Thanks for the replies, some have been helpful. Let me explain further...
A mate feed his african cichlids chinese bloodworms, not words, and several died...he has fed them bloodworms before but not with the brand he recently purchased, which as the post suggests are from china. I know that they cause dropsey in fighters but we/he was unsure of any problems with other fish. Thanks again, I shall pass on the information. Cheers.