The phrase "dead worms" means something that is useless or pointless, like worms that have died and are no longer able to serve their purpose. Full definition
The separation of dead worms from compost is a relatively straightforward process allowing the heavy metal to be removed from the organic waste. (treehugger.com)
This is because the small diameter of the blood vessels exiting the ferret heart make them prone to plugging with dead worms after the treatment. (2ndchance.info)
If the heartworm treatment has been in the past few weeks I would suspect an inflammatory reaction to dead worm fragments causing the fever and lack of appetite. (homevet.com)