My new horse, Crystal, came with a bad outbreak of sweet itch.  It is her first outbreak but several horses in the herd where she came from have developed the condition over the past three years or so.  I am looking for ORIGINAL RESEARCH articles, or documents written by actual veterinarians, that demonstrate frequent dosage of Ivermectin wormer (more than once a month) are an effective treatment.  There seems to be common practice of treating this condition with anything from double doses to daily doses to weekly to monthly depending on who you talk to.

For those who are curious, I have some links with more info on the onchocerca (a parasite transmitted by biting midges) and sweet itch

Wormer Club - Equine & Animal Worms - About Horse Worms, Roundworms, Lungworms, Threadworms and Tapeworms
(scroll down to onchocerca on that link and it has a lot of good info)

Re: CS>CS for Equine sweet itch


Efficacy of ivermectin against Onchocerca cervical... [Am J Vet Res. 1983] - PubMed result


The Merck Veterinary Manual -Onchocerciasis