Here is the Info To show Doubtful Vets. !!
From this site: http://www.drugs.com/vet/eqvalan-liquid.html
[B]
Information For Horse Owners[/B]
Owners should be advised of the potential that swelling and itching reactions may occur after treatment with EQVALAN Liquid in horses carrying heavy infections of neck threadworm microfilariae, Onchocerca sp. These reactions are most likely the result of microfilariae dying in large numbers. Symptomatic treatment may be advisable.
Healing of summer sores involving extensive tissue changes may require other therapy in conjunction with EQVALAN Liquid. Reinfection, and measures for its prevention, should also be considered.
Owners should be advised to consult their veterinarian if these conditions do not improve.
Equalvan is Ivemectin in liquid form. no different than Ivermectin paste. See this description of Ivermectin Paste.
http://www.drugs.com/vet/ivermectin-paste-1-87.html
Information For Horse Owners
Swelling and itching reactions after treatment with Ivermectin Paste 1.87% (ivermectin) have occurred in horses carrying heavy infections of neck threadworm (Onchocerca sp. microfilariae). These reactions were most likely the result of microfilariae dying in large numbers. Symptomatic treatment may be advisable. Consult your veterinarian should any such reactions occur. Healing of summer sores involving extensive tissue changes may require other appropriate therapy in conjunction with treatment with Ivermectin Paste 1.87% (ivermectin). Reinfection, and measures for its prevention, should also be considered. Consult your veterinarian if the condition does not improve.