Fungus Controls Small Strongyle Larvae in Horses

A fungus that has been used to control nematodes in sheep and goats is also effective against small strongyles in horses, according to a study conducted in Brazil. Use of this fungus as an antiparasitic agent is an important discovery because many equine parasites have developed resistance to the chemicals that have been used previously for control of various parasites in equines.

Twenty Thoroughbred horses used in the study were split into three treatment groups and a control group. For five days, horses in the treatment groups were given oral doses of Duddingtonia flagrans spores mixed with ground corn. Different doses of the spores (from 250,000 to 1,000,000 per kg of body weight) were administered to horses in the treatment groups. Fecal parasite egg counts were made for each horse daily during the treatment period and for five days following treatment. Small strongyle eggs were the most common parasite eggs found in the feces for all horses. There was no difference in result due to variations of spore dosage among the groups.

Small strongyle larvae from the fecal samples were also counted for each horse. An effect from the fungal spores was seen after four days of treatment when larval numbers were reduced 97% in treated horses compared to the control group. This effect was seen for an additional four days after treatment ended.