When a dog that is doing poorly comes to a veterinarian, it will be given a thorough physical examination. The vet will probably also take blood, urine and stool samples, to evaluate the dog’s overall health and to look for the presence of parasite eggs or larvae. Dogs with a heavy hookworm infection usually are anemic, which means that they have an abnormally low number of circulating red blood cells. This happens because hookworms feed on the dog’s blood. Infected dogs also are often iron-deficient as a result of blood loss.
Stool samples can be assessed through a process called “fecal floatation.” This is a fairly simple procedure that can be done at the local veterinary clinic. Basically, the veterinarian will mix a fresh fecal sample from the dog with a special solution, strain the mixture, put it into a test tube covered with a glass lid, spin it down in a centrifuge and then look at the material that sticks to the underside of the glass coverslip under a microscope. If the dog has internal parasites, the eggs or larvae usually can be identified using this method. However, the test probably should be repeated several times, just to make sure whether the dog is or is not infected.
Unfortunately, hookworm infections can be fatal, especially in newborn puppies. When one or more littermates die, it may be helpful to have necropsies performed, to determine the precise cause of death. A necropsy is the same thing as an autopsy on people. If hookworms are present, the lining of the dog’s small intestine will still have the worms attached to it. There will be bloody bite sites along the small intestinal mucosa, as well.