Case No. 2 microscopic aspects of the ileo-colic specimen stained with HES. A. Section of the intestine showing two thin-shelled eggs (darts) surrounded by a granulomatous reaction with giant cells (HES, 100x). B. Section of the intestine showing two A. costaricensis larvae (darts) surrounded by a granulomatous reaction with giant cells and a considerable number of eosinophils cells (HES, 100x). C. Transversal section of a mesenteric artery showing A. costaricensis adult worm (dart) with a single reproductive tube (RT) and intestine (IN) (HES, 100x). D. Transversal section of a mesenteric small artery showing three sections of adult worms (darts) (HES, 100x).