cervicalis, reducing their population significantly within 21 days.
- Further, the treatment also manages to greatly reduce or completely resolve associated skin conditions, albeit with some remaining inflammation.
- The treatment was well-tolerated by all horses as there were no notable adverse effects post administration.
Cite This Article
APA
French DD, Klei TM, Foil CS, Miller RI, Foil LD, Chapman MR, McClure JJ.
(1988).
Efficacy of ivermectin in paste and injectable formulations against microfilariae of Onchocerca cervicalis and resolution of associated dermatitis in horses.
Am J Vet Res, 49(9), 1550-1554.
Publication
Researcher Affiliations
- Department of Veterinary Science, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803-6002.
MeSH Terms
- Animals
- Antiparasitic Agents
- Biopsy / veterinary
- Dermatitis / drug therapy
- Dermatitis / parasitology
- Dermatitis / pathology
- Dermatitis / veterinary
- Horse Diseases / drug therapy
- Horse Diseases / parasitology
- Horse Diseases / pathology
- Horses
- Injections, Intramuscular
- Ivermectin / administration & dosage
- Ivermectin / therapeutic use
- Microfilariae
- Ointments
- Onchocerciasis / drug therapy
- Onchocerciasis / pathology
- Onchocerciasis / veterinary
- Skin Diseases, Parasitic / pathology
- Skin Diseases, Parasitic / veterinary
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