What types of parasites can a horse have?

Horses can have several types of parasites, including internal parasites such as intestinal worms (strongylides, roundworms) and lungworms, which are ingested through food or grass. External parasites include lice, mites and flies that live on the horse's skin or coat. Ticks and horseflies are other examples of parasites that can transmit disease. Proper parasitic control, including regular deworming and preventative measures, is important to keep horses healthy.