The second treatment for alpaca mites that I am aware of was the subject a UK research study in early 2001. The study was designed to compare the effectiveness of two ivermectin formulations for the treatment of Chorioptes mite infestations in alpacas. Which by the way are the most common type of alpaca mite infection in Oregon.

Of the 218 UK alpaca farms that took part in the trial 112 farms (just over 52%) reported skin lesions in their alpacas. Where veterinary surgeons had examined the alpacas the most common diagnosis was zinc deficiency but in total 21 different diagnoses were made. Quite a confusing picture for any alpaca breeder!

Without going into the detailed protocol for the conduct of the clinical trial here are the important points.

The infected alpacas were split into two groups:
Group A received eprinomectin pour on at day zero of the trial. (500mcg/kg)
Group B received ivermectin subcutaneously at day zero, day 14 and day 28 of the trial. (400mcg/kg)

Skin scrapings and mite counts were taken at days 7, 14, 28, 42 and 63 of the trial.

In both groups the mite count dropped drastically at day 7 but then peaked again at day 14 and remained high for the rest of the trial.

The conclusions drawn were that more work needs to be done with dosage to combat the mites effectively and that the injection of ivermectin alone is not likely to be effective in alpacas.

To my mind this supports the use of the first approach which I discussed yesterday which involves injection and topical treatment.

Adrian Stewart