What type can parasites can I get from eating undercooked shellfish?

Various. Depending on your location, they can transmit a variety of parasites. In the mid-west we are seeing a lot of paragonimus infestations in the lungs.
Parasites. One example is anisakis worm a roundworm which usually is found in shellfish. Most people get very sick and eventually get rid of it by 3 weeks, occ by surgical means.