This is a parasite of the horse and is most commonly seen in young foals, less than six months in age. This is usually the fisrt parasite to which foals are exposed and therfore they have very little immunity to these infections. The predeliction site for these worms is the small intestine. | This is a parasite of the horse and is most commonly seen in young foals, less than six months in age. This is usually the fisrt parasite to which foals are exposed and therfore they have very little immunity to these infections. The predeliction site for these worms is the small intestine. |