I went to Meguro Parasitological Museum with my son. It is located in the southern Tokyo. It takes 15 minutes from Meguro station (JR Yamanote-line) to the museum on foot. It displays 300 actual specimens of parasites and there is no charge to enter. The museum accepts donation. I donated some money. Its official site is Meguro Parasitological Museum.
These days the museum is popular. There were many visitors today. The most famous specimen is the 8.8 m (28.87 ft) tape worm. It was retrieved from a human body who ate a trout sushi. You can see photos at another site http://funabashi.mypl.net/mp/thousand/?sid=420.
I visited the museum with my friend many years ago. At that time the museum was not so popular, when we arrived the museum the door was locked and we asked the staff of the museum to show us the specimens. The staff explained us many things about the museum and told us how to retrieve the tape worm from the body. At first the doctor made the patient sitting in hot water for a while. Then the top of the tape worm came out from the anus. The doctor winded up and pulled the worm slowly.