Parasites. Eosinophilia is most often associated with roundworms and infestation by various flukes. In the United States, roundworms predominate, such as Ascaris, Strongyloides, and Trichinella (Trichina). The condition known as visceral larva migrans, caused by the nematode Toxocara canis (common in dogs) is sometimes seen in humans. In Trichinella infection an almost diagnostic triad is […]