In most cases, dogs with tapeworms do not show many signs of discomfort or distress. Frequently, they act (and presumably feel) completely normal, even if they have a severe tapeworm infection. It is very common for owners to be astonished, and usually disgusted, when they find out that their dogs are carrying a heavy tapeworm load. While these parasites survive by sucking blood and key nutrients out of their canine hosts, they tend to do so slowly and steadily over a long period of time, without causing any sudden symptoms or dramatic changes in the dog. Certainly, dogs with tapeworms probably will lose weight over time, but it will happen so gradually that it will be almost imperceptible to their owners. It is unusual for dogs with tapeworms to show overt signs of intense abdominal pain or discomfort, even though it seems that those symptoms would show up in dogs infected with blood-sucking intestinal parasites.