Aberrant Toxocara canis in a red fox.

During necropsy of a red fox (Vulpes vulpes) heart an adult, male Toxocara canis was found under the pericardium at the junction of the right ventricle and right atrium. The life cycle of T. canis is complex and includes tracheal and somatic migrations of larvae, and they can be found in many tissues throughout the host's body. However, it is rare for adult ascarids to be recovered outside of the small intestine. This is the first report of an adult T. canis inside the pericardial space.