Coccidia.

A worm by any other name is still a worm, right? Not if "worm" is used to mean "intestinal parasite." One especially severe parasite is the coccidia even though it is only one cell big. Even under the microscope these energy sappers do not resemble a worm.

Coccidia are passed in the stool. Their next victim swallows something contaminated by the stool, like grass. Each coccidian egg enters a cell lining the membranes. Eventually this egg develops into numerous intermediate stage coccidia. These break out of their intestinal cell home and swim down to another intestinal cell to grow some more. Soon thousands of new eggs are formed and these pass out with the stool to begin a new cycle.

When the developing parasites break out of the intestinal cells, they destroy the cell and make it bleed. When a lot of these coccidia do the same thing, you see bloody diarrhea. This can be a major health threat at any age but puppies and kittens are much more likely to die than adults. Some adults can every carry these parasites around without showing any visible signs. They pass the infestation on to other pets.

Treatment for these coccidia is best started before severe illness sets in. Regular microscopic examination of your pet's stools can avoid unnecessary suffering and expense.