Lufenuron is a once-a-month flea control product for dogs and cats. The active ingredient inhibits chitin production; chitin is a component of the outer surface of many insects. Fungal organisms also contain chitin in their cell walls, making them susceptible to lufenuron. Researchers at the Virginia-Maryland Regional College of Veterinary Medicine recently published a series of cases where lufenuron was used to treat chronic fungal infection in the uterus of mares–fungal endometritis–which can end a mare’s useful reproductive life.

Four mares with a history of fungal endometritis were referred to the veterinary school for treatment. The first mare was evaluated after 20 failed treatments over a one-year period. The other three mares were referred because of abnormal fluid accumulation in the uterus that interfered with artificial insemination.

All four mares were first treated with uterine lavage using sterile saline followed by oxytocin to clear the infected fluids from their uteri. A solution of lufenuron was then infused into the uteri, and oxytocin treatment was repeated. The first mare required a second treatment with lufenuron to completely clear the infection from her uterus, but the other three mares responded after a single treatment.

It appears that lufenuron might be an effective treatment for fungal endometritis, and could help shorten the course of this typically chronic disease in mares. Finally, the first mare in this series went on to serve as an embryo donor after she recovered. Thus, lufenuron might also preserve some reproductive function in affected mares