Topic:Microfilariasis
Microfilariasis in horses is a parasitic infection caused by filarial worms, which are transmitted through the bites of infected insects. These worms can inhabit various tissues and body cavities of the horse, leading to a range of clinical symptoms depending on the species of filaria involved and the severity of the infection. The disease can manifest through signs such as skin lesions, ocular issues, and generalized discomfort. Diagnosis typically involves identifying microfilariae in blood smears or skin biopsies. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, diagnosis, and management of microfilariasis in equine populations.
Efficacy of ivermectin in paste and injectable formulations against microfilariae of Onchocerca cervicalis and resolution of associated dermatitis in horses. 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 h...
Treatment of equine onchocerciasis with ivermectin paste. A single oral dose of ivermectin paste was administered to 12 horses with dermatitis and clinical signs typical of onchocerciasis. Two of the horses also had lesions of Queensland itch. Microfilarias of Onchocerca cervicalis were identified in fresh, macerated, skin biopsies from the neck, brisket or umbilical regions of all horses and microfilarias of O. gutturosa from the neck of 2. Eight of the horses developed skin reactions 4 to 24 h after the administration of the ivermectin, notably weals over the neck, shoulders and flanks and pitting oedema of the ventral midline and intermandibular s...
Immunoglobulin levels in tears and aqueous humor of horses before and after diethylcarbamazine (DEC) therapy. A quantitative investigation of equine tear and aqueous humor immunoglobulins was done using normal horses and ponies as well as horses and ponies infected with Onchocerca cervicalis. The equine immunoglobulin isotypes IgGa, IgM, IgA and IgG(T) were quantitated by either single radial immunodiffusion (SRID) or radioimmunoassay (RIA). Tear immunoglobulin levels for IgGa (128 +/- 151 micrograms/ml), IgA (1,664 +/- 1,038 micrograms/ml) and IgM (106 +/- 74 micrograms/ml) were measured, while IgG(T) was not detectable. In horses with ocular inflammation the IgGa was 18-fold higher in the tears, 2,2...
Efficacy of ivermectin against Onchocerca cervicalis microfilarial dermatitis in horses. Forty horses having microfilariae of Onchocerca cervicalis in association with dermatitis, alopecia, and pruritus on the ventral midline were given a single IM injection of 0.2 mg of ivermectin/kg of body weight (June to August 1981). Microfilarial counts in the 40 horses ranged from 18 to 42,446 microfilariae/skin snip on the day of treatment, and histopathologic examination of these skin sections indicated a chronic eosinophilic dermatitis. Numerous microfilariae were in the dermis, but there was no consistent relationship between the presence of microfilariae and the severity of the inflamm...
Equine immunology 3: immunopharmacology–anti-inflammatory and antihypersensitivity drugs. This article reviews anti-inflammatory and antihypersensitivity drugs under these 4 headings: Functional or physiological antagonists; Selective pharmacological inhibitors; Broad spectrum anti-inflammatory drugs; Miscellaneous inhibitors. The compounds considered include sympathomimetic amines, anticholinergic drugs, antihistamine drugs, tryptamine antagonists and dopamine antagonists, glucocorticosteroids and non-steroidal anti-inflammatory drugs, disodium cromoglycate and diethylcarbamazine citrate. The relationship of the pharmacological actions of these compounds is considered in the conte...