Trematode parasites of the genus Nasitrema cause severe problems in both captive and wild dolphins. Migration of the worms from the air sinuses to the brain results in loss of equilibrium and probable diminished echolocation ability.  Transmission patterns and larval stages have never been elucidated for any marine mammal trematodes.

Eggs were collected and hatched in the laboratory in 12-36 days.  Miracidial-like stages were found on wild caught cardinal fish Apogon brachygrammus taken from coral heads near the pen of infected dolphins.  Additional stages were recovered from the muscle of the same fishes.  Examination of these stages indicate they could possibly represent the sporocyst, redial and metacercarial portions of the trematodes life-cycle.