AAEP updates internal parasite control guidelines

The American Association of Equine Practitioners (AAEP) recently issued revised Internal Parasite Control Guidelines to help minimize the risk of parasitic disease and maintain the effectiveness of current drugs for as long as possible by delaying further development of anthelmintic resistance.

Last revised in 2019, the guidelines account for recent advances in knowledge concerning increased anthelmintic resistance and optimization of parasite control management practices. The guidelines also address common misconceptions and offer parasite control program recommendations for senior horses (over 15 years old), mature horses (between 5 and 15 years old), and young horses (under 5 years old).

Dr. Martin Nielsen, chair of the AAEP task force that wrote the updated guidelines, said in a statement, “We have seen dramatic development in the field of equine parasite control over the past 10 years, since we first launched these guidelines, and we work hard to keep our recommendations up to date.”

The guidelines include several key considerations, such as the following:

• Perform fecal egg count reduction tests annually to ensure that you are using effective dewormers in every herd or barn.
• Recognize that no anthelmintic will eliminate all parasitic stages from a horse.
• Continue using fecal egg counts once or twice per year to stratify horses into low, medium, and high shedders to reduce pasture contamination.
• Deworm all horses at a baseline rate and target selected horses more often based on fecal egg counts.
• Do not use fecal egg counts to diagnose disease in horses as there is no correlation between fecal egg counts and disease-causing parasite life stages.
• Discontinue deworming all horses with fixed intervals year-round and stop blindly rotating anthelmintic classes.

In addition to Dr. Nielsen, the task force was composed of 10 AAEP members predominantly board certified in veterinary internal medicine, veterinary parasitology, or veterinary microbiology. The updated guidelines were reviewed and approved by the AAEP Infectious Disease Committee and board of directors.